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swift-mirror/lib/Sema/CSApply.cpp
Pavel Yaskevich 5758ae2bcc [ConstraintSystem] Filtering for static member lookup on protocol metatypes 
Detect and filter some of the overload choices which can't possibly
match because their result type cannot conform to the expected protocol.
2021-02-23 11:33:10 -08:00

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//===--- CSApply.cpp - Constraint Application -----------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file implements application of a solution to a constraint
// system to a particular expression, resulting in a
// fully-type-checked expression.
//
//===----------------------------------------------------------------------===//
#include "CSDiagnostics.h"
#include "CodeSynthesis.h"
#include "MiscDiagnostics.h"
#include "TypeCheckProtocol.h"
#include "TypeCheckType.h"
#include "swift/AST/ASTVisitor.h"
#include "swift/AST/ASTWalker.h"
#include "swift/AST/ClangModuleLoader.h"
#include "swift/AST/ExistentialLayout.h"
#include "swift/AST/GenericEnvironment.h"
#include "swift/AST/GenericSignature.h"
#include "swift/AST/Initializer.h"
#include "swift/AST/OperatorNameLookup.h"
#include "swift/AST/ParameterList.h"
#include "swift/AST/ProtocolConformance.h"
#include "swift/AST/SubstitutionMap.h"
#include "swift/Basic/Defer.h"
#include "swift/Basic/StringExtras.h"
#include "swift/Sema/ConstraintSystem.h"
#include "swift/Sema/SolutionResult.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/Mangle.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Sema/Sema.h"
#include "clang/Sema/Template.h"
#include "clang/Sema/TemplateDeduction.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/SaveAndRestore.h"
using namespace swift;
using namespace constraints;
/// Retrieve the fixed type for the given type variable.
Type Solution::getFixedType(TypeVariableType *typeVar) const {
auto knownBinding = typeBindings.find(typeVar);
assert(knownBinding != typeBindings.end());
return knownBinding->second;
}
/// Determine whether the given type is an opened AnyObject.
///
/// This comes up in computeSubstitutions() when accessing
/// members via dynamic lookup.
static bool isOpenedAnyObject(Type type) {
auto archetype = type->getAs<OpenedArchetypeType>();
if (!archetype)
return false;
return archetype->getOpenedExistentialType()->isAnyObject();
}
SubstitutionMap
Solution::computeSubstitutions(GenericSignature sig,
ConstraintLocator *locator) const {
if (sig.isNull())
return SubstitutionMap();
// Gather the substitutions from dependent types to concrete types.
auto openedTypes = OpenedTypes.find(locator);
// If we have a member reference on an existential, there are no
// opened types or substitutions.
if (openedTypes == OpenedTypes.end())
return SubstitutionMap();
TypeSubstitutionMap subs;
for (const auto &opened : openedTypes->second)
subs[opened.first] = getFixedType(opened.second);
auto lookupConformanceFn =
[&](CanType original, Type replacement,
ProtocolDecl *protoType) -> ProtocolConformanceRef {
if (replacement->hasError() ||
isOpenedAnyObject(replacement) ||
replacement->is<GenericTypeParamType>()) {
return ProtocolConformanceRef(protoType);
}
// FIXME: Retrieve the conformance from the solution itself.
return TypeChecker::conformsToProtocol(replacement, protoType,
getConstraintSystem().DC);
};
return SubstitutionMap::get(sig,
QueryTypeSubstitutionMap{subs},
lookupConformanceFn);
}
static ConcreteDeclRef generateDeclRefForSpecializedCXXFunctionTemplate(
ASTContext &ctx, AbstractFunctionDecl *oldDecl, SubstitutionMap subst,
clang::FunctionDecl *specialized) {
// Create a new ParameterList with the substituted type.
auto oldFnType =
cast<GenericFunctionType>(oldDecl->getInterfaceType().getPointer());
auto newFnType = oldFnType->substGenericArgs(subst);
// The constructor type is a function type as follows:
// (CType.Type) -> (Generic) -> CType
// And a method's function type is as follows:
// (inout CType) -> (Generic) -> Void
// In either case, we only want the result of that function type because that
// is the function type with the generic params that need to be substituted:
// (Generic) -> CType
if (isa<ConstructorDecl>(oldDecl) || oldDecl->isInstanceMember() ||
oldDecl->isStatic())
newFnType = cast<FunctionType>(newFnType->getResult().getPointer());
SmallVector<ParamDecl *, 4> newParams;
unsigned i = 0;
for (auto paramTy : newFnType->getParams()) {
auto *oldParamDecl = oldDecl->getParameters()->get(i);
auto *newParamDecl =
ParamDecl::cloneWithoutType(oldDecl->getASTContext(), oldParamDecl);
newParamDecl->setInterfaceType(paramTy.getParameterType());
newParams.push_back(newParamDecl);
(void)++i;
}
auto *newParamList =
ParameterList::create(ctx, SourceLoc(), newParams, SourceLoc());
if (isa<ConstructorDecl>(oldDecl)) {
DeclName ctorName(ctx, DeclBaseName::createConstructor(), newParamList);
auto newCtorDecl = ConstructorDecl::createImported(
ctx, specialized, ctorName, oldDecl->getLoc(), /*failable=*/false,
/*failabilityLoc=*/SourceLoc(), /*throws=*/false,
/*throwsLoc=*/SourceLoc(), newParamList, /*genericParams=*/nullptr,
oldDecl->getDeclContext());
return ConcreteDeclRef(newCtorDecl);
}
// Generate a name for the specialized function.
std::string newNameStr;
llvm::raw_string_ostream buffer(newNameStr);
clang::MangleContext *mangler =
specialized->getASTContext().createMangleContext();
mangler->mangleName(specialized, buffer);
buffer.flush();
// Add all parameters as empty parameters.
auto newName = DeclName(
ctx, DeclName(ctx.getIdentifier(newNameStr)).getBaseName(), newParamList);
auto newFnDecl = FuncDecl::createImported(
ctx, oldDecl->getLoc(), newName, oldDecl->getNameLoc(),
/*Async=*/false, oldDecl->hasThrows(), newParamList,
newFnType->getResult(), /*GenericParams=*/nullptr,
oldDecl->getDeclContext(), specialized);
if (oldDecl->isStatic()) {
newFnDecl->setStatic();
newFnDecl->setImportAsStaticMember();
}
newFnDecl->setSelfAccessKind(cast<FuncDecl>(oldDecl)->getSelfAccessKind());
return ConcreteDeclRef(newFnDecl);
}
ConcreteDeclRef
Solution::resolveConcreteDeclRef(ValueDecl *decl,
ConstraintLocator *locator) const {
if (!decl)
return ConcreteDeclRef();
// Get the generic signatue of the decl and compute the substitutions.
auto sig = decl->getInnermostDeclContext()->getGenericSignatureOfContext();
auto subst = computeSubstitutions(sig, locator);
// If this is a C++ function template, get it's specialization for the given
// substitution map and update the decl accordingly.
if (decl->getClangDecl() &&
isa<clang::FunctionTemplateDecl>(decl->getClangDecl())) {
auto *newFn =
decl->getASTContext()
.getClangModuleLoader()
->instantiateCXXFunctionTemplate(
decl->getASTContext(),
const_cast<clang::FunctionTemplateDecl *>(
cast<clang::FunctionTemplateDecl>(decl->getClangDecl())),
subst);
return generateDeclRefForSpecializedCXXFunctionTemplate(
decl->getASTContext(), cast<AbstractFunctionDecl>(decl), subst, newFn);
}
return ConcreteDeclRef(decl, subst);
}
ConstraintLocator *Solution::getCalleeLocator(ConstraintLocator *locator,
bool lookThroughApply) const {
auto &cs = getConstraintSystem();
return cs.getCalleeLocator(
locator, lookThroughApply,
[&](Expr *expr) -> Type { return getType(expr); },
[&](Type type) -> Type { return simplifyType(type)->getRValueType(); },
[&](ConstraintLocator *locator) -> Optional<SelectedOverload> {
return getOverloadChoiceIfAvailable(locator);
});
}
ConstraintLocator *
Solution::getConstraintLocator(ASTNode anchor,
ArrayRef<LocatorPathElt> path) const {
auto &cs = getConstraintSystem();
return cs.getConstraintLocator(anchor, path);
}
ConstraintLocator *
Solution::getConstraintLocator(ConstraintLocator *base,
ArrayRef<LocatorPathElt> path) const {
auto &cs = getConstraintSystem();
return cs.getConstraintLocator(base, path);
}
/// Return the implicit access kind for a MemberRefExpr with the
/// specified base and member in the specified DeclContext.
static AccessSemantics
getImplicitMemberReferenceAccessSemantics(Expr *base, VarDecl *member,
DeclContext *DC) {
// Check whether this is a member access on 'self'.
bool isAccessOnSelf = false;
if (auto *baseDRE = dyn_cast<DeclRefExpr>(base->getValueProvidingExpr()))
if (auto *baseVar = dyn_cast<VarDecl>(baseDRE->getDecl()))
isAccessOnSelf = baseVar->isSelfParameter();
// If the value is always directly accessed from this context, do it.
return member->getAccessSemanticsFromContext(DC, isAccessOnSelf);
}
/// This extends functionality of `Expr::isTypeReference` with
/// support for `UnresolvedDotExpr` and `UnresolvedMemberExpr`.
/// This method could be used on not yet fully type-checked AST.
bool ConstraintSystem::isTypeReference(Expr *E) {
return E->isTypeReference(
[&](Expr *E) -> Type { return simplifyType(getType(E)); },
[&](Expr *E) -> Decl * {
if (auto *UDE = dyn_cast<UnresolvedDotExpr>(E)) {
return findResolvedMemberRef(
getConstraintLocator(UDE, ConstraintLocator::Member));
}
if (auto *UME = dyn_cast<UnresolvedMemberExpr>(E)) {
return findResolvedMemberRef(
getConstraintLocator(UME, ConstraintLocator::UnresolvedMember));
}
if (isa<OverloadSetRefExpr>(E))
return findResolvedMemberRef(
getConstraintLocator(const_cast<Expr *>(E)));
return nullptr;
});
}
bool Solution::isTypeReference(Expr *E) const {
return E->isTypeReference(
[&](Expr *expr) -> Type { return simplifyType(getType(expr)); },
[&](Expr *expr) -> Decl * {
ConstraintLocator *locator = nullptr;
if (auto *UDE = dyn_cast<UnresolvedDotExpr>(E)) {
locator = getConstraintLocator(UDE, {ConstraintLocator::Member});
}
if (auto *UME = dyn_cast<UnresolvedMemberExpr>(E)) {
locator =
getConstraintLocator(UME, {ConstraintLocator::UnresolvedMember});
}
if (isa<OverloadSetRefExpr>(E))
locator = getConstraintLocator(const_cast<Expr *>(E));
if (locator) {
if (auto selectedOverload = getOverloadChoiceIfAvailable(locator)) {
const auto &choice = selectedOverload->choice;
return choice.getDeclOrNull();
}
}
return nullptr;
});
}
bool ConstraintSystem::isStaticallyDerivedMetatype(Expr *E) {
return E->isStaticallyDerivedMetatype(
[&](Expr *E) -> Type { return simplifyType(getType(E)); },
[&](Expr *E) -> bool { return isTypeReference(E); });
}
bool Solution::isStaticallyDerivedMetatype(Expr *E) const {
return E->isStaticallyDerivedMetatype(
[&](Expr *E) -> Type { return simplifyType(getType(E)); },
[&](Expr *E) -> bool { return isTypeReference(E); });
}
Type ConstraintSystem::getInstanceType(TypeExpr *E) {
if (!hasType(E))
return Type();
if (auto metaType = getType(E)->getAs<MetatypeType>())
return metaType->getInstanceType();
return ErrorType::get(getType(E)->getASTContext());
}
Type ConstraintSystem::getResultType(const AbstractClosureExpr *E) {
return E->getResultType([&](Expr *E) -> Type { return getType(E); });
}
static bool buildObjCKeyPathString(KeyPathExpr *E,
llvm::SmallVectorImpl<char> &buf) {
for (auto &component : E->getComponents()) {
switch (component.getKind()) {
case KeyPathExpr::Component::Kind::OptionalChain:
case KeyPathExpr::Component::Kind::OptionalForce:
case KeyPathExpr::Component::Kind::OptionalWrap:
// KVC propagates nulls, so these don't affect the key path string.
continue;
case KeyPathExpr::Component::Kind::Identity:
// The identity component can be elided from the KVC string (unless it's
// the only component, in which case we use @"self").
continue;
case KeyPathExpr::Component::Kind::Property: {
// Property references must be to @objc properties.
// TODO: If we added special properties matching KVC operators like '@sum',
// '@count', etc. those could be mapped too.
auto property = cast<VarDecl>(component.getDeclRef().getDecl());
if (!property->isObjC())
return false;
if (!buf.empty()) {
buf.push_back('.');
}
auto objcName = property->getObjCPropertyName().str();
buf.append(objcName.begin(), objcName.end());
continue;
}
case KeyPathExpr::Component::Kind::TupleElement:
case KeyPathExpr::Component::Kind::Subscript:
// Subscripts and tuples aren't generally represented in KVC.
// TODO: There are some subscript forms we could map to KVC, such as
// when indexing a Dictionary or NSDictionary by string, or when applying
// a mapping subscript operation to Array/Set or NSArray/NSSet.
return false;
case KeyPathExpr::Component::Kind::Invalid:
case KeyPathExpr::Component::Kind::UnresolvedProperty:
case KeyPathExpr::Component::Kind::UnresolvedSubscript:
// Don't bother building the key path string if the key path didn't even
// resolve.
return false;
case KeyPathExpr::Component::Kind::DictionaryKey:
llvm_unreachable("DictionaryKey only valid in #keyPath expressions.");
return false;
}
}
// If there are no non-identity components, this is the "self" key.
if (buf.empty()) {
auto self = StringRef("self");
buf.append(self.begin(), self.end());
}
return true;
}
namespace {
/// Rewrites an expression by applying the solution of a constraint
/// system to that expression.
class ExprRewriter : public ExprVisitor<ExprRewriter, Expr *> {
public:
ConstraintSystem &cs;
DeclContext *dc;
Solution &solution;
Optional<SolutionApplicationTarget> target;
bool SuppressDiagnostics;
/// Coerce the given tuple to another tuple type.
///
/// \param expr The expression we're converting.
///
/// \param fromTuple The tuple type we're converting from, which is the same
/// as \c expr->getType().
///
/// \param toTuple The tuple type we're converting to.
///
/// \param locator Locator describing where this tuple conversion occurs.
///
/// \param sources The sources of each of the elements to be used in the
/// resulting tuple, as provided by \c computeTupleShuffle.
Expr *coerceTupleToTuple(Expr *expr, TupleType *fromTuple,
TupleType *toTuple,
ConstraintLocatorBuilder locator,
ArrayRef<unsigned> sources);
/// Coerce a subclass, class-constrained archetype, class-constrained
/// existential or to a superclass type.
///
/// Also supports metatypes of the above.
///
/// \param expr The expression to be coerced.
/// \param toType The type to which the expression will be coerced.
///
/// \return The coerced expression, whose type will be equivalent to
/// \c toType.
Expr *coerceSuperclass(Expr *expr, Type toType);
/// Coerce the given value to existential type.
///
/// The following conversions are supported:
/// - concrete to existential
/// - existential to existential
/// - concrete metatype to existential metatype
/// - existential metatype to existential metatype
///
/// \param expr The expression to be coerced.
/// \param toType The type to which the expression will be coerced.
///
/// \return The coerced expression, whose type will be equivalent to
/// \c toType.
Expr *coerceExistential(Expr *expr, Type toType);
/// Coerce an expression of (possibly unchecked) optional
/// type to have a different (possibly unchecked) optional type.
Expr *coerceOptionalToOptional(Expr *expr, Type toType,
ConstraintLocatorBuilder locator,
Optional<Pattern*> typeFromPattern = None);
/// Coerce an expression of implicitly unwrapped optional type to its
/// underlying value type, in the correct way for an implicit
/// look-through.
Expr *coerceImplicitlyUnwrappedOptionalToValue(Expr *expr, Type objTy);
/// Peephole an array upcast.
void peepholeArrayUpcast(ArrayExpr *expr, Type toType, bool bridged,
Type elementType,
ConstraintLocatorBuilder locator);
/// Peephole a dictionary upcast.
void peepholeDictionaryUpcast(DictionaryExpr *expr, Type toType,
bool bridged, Type keyType,
Type valueType,
ConstraintLocatorBuilder locator);
/// Try to peephole the collection upcast, eliminating the need for
/// a separate collection-upcast expression.
///
/// \returns true if the peephole operation succeeded, in which case
/// \c expr already subsumes the upcast.
bool peepholeCollectionUpcast(Expr *expr, Type toType, bool bridged,
ConstraintLocatorBuilder locator);
/// Build a collection upcast expression.
///
/// \param bridged Whether this is a bridging conversion, meaning that the
/// element types themselves are bridged (vs. simply coerced).
Expr *buildCollectionUpcastExpr(Expr *expr, Type toType,
bool bridged,
ConstraintLocatorBuilder locator);
/// Build the expression that performs a bridging operation from the
/// given expression to the given \c toType.
Expr *buildObjCBridgeExpr(Expr *expr, Type toType,
ConstraintLocatorBuilder locator);
static Type getBaseType(AnyFunctionType *fnType,
bool wantsRValueInstanceType = true) {
auto params = fnType->getParams();
assert(params.size() == 1);
const auto &base = params.front();
if (wantsRValueInstanceType)
return base.getPlainType()->getMetatypeInstanceType();
return base.getOldType();
}
/// Check whether it is possible to have an ObjC key path string for the keypath expression
/// and set the key path string, if yes
void checkAndSetObjCKeyPathString(KeyPathExpr *keyPath) {
if (cs.getASTContext().LangOpts.EnableObjCInterop) {
SmallString<64> compatStringBuf;
if (buildObjCKeyPathString(keyPath, compatStringBuf)) {
auto stringCopy = cs.getASTContext().AllocateCopy<char>(compatStringBuf.begin(),
compatStringBuf.end());
auto stringExpr = new (cs.getASTContext()) StringLiteralExpr(
StringRef(stringCopy, compatStringBuf.size()),
SourceRange(),
/*implicit*/ true);
cs.setType(
stringExpr,
cs.getASTContext().getStringDecl()->getDeclaredInterfaceType());
keyPath->setObjCStringLiteralExpr(stringExpr);
}
}
}
// Returns None if the AST does not contain enough information to recover
// substitutions; this is different from an Optional(SubstitutionMap()),
// indicating a valid call to a non-generic operator.
Optional<SubstitutionMap>
getOperatorSubstitutions(ValueDecl *witness, Type refType) {
// We have to recover substitutions in this hacky way because
// the AST does not retain enough information to devirtualize
// calls like this.
auto witnessType = witness->getInterfaceType();
// Compute the substitutions.
auto *gft = witnessType->getAs<GenericFunctionType>();
if (gft == nullptr) {
if (refType->isEqual(witnessType))
return SubstitutionMap();
return None;
}
auto sig = gft->getGenericSignature();
auto *env = sig->getGenericEnvironment();
witnessType = FunctionType::get(gft->getParams(),
gft->getResult(),
gft->getExtInfo());
witnessType = env->mapTypeIntoContext(witnessType);
TypeSubstitutionMap subs;
auto substType = witnessType->substituteBindingsTo(
refType,
[&](ArchetypeType *origType, CanType substType,
ArchetypeType*, ArrayRef<ProtocolConformanceRef>) -> CanType {
if (auto gpType = dyn_cast<GenericTypeParamType>(
origType->getInterfaceType()->getCanonicalType()))
subs[gpType] = substType;
return substType;
});
// If substitution failed, it means that the protocol requirement type
// and the witness type did not match up. The only time that this
// should happen is when the witness is defined in a base class and
// the actual call uses a derived class. For example,
//
// protocol P { func +(lhs: Self, rhs: Self) }
// class Base : P { func +(lhs: Base, rhs: Base) {} }
// class Derived : Base {}
//
// If we enter this code path with two operands of type Derived,
// we know we're calling the protocol requirement P.+, with a
// substituted type of (Derived, Derived) -> (). But the type of
// the witness is (Base, Base) -> (). Just bail out and make a
// witness method call in this rare case; SIL mandatory optimizations
// will likely devirtualize it anyway.
if (!substType)
return None;
return SubstitutionMap::get(sig,
QueryTypeSubstitutionMap{subs},
LookUpConformanceInModule(cs.DC->getParentModule()));
}
public:
/// Build a reference to the given declaration.
Expr *buildDeclRef(SelectedOverload overload, DeclNameLoc loc,
ConstraintLocatorBuilder locator, bool implicit) {
auto choice = overload.choice;
assert(choice.getKind() != OverloadChoiceKind::DeclViaDynamic);
auto *decl = choice.getDecl();
auto fullType = simplifyType(overload.openedFullType);
// Determine the declaration selected for this overloaded reference.
auto &ctx = cs.getASTContext();
auto semantics = decl->getAccessSemanticsFromContext(cs.DC,
/*isAccessOnSelf*/false);
// If this is a member of a nominal type, build a reference to the
// member with an implied base type.
if (decl->getDeclContext()->isTypeContext() && isa<FuncDecl>(decl)) {
assert(cast<FuncDecl>(decl)->isOperator() && "Must be an operator");
auto baseTy = getBaseType(fullType->castTo<FunctionType>());
// Handle operator requirements found in protocols.
if (auto proto = dyn_cast<ProtocolDecl>(decl->getDeclContext())) {
bool isCurried = shouldBuildCurryThunk(choice, /*baseIsInstance=*/false);
// If we have a concrete conformance, build a call to the witness.
//
// FIXME: This is awful. We should be able to handle this as a call to
// the protocol requirement with Self == the concrete type, and SILGen
// (or later) can devirtualize as appropriate.
auto conformance =
TypeChecker::conformsToProtocol(baseTy, proto, cs.DC);
if (conformance.isConcrete()) {
if (auto witness = conformance.getConcrete()->getWitnessDecl(decl)) {
bool isMemberOperator = witness->getDeclContext()->isTypeContext();
if (!isMemberOperator || !isCurried) {
// The fullType was computed by substituting the protocol
// requirement so it always has a (Self) -> ... curried
// application. Strip it off if the witness was a top-level
// function.
Type refType;
if (isMemberOperator)
refType = fullType;
else
refType = fullType->castTo<AnyFunctionType>()->getResult();
// Build the AST for the call to the witness.
auto subMap = getOperatorSubstitutions(witness, refType);
if (subMap) {
ConcreteDeclRef witnessRef(witness, *subMap);
auto declRefExpr = new (ctx) DeclRefExpr(witnessRef, loc,
/*Implicit=*/false);
declRefExpr->setFunctionRefKind(choice.getFunctionRefKind());
cs.setType(declRefExpr, refType);
Expr *refExpr;
if (isMemberOperator) {
// If the operator is a type member, add the implicit
// (Self) -> ... call.
Expr *base =
TypeExpr::createImplicitHack(loc.getBaseNameLoc(), baseTy,
ctx);
cs.setType(base, MetatypeType::get(baseTy));
refExpr = new (ctx) DotSyntaxCallExpr(declRefExpr,
SourceLoc(), base);
auto refType = fullType->castTo<FunctionType>()->getResult();
cs.setType(refExpr, refType);
} else {
refExpr = declRefExpr;
}
return forceUnwrapIfExpected(refExpr, choice, locator);
}
}
}
}
}
// Build a reference to the member.
Expr *base =
TypeExpr::createImplicitHack(loc.getBaseNameLoc(), baseTy, ctx);
cs.cacheExprTypes(base);
return buildMemberRef(base, SourceLoc(), overload, loc, locator,
locator, implicit, semantics);
}
if (isa<TypeDecl>(decl) && !isa<ModuleDecl>(decl)) {
auto typeExpr = TypeExpr::createImplicitHack(
loc.getBaseNameLoc(), fullType->getMetatypeInstanceType(), ctx);
cs.cacheType(typeExpr);
return typeExpr;
}
auto ref = resolveConcreteDeclRef(decl, locator);
auto declRefExpr =
new (ctx) DeclRefExpr(ref, loc, implicit, semantics, fullType);
cs.cacheType(declRefExpr);
declRefExpr->setFunctionRefKind(choice.getFunctionRefKind());
return forceUnwrapIfExpected(declRefExpr, choice, locator);
}
/// Describes an opened existential that has not yet been closed.
struct OpenedExistential {
/// The archetype describing this opened existential.
OpenedArchetypeType *Archetype;
/// The existential value being opened.
Expr *ExistentialValue;
/// The opaque value (of archetype type) stored within the
/// existential.
OpaqueValueExpr *OpaqueValue;
/// The depth of this currently-opened existential. Once the
/// depth of the expression stack is equal to this value, the
/// existential can be closed.
unsigned Depth;
};
/// A stack of opened existentials that have not yet been closed.
/// Ordered by decreasing depth.
llvm::SmallVector<OpenedExistential, 2> OpenedExistentials;
/// A stack of expressions being walked, used to compute existential depth.
llvm::SmallVector<Expr *, 8> ExprStack;
/// A map of apply exprs to their callee locators. This is necessary
/// because after rewriting an apply's function expr, its callee locator
/// will no longer be equivalent to the one stored in the solution.
llvm::DenseMap<ApplyExpr *, ConstraintLocator *> CalleeLocators;
/// A cache of decl references with their contextual substitutions for a
/// given callee locator.
llvm::DenseMap<ConstraintLocator *, ConcreteDeclRef> CachedConcreteRefs;
/// Resolves the contextual substitutions for a reference to a declaration
/// at a given locator. This should be preferred to
/// Solution::resolveConcreteDeclRef as it caches the result.
ConcreteDeclRef
resolveConcreteDeclRef(ValueDecl *decl, ConstraintLocatorBuilder locator) {
if (!decl)
return ConcreteDeclRef();
// Cache the resulting concrete reference. Ideally this would be done on
// Solution, however unfortunately that would require a const_cast which
// would be undefined behaviour if we ever had a `const Solution`.
auto *loc = getConstraintSystem().getConstraintLocator(locator);
auto &ref = CachedConcreteRefs[loc];
if (!ref)
ref = solution.resolveConcreteDeclRef(decl, loc);
return ref;
}
/// Members which are AbstractFunctionDecls but not FuncDecls cannot
/// mutate self.
bool isNonMutatingMember(ValueDecl *member) {
if (!isa<AbstractFunctionDecl>(member))
return false;
return !isa<FuncDecl>(member) || !cast<FuncDecl>(member)->isMutating();
}
/// If the expression might be a dynamic method call, return the base
/// value for the call.
Expr *getBaseExpr(Expr *expr) {
// Keep going up as long as this expression is the parent's base.
if (auto unresolvedDot = dyn_cast<UnresolvedDotExpr>(expr)) {
return unresolvedDot->getBase();
// Remaining cases should only come up when we're re-typechecking.
// FIXME: really it would be much better if Sema had stricter phase
// separation.
} else if (auto dotSyntax = dyn_cast<DotSyntaxCallExpr>(expr)) {
return dotSyntax->getArg();
} else if (auto ctorRef = dyn_cast<ConstructorRefCallExpr>(expr)) {
return ctorRef->getArg();
} else if (auto apply = dyn_cast<ApplyExpr>(expr)) {
return apply->getFn();
} else if (auto lookupRef = dyn_cast<LookupExpr>(expr)) {
return lookupRef->getBase();
} else if (auto load = dyn_cast<LoadExpr>(expr)) {
return load->getSubExpr();
} else if (auto inout = dyn_cast<InOutExpr>(expr)) {
return inout->getSubExpr();
} else if (auto force = dyn_cast<ForceValueExpr>(expr)) {
return force->getSubExpr();
} else {
return nullptr;
}
}
/// Calculates the nesting depth of the current application.
unsigned getArgCount(unsigned maxArgCount) {
// FIXME: Walking over the ExprStack to figure out the number of argument
// lists being applied is brittle. We should instead be checking
// hasAppliedSelf to figure out if the self param is applied, and looking
// at the FunctionRefKind to see if the parameter list is applied.
unsigned e = ExprStack.size();
unsigned argCount;
// Starting from the current expression, count up if the expression is
// equal to its parent expression's base.
Expr *prev = ExprStack.back();
for (argCount = 1; argCount < maxArgCount && argCount < e; ++argCount) {
Expr *result = ExprStack[e - argCount - 1];
Expr *base = getBaseExpr(result);
if (base != prev)
break;
prev = result;
}
return argCount;
}
/// Open an existential value into a new, opaque value of
/// archetype type.
///
/// \param base An expression of existential type whose value will
/// be opened.
///
/// \param archetype The archetype that describes the opened existential
/// type.
///
/// \param member The member that is being referenced on the existential
/// type.
///
/// \returns An OpaqueValueExpr that provides a reference to the value
/// stored within the expression or its metatype (if the base was a
/// metatype).
Expr *openExistentialReference(Expr *base, OpenedArchetypeType *archetype,
ValueDecl *member) {
assert(archetype && "archetype not already opened?");
// Dig out the base type.
Type baseTy = cs.getType(base);
// Look through lvalues.
bool isLValue = false;
if (auto lvalueTy = baseTy->getAs<LValueType>()) {
isLValue = true;
baseTy = lvalueTy->getObjectType();
}
// Look through metatypes.
bool isMetatype = false;
if (auto metaTy = baseTy->getAs<AnyMetatypeType>()) {
isMetatype = true;
baseTy = metaTy->getInstanceType();
}
assert(baseTy->isAnyExistentialType() && "Type must be existential");
// If the base was an lvalue but it will only be treated as an
// rvalue, turn the base into an rvalue now. This results in
// better SILGen.
if (isLValue &&
(isNonMutatingMember(member) ||
member->getDeclContext()->getDeclaredInterfaceType()
->hasReferenceSemantics())) {
base = cs.coerceToRValue(base);
isLValue = false;
}
// Determine the number of applications that need to occur before
// we can close this existential, and record it.
unsigned maxArgCount = member->getNumCurryLevels();
unsigned depth = ExprStack.size() - getArgCount(maxArgCount);
// Invalid case -- direct call of a metatype. Has one less argument
// application because there's no ".init".
if (isa<ApplyExpr>(ExprStack.back()))
depth++;
// Create the opaque opened value. If we started with a
// metatype, it's a metatype.
Type opaqueType = archetype;
if (isMetatype)
opaqueType = MetatypeType::get(opaqueType);
if (isLValue)
opaqueType = LValueType::get(opaqueType);
ASTContext &ctx = cs.getASTContext();
auto archetypeVal =
new (ctx) OpaqueValueExpr(base->getSourceRange(), opaqueType);
cs.cacheType(archetypeVal);
// Record the opened existential.
OpenedExistentials.push_back({archetype, base, archetypeVal, depth});
return archetypeVal;
}
/// Trying to close the active existential, if there is one.
bool closeExistential(Expr *&result, ConstraintLocatorBuilder locator,
bool force=false) {
if (OpenedExistentials.empty())
return false;
auto &record = OpenedExistentials.back();
assert(record.Depth <= ExprStack.size());
if (!force && record.Depth < ExprStack.size() - 1)
return false;
// If we had a return type of 'Self', erase it.
Type resultTy;
resultTy = cs.getType(result);
if (resultTy->hasOpenedExistential(record.Archetype)) {
Type erasedTy = resultTy->eraseOpenedExistential(record.Archetype);
auto range = result->getSourceRange();
result = coerceToType(result, erasedTy, locator);
// FIXME: Implement missing tuple-to-tuple conversion
if (result == nullptr) {
result = new (cs.getASTContext()) ErrorExpr(range);
cs.setType(result, erasedTy);
// The opaque value is no longer reachable in an AST walk as
// a result of the result above being replaced with an
// ErrorExpr, but there is code expecting to have a type set
// on it. Since we no longer have a reachable reference,
// we'll null this out.
record.OpaqueValue = nullptr;
}
}
// Form the open-existential expression.
result = new (cs.getASTContext()) OpenExistentialExpr(
record.ExistentialValue,
record.OpaqueValue,
result, cs.getType(result));
cs.cacheType(result);
OpenedExistentials.pop_back();
return true;
}
/// Determines if a partially-applied member reference should be
/// converted into a fully-applied member reference with a pair of
/// closures.
bool shouldBuildCurryThunk(OverloadChoice choice,
bool baseIsInstance) {
ValueDecl *member = choice.getDecl();
auto isDynamic = choice.getKind() == OverloadChoiceKind::DeclViaDynamic;
// FIXME: We should finish plumbing this through for dynamic
// lookup as well.
if (isDynamic || member->getAttrs().hasAttribute<OptionalAttr>())
return false;
// If we're inside a selector expression, don't build the thunk.
// Were not actually going to emit the member reference, just
// look at the AST.
for (auto expr : ExprStack)
if (isa<ObjCSelectorExpr>(expr))
return false;
// Unbound instance method references always build a thunk, even if
// we apply the arguments (eg, SomeClass.method(self)(a)), to avoid
// representational issues.
if (!baseIsInstance && member->isInstanceMember())
return true;
// Figure out how many argument lists we need.
unsigned maxArgCount = member->getNumCurryLevels();
unsigned argCount = [&]() -> unsigned {
Expr *prev = ExprStack.back();
// FIXME: Representational gunk because "T(...)" is really
// "T.init(...)" -- pretend it has two argument lists like
// a real '.' call.
if (isa<ConstructorDecl>(member) &&
isa<CallExpr>(prev) &&
isa<TypeExpr>(cast<CallExpr>(prev)->getFn())) {
assert(maxArgCount == 2);
return 2;
}
// Similarly, ".foo(...)" really applies two argument lists.
if (isa<CallExpr>(prev) &&
isa<UnresolvedMemberExpr>(cast<CallExpr>(prev)->getFn()))
return 2;
return getArgCount(maxArgCount);
}();
// If we have fewer argument lists than expected, build a thunk.
if (argCount < maxArgCount)
return true;
return false;
}
AutoClosureExpr *buildCurryThunk(ValueDecl *member,
FunctionType *selfFnTy,
Expr *selfParamRef,
Expr *ref,
ConstraintLocatorBuilder locator) {
auto &context = cs.getASTContext();
OptionSet<ParameterList::CloneFlags> options
= (ParameterList::Implicit |
ParameterList::NamedArguments);
auto *params = getParameterList(member)->clone(context, options);
for (auto idx : indices(*params)) {
auto *param = params->get(idx);
auto arg = selfFnTy->getParams()[idx];
param->setInterfaceType(
arg.getParameterType()->mapTypeOutOfContext());
param->setSpecifier(
ParamDecl::getParameterSpecifierForValueOwnership(
arg.getValueOwnership()));
}
auto resultTy = selfFnTy->getResult();
auto discriminator = AutoClosureExpr::InvalidDiscriminator;
auto closure =
new (context) AutoClosureExpr(/*set body later*/nullptr, resultTy,
discriminator, cs.DC);
closure->setParameterList(params);
closure->setType(selfFnTy);
closure->setThunkKind(AutoClosureExpr::Kind::SingleCurryThunk);
cs.cacheType(closure);
auto refTy = cs.getType(ref)->castTo<FunctionType>();
auto calleeParams = refTy->getResult()->castTo<FunctionType>()->getParams();
auto calleeResultTy = refTy->getResult()->castTo<FunctionType>()->getResult();
auto selfParam = refTy->getParams()[0];
auto selfParamTy = selfParam.getPlainType();
Expr *selfOpenedRef = selfParamRef;
// If the 'self' parameter has non-trivial ownership, adjust the
// argument accordingly.
switch (selfParam.getValueOwnership()) {
case ValueOwnership::Default:
case ValueOwnership::InOut:
break;
case ValueOwnership::Owned:
case ValueOwnership::Shared:
auto selfArgTy = ParenType::get(context,
selfParam.getPlainType(),
selfParam.getParameterFlags());
selfOpenedRef->setType(selfArgTy);
cs.cacheType(selfOpenedRef);
break;
}
if (selfParamTy->hasOpenedExistential()) {
// If we're opening an existential:
// - the type of 'ref' inside the closure is written in terms of the
// open existental archetype
// - the type of the closure, 'selfFnTy' is written in terms of the
// erased existential bounds
if (selfParam.isInOut())
selfParamTy = LValueType::get(selfParamTy);
selfOpenedRef =
new (context) OpaqueValueExpr(SourceLoc(), selfParamTy);
cs.cacheType(selfOpenedRef);
}
// (Self) -> ...
ApplyExpr *selfCall = new (context) DotSyntaxCallExpr(
ref, SourceLoc(), selfOpenedRef);
selfCall->setType(refTy->getResult());
cs.cacheType(selfCall);
if (selfParamRef->isSuperExpr())
selfCall->setIsSuper(true);
// Pass all the closure parameters to the call.
SmallVector<Identifier, 4> labels;
SmallVector<SourceLoc, 4> labelLocs;
SmallVector<Expr *, 4> args;
for (auto idx : indices(*params)) {
auto *param = params->get(idx);
auto calleeParamType = calleeParams[idx].getParameterType();
auto type = param->getType();
Expr *paramRef =
new (context) DeclRefExpr(param, DeclNameLoc(), /*implicit*/ true);
paramRef->setType(
param->isInOut()
? LValueType::get(type)
: type);
cs.cacheType(paramRef);
paramRef = coerceToType(
paramRef,
param->isInOut()
? LValueType::get(calleeParamType)
: calleeParamType,
locator);
if (param->isInOut()) {
paramRef =
new (context) InOutExpr(SourceLoc(), paramRef, calleeParamType,
/*implicit=*/true);
cs.cacheType(paramRef);
} else if (param->isVariadic()) {
paramRef =
new (context) VarargExpansionExpr(paramRef, /*implicit*/ true);
paramRef->setType(calleeParamType);
cs.cacheType(paramRef);
}
args.push_back(paramRef);
labels.push_back(calleeParams[idx].getLabel());
labelLocs.push_back(SourceLoc());
}
Expr *closureArg;
if (args.size() == 1 &&
labels[0].empty() &&
!calleeParams[0].getParameterFlags().isVariadic()) {
closureArg = new (context) ParenExpr(SourceLoc(), args[0], SourceLoc(),
/*hasTrailingClosure=*/false);
closureArg->setImplicit();
} else {
closureArg = TupleExpr::create(context, SourceLoc(), args, labels, labelLocs,
SourceLoc(), /*hasTrailingClosure=*/false,
/*implicit=*/true);
}
auto argTy = AnyFunctionType::composeInput(context, calleeParams,
/*canonical*/false);
closureArg->setType(argTy);
cs.cacheType(closureArg);
// (Self) -> (Args...) -> ...
auto *closureCall =
CallExpr::create(context, selfCall, closureArg, { }, { },
/*hasTrailingClosure=*/false,
/*implicit=*/true);
closureCall->setType(calleeResultTy);
cs.cacheType(closureCall);
Expr *closureBody = closureCall;
closureBody = coerceToType(closureCall, resultTy, locator);
if (selfFnTy->getExtInfo().isThrowing()) {
closureBody = new (context) TryExpr(closureBody->getStartLoc(), closureBody,
cs.getType(closureBody),
/*implicit=*/true);
cs.cacheType(closureBody);
}
if (selfParam.getPlainType()->hasOpenedExistential()) {
closureBody =
new (context) OpenExistentialExpr(
selfParamRef, cast<OpaqueValueExpr>(selfOpenedRef),
closureBody, resultTy);
cs.cacheType(closureBody);
}
closure->setBody(closureBody);
return closure;
}
/// Build a new member reference with the given base and member.
Expr *buildMemberRef(Expr *base, SourceLoc dotLoc,
SelectedOverload overload, DeclNameLoc memberLoc,
ConstraintLocatorBuilder locator,
ConstraintLocatorBuilder memberLocator, bool Implicit,
AccessSemantics semantics) {
auto choice = overload.choice;
auto openedType = overload.openedType;
ValueDecl *member = choice.getDecl();
auto &context = cs.getASTContext();
bool isSuper = base->isSuperExpr();
// The formal type of the 'self' value for the call.
Type baseTy = cs.getType(base)->getRValueType();
// Figure out the actual base type, and whether we have an instance of
// that type or its metatype.
bool baseIsInstance = true;
bool isExistentialMetatype = false;
if (auto baseMeta = baseTy->getAs<AnyMetatypeType>()) {
baseIsInstance = false;
isExistentialMetatype = baseMeta->is<ExistentialMetatypeType>();
baseTy = baseMeta->getInstanceType();
// A valid reference to a static member (computed property or a method)
// declared on a protocol is only possible if result type conforms to
// that protocol, otherwise it would be impossible to find a witness to
// use.
// Such means that (for valid references) base expression here could be
// adjusted to point to a type conforming to a protocol as-if reference
// has originated directly from it e.g.
//
// \code
// protocol P {}
// struct S : P {}
//
// extension P {
// static var foo: S { S() }
// }
//
// _ = P.foo
// \endcode
//
// Here `P.foo` would be replaced with `S.foo`
if (!isExistentialMetatype && baseTy->is<ProtocolType>() &&
member->isStatic()) {
Type baseTy =
simplifyType(openedType->is<FunctionType>()
? openedType->castTo<FunctionType>()->getResult()
: openedType);
base = TypeExpr::createImplicitHack(base->getLoc(), baseTy, context);
cs.cacheType(base);
}
}
// Build a member reference.
auto memberRef = resolveConcreteDeclRef(member, memberLocator);
// If we're referring to a member type, it's just a type
// reference.
if (auto *TD = dyn_cast<TypeDecl>(member)) {
Type refType = simplifyType(openedType);
auto ref = TypeExpr::createForDecl(memberLoc, TD, cs.DC);
cs.setType(ref, refType);
auto *result = new (context) DotSyntaxBaseIgnoredExpr(
base, dotLoc, ref, refType);
cs.setType(result, refType);
return result;
}
auto refTy = simplifyType(overload.openedFullType);
// If we're referring to the member of a module, it's just a simple
// reference.
if (baseTy->is<ModuleType>()) {
assert(semantics == AccessSemantics::Ordinary &&
"Direct property access doesn't make sense for this");
auto ref = new (context) DeclRefExpr(memberRef, memberLoc, Implicit);
cs.setType(ref, refTy);
ref->setFunctionRefKind(choice.getFunctionRefKind());
auto *DSBI = cs.cacheType(new (context) DotSyntaxBaseIgnoredExpr(
base, dotLoc, ref, cs.getType(ref)));
return forceUnwrapIfExpected(DSBI, choice, memberLocator);
}
bool isUnboundInstanceMember =
(!baseIsInstance && member->isInstanceMember());
bool isPartialApplication = shouldBuildCurryThunk(choice, baseIsInstance);
// The formal type of the 'self' value for the member's declaration.
Type containerTy = getBaseType(refTy->castTo<FunctionType>());
// If we have an opened existential, selfTy and baseTy will both be
// the same opened existential type.
Type selfTy = containerTy;
// If we opened up an existential when referencing this member, update
// the base accordingly.
bool openedExistential = false;
// For a partial application, we have to open the existential inside
// the thunk itself.
auto knownOpened = solution.OpenedExistentialTypes.find(
getConstraintSystem().getConstraintLocator(
memberLocator));
if (knownOpened != solution.OpenedExistentialTypes.end()) {
// Determine if we're going to have an OpenExistentialExpr around
// this member reference.
//
// If we have a partial application of a protocol method, we open
// the existential in the curry thunk, instead of opening it here,
// because we won't have a 'self' value until the curry thunk is
// applied.
//
// However, a partial application of a class method on a subclass
// existential does need to open the existential, so that it can be
// upcast to the appropriate class reference type.
if (!isPartialApplication || !containerTy->hasOpenedExistential()) {
// Open the existential before performing the member reference.
base = openExistentialReference(base, knownOpened->second, member);
baseTy = knownOpened->second;
selfTy = baseTy;
openedExistential = true;
} else {
// Erase opened existentials from the type of the thunk; we're
// going to open the existential inside the thunk's body.
containerTy = containerTy->eraseOpenedExistential(knownOpened->second);
selfTy = containerTy;
}
}
// References to properties with accessors and storage usually go
// through the accessors, but sometimes are direct.
if (auto *VD = dyn_cast<VarDecl>(member)) {
if (semantics == AccessSemantics::Ordinary)
semantics = getImplicitMemberReferenceAccessSemantics(base, VD, dc);
}
auto isDynamic = choice.getKind() == OverloadChoiceKind::DeclViaDynamic;
if (baseIsInstance) {
// Convert the base to the appropriate container type, turning it
// into an lvalue if required.
// If the base is already an lvalue with the right base type, we can
// pass it as an inout qualified type.
auto selfParamTy = isDynamic ? selfTy : containerTy;
if (selfTy->isEqual(baseTy))
if (cs.getType(base)->is<LValueType>())
selfParamTy = InOutType::get(selfTy);
base = coerceSelfArgumentToType(
base, selfParamTy, member,
locator.withPathElement(ConstraintLocator::MemberRefBase));
} else {
if (!isExistentialMetatype || openedExistential) {
// Convert the base to an rvalue of the appropriate metatype.
base = coerceToType(base,
MetatypeType::get(
isDynamic ? selfTy : containerTy),
locator.withPathElement(
ConstraintLocator::MemberRefBase));
}
if (!base)
return nullptr;
base = cs.coerceToRValue(base);
}
assert(base && "Unable to convert base?");
// Handle dynamic references.
if (isDynamic || member->getAttrs().hasAttribute<OptionalAttr>()) {
base = cs.coerceToRValue(base);
Expr *ref = new (context) DynamicMemberRefExpr(base, dotLoc, memberRef,
memberLoc);
ref->setImplicit(Implicit);
// FIXME: FunctionRefKind
// Compute the type of the reference.
Type refType = simplifyType(openedType);
// If the base was an opened existential, erase the opened
// existential.
if (openedExistential) {
refType = refType->eraseOpenedExistential(
baseTy->castTo<OpenedArchetypeType>());
}
cs.setType(ref, refType);
closeExistential(ref, locator, /*force=*/openedExistential);
// If this attribute was inferred based on deprecated Swift 3 rules,
// complain.
if (auto attr = member->getAttrs().getAttribute<ObjCAttr>()) {
if (attr->isSwift3Inferred() &&
context.LangOpts.WarnSwift3ObjCInference ==
Swift3ObjCInferenceWarnings::Minimal) {
context.Diags.diagnose(
memberLoc, diag::expr_dynamic_lookup_swift3_objc_inference,
member->getDescriptiveKind(), member->getName(),
member->getDeclContext()->getSelfNominalTypeDecl()->getName());
context.Diags
.diagnose(member, diag::make_decl_objc,
member->getDescriptiveKind())
.fixItInsert(member->getAttributeInsertionLoc(false), "@objc ");
}
}
if (isDynamic) {
// Rewrite for implicit unwrapping if the solution requires it.
auto *dynamicLocator =
cs.getConstraintLocator(memberLocator.withPathElement(
ConstraintLocator::DynamicLookupResult));
if (solution.getDisjunctionChoice(dynamicLocator)) {
auto *forceValue =
new (context) ForceValueExpr(ref, ref->getEndLoc());
auto optTy = cs.getType(forceValue->getSubExpr());
cs.setType(forceValue, optTy->getOptionalObjectType());
ref = forceValue;
}
}
// We also need to handle the implicitly unwrap of the result
// of the called function if that's the type checking solution
// we ended up with.
return forceUnwrapIfExpected(
ref, choice, memberLocator,
member->getAttrs().hasAttribute<OptionalAttr>());
}
// For properties, build member references.
if (auto *varDecl = dyn_cast<VarDecl>(member)) {
if (isUnboundInstanceMember) {
assert(memberLocator.getBaseLocator() &&
cs.UnevaluatedRootExprs.count(
getAsExpr(memberLocator.getBaseLocator()->getAnchor())) &&
"Attempt to reference an instance member of a metatype");
auto baseInstanceTy = cs.getType(base)
->getInOutObjectType()->getMetatypeInstanceType();
base = new (context) UnevaluatedInstanceExpr(base, baseInstanceTy);
cs.cacheType(base);
base->setImplicit();
}
auto hasDynamicSelf =
varDecl->getValueInterfaceType()->hasDynamicSelfType();
auto memberRefExpr
= new (context) MemberRefExpr(base, dotLoc, memberRef,
memberLoc, Implicit, semantics);
memberRefExpr->setIsSuper(isSuper);
if (hasDynamicSelf)
refTy = refTy->replaceCovariantResultType(containerTy, 1);
cs.setType(memberRefExpr, refTy->castTo<FunctionType>()->getResult());
Expr *result = memberRefExpr;
closeExistential(result, locator);
if (hasDynamicSelf) {
if (!baseTy->isEqual(containerTy)) {
result = new (context) CovariantReturnConversionExpr(
result, simplifyType(openedType));
cs.cacheType(result);
}
}
return forceUnwrapIfExpected(result, choice, memberLocator);
}
if (member->getInterfaceType()->hasDynamicSelfType())
refTy = refTy->replaceCovariantResultType(containerTy, 2);
// Handle all other references.
auto declRefExpr = new (context) DeclRefExpr(memberRef, memberLoc,
Implicit, semantics);
declRefExpr->setFunctionRefKind(choice.getFunctionRefKind());
declRefExpr->setType(refTy);
cs.setType(declRefExpr, refTy);
Expr *ref = declRefExpr;
if (isPartialApplication) {
auto curryThunkTy = refTy->castTo<FunctionType>();
// A partial application thunk consists of two nested closures:
//
// { self in { args... in self.method(args...) } }
//
// If the reference has an applied 'self', eg 'let fn = foo.method',
// the outermost closure is wrapped inside a single ApplyExpr:
//
// { self in { args... in self.method(args...) } }(foo)
//
// This is done instead of just hoising the expression 'foo' up
// into the closure, which would change evaluation order.
//
// However, for a super method reference, eg, 'let fn = super.foo',
// the base expression is always a SuperRefExpr, possibly wrapped
// by an upcast. Since SILGen expects super method calls to have a
// very specific shape, we only emit a single closure here and
// capture the original SuperRefExpr, since its evaluation does not
// have side effects, instead of abstracting out a 'self' parameter.
if (isSuper) {
auto selfFnTy = curryThunkTy->getResult()->castTo<FunctionType>();
auto closure = buildCurryThunk(member, selfFnTy, base, ref,
memberLocator);
// Skip the code below -- we're not building an extra level of
// call by applying the 'super', instead the closure we just
// built is the curried reference.
return closure;
}
// Another case where we want to build a single closure is when
// we have a partial application of a constructor on a statically-
// derived metatype value. Again, there are no order of evaluation
// concerns here, and keeping the call and base together in the AST
// improves SILGen.
if (isa<ConstructorDecl>(member) &&
cs.isStaticallyDerivedMetatype(base)) {
auto selfFnTy = curryThunkTy->getResult()->castTo<FunctionType>();
// Add a useless ".self" to avoid downstream diagnostics.
base = new (context) DotSelfExpr(base, SourceLoc(), base->getEndLoc(),
cs.getType(base));
cs.setType(base, base->getType());
auto closure = buildCurryThunk(member, selfFnTy, base, ref,
memberLocator);
// Skip the code below -- we're not building an extra level of
// call by applying the metatype instead the closure we just
// built is the curried reference.
return closure;
}
// Check if we need to open an existential stored inside 'self'.
auto knownOpened = solution.OpenedExistentialTypes.find(
getConstraintSystem().getConstraintLocator(
memberLocator));
if (knownOpened != solution.OpenedExistentialTypes.end()) {
curryThunkTy =
curryThunkTy->eraseOpenedExistential(knownOpened->second)
->castTo<FunctionType>();
}
auto discriminator = AutoClosureExpr::InvalidDiscriminator;
// The outer closure.
//
// let outerClosure = "{ self in \(closure) }"
auto selfParam = curryThunkTy->getParams()[0];
auto selfParamDecl = new (context) ParamDecl(
SourceLoc(),
/*argument label*/ SourceLoc(), Identifier(),
/*parameter name*/ SourceLoc(), context.Id_self,
cs.DC);
auto selfParamTy = selfParam.getPlainType();
bool isLValue = selfParam.isInOut();
selfParamDecl->setInterfaceType(selfParamTy->mapTypeOutOfContext());
selfParamDecl->setSpecifier(
ParamDecl::getParameterSpecifierForValueOwnership(
selfParam.getValueOwnership()));
selfParamDecl->setImplicit();
auto *outerParams =
ParameterList::create(context, SourceLoc(), selfParamDecl,
SourceLoc());
// The inner closure.
//
// let closure = "{ args... in self.member(args...) }"
auto selfFnTy = curryThunkTy->getResult()->castTo<FunctionType>();
Expr *selfParamRef =
new (context) DeclRefExpr(selfParamDecl, DeclNameLoc(),
/*implicit=*/true);
selfParamRef->setType(
isLValue ? LValueType::get(selfParamTy) : selfParamTy);
cs.cacheType(selfParamRef);
if (isLValue) {
selfParamRef =
new (context) InOutExpr(SourceLoc(), selfParamRef, selfParamTy,
/*implicit=*/true);
cs.cacheType(selfParamRef);
}
auto closure = buildCurryThunk(member, selfFnTy, selfParamRef, ref,
memberLocator);
auto outerClosure =
new (context) AutoClosureExpr(closure, selfFnTy,
discriminator, cs.DC);
outerClosure->setThunkKind(AutoClosureExpr::Kind::DoubleCurryThunk);
outerClosure->setParameterList(outerParams);
outerClosure->setType(curryThunkTy);
cs.cacheType(outerClosure);
// Replace the DeclRefExpr with a closure expression which SILGen
// knows how to emit.
ref = outerClosure;
}
// If this is a method whose result type is dynamic Self, or a
// construction, replace the result type with the actual object type.
if (!member->getDeclContext()->getSelfProtocolDecl()) {
if (auto func = dyn_cast<AbstractFunctionDecl>(member)) {
if (func->hasDynamicSelfResult() &&
!baseTy->getOptionalObjectType()) {
if (!baseTy->isEqual(containerTy)) {
auto dynamicSelfFnType = refTy->replaceCovariantResultType(baseTy, 2);
ref = new (context) CovariantFunctionConversionExpr(ref,
dynamicSelfFnType);
cs.cacheType(ref);
}
}
}
}
ApplyExpr *apply;
if (isa<ConstructorDecl>(member)) {
// FIXME: Provide type annotation.
ref = forceUnwrapIfExpected(ref, choice, memberLocator);
apply = new (context) ConstructorRefCallExpr(ref, base);
} else if (isUnboundInstanceMember) {
auto refType = cs.simplifyType(openedType);
if (!cs.getType(ref)->isEqual(refType)) {
ref = new (context) FunctionConversionExpr(ref, refType);
cs.cacheType(ref);
}
// Reference to an unbound instance method.
Expr *result = new (context) DotSyntaxBaseIgnoredExpr(base, dotLoc,
ref,
cs.getType(ref));
cs.cacheType(result);
closeExistential(result, locator, /*force=*/openedExistential);
return forceUnwrapIfExpected(result, choice, memberLocator);
} else {
assert((!baseIsInstance || member->isInstanceMember()) &&
"can't call a static method on an instance");
ref = forceUnwrapIfExpected(ref, choice, memberLocator);
apply = new (context) DotSyntaxCallExpr(ref, dotLoc, base);
if (Implicit) {
apply->setImplicit();
}
}
return finishApply(apply, openedType, locator, memberLocator);
}
/// Convert the given literal expression via a protocol pair.
///
/// This routine handles the two-step literal conversion process used
/// by integer, float, character, extended grapheme cluster, and string
/// literals. The first step uses \c builtinProtocol while the second
/// step uses \c protocol.
///
/// \param literal The literal expression.
///
/// \param type The literal type. This type conforms to \c protocol,
/// and may also conform to \c builtinProtocol.
///
/// \param protocol The protocol that describes the literal requirement.
///
/// \param literalType The name of the associated type in \c protocol that
/// describes the argument type of the conversion function (\c
/// literalFuncName).
///
/// \param literalFuncName The name of the conversion function requirement
/// in \c protocol.
///
/// \param builtinProtocol The "builtin" form of the protocol, which
/// always takes builtin types and can only be properly implemented
/// by standard library types. If \c type does not conform to this
/// protocol, it's literal type will.
///
/// \param builtinLiteralFuncName The name of the conversion function
/// requirement in \c builtinProtocol.
///
/// \param brokenProtocolDiag The diagnostic to emit if the protocol
/// is broken.
///
/// \param brokenBuiltinProtocolDiag The diagnostic to emit if the builtin
/// protocol is broken.
///
/// \returns the converted literal expression.
Expr *convertLiteralInPlace(LiteralExpr *literal, Type type,
ProtocolDecl *protocol, Identifier literalType,
DeclName literalFuncName,
ProtocolDecl *builtinProtocol,
DeclName builtinLiteralFuncName,
Diag<> brokenProtocolDiag,
Diag<> brokenBuiltinProtocolDiag);
/// Finish a function application by performing the appropriate
/// conversions on the function and argument expressions and setting
/// the resulting type.
///
/// \param apply The function application to finish type-checking, which
/// may be a newly-built expression.
///
/// \param openedType The "opened" type this expression had during
/// type checking, which will be used to specialize the resulting,
/// type-checked expression appropriately.
///
/// \param locator The locator for the original expression.
///
/// \param calleeLocator The locator that identifies the apply's callee.
Expr *finishApply(ApplyExpr *apply, Type openedType,
ConstraintLocatorBuilder locator,
ConstraintLocatorBuilder calleeLocator);
/// Build the function and argument for a `@dynamicCallable` application.
std::pair</*fn*/ Expr *, /*arg*/ Expr *>
buildDynamicCallable(ApplyExpr *apply, SelectedOverload selected,
FuncDecl *method, AnyFunctionType *methodType,
ConstraintLocatorBuilder applyFunctionLoc);
private:
/// Simplify the given type by substituting all occurrences of
/// type variables for their fixed types.
Type simplifyType(Type type) {
return solution.simplifyType(type);
}
public:
/// Coerce the given expression to the given type.
///
/// This operation cannot fail.
///
/// \param expr The expression to coerce.
/// \param toType The type to coerce the expression to.
/// \param locator Locator used to describe where in this expression we are.
/// \param typeFromPattern Optionally, the caller can specify the pattern
/// from where the toType is derived, so that we can deliver better fixit.
///
/// \returns the coerced expression, which will have type \c ToType.
Expr *coerceToType(Expr *expr, Type toType,
ConstraintLocatorBuilder locator,
Optional<Pattern*> typeFromPattern = None);
/// Coerce the given expression (which is the argument to a call) to
/// the given parameter type.
///
/// This operation cannot fail.
///
/// \param arg The argument expression.
/// \param funcType The function type.
/// \param callee The callee for the function being applied.
/// \param apply The ApplyExpr that forms the call.
/// \param argLabels The argument labels provided for the call.
/// \param locator Locator used to describe where in this expression we are.
///
/// \returns the coerced expression, which will have type \c ToType.
Expr *
coerceCallArguments(Expr *arg, AnyFunctionType *funcType,
ConcreteDeclRef callee, ApplyExpr *apply,
ArrayRef<Identifier> argLabels,
ConstraintLocatorBuilder locator);
/// Coerce the given 'self' argument (e.g., for the base of a
/// member expression) to the given type.
///
/// \param expr The expression to coerce.
///
/// \param baseTy The base type
///
/// \param member The member being accessed.
///
/// \param locator Locator used to describe where in this expression we are.
Expr *coerceSelfArgumentToType(Expr *expr,
Type baseTy, ValueDecl *member,
ConstraintLocatorBuilder locator);
private:
/// Build a new subscript.
///
/// \param base The base of the subscript.
/// \param index The index of the subscript.
/// \param locator The locator used to refer to the subscript.
/// \param isImplicit Whether this is an implicit subscript.
Expr *buildSubscript(Expr *base, Expr *index,
ArrayRef<Identifier> argLabels,
bool hasTrailingClosure,
ConstraintLocatorBuilder locator, bool isImplicit,
AccessSemantics semantics,
const SelectedOverload &selected) {
// Build the new subscript.
auto newSubscript = buildSubscriptHelper(base, index, argLabels,
selected, hasTrailingClosure,
locator, isImplicit, semantics);
if (selected.choice.getKind() == OverloadChoiceKind::DeclViaDynamic) {
// Rewrite for implicit unwrapping if the solution requires it.
auto *dynamicLocator = cs.getConstraintLocator(
locator, {ConstraintLocator::SubscriptMember,
ConstraintLocator::DynamicLookupResult});
if (solution.getDisjunctionChoice(dynamicLocator)) {
auto *forceValue = new (cs.getASTContext())
ForceValueExpr(newSubscript, newSubscript->getEndLoc());
auto optTy = cs.getType(forceValue->getSubExpr());
cs.setType(forceValue, optTy->getOptionalObjectType());
newSubscript = forceValue;
}
}
if (selected.choice.isDecl()) {
auto locatorKind = ConstraintLocator::SubscriptMember;
if (selected.choice.getKind() ==
OverloadChoiceKind::DynamicMemberLookup)
locatorKind = ConstraintLocator::Member;
if (selected.choice.getKind() ==
OverloadChoiceKind::KeyPathDynamicMemberLookup &&
!isExpr<SubscriptExpr>(locator.getAnchor()))
locatorKind = ConstraintLocator::Member;
newSubscript =
forceUnwrapIfExpected(newSubscript, selected.choice,
locator.withPathElement(locatorKind));
}
return newSubscript;
}
Expr *buildSubscriptHelper(Expr *base, Expr *index,
ArrayRef<Identifier> argLabels,
const SelectedOverload &selected,
bool hasTrailingClosure,
ConstraintLocatorBuilder locator,
bool isImplicit, AccessSemantics semantics) {
auto choice = selected.choice;
auto &ctx = cs.getASTContext();
// Apply a key path if we have one.
if (choice.getKind() == OverloadChoiceKind::KeyPathApplication) {
auto applicationTy =
simplifyType(selected.openedType)->castTo<FunctionType>();
index = cs.coerceToRValue(index);
// The index argument should be (keyPath: KeyPath<Root, Value>).
// Dig the key path expression out of the arguments.
auto indexKP = cast<TupleExpr>(index)->getElement(0);
auto keyPathExprTy = cs.getType(indexKP);
auto keyPathTy = applicationTy->getParams().front().getOldType();
Type valueTy;
Type baseTy;
bool resultIsLValue;
if (auto nom = keyPathTy->getAs<NominalType>()) {
// AnyKeyPath is <T> rvalue T -> rvalue Any?
if (nom->getDecl() == cs.getASTContext().getAnyKeyPathDecl()) {
valueTy = ProtocolCompositionType::get(cs.getASTContext(), {},
/*explicit anyobject*/ false);
valueTy = OptionalType::get(valueTy);
resultIsLValue = false;
base = cs.coerceToRValue(base);
baseTy = cs.getType(base);
// We don't really want to attempt AnyKeyPath application
// if we know a more specific key path type is being applied.
if (!keyPathTy->isEqual(keyPathExprTy)) {
ctx.Diags
.diagnose(base->getLoc(),
diag::expr_smart_keypath_application_type_mismatch,
keyPathExprTy, baseTy)
.highlight(index->getSourceRange());
}
} else {
llvm_unreachable("unknown key path class!");
}
} else {
auto keyPathBGT = keyPathTy->castTo<BoundGenericType>();
baseTy = keyPathBGT->getGenericArgs()[0];
// Coerce the index to the key path's type
indexKP = coerceToType(indexKP, keyPathTy, locator);
// Coerce the base to the key path's expected base type.
if (!baseTy->isEqual(cs.getType(base)->getRValueType()))
base = coerceToType(base, baseTy, locator);
if (keyPathBGT->getDecl()
== cs.getASTContext().getPartialKeyPathDecl()) {
// PartialKeyPath<T> is rvalue T -> rvalue Any
valueTy = ProtocolCompositionType::get(cs.getASTContext(), {},
/*explicit anyobject*/ false);
resultIsLValue = false;
base = cs.coerceToRValue(base);
} else {
// *KeyPath<T, U> is T -> U, with rvalueness based on mutability
// of base and keypath
valueTy = keyPathBGT->getGenericArgs()[1];
// The result may be an lvalue based on the base and key path kind.
if (keyPathBGT->getDecl() == cs.getASTContext().getKeyPathDecl()) {
resultIsLValue = false;
base = cs.coerceToRValue(base);
} else if (keyPathBGT->getDecl() ==
cs.getASTContext().getWritableKeyPathDecl()) {
resultIsLValue = cs.getType(base)->hasLValueType();
} else if (keyPathBGT->getDecl() ==
cs.getASTContext().getReferenceWritableKeyPathDecl()) {
resultIsLValue = true;
base = cs.coerceToRValue(base);
} else {
llvm_unreachable("unknown key path class!");
}
}
}
if (resultIsLValue)
valueTy = LValueType::get(valueTy);
auto keyPathAp = new (cs.getASTContext())
KeyPathApplicationExpr(base, index->getStartLoc(), indexKP,
index->getEndLoc(), valueTy,
base->isImplicit() && index->isImplicit());
cs.setType(keyPathAp, valueTy);
return keyPathAp;
}
auto subscript = cast<SubscriptDecl>(choice.getDecl());
auto baseTy = cs.getType(base)->getRValueType();
bool baseIsInstance = true;
if (auto baseMeta = baseTy->getAs<AnyMetatypeType>()) {
baseIsInstance = false;
baseTy = baseMeta->getInstanceType();
}
// Check whether the base is 'super'.
bool isSuper = base->isSuperExpr();
// Use the correct locator kind based on the subscript kind.
auto locatorKind = ConstraintLocator::SubscriptMember;
if (choice.getKind() == OverloadChoiceKind::DynamicMemberLookup)
locatorKind = ConstraintLocator::Member;
if (choice.getKind() == OverloadChoiceKind::KeyPathDynamicMemberLookup) {
locatorKind = isExpr<SubscriptExpr>(locator.getAnchor())
? ConstraintLocator::SubscriptMember
: ConstraintLocator::Member;
}
// If we opened up an existential when performing the subscript, open
// the base accordingly.
auto memberLoc = locator.withPathElement(locatorKind);
auto knownOpened = solution.OpenedExistentialTypes.find(
cs.getConstraintLocator(memberLoc));
if (knownOpened != solution.OpenedExistentialTypes.end()) {
base = openExistentialReference(base, knownOpened->second, subscript);
baseTy = knownOpened->second;
}
// Compute the concrete reference to the subscript.
auto subscriptRef = resolveConcreteDeclRef(subscript, memberLoc);
// Coerce the index argument.
auto openedFullFnType = simplifyType(selected.openedFullType)
->castTo<FunctionType>();
auto fullSubscriptTy = openedFullFnType->getResult()
->castTo<FunctionType>();
index = coerceCallArguments(index, fullSubscriptTy, subscriptRef, nullptr,
argLabels,
locator.withPathElement(
ConstraintLocator::ApplyArgument));
if (!index)
return nullptr;
auto getType = [&](Expr *E) -> Type { return cs.getType(E); };
// Handle dynamic lookup.
if (choice.getKind() == OverloadChoiceKind::DeclViaDynamic ||
subscript->getAttrs().hasAttribute<OptionalAttr>()) {
base = coerceSelfArgumentToType(base, baseTy, subscript, locator);
if (!base)
return nullptr;
// TODO: diagnose if semantics != AccessSemantics::Ordinary?
auto subscriptExpr = DynamicSubscriptExpr::create(
ctx, base, index, subscriptRef, isImplicit, getType);
auto resultTy = simplifyType(selected.openedType)
->castTo<FunctionType>()
->getResult();
assert(!selected.openedFullType->hasOpenedExistential()
&& "open existential archetype in AnyObject subscript type?");
cs.setType(subscriptExpr, resultTy);
Expr *result = subscriptExpr;
closeExistential(result, locator);
return result;
}
// Convert the base.
auto openedBaseType =
getBaseType(openedFullFnType, /*wantsRValue*/ false);
auto containerTy = solution.simplifyType(openedBaseType);
if (baseIsInstance) {
base = coerceSelfArgumentToType(
base, containerTy, subscript,
locator.withPathElement(ConstraintLocator::MemberRefBase));
} else {
base = coerceToType(base,
MetatypeType::get(containerTy),
locator.withPathElement(
ConstraintLocator::MemberRefBase));
if (!base)
return nullptr;
base = cs.coerceToRValue(base);
}
if (!base)
return nullptr;
// Form the subscript expression.
auto subscriptExpr = SubscriptExpr::create(
ctx, base, index, subscriptRef, isImplicit, semantics, getType);
cs.setType(subscriptExpr, fullSubscriptTy->getResult());
subscriptExpr->setIsSuper(isSuper);
Expr *result = subscriptExpr;
closeExistential(result, locator);
if (subscript->getElementInterfaceType()->hasDynamicSelfType()) {
auto dynamicSelfFnType =
openedFullFnType->replaceCovariantResultType(baseTy, 2);
result =
new (ctx) CovariantReturnConversionExpr(result, dynamicSelfFnType);
cs.cacheType(result);
cs.setType(result, simplifyType(baseTy));
}
return result;
}
/// Build a new reference to another constructor.
Expr *buildOtherConstructorRef(Type openedFullType,
ConcreteDeclRef ref, Expr *base,
DeclNameLoc loc,
ConstraintLocatorBuilder locator,
bool implicit) {
auto &ctx = cs.getASTContext();
// The constructor was opened with the allocating type, not the
// initializer type. Map the former into the latter.
auto resultTy = solution.simplifyType(openedFullType);
auto selfTy = getBaseType(resultTy->castTo<FunctionType>());
// Also replace the result type with the base type, so that calls
// to constructors defined in a superclass will know to cast the
// result to the derived type.
resultTy = resultTy->replaceCovariantResultType(selfTy, 2);
ParameterTypeFlags flags;
if (!selfTy->hasReferenceSemantics())
flags = flags.withInOut(true);
auto selfParam = AnyFunctionType::Param(selfTy, Identifier(), flags);
resultTy = FunctionType::get({selfParam},
resultTy->castTo<FunctionType>()->getResult(),
resultTy->castTo<FunctionType>()->getExtInfo());
// Build the constructor reference.
Expr *ctorRef = cs.cacheType(
new (ctx) OtherConstructorDeclRefExpr(ref, loc, implicit, resultTy));
// Wrap in covariant `Self` return if needed.
if (selfTy->hasReferenceSemantics()) {
auto covariantTy = resultTy->replaceCovariantResultType(
cs.getType(base)->getWithoutSpecifierType(), 2);
if (!covariantTy->isEqual(resultTy))
ctorRef = cs.cacheType(
new (ctx) CovariantFunctionConversionExpr(ctorRef, covariantTy));
}
return ctorRef;
}
/// Build an implicit argument for keypath based dynamic lookup,
/// which consists of KeyPath expression and a single component.
///
/// \param keyPathTy The type of the keypath argument.
/// \param dotLoc The location of the '.' preceding member name.
/// \param memberLoc The locator to be associated with new argument.
Expr *buildKeyPathDynamicMemberIndexExpr(BoundGenericType *keyPathTy,
SourceLoc dotLoc,
ConstraintLocator *memberLoc) {
auto &ctx = cs.getASTContext();
auto *anchor = getAsExpr(memberLoc->getAnchor());
SmallVector<KeyPathExpr::Component, 2> components;
// Let's create a KeyPath expression and fill in "parsed path"
// after component is built.
auto *keyPath = new (ctx) KeyPathExpr(/*backslashLoc=*/dotLoc,
/*parsedRoot=*/nullptr,
/*parsedPath=*/anchor,
/*hasLeadingDot=*/false,
/*isImplicit=*/true);
// Type of the keypath expression we are forming is known
// in advance, so let's set it right away.
keyPath->setType(keyPathTy);
cs.cacheType(keyPath);
auto *componentLoc = cs.getConstraintLocator(
memberLoc,
LocatorPathElt::KeyPathDynamicMember(keyPathTy->getAnyNominal()));
auto overload = solution.getOverloadChoice(componentLoc);
// Looks like there is a chain of implicit `subscript(dynamicMember:)`
// calls necessary to resolve a member reference.
switch (overload.choice.getKind()) {
case OverloadChoiceKind::DynamicMemberLookup:
case OverloadChoiceKind::KeyPathDynamicMemberLookup: {
buildKeyPathSubscriptComponent(overload, dotLoc, /*indexExpr=*/nullptr,
ctx.Id_dynamicMember, componentLoc,
components);
keyPath->resolveComponents(ctx, components);
cs.cacheExprTypes(keyPath);
return keyPath;
}
default:
break;
}
// We can't reuse existing expression because type-check
// based diagnostics could hold the reference to original AST.
Expr *componentExpr = nullptr;
auto *dotExpr = new (ctx) KeyPathDotExpr(dotLoc);
// Determines whether this index is built to be used for
// one of the existing keypath components e.g. `\Lens<[Int]>.count`
// instead of a regular expression e.g. `lens[0]`.
bool forKeyPathComponent = false;
// Looks like keypath dynamic member lookup was used inside
// of a keypath expression e.g. `\Lens<[Int]>.count` where
// `count` is referenced using dynamic lookup.
if (auto *KPE = dyn_cast<KeyPathExpr>(anchor)) {
auto kpElt = memberLoc->findFirst<LocatorPathElt::KeyPathComponent>();
assert(kpElt && "no keypath component node");
auto &origComponent = KPE->getComponents()[kpElt->getIndex()];
using ComponentKind = KeyPathExpr::Component::Kind;
if (origComponent.getKind() == ComponentKind::UnresolvedProperty) {
anchor = new (ctx) UnresolvedDotExpr(
dotExpr, dotLoc, origComponent.getUnresolvedDeclName(),
DeclNameLoc(origComponent.getLoc()),
/*Implicit=*/true);
} else if (origComponent.getKind() ==
ComponentKind::UnresolvedSubscript) {
anchor = SubscriptExpr::create(
ctx, dotExpr, origComponent.getIndexExpr(), ConcreteDeclRef(),
/*implicit=*/true, AccessSemantics::Ordinary,
[&](Expr *expr) { return simplifyType(cs.getType(expr)); });
} else {
return nullptr;
}
anchor->setType(simplifyType(overload.openedType));
cs.cacheType(anchor);
forKeyPathComponent = true;
}
if (auto *UDE = dyn_cast<UnresolvedDotExpr>(anchor)) {
componentExpr =
forKeyPathComponent
? UDE
: new (ctx) UnresolvedDotExpr(dotExpr, dotLoc, UDE->getName(),
UDE->getNameLoc(),
/*Implicit=*/true);
buildKeyPathPropertyComponent(overload, UDE->getLoc(), componentLoc,
components);
} else if (auto *SE = dyn_cast<SubscriptExpr>(anchor)) {
componentExpr = SE;
// If this is not for a keypath component, we have to copy
// original subscript expression because expression based
// diagnostics might have a reference to it, so it couldn't
// be modified.
if (!forKeyPathComponent) {
SmallVector<Expr *, 4> arguments;
if (auto *TE = dyn_cast<TupleExpr>(SE->getIndex())) {
auto args = TE->getElements();
arguments.append(args.begin(), args.end());
} else {
arguments.push_back(SE->getIndex()->getSemanticsProvidingExpr());
}
SmallVector<TrailingClosure, 2> trailingClosures;
if (SE->hasTrailingClosure()) {
auto *closure = arguments.back();
trailingClosures.push_back({closure});
}
componentExpr = SubscriptExpr::create(
ctx, dotExpr, SE->getStartLoc(), arguments,
SE->getArgumentLabels(), SE->getArgumentLabelLocs(),
SE->getEndLoc(), trailingClosures,
SE->hasDecl() ? SE->getDecl() : ConcreteDeclRef(),
/*implicit=*/true, SE->getAccessSemantics());
}
buildKeyPathSubscriptComponent(overload, SE->getLoc(), SE->getIndex(),
SE->getArgumentLabels(), componentLoc,
components);
} else {
return nullptr;
}
assert(componentExpr);
Type ty = simplifyType(cs.getType(anchor));
componentExpr->setType(ty);
cs.cacheType(componentExpr);
keyPath->setParsedPath(componentExpr);
keyPath->resolveComponents(ctx, components);
cs.cacheExprTypes(keyPath);
// See whether there's an equivalent ObjC key path string we can produce
// for interop purposes.
checkAndSetObjCKeyPathString(keyPath);
return keyPath;
}
/// Bridge the given value (which is an error type) to NSError.
Expr *bridgeErrorToObjectiveC(Expr *value) {
auto &ctx = cs.getASTContext();
auto nsErrorType = ctx.getNSErrorType();
assert(nsErrorType && "Missing NSError?");
auto result = new (ctx) BridgeToObjCExpr(value, nsErrorType);
return cs.cacheType(result);
}
/// Bridge the given value to its corresponding Objective-C object
/// type.
///
/// This routine should only be used for bridging value types.
///
/// \param value The value to be bridged.
Expr *bridgeToObjectiveC(Expr *value, Type objcType) {
auto result = new (cs.getASTContext()) BridgeToObjCExpr(value, objcType);
return cs.cacheType(result);
}
/// Bridge the given object from Objective-C to its value type.
///
/// This routine should only be used for bridging value types.
///
/// \param object The object, whose type should already be of the type
/// that the value type bridges through.
///
/// \param valueType The value type to which we are bridging.
///
/// \param conditional Whether the bridging should be conditional. If false,
/// uses forced bridging.
///
/// \returns a value of type \c valueType (optional if \c conditional) that
/// stores the bridged result or (when \c conditional) an empty optional if
/// conditional bridging fails.
Expr *bridgeFromObjectiveC(Expr *object, Type valueType, bool conditional) {
auto &ctx = cs.getASTContext();
if (!conditional) {
auto result = new (ctx) BridgeFromObjCExpr(object, valueType);
return cs.cacheType(result);
}
// Find the _BridgedToObjectiveC protocol.
auto bridgedProto =
ctx.getProtocol(KnownProtocolKind::ObjectiveCBridgeable);
// Try to find the conformance of the value type to _BridgedToObjectiveC.
auto bridgedToObjectiveCConformance
= TypeChecker::conformsToProtocol(valueType,
bridgedProto,
cs.DC);
FuncDecl *fn = nullptr;
if (bridgedToObjectiveCConformance) {
assert(bridgedToObjectiveCConformance.getConditionalRequirements()
.empty() &&
"cannot conditionally conform to _BridgedToObjectiveC");
// The conformance to _BridgedToObjectiveC is statically known.
// Retrieve the bridging operation to be used if a static conformance
// to _BridgedToObjectiveC can be proven.
fn = conditional ? ctx.getConditionallyBridgeFromObjectiveCBridgeable()
: ctx.getForceBridgeFromObjectiveCBridgeable();
} else {
// Retrieve the bridging operation to be used if a static conformance
// to _BridgedToObjectiveC cannot be proven.
fn = conditional ? ctx.getConditionallyBridgeFromObjectiveC()
: ctx.getForceBridgeFromObjectiveC();
}
if (!fn) {
ctx.Diags.diagnose(object->getLoc(), diag::missing_bridging_function,
conditional);
return nullptr;
}
// Form a reference to the function. The bridging operations are generic,
// so we need to form substitutions and compute the resulting type.
auto genericSig = fn->getGenericSignature();
auto subMap = SubstitutionMap::get(
genericSig,
[&](SubstitutableType *type) -> Type {
assert(type->isEqual(genericSig->getGenericParams()[0]));
return valueType;
},
[&](CanType origType, Type replacementType,
ProtocolDecl *protoType) -> ProtocolConformanceRef {
assert(bridgedToObjectiveCConformance);
return bridgedToObjectiveCConformance;
});
ConcreteDeclRef fnSpecRef(fn, subMap);
auto resultType = OptionalType::get(valueType);
auto result = new (ctx)
ConditionalBridgeFromObjCExpr(object, resultType, fnSpecRef);
return cs.cacheType(result);
}
/// Bridge the given object from Objective-C to its value type.
///
/// This routine should only be used for bridging value types.
///
/// \param object The object, whose type should already be of the type
/// that the value type bridges through.
///
/// \param valueType The value type to which we are bridging.
///
/// \returns a value of type \c valueType that stores the bridged result.
Expr *forceBridgeFromObjectiveC(Expr *object, Type valueType) {
return bridgeFromObjectiveC(object, valueType, false);
}
public:
ExprRewriter(ConstraintSystem &cs, Solution &solution,
Optional<SolutionApplicationTarget> target,
bool suppressDiagnostics)
: cs(cs), dc(cs.DC), solution(solution), target(target),
SuppressDiagnostics(suppressDiagnostics) {}
ConstraintSystem &getConstraintSystem() const { return cs; }
/// Simplify the expression type and return the expression.
///
/// This routine is used for 'simple' expressions that only need their
/// types simplified, with no further computation.
Expr *simplifyExprType(Expr *expr) {
auto toType = simplifyType(cs.getType(expr));
cs.setType(expr, toType);
return expr;
}
Expr *visitErrorExpr(ErrorExpr *expr) {
// Do nothing with error expressions.
return expr;
}
Expr *visitCodeCompletionExpr(CodeCompletionExpr *expr) {
// Do nothing with code completion expressions.
auto toType = simplifyType(cs.getType(expr));
cs.setType(expr, toType);
return expr;
}
Expr *handleIntegerLiteralExpr(LiteralExpr *expr) {
// If the literal has been assigned a builtin integer type,
// don't mess with it.
if (cs.getType(expr)->is<AnyBuiltinIntegerType>())
return expr;
auto &ctx = cs.getASTContext();
ProtocolDecl *protocol = TypeChecker::getProtocol(
cs.getASTContext(), expr->getLoc(),
KnownProtocolKind::ExpressibleByIntegerLiteral);
ProtocolDecl *builtinProtocol = TypeChecker::getProtocol(
cs.getASTContext(), expr->getLoc(),
KnownProtocolKind::ExpressibleByBuiltinIntegerLiteral);
// For type-sugar reasons, prefer the spelling of the default literal
// type.
auto type = simplifyType(cs.getType(expr));
if (auto defaultType = TypeChecker::getDefaultType(protocol, dc)) {
if (defaultType->isEqual(type))
type = defaultType;
}
if (auto floatProtocol = TypeChecker::getProtocol(
cs.getASTContext(), expr->getLoc(),
KnownProtocolKind::ExpressibleByFloatLiteral)) {
if (auto defaultFloatType =
TypeChecker::getDefaultType(floatProtocol, dc)) {
if (defaultFloatType->isEqual(type))
type = defaultFloatType;
}
}
DeclName initName(ctx, DeclBaseName::createConstructor(),
{ctx.Id_integerLiteral});
DeclName builtinInitName(ctx, DeclBaseName::createConstructor(),
{ctx.Id_builtinIntegerLiteral});
auto *result = convertLiteralInPlace(
expr, type, protocol, ctx.Id_IntegerLiteralType, initName,
builtinProtocol, builtinInitName, diag::integer_literal_broken_proto,
diag::builtin_integer_literal_broken_proto);
if (result) {
// TODO: It seems that callers expect this to have types assigned...
result->setType(cs.getType(result));
}
return result;
}
Expr *visitNilLiteralExpr(NilLiteralExpr *expr) {
auto type = simplifyType(cs.getType(expr));
// By far the most common 'nil' literal is for Optional<T>.none.
// We don't have to look up the witness in this case since SILGen
// knows how to lower it directly.
if (auto objectType = type->getOptionalObjectType()) {
cs.setType(expr, type);
return expr;
}
auto &ctx = cs.getASTContext();
auto *protocol = TypeChecker::getProtocol(
ctx, expr->getLoc(), KnownProtocolKind::ExpressibleByNilLiteral);
// For type-sugar reasons, prefer the spelling of the default literal
// type.
if (auto defaultType = TypeChecker::getDefaultType(protocol, dc)) {
if (defaultType->isEqual(type))
type = defaultType;
}
DeclName initName(ctx, DeclBaseName::createConstructor(),
{ctx.Id_nilLiteral});
return convertLiteralInPlace(expr, type, protocol,
Identifier(), initName,
nullptr,
Identifier(),
diag::nil_literal_broken_proto,
diag::nil_literal_broken_proto);
}
Expr *visitIntegerLiteralExpr(IntegerLiteralExpr *expr) {
return handleIntegerLiteralExpr(expr);
}
Expr *visitFloatLiteralExpr(FloatLiteralExpr *expr) {
// If the literal has been assigned a builtin float type,
// don't mess with it.
if (cs.getType(expr)->is<BuiltinFloatType>())
return expr;
auto &ctx = cs.getASTContext();
ProtocolDecl *protocol = TypeChecker::getProtocol(
cs.getASTContext(), expr->getLoc(),
KnownProtocolKind::ExpressibleByFloatLiteral);
ProtocolDecl *builtinProtocol = TypeChecker::getProtocol(
cs.getASTContext(), expr->getLoc(),
KnownProtocolKind::ExpressibleByBuiltinFloatLiteral);
// For type-sugar reasons, prefer the spelling of the default literal
// type.
auto type = simplifyType(cs.getType(expr));
if (auto defaultType = TypeChecker::getDefaultType(protocol, dc)) {
if (defaultType->isEqual(type))
type = defaultType;
}
// Get the _MaxBuiltinFloatType decl, or look for it if it's not cached.
auto maxFloatTypeDecl = ctx.get_MaxBuiltinFloatTypeDecl();
// Presence of this declaration has been validated in CSGen.
assert(maxFloatTypeDecl);
auto maxType = maxFloatTypeDecl->getUnderlyingType();
DeclName initName(ctx, DeclBaseName::createConstructor(),
{ctx.Id_floatLiteral});
DeclName builtinInitName(ctx, DeclBaseName::createConstructor(),
{ctx.Id_builtinFloatLiteral});
expr->setBuiltinType(maxType);
return convertLiteralInPlace(
expr, type, protocol, ctx.Id_FloatLiteralType, initName,
builtinProtocol, builtinInitName, diag::float_literal_broken_proto,
diag::builtin_float_literal_broken_proto);
}
Expr *visitBooleanLiteralExpr(BooleanLiteralExpr *expr) {
if (cs.getType(expr) && cs.getType(expr)->is<BuiltinIntegerType>())
return expr;
auto &ctx = cs.getASTContext();
ProtocolDecl *protocol = TypeChecker::getProtocol(
cs.getASTContext(), expr->getLoc(),
KnownProtocolKind::ExpressibleByBooleanLiteral);
ProtocolDecl *builtinProtocol = TypeChecker::getProtocol(
cs.getASTContext(), expr->getLoc(),
KnownProtocolKind::ExpressibleByBuiltinBooleanLiteral);
if (!protocol || !builtinProtocol)
return nullptr;
auto type = simplifyType(cs.getType(expr));
DeclName initName(ctx, DeclBaseName::createConstructor(),
{ctx.Id_booleanLiteral});
DeclName builtinInitName(ctx, DeclBaseName::createConstructor(),
{ctx.Id_builtinBooleanLiteral});
return convertLiteralInPlace(
expr, type, protocol, ctx.Id_BooleanLiteralType, initName,
builtinProtocol, builtinInitName, diag::boolean_literal_broken_proto,
diag::builtin_boolean_literal_broken_proto);
}
Expr *handleStringLiteralExpr(LiteralExpr *expr) {
auto stringLiteral = dyn_cast<StringLiteralExpr>(expr);
auto magicLiteral = dyn_cast<MagicIdentifierLiteralExpr>(expr);
assert(bool(stringLiteral) != bool(magicLiteral) &&
"literal must be either a string literal or a magic literal");
auto type = simplifyType(cs.getType(expr));
auto &ctx = cs.getASTContext();
bool isStringLiteral = true;
bool isGraphemeClusterLiteral = false;
ProtocolDecl *protocol = TypeChecker::getProtocol(
ctx, expr->getLoc(), KnownProtocolKind::ExpressibleByStringLiteral);
if (!TypeChecker::conformsToProtocol(type, protocol, cs.DC)) {
// If the type does not conform to ExpressibleByStringLiteral, it should
// be ExpressibleByExtendedGraphemeClusterLiteral.
protocol = TypeChecker::getProtocol(
cs.getASTContext(), expr->getLoc(),
KnownProtocolKind::ExpressibleByExtendedGraphemeClusterLiteral);
isStringLiteral = false;
isGraphemeClusterLiteral = true;
}
if (!TypeChecker::conformsToProtocol(type, protocol, cs.DC)) {
// ... or it should be ExpressibleByUnicodeScalarLiteral.
protocol = TypeChecker::getProtocol(
cs.getASTContext(), expr->getLoc(),
KnownProtocolKind::ExpressibleByUnicodeScalarLiteral);
isStringLiteral = false;
isGraphemeClusterLiteral = false;
}
// For type-sugar reasons, prefer the spelling of the default literal
// type.
if (auto defaultType = TypeChecker::getDefaultType(protocol, dc)) {
if (defaultType->isEqual(type))
type = defaultType;
}
ProtocolDecl *builtinProtocol;
Identifier literalType;
DeclName literalFuncName;
DeclName builtinLiteralFuncName;
Diag<> brokenProtocolDiag;
Diag<> brokenBuiltinProtocolDiag;
if (isStringLiteral) {
literalType = ctx.Id_StringLiteralType;
literalFuncName = DeclName(ctx, DeclBaseName::createConstructor(),
{ctx.Id_stringLiteral});
builtinProtocol = TypeChecker::getProtocol(
cs.getASTContext(), expr->getLoc(),
KnownProtocolKind::ExpressibleByBuiltinStringLiteral);
builtinLiteralFuncName =
DeclName(ctx, DeclBaseName::createConstructor(),
{ctx.Id_builtinStringLiteral,
ctx.getIdentifier("utf8CodeUnitCount"),
ctx.getIdentifier("isASCII")});
if (stringLiteral)
stringLiteral->setEncoding(StringLiteralExpr::UTF8);
else
magicLiteral->setStringEncoding(StringLiteralExpr::UTF8);
brokenProtocolDiag = diag::string_literal_broken_proto;
brokenBuiltinProtocolDiag = diag::builtin_string_literal_broken_proto;
} else if (isGraphemeClusterLiteral) {
literalType = ctx.Id_ExtendedGraphemeClusterLiteralType;
literalFuncName = DeclName(ctx, DeclBaseName::createConstructor(),
{ctx.Id_extendedGraphemeClusterLiteral});
builtinLiteralFuncName =
DeclName(ctx, DeclBaseName::createConstructor(),
{ctx.Id_builtinExtendedGraphemeClusterLiteral,
ctx.getIdentifier("utf8CodeUnitCount"),
ctx.getIdentifier("isASCII")});
builtinProtocol = TypeChecker::getProtocol(
cs.getASTContext(), expr->getLoc(),
KnownProtocolKind::
ExpressibleByBuiltinExtendedGraphemeClusterLiteral);
brokenProtocolDiag =
diag::extended_grapheme_cluster_literal_broken_proto;
brokenBuiltinProtocolDiag =
diag::builtin_extended_grapheme_cluster_literal_broken_proto;
} else {
// Otherwise, we should have just one Unicode scalar.
literalType = ctx.Id_UnicodeScalarLiteralType;
literalFuncName = DeclName(ctx, DeclBaseName::createConstructor(),
{ctx.Id_unicodeScalarLiteral});
builtinLiteralFuncName =
DeclName(ctx, DeclBaseName::createConstructor(),
{ctx.Id_builtinUnicodeScalarLiteral});
builtinProtocol = TypeChecker::getProtocol(
cs.getASTContext(), expr->getLoc(),
KnownProtocolKind::ExpressibleByBuiltinUnicodeScalarLiteral);
brokenProtocolDiag = diag::unicode_scalar_literal_broken_proto;
brokenBuiltinProtocolDiag =
diag::builtin_unicode_scalar_literal_broken_proto;
stringLiteral->setEncoding(StringLiteralExpr::OneUnicodeScalar);
}
return convertLiteralInPlace(expr,
type,
protocol,
literalType,
literalFuncName,
builtinProtocol,
builtinLiteralFuncName,
brokenProtocolDiag,
brokenBuiltinProtocolDiag);
}
Expr *visitStringLiteralExpr(StringLiteralExpr *expr) {
return handleStringLiteralExpr(expr);
}
Expr *
visitInterpolatedStringLiteralExpr(InterpolatedStringLiteralExpr *expr) {
// Figure out the string type we're converting to.
auto openedType = cs.getType(expr);
auto type = simplifyType(openedType);
cs.setType(expr, type);
auto &ctx = cs.getASTContext();
auto loc = expr->getStartLoc();
auto fetchProtocolInitWitness =
[&](KnownProtocolKind protocolKind, Type type,
ArrayRef<Identifier> argLabels) -> ConcreteDeclRef {
auto proto = TypeChecker::getProtocol(ctx, loc, protocolKind);
assert(proto && "Missing string interpolation protocol?");
auto conformance =
TypeChecker::conformsToProtocol(type, proto, cs.DC);
assert(conformance && "string interpolation type conforms to protocol");
DeclName constrName(ctx, DeclBaseName::createConstructor(), argLabels);
ConcreteDeclRef witness =
conformance.getWitnessByName(type->getRValueType(), constrName);
if (!witness || !isa<AbstractFunctionDecl>(witness.getDecl()))
return nullptr;
return witness;
};
auto *interpolationProto = TypeChecker::getProtocol(
cs.getASTContext(), expr->getLoc(),
KnownProtocolKind::ExpressibleByStringInterpolation);
auto associatedTypeDecl =
interpolationProto->getAssociatedType(ctx.Id_StringInterpolation);
if (associatedTypeDecl == nullptr) {
ctx.Diags.diagnose(expr->getStartLoc(),
diag::interpolation_broken_proto);
return nullptr;
}
auto interpolationType =
simplifyType(DependentMemberType::get(openedType, associatedTypeDecl));
// Fetch needed witnesses.
ConcreteDeclRef builderInit = fetchProtocolInitWitness(
KnownProtocolKind::StringInterpolationProtocol, interpolationType,
{ctx.Id_literalCapacity, ctx.Id_interpolationCount});
if (!builderInit) return nullptr;
expr->setBuilderInit(builderInit);
ConcreteDeclRef resultInit = fetchProtocolInitWitness(
KnownProtocolKind::ExpressibleByStringInterpolation, type,
{ctx.Id_stringInterpolation});
if (!resultInit) return nullptr;
expr->setInitializer(resultInit);
// Make the integer literals for the parameters.
auto buildExprFromUnsigned = [&](unsigned value) {
LiteralExpr *expr = IntegerLiteralExpr::createFromUnsigned(ctx, value);
cs.setType(expr, ctx.getIntDecl()->getDeclaredInterfaceType());
return handleIntegerLiteralExpr(expr);
};
expr->setLiteralCapacityExpr(
buildExprFromUnsigned(expr->getLiteralCapacity()));
expr->setInterpolationCountExpr(
buildExprFromUnsigned(expr->getInterpolationCount()));
// This OpaqueValueExpr represents the result of builderInit above in
// silgen.
OpaqueValueExpr *interpolationExpr =
new (ctx) OpaqueValueExpr(expr->getSourceRange(), interpolationType);
cs.setType(interpolationExpr, interpolationType);
expr->setInterpolationExpr(interpolationExpr);
auto appendingExpr = expr->getAppendingExpr();
appendingExpr->setSubExpr(interpolationExpr);
return expr;
}
Expr *visitMagicIdentifierLiteralExpr(MagicIdentifierLiteralExpr *expr) {
switch (expr->getKind()) {
#define MAGIC_STRING_IDENTIFIER(NAME, STRING, SYNTAX_KIND) \
case MagicIdentifierLiteralExpr::NAME: \
return handleStringLiteralExpr(expr);
#define MAGIC_INT_IDENTIFIER(NAME, STRING, SYNTAX_KIND) \
case MagicIdentifierLiteralExpr::NAME: \
return handleIntegerLiteralExpr(expr);
#define MAGIC_POINTER_IDENTIFIER(NAME, STRING, SYNTAX_KIND) \
case MagicIdentifierLiteralExpr::NAME: \
return expr;
#include "swift/AST/MagicIdentifierKinds.def"
}
llvm_unreachable("Unhandled MagicIdentifierLiteralExpr in switch.");
}
Expr *visitObjectLiteralExpr(ObjectLiteralExpr *expr) {
if (cs.getType(expr) && !cs.getType(expr)->hasTypeVariable())
return expr;
// Figure out the type we're converting to.
auto openedType = cs.getType(expr);
auto type = simplifyType(openedType);
cs.setType(expr, type);
assert(!type->is<UnresolvedType>());
auto &ctx = cs.getASTContext();
Type conformingType = type;
if (auto baseType = conformingType->getOptionalObjectType()) {
// The type may be optional due to a failable initializer in the
// protocol.
conformingType = baseType;
}
// Find the appropriate object literal protocol.
auto proto = TypeChecker::getLiteralProtocol(ctx, expr);
assert(proto && "Missing object literal protocol?");
auto conformance =
TypeChecker::conformsToProtocol(conformingType, proto, cs.DC);
assert(conformance && "object literal type conforms to protocol");
auto constrName = TypeChecker::getObjectLiteralConstructorName(ctx, expr);
ConcreteDeclRef witness = conformance.getWitnessByName(
conformingType->getRValueType(), constrName);
auto selectedOverload = solution.getOverloadChoice(
cs.getConstraintLocator(expr, ConstraintLocator::ConstructorMember));
auto fnType =
simplifyType(selectedOverload.openedType)->castTo<FunctionType>();
auto newArg = coerceCallArguments(
expr->getArg(), fnType, witness,
/*applyExpr=*/nullptr, expr->getArgumentLabels(),
cs.getConstraintLocator(expr, ConstraintLocator::ApplyArgument));
expr->setInitializer(witness);
expr->setArg(newArg);
return expr;
}
// Add a forced unwrap of an expression which either has type Optional<T>
// or is a function that returns an Optional<T>. The latter turns into a
// conversion expression that we will hoist above the ApplyExpr
// that needs to be forced during the process of rewriting the expression.
//
// forForcedOptional is used to indicate that we will further need
// to hoist this result above an explicit force of an optional that is
// in place for something like an @optional protocol member from
// Objective C that we might otherwise mistake for the thing we mean to
// force here.
Expr *forceUnwrapResult(Expr *expr, bool forForcedOptional =false) {
auto ty = simplifyType(cs.getType(expr));
if (forForcedOptional)
ty = ty->getOptionalObjectType();
if (auto *fnTy = ty->getAs<AnyFunctionType>()) {
auto underlyingType = cs.replaceFinalResultTypeWithUnderlying(fnTy);
auto &ctx = cs.getASTContext();
return cs.cacheType(new (ctx) ImplicitlyUnwrappedFunctionConversionExpr(
expr, underlyingType));
} else {
return coerceImplicitlyUnwrappedOptionalToValue(
expr, ty->getWithoutSpecifierType()->getOptionalObjectType());
}
}
bool shouldForceUnwrapResult(OverloadChoice choice,
ConstraintLocatorBuilder locator) {
if (!choice.isImplicitlyUnwrappedValueOrReturnValue())
return false;
auto *choiceLocator = cs.getConstraintLocator(locator.withPathElement(
ConstraintLocator::ImplicitlyUnwrappedDisjunctionChoice));
return solution.getDisjunctionChoice(choiceLocator);
}
Expr *forceUnwrapIfExpected(Expr *expr, OverloadChoice choice,
ConstraintLocatorBuilder locator,
bool forForcedOptional = false) {
if (!shouldForceUnwrapResult(choice, locator))
return expr;
// Force the expression if required for the solution.
return forceUnwrapResult(expr, forForcedOptional);
}
Expr *visitDeclRefExpr(DeclRefExpr *expr) {
auto locator = cs.getConstraintLocator(expr);
// Find the overload choice used for this declaration reference.
auto selected = solution.getOverloadChoice(locator);
return buildDeclRef(selected, expr->getNameLoc(), locator,
expr->isImplicit());
}
Expr *visitSuperRefExpr(SuperRefExpr *expr) {
simplifyExprType(expr);
return expr;
}
Expr *visitTypeExpr(TypeExpr *expr) {
auto toType = simplifyType(cs.getType(expr));
assert(toType->is<MetatypeType>());
cs.setType(expr, toType);
return expr;
}
Expr *visitOtherConstructorDeclRefExpr(OtherConstructorDeclRefExpr *expr) {
cs.setType(expr, expr->getDecl()->getInitializerInterfaceType());
return expr;
}
Expr *visitDotSyntaxBaseIgnoredExpr(DotSyntaxBaseIgnoredExpr *expr) {
return simplifyExprType(expr);
}
Expr *visitOverloadedDeclRefExpr(OverloadedDeclRefExpr *expr) {
// Determine the declaration selected for this overloaded reference.
auto locator = cs.getConstraintLocator(expr);
auto selected = solution.getOverloadChoice(locator);
return buildDeclRef(selected, expr->getNameLoc(), locator,
expr->isImplicit());
}
Expr *visitUnresolvedDeclRefExpr(UnresolvedDeclRefExpr *expr) {
// FIXME: We should have generated an overload set from this, in which
// case we can emit a typo-correction error here but recover well.
return nullptr;
}
Expr *visitUnresolvedSpecializeExpr(UnresolvedSpecializeExpr *expr) {
// Our specializations should have resolved the subexpr to the right type.
return expr->getSubExpr();
}
Expr *visitMemberRefExpr(MemberRefExpr *expr) {
auto memberLocator = cs.getConstraintLocator(expr,
ConstraintLocator::Member);
auto selected = solution.getOverloadChoice(memberLocator);
return buildMemberRef(
expr->getBase(), expr->getDotLoc(), selected, expr->getNameLoc(),
cs.getConstraintLocator(expr), memberLocator, expr->isImplicit(),
expr->getAccessSemantics());
}
Expr *visitDynamicMemberRefExpr(DynamicMemberRefExpr *expr) {
llvm_unreachable("already type-checked?");
}
Expr *visitUnresolvedMemberExpr(UnresolvedMemberExpr *expr) {
// If constraint solving resolved this to an UnresolvedType, then we're in
// an ambiguity tolerant mode used for diagnostic generation. Just leave
// this as an unresolved member reference.
Type resultTy = simplifyType(cs.getType(expr));
if (resultTy->hasUnresolvedType()) {
cs.setType(expr, resultTy);
return expr;
}
auto &ctx = cs.getASTContext();
// Find the selected member and base type.
auto memberLocator = cs.getConstraintLocator(
expr, ConstraintLocator::UnresolvedMember);
auto selected = solution.getOverloadChoice(memberLocator);
// Unresolved member lookup always happens in a metatype so dig out the
// instance type.
auto baseTy = selected.choice.getBaseType()->getMetatypeInstanceType();
baseTy = simplifyType(baseTy);
// The base expression is simply the metatype of the base type.
// FIXME: This location info is bogus.
auto base = TypeExpr::createImplicitHack(expr->getDotLoc(), baseTy, ctx);
cs.cacheExprTypes(base);
// Build the member reference.
auto *exprLoc = cs.getConstraintLocator(expr);
auto result = buildMemberRef(
base, expr->getDotLoc(), selected, expr->getNameLoc(), exprLoc,
memberLocator, expr->isImplicit(), AccessSemantics::Ordinary);
if (!result)
return nullptr;
return coerceToType(result, resultTy, cs.getConstraintLocator(expr));
}
private:
/// A list of "suspicious" optional injections that come from
/// forced downcasts.
SmallVector<InjectIntoOptionalExpr *, 4> SuspiciousOptionalInjections;
/// Create a member reference to the given constructor.
Expr *applyCtorRefExpr(Expr *expr, Expr *base, SourceLoc dotLoc,
DeclNameLoc nameLoc, bool implicit,
ConstraintLocator *ctorLocator,
SelectedOverload overload) {
auto choice = overload.choice;
assert(choice.getKind() != OverloadChoiceKind::DeclViaDynamic);
auto *ctor = cast<ConstructorDecl>(choice.getDecl());
// If the subexpression is a metatype, build a direct reference to the
// constructor.
if (cs.getType(base)->is<AnyMetatypeType>()) {
return buildMemberRef(
base, dotLoc, overload, nameLoc, cs.getConstraintLocator(expr),
ctorLocator, implicit, AccessSemantics::Ordinary);
}
// The subexpression must be either 'self' or 'super'.
if (!base->isSuperExpr()) {
// 'super' references have already been fully checked; handle the
// 'self' case below.
auto &de = cs.getASTContext().Diags;
bool diagnoseBadInitRef = true;
auto arg = base->getSemanticsProvidingExpr();
if (auto dre = dyn_cast<DeclRefExpr>(arg)) {
if (dre->getDecl()->getName() == cs.getASTContext().Id_self) {
// We have a reference to 'self'.
diagnoseBadInitRef = false;
// Make sure the reference to 'self' occurs within an initializer.
if (!dyn_cast_or_null<ConstructorDecl>(
cs.DC->getInnermostMethodContext())) {
if (!SuppressDiagnostics)
de.diagnose(dotLoc, diag::init_delegation_outside_initializer);
return nullptr;
}
}
}
// If we need to diagnose this as a bad reference to an initializer,
// do so now.
if (diagnoseBadInitRef) {
// Determine whether 'super' would have made sense as a base.
bool hasSuper = false;
if (auto func = cs.DC->getInnermostMethodContext()) {
if (auto classDecl = func->getDeclContext()->getSelfClassDecl()) {
hasSuper = classDecl->hasSuperclass();
}
}
if (SuppressDiagnostics)
return nullptr;
de.diagnose(dotLoc, diag::bad_init_ref_base, hasSuper);
}
}
// Build a partial application of the delegated initializer.
auto callee = resolveConcreteDeclRef(ctor, ctorLocator);
Expr *ctorRef = buildOtherConstructorRef(overload.openedFullType, callee,
base, nameLoc, ctorLocator,
implicit);
auto *call = new (cs.getASTContext()) DotSyntaxCallExpr(ctorRef, dotLoc,
base);
return finishApply(call, cs.getType(expr), cs.getConstraintLocator(expr),
ctorLocator);
}
/// Give the deprecation warning for referring to a global function
/// when there's a method from a conditional conformance in a smaller/closer
/// scope.
void
diagnoseDeprecatedConditionalConformanceOuterAccess(UnresolvedDotExpr *UDE,
ValueDecl *choice) {
auto getBaseName = [](DeclContext *context) -> DeclName {
if (auto generic = context->getSelfNominalTypeDecl()) {
return generic->getName();
} else if (context->isModuleScopeContext())
return context->getParentModule()->getName();
else
llvm_unreachable("Unsupported base");
};
auto result =
TypeChecker::lookupUnqualified(cs.DC, UDE->getName(), UDE->getLoc());
assert(result && "names can't just disappear");
// These should all come from the same place.
auto exampleInner = result.front();
auto innerChoice = exampleInner.getValueDecl();
auto innerDC = exampleInner.getDeclContext()->getInnermostTypeContext();
auto innerParentDecl = innerDC->getSelfNominalTypeDecl();
auto innerBaseName = getBaseName(innerDC);
auto choiceKind = choice->getDescriptiveKind();
auto choiceDC = choice->getDeclContext();
auto choiceBaseName = getBaseName(choiceDC);
auto choiceParentDecl = choiceDC->getAsDecl();
auto choiceParentKind = choiceParentDecl
? choiceParentDecl->getDescriptiveKind()
: DescriptiveDeclKind::Module;
auto &DE = cs.getASTContext().Diags;
DE.diagnose(UDE->getLoc(),
diag::warn_deprecated_conditional_conformance_outer_access,
UDE->getName(), choiceKind, choiceParentKind, choiceBaseName,
innerChoice->getDescriptiveKind(),
innerParentDecl->getDescriptiveKind(), innerBaseName);
auto name = choiceBaseName.getBaseIdentifier();
SmallString<32> namePlusDot = name.str();
namePlusDot.push_back('.');
DE.diagnose(UDE->getLoc(),
diag::fix_deprecated_conditional_conformance_outer_access,
namePlusDot, choiceKind, name)
.fixItInsert(UDE->getStartLoc(), namePlusDot);
}
Expr *applyMemberRefExpr(Expr *expr, Expr *base, SourceLoc dotLoc,
DeclNameLoc nameLoc, bool implicit) {
// If we have a constructor member, handle it as a constructor.
auto ctorLocator = cs.getConstraintLocator(
expr,
ConstraintLocator::ConstructorMember);
if (auto selected = solution.getOverloadChoiceIfAvailable(ctorLocator)) {
return applyCtorRefExpr(
expr, base, dotLoc, nameLoc, implicit, ctorLocator, *selected);
}
// Determine the declaration selected for this overloaded reference.
auto memberLocator = cs.getConstraintLocator(expr,
ConstraintLocator::Member);
auto selected = solution.getOverloadChoice(memberLocator);
if (!selected.choice.getBaseType()) {
// This is one of the "outer alternatives", meaning the innermost
// methods didn't work out.
//
// The only way to get here is via an UnresolvedDotExpr with outer
// alternatives.
auto UDE = cast<UnresolvedDotExpr>(expr);
diagnoseDeprecatedConditionalConformanceOuterAccess(
UDE, selected.choice.getDecl());
return buildDeclRef(selected, nameLoc, memberLocator, implicit);
}
switch (selected.choice.getKind()) {
case OverloadChoiceKind::DeclViaBridge: {
base = cs.coerceToRValue(base);
// Look through an implicitly unwrapped optional.
auto baseTy = cs.getType(base);
auto &ctx = cs.getASTContext();
auto baseMetaTy = baseTy->getAs<MetatypeType>();
auto baseInstTy = (baseMetaTy ? baseMetaTy->getInstanceType() : baseTy);
auto classTy = ctx.getBridgedToObjC(cs.DC, baseInstTy);
if (baseMetaTy) {
// FIXME: We're dropping side effects in the base here!
base = TypeExpr::createImplicitHack(base->getLoc(), classTy, ctx);
cs.cacheExprTypes(base);
} else {
// Bridge the base to its corresponding Objective-C object.
base = bridgeToObjectiveC(base, classTy);
}
// Fall through to build the member reference.
LLVM_FALLTHROUGH;
}
case OverloadChoiceKind::Decl:
case OverloadChoiceKind::DeclViaUnwrappedOptional:
case OverloadChoiceKind::DeclViaDynamic:
return buildMemberRef(base, dotLoc, selected, nameLoc,
cs.getConstraintLocator(expr), memberLocator,
implicit, AccessSemantics::Ordinary);
case OverloadChoiceKind::TupleIndex: {
Type toType = simplifyType(cs.getType(expr));
auto baseTy = cs.getType(base);
// If the base type is not a tuple l-value, access to
// its elements supposed to be r-value as well.
//
// This is modeled in constraint system in a way
// that when member type is resolved by `resolveOverload`
// it would take r-value type of the element at
// specified index, but if it's a type variable it
// could still be bound to l-value later.
if (!baseTy->is<LValueType>())
toType = toType->getRValueType();
// If the result type is an rvalue and the base contains lvalues,
// need a full tuple coercion to properly load & set access kind
// on all underlying elements before taking a single element.
if (!toType->hasLValueType() && baseTy->hasLValueType())
base = coerceToType(base, baseTy->getRValueType(),
cs.getConstraintLocator(base));
return cs.cacheType(new (cs.getASTContext())
TupleElementExpr(base, dotLoc,
selected.choice.getTupleIndex(),
nameLoc.getBaseNameLoc(), toType));
}
case OverloadChoiceKind::KeyPathApplication:
llvm_unreachable("should only happen in a subscript");
case OverloadChoiceKind::DynamicMemberLookup:
case OverloadChoiceKind::KeyPathDynamicMemberLookup: {
return buildDynamicMemberLookupRef(
expr, base, dotLoc, nameLoc.getStartLoc(), selected, memberLocator);
}
}
llvm_unreachable("Unhandled OverloadChoiceKind in switch.");
}
/// Form a type checked expression for the index of a @dynamicMemberLookup
/// subscript index parameter.
Expr *buildDynamicMemberLookupIndexExpr(StringRef name, SourceLoc loc,
Type literalTy) {
// Build and type check the string literal index value to the specific
// string type expected by the subscript.
auto &ctx = cs.getASTContext();
auto *nameExpr = new (ctx) StringLiteralExpr(name, loc, /*implicit*/true);
cs.setType(nameExpr, literalTy);
return handleStringLiteralExpr(nameExpr);
}
Expr *buildDynamicMemberLookupRef(Expr *expr, Expr *base, SourceLoc dotLoc,
SourceLoc nameLoc,
const SelectedOverload &overload,
ConstraintLocator *memberLocator) {
// Application of a DynamicMemberLookup result turns
// a member access of `x.foo` into x[dynamicMember: "foo"], or
// x[dynamicMember: KeyPath<T, U>]
auto &ctx = cs.getASTContext();
// Figure out the expected type of the lookup parameter. We know the
// openedFullType will be "xType -> indexType -> resultType". Dig out
// its index type.
auto paramTy = getTypeOfDynamicMemberIndex(overload);
Expr *argExpr = nullptr;
if (overload.choice.getKind() ==
OverloadChoiceKind::DynamicMemberLookup) {
// Build and type check the string literal index value to the specific
// string type expected by the subscript.
auto fieldName = overload.choice.getName().getBaseIdentifier().str();
argExpr = buildDynamicMemberLookupIndexExpr(fieldName, nameLoc,
paramTy);
} else {
argExpr = buildKeyPathDynamicMemberIndexExpr(
paramTy->castTo<BoundGenericType>(), dotLoc, memberLocator);
}
if (!argExpr)
return nullptr;
// Build a tuple so that the argument has a label.
auto tupleTy =
TupleType::get(TupleTypeElt(paramTy, ctx.Id_dynamicMember), ctx);
Expr *index =
TupleExpr::createImplicit(ctx, argExpr, ctx.Id_dynamicMember);
index->setType(tupleTy);
cs.cacheType(index);
// Build and return a subscript that uses this string as the index.
return buildSubscript(
base, index, ctx.Id_dynamicMember,
/*trailingClosure*/ false, cs.getConstraintLocator(expr),
/*isImplicit*/ true, AccessSemantics::Ordinary, overload);
}
Type getTypeOfDynamicMemberIndex(const SelectedOverload &overload) {
assert(overload.choice.getKind() ==
OverloadChoiceKind::DynamicMemberLookup ||
overload.choice.getKind() ==
OverloadChoiceKind::KeyPathDynamicMemberLookup);
auto declTy = solution.simplifyType(overload.openedFullType);
auto subscriptTy = declTy->castTo<FunctionType>()->getResult();
auto refFnType = subscriptTy->castTo<FunctionType>();
assert(refFnType->getParams().size() == 1 &&
"subscript always has one arg");
return refFnType->getParams()[0].getPlainType();
}
public:
Expr *visitUnresolvedDotExpr(UnresolvedDotExpr *expr) {
return applyMemberRefExpr(expr, expr->getBase(), expr->getDotLoc(),
expr->getNameLoc(), expr->isImplicit());
}
Expr *visitSequenceExpr(SequenceExpr *expr) {
llvm_unreachable("Expression wasn't parsed?");
}
Expr *visitArrowExpr(ArrowExpr *expr) {
llvm_unreachable("Arrow expr wasn't converted to type?");
}
Expr *visitIdentityExpr(IdentityExpr *expr) {
cs.setType(expr, cs.getType(expr->getSubExpr()));
return expr;
}
Expr *visitAnyTryExpr(AnyTryExpr *expr) {
cs.setType(expr, cs.getType(expr->getSubExpr()));
return expr;
}
Expr *visitOptionalTryExpr(OptionalTryExpr *expr) {
// Prior to Swift 5, 'try?' simply wraps the type of its sub-expression
// in an Optional, regardless of the sub-expression type.
//
// In Swift 5+, the type of a 'try?' expression of static type T is:
// - Equal to T if T is optional
// - Equal to T? if T is not optional
//
// The result is that in Swift 5, 'try?' avoids producing nested optionals.
if (!cs.getASTContext().LangOpts.isSwiftVersionAtLeast(5)) {
// Nothing to do for Swift 4 and earlier!
return simplifyExprType(expr);
}
Type exprType = simplifyType(cs.getType(expr));
auto subExpr = coerceToType(expr->getSubExpr(), exprType,
cs.getConstraintLocator(expr));
if (!subExpr) return nullptr;
expr->setSubExpr(subExpr);
cs.setType(expr, exprType);
return expr;
}
Expr *visitParenExpr(ParenExpr *expr) {
return simplifyExprType(expr);
}
Expr *visitUnresolvedMemberChainResultExpr(
UnresolvedMemberChainResultExpr *expr) {
// Since this expression only exists to give the result type of an
// unresolved member chain visibility in the AST, remove it from the AST
// now that we have a solution and coerce the subexpr to the resulting
// type.
auto *subExpr = expr->getSubExpr();
auto type = simplifyType(cs.getType(expr));
subExpr = coerceToType(subExpr, type, cs.getConstraintLocator(subExpr));
cs.setType(subExpr, type);
return subExpr;
}
Expr *visitTupleExpr(TupleExpr *expr) {
return simplifyExprType(expr);
}
Expr *visitSubscriptExpr(SubscriptExpr *expr) {
auto *memberLocator =
cs.getConstraintLocator(expr, ConstraintLocator::SubscriptMember);
auto overload = solution.getOverloadChoice(memberLocator);
if (overload.choice.getKind() ==
OverloadChoiceKind::KeyPathDynamicMemberLookup) {
return buildDynamicMemberLookupRef(
expr, expr->getBase(), expr->getIndex()->getStartLoc(), SourceLoc(),
overload, memberLocator);
}
return buildSubscript(
expr->getBase(), expr->getIndex(), expr->getArgumentLabels(),
expr->hasTrailingClosure(), cs.getConstraintLocator(expr),
expr->isImplicit(), expr->getAccessSemantics(), overload);
}
/// "Finish" an array expression by filling in the semantic expression.
ArrayExpr *finishArrayExpr(ArrayExpr *expr) {
Type arrayTy = cs.getType(expr);
auto &ctx = cs.getASTContext();
ProtocolDecl *arrayProto = TypeChecker::getProtocol(
ctx, expr->getLoc(), KnownProtocolKind::ExpressibleByArrayLiteral);
assert(arrayProto && "type-checked array literal w/o protocol?!");
auto conformance =
TypeChecker::conformsToProtocol(arrayTy, arrayProto, cs.DC);
assert(conformance && "Type does not conform to protocol?");
DeclName name(ctx, DeclBaseName::createConstructor(),
{ctx.Id_arrayLiteral});
ConcreteDeclRef witness =
conformance.getWitnessByName(arrayTy->getRValueType(), name);
if (!witness || !isa<AbstractFunctionDecl>(witness.getDecl()))
return nullptr;
expr->setInitializer(witness);
auto elementType = expr->getElementType();
for (auto &element : expr->getElements()) {
element = coerceToType(element, elementType,
cs.getConstraintLocator(element));
}
return expr;
}
Expr *visitArrayExpr(ArrayExpr *expr) {
Type openedType = cs.getType(expr);
Type arrayTy = simplifyType(openedType);
cs.setType(expr, arrayTy);
if (!finishArrayExpr(expr)) return nullptr;
// If the array element type was defaulted, note that in the expression.
if (solution.DefaultedConstraints.count(cs.getConstraintLocator(expr)))
expr->setIsTypeDefaulted();
return expr;
}
/// "Finish" a dictionary expression by filling in the semantic expression.
DictionaryExpr *finishDictionaryExpr(DictionaryExpr *expr) {
Type dictionaryTy = cs.getType(expr);
auto &ctx = cs.getASTContext();
ProtocolDecl *dictionaryProto = TypeChecker::getProtocol(
cs.getASTContext(), expr->getLoc(),
KnownProtocolKind::ExpressibleByDictionaryLiteral);
auto conformance =
TypeChecker::conformsToProtocol(dictionaryTy, dictionaryProto, cs.DC);
if (conformance.isInvalid())
return nullptr;
DeclName name(ctx, DeclBaseName::createConstructor(),
{ctx.Id_dictionaryLiteral});
ConcreteDeclRef witness =
conformance.getWitnessByName(dictionaryTy->getRValueType(), name);
if (!witness || !isa<AbstractFunctionDecl>(witness.getDecl()))
return nullptr;
expr->setInitializer(witness);
auto elementType = expr->getElementType();
for (auto &element : expr->getElements()) {
element = coerceToType(element, elementType,
cs.getConstraintLocator(element));
}
return expr;
}
Expr *visitDictionaryExpr(DictionaryExpr *expr) {
Type openedType = cs.getType(expr);
Type dictionaryTy = simplifyType(openedType);
cs.setType(expr, dictionaryTy);
if (!finishDictionaryExpr(expr)) return nullptr;
// If the dictionary key or value type was defaulted, note that in the
// expression.
if (solution.DefaultedConstraints.count(cs.getConstraintLocator(expr)))
expr->setIsTypeDefaulted();
return expr;
}
Expr *visitDynamicSubscriptExpr(DynamicSubscriptExpr *expr) {
auto *memberLocator =
cs.getConstraintLocator(expr, ConstraintLocator::SubscriptMember);
return buildSubscript(expr->getBase(), expr->getIndex(),
expr->getArgumentLabels(),
expr->hasTrailingClosure(),
cs.getConstraintLocator(expr),
expr->isImplicit(), AccessSemantics::Ordinary,
solution.getOverloadChoice(memberLocator));
}
Expr *visitTupleElementExpr(TupleElementExpr *expr) {
simplifyExprType(expr);
return expr;
}
Expr *visitCaptureListExpr(CaptureListExpr *expr) {
// The type of the capture list is the type of the closure contained
// inside it.
cs.setType(expr, cs.getType(expr->getClosureBody()));
return expr;
}
Expr *visitClosureExpr(ClosureExpr *expr) {
llvm_unreachable("Handled by the walker directly");
}
Expr *visitAutoClosureExpr(AutoClosureExpr *expr) {
llvm_unreachable("Already type-checked");
}
Expr *visitInOutExpr(InOutExpr *expr) {
auto objectTy = cs.getType(expr->getSubExpr())->getRValueType();
// The type is simply inout of whatever the lvalue's object type was.
cs.setType(expr, InOutType::get(objectTy));
return expr;
}
Expr *visitVarargExpansionExpr(VarargExpansionExpr *expr) {
simplifyExprType(expr);
auto arrayTy = cs.getType(expr);
expr->setSubExpr(coerceToType(expr->getSubExpr(), arrayTy,
cs.getConstraintLocator(expr)));
return expr;
}
Expr *visitDynamicTypeExpr(DynamicTypeExpr *expr) {
Expr *base = expr->getBase();
base = cs.coerceToRValue(base);
expr->setBase(base);
return simplifyExprType(expr);
}
Expr *visitOpaqueValueExpr(OpaqueValueExpr *expr) {
assert(expr->isPlaceholder() && "Already type-checked");
return expr;
}
Expr *visitPropertyWrapperValuePlaceholderExpr(
PropertyWrapperValuePlaceholderExpr *expr) {
return expr;
}
Expr *visitDefaultArgumentExpr(DefaultArgumentExpr *expr) {
llvm_unreachable("Already type-checked");
}
Expr *visitApplyExpr(ApplyExpr *expr) {
auto *calleeLoc = CalleeLocators[expr];
assert(calleeLoc);
return finishApply(expr, cs.getType(expr), cs.getConstraintLocator(expr),
calleeLoc);
}
Expr *visitRebindSelfInConstructorExpr(RebindSelfInConstructorExpr *expr) {
// A non-failable initializer cannot delegate to a failable
// initializer.
Expr *unwrappedSubExpr = expr->getSubExpr()->getSemanticsProvidingExpr();
Type valueTy = cs.getType(unwrappedSubExpr)->getOptionalObjectType();
auto inCtor = cast<ConstructorDecl>(cs.DC->getInnermostMethodContext());
if (valueTy && !inCtor->isFailable()) {
bool isChaining;
auto *otherCtorRef = expr->getCalledConstructor(isChaining);
ConstructorDecl *ctor = otherCtorRef->getDecl();
assert(ctor);
// If the initializer we're calling is not declared as
// checked, it's an error.
bool isError = !ctor->isImplicitlyUnwrappedOptional();
// If we're suppressing diagnostics, just fail.
if (isError && SuppressDiagnostics)
return nullptr;
auto &ctx = cs.getASTContext();
auto &de = cs.getASTContext().Diags;
if (isError) {
if (auto *optTry = dyn_cast<OptionalTryExpr>(unwrappedSubExpr)) {
de.diagnose(optTry->getTryLoc(),
diag::delegate_chain_nonoptional_to_optional_try,
isChaining);
de.diagnose(optTry->getTryLoc(), diag::init_delegate_force_try)
.fixItReplace({optTry->getTryLoc(), optTry->getQuestionLoc()},
"try!");
de.diagnose(inCtor->getLoc(), diag::init_propagate_failure)
.fixItInsertAfter(inCtor->getLoc(), "?");
} else {
// Give the user the option of adding '!' or making the enclosing
// initializer failable.
de.diagnose(otherCtorRef->getLoc(),
diag::delegate_chain_nonoptional_to_optional,
isChaining, ctor->getName());
de.diagnose(otherCtorRef->getLoc(), diag::init_force_unwrap)
.fixItInsertAfter(expr->getEndLoc(), "!");
de.diagnose(inCtor->getLoc(), diag::init_propagate_failure)
.fixItInsertAfter(inCtor->getLoc(), "?");
}
}
// Recover by injecting the force operation (the first option).
Expr *newSub = new (ctx) ForceValueExpr(expr->getSubExpr(),
expr->getEndLoc());
cs.setType(newSub, valueTy);
newSub->setImplicit();
expr->setSubExpr(newSub);
}
return expr;
}
Expr *visitIfExpr(IfExpr *expr) {
auto resultTy = simplifyType(cs.getType(expr));
cs.setType(expr, resultTy);
auto cond = cs.coerceToRValue(expr->getCondExpr());
expr->setCondExpr(cond);
// Coerce the then/else branches to the common type.
expr->setThenExpr(coerceToType(expr->getThenExpr(), resultTy,
cs.getConstraintLocator(expr->getThenExpr())));
expr->setElseExpr(coerceToType(expr->getElseExpr(), resultTy,
cs.getConstraintLocator(expr->getElseExpr())));
return expr;
}
Expr *visitImplicitConversionExpr(ImplicitConversionExpr *expr) {
llvm_unreachable("Already type-checked");
}
Expr *visitIsExpr(IsExpr *expr) {
// Turn the subexpression into an rvalue.
auto &ctx = cs.getASTContext();
auto sub = cs.coerceToRValue(expr->getSubExpr());
expr->setSubExpr(sub);
// Simplify and update the type we checked against.
auto *const castTypeRepr = expr->getCastTypeRepr();
const auto fromType = cs.getType(sub);
const auto toType = simplifyType(cs.getType(castTypeRepr));
expr->setCastType(toType);
cs.setType(castTypeRepr, toType);
auto castContextKind =
SuppressDiagnostics ? CheckedCastContextKind::None
: CheckedCastContextKind::IsExpr;
auto castKind = TypeChecker::typeCheckCheckedCast(
fromType, toType, castContextKind, cs.DC, expr->getLoc(), sub,
castTypeRepr->getSourceRange());
switch (castKind) {
case CheckedCastKind::Unresolved:
expr->setCastKind(CheckedCastKind::ValueCast);
break;
case CheckedCastKind::Coercion:
case CheckedCastKind::BridgingCoercion:
expr->setCastKind(castKind);
break;
case CheckedCastKind::ValueCast:
// Check the cast target is a non-foreign type
if (auto cls = toType->getAs<ClassType>()) {
if (cls->getDecl()->getForeignClassKind() ==
ClassDecl::ForeignKind::CFType) {
ctx.Diags.diagnose(expr->getLoc(), diag::isa_is_foreign_check,
toType);
}
}
expr->setCastKind(castKind);
break;
case CheckedCastKind::ArrayDowncast:
case CheckedCastKind::DictionaryDowncast:
case CheckedCastKind::SetDowncast:
// Valid checks.
expr->setCastKind(castKind);
break;
}
// SIL-generation magically turns this into a Bool; make sure it can.
if (!ctx.getBoolBuiltinInitDecl()) {
ctx.Diags.diagnose(expr->getLoc(), diag::broken_bool);
// Continue anyway.
}
// Dig through the optionals in the from/to types.
SmallVector<Type, 2> fromOptionals;
fromType->lookThroughAllOptionalTypes(fromOptionals);
SmallVector<Type, 2> toOptionals;
toType->lookThroughAllOptionalTypes(toOptionals);
// If we have an imbalance of optionals or a collection
// downcast, handle this as a checked cast followed by a
// a 'hasValue' check.
if (fromOptionals.size() != toOptionals.size() ||
castKind == CheckedCastKind::ArrayDowncast ||
castKind == CheckedCastKind::DictionaryDowncast ||
castKind == CheckedCastKind::SetDowncast) {
auto *const cast =
ConditionalCheckedCastExpr::createImplicit(ctx, sub, toType);
cast->setType(OptionalType::get(toType));
cast->setCastType(toType);
cs.setType(cast, cast->getType());
// Type-check this conditional case.
Expr *result = handleConditionalCheckedCastExpr(cast, castTypeRepr);
if (!result)
return nullptr;
// Extract a Bool from the resulting expression.
TypeChecker::requireOptionalIntrinsics(ctx, expr->getLoc());
// Match the optional value against its `Some` case.
auto *someDecl = ctx.getOptionalSomeDecl();
auto isSomeExpr =
new (ctx) EnumIsCaseExpr(result, castTypeRepr, someDecl);
auto boolDecl = ctx.getBoolDecl();
if (!boolDecl) {
ctx.Diags.diagnose(SourceLoc(), diag::broken_bool);
}
cs.setType(isSomeExpr,
boolDecl
? boolDecl->getDeclaredInterfaceType()
: Type());
return isSomeExpr;
}
return expr;
}
/// The kind of cast we're working with for handling optional bindings.
enum class OptionalBindingsCastKind {
/// An explicit bridging conversion, spelled "as".
Bridged,
/// A forced cast, spelled "as!".
Forced,
/// A conditional cast, spelled "as?".
Conditional,
};
/// Handle optional operands and results in an explicit cast.
Expr *handleOptionalBindingsForCast(ExplicitCastExpr *cast,
Type finalResultType,
OptionalBindingsCastKind castKind) {
return handleOptionalBindings(cast->getSubExpr(), finalResultType,
castKind,
[&](Expr *sub, Type resultType) -> Expr* {
// Complain about conditional casts to CF class types; they can't
// actually be conditionally checked.
if (castKind == OptionalBindingsCastKind::Conditional) {
Type destValueType = resultType->getOptionalObjectType();
auto destObjectType = destValueType;
if (auto metaTy = destObjectType->getAs<MetatypeType>())
destObjectType = metaTy->getInstanceType();
if (auto destClass = destObjectType->getClassOrBoundGenericClass()) {
if (destClass->getForeignClassKind() ==
ClassDecl::ForeignKind::CFType) {
if (SuppressDiagnostics)
return nullptr;
auto &de = cs.getASTContext().Diags;
de.diagnose(cast->getLoc(), diag::conditional_downcast_foreign,
destValueType);
ConcreteDeclRef refDecl = sub->getReferencedDecl();
if (refDecl) {
de.diagnose(cast->getLoc(),
diag::note_explicitly_compare_cftypeid,
refDecl.getDecl()->getBaseName(), destValueType);
}
}
}
}
// Set the expression as the sub-expression of the cast, then
// use the cast as the inner operation.
cast->setSubExpr(sub);
cs.setType(cast, resultType);
return cast;
});
}
/// A helper function to build an operation. The inner result type
/// is the expected type of the operation; it will be a non-optional
/// type unless the castKind is Conditional.
using OperationBuilderRef =
llvm::function_ref<Expr*(Expr *subExpr, Type innerResultType)>;
/// Handle optional operands and results in an explicit cast.
Expr *handleOptionalBindings(Expr *subExpr, Type finalResultType,
OptionalBindingsCastKind castKind,
OperationBuilderRef buildInnerOperation) {
auto &ctx = cs.getASTContext();
unsigned destExtraOptionals;
bool forceExtraSourceOptionals;
switch (castKind) {
case OptionalBindingsCastKind::Bridged:
destExtraOptionals = 0;
forceExtraSourceOptionals = true;
break;
case OptionalBindingsCastKind::Forced:
destExtraOptionals = 0;
forceExtraSourceOptionals = true;
break;
case OptionalBindingsCastKind::Conditional:
destExtraOptionals = 1;
forceExtraSourceOptionals = false;
break;
}
// FIXME: some of this work needs to be delayed until runtime to
// properly account for archetypes dynamically being optional
// types. For example, if we're casting T to NSView?, that
// should succeed if T=NSObject? and its value is actually nil.
Type srcType = cs.getType(subExpr);
SmallVector<Type, 4> srcOptionals;
srcType = srcType->lookThroughAllOptionalTypes(srcOptionals);
SmallVector<Type, 4> destOptionals;
auto destValueType
= finalResultType->lookThroughAllOptionalTypes(destOptionals);
auto isBridgeToAnyObject =
castKind == OptionalBindingsCastKind::Bridged &&
destValueType->isAnyObject();
// If the destination value type is 'AnyObject' when performing a
// bridging operation, or if the destination value type could dynamically
// be an optional type, leave any extra optionals on the source in place.
// Only apply the latter condition in Swift 5 mode to best preserve
// compatibility with Swift 4.1's casting behaviour.
if (isBridgeToAnyObject || (ctx.isSwiftVersionAtLeast(5) &&
destValueType->canDynamicallyBeOptionalType(
/*includeExistential*/ false))) {
auto destOptionalsCount = destOptionals.size() - destExtraOptionals;
if (srcOptionals.size() > destOptionalsCount) {
srcType = srcOptionals[destOptionalsCount];
srcOptionals.erase(srcOptionals.begin() + destOptionalsCount,
srcOptionals.end());
}
}
// When performing a bridging operation, if the destination type
// is more optional than the source, we'll add extra optional injections
// at the end.
SmallVector<Type, 4> destOptionalInjections;
if (castKind == OptionalBindingsCastKind::Bridged &&
destOptionals.size() > srcOptionals.size()) {
// Remove the extra optionals from destOptionals, but keep them around
// separately so we can perform the injections on the final result of
// the cast.
auto cutPoint = destOptionals.end() - srcOptionals.size();
destOptionalInjections.append(destOptionals.begin(), cutPoint);
destOptionals.erase(destOptionals.begin(), cutPoint);
finalResultType = destOptionals.empty() ? destValueType
: destOptionals.front();
}
// Local function to add the optional injections to final result.
auto addFinalOptionalInjections = [&](Expr *result) {
for (auto destType : llvm::reverse(destOptionalInjections)) {
result =
cs.cacheType(new (ctx) InjectIntoOptionalExpr(result, destType));
}
return result;
};
// There's nothing special to do if the operand isn't optional
// (or is insufficiently optional) and we don't need any bridging.
if (srcOptionals.empty()
|| (srcOptionals.size() < destOptionals.size() - destExtraOptionals)) {
Expr *result = buildInnerOperation(subExpr, finalResultType);
if (!result) return nullptr;
return addFinalOptionalInjections(result);
}
// The outermost N levels of optionals on the operand must all
// be present or the cast fails. The innermost M levels of
// optionals on the operand are reflected in the requested
// destination type, so we should map these nils into the result.
unsigned numRequiredOptionals =
srcOptionals.size() - (destOptionals.size() - destExtraOptionals);
// The number of OptionalEvaluationExprs between the point of the
// inner cast and the enclosing OptionalEvaluationExpr (exclusive)
// which represents failure for the entire operation.
unsigned failureDepth = destOptionals.size() - destExtraOptionals;
// Drill down on the operand until it's non-optional.
SourceLoc fakeQuestionLoc = subExpr->getEndLoc();
for (unsigned i : indices(srcOptionals)) {
Type valueType =
(i + 1 == srcOptionals.size() ? srcType : srcOptionals[i+1]);
// As we move into the range of mapped optionals, start
// lowering the depth.
unsigned depth = failureDepth;
if (i >= numRequiredOptionals) {
depth -= (i - numRequiredOptionals) + 1;
} else if (forceExtraSourceOptionals) {
// For a forced cast, force the required optionals.
subExpr = new (ctx) ForceValueExpr(subExpr, fakeQuestionLoc);
cs.setType(subExpr, valueType);
subExpr->setImplicit(true);
continue;
}
subExpr = cs.cacheType(new (ctx) BindOptionalExpr(
subExpr, fakeQuestionLoc, depth, valueType));
subExpr->setImplicit(true);
}
// If this is a conditional cast, the result type will always
// have at least one level of optional, which should become the
// type of the checked-cast expression.
Expr *result;
if (castKind == OptionalBindingsCastKind::Conditional) {
assert(!destOptionals.empty() &&
"result of checked cast is not an optional type");
result = buildInnerOperation(subExpr, destOptionals.back());
} else {
result = buildInnerOperation(subExpr, destValueType);
}
if (!result) return nullptr;
// If we're casting to an optional type, we need to capture the
// final M bindings.
if (destOptionals.size() > destExtraOptionals) {
if (castKind == OptionalBindingsCastKind::Conditional) {
// If the innermost cast fails, the entire expression fails. To
// get this behavior, we have to bind and then re-inject the result.
// (SILGen should know how to peephole this.)
result = cs.cacheType(new (ctx) BindOptionalExpr(
result, result->getEndLoc(), failureDepth, destValueType));
result->setImplicit(true);
}
for (unsigned i = destOptionals.size(); i != 0; --i) {
Type destType = destOptionals[i-1];
result =
cs.cacheType(new (ctx) InjectIntoOptionalExpr(result, destType));
result =
cs.cacheType(new (ctx) OptionalEvaluationExpr(result, destType));
}
// Otherwise, we just need to capture the failure-depth binding.
} else if (!forceExtraSourceOptionals) {
result = cs.cacheType(
new (ctx) OptionalEvaluationExpr(result, finalResultType));
}
return addFinalOptionalInjections(result);
}
bool hasForcedOptionalResult(ExplicitCastExpr *expr) {
const auto *const TR = expr->getCastTypeRepr();
if (TR && TR->getKind() == TypeReprKind::ImplicitlyUnwrappedOptional) {
auto *locator = cs.getConstraintLocator(
expr, ConstraintLocator::ImplicitlyUnwrappedDisjunctionChoice);
return solution.getDisjunctionChoice(locator);
}
return false;
}
Expr *visitCoerceExpr(CoerceExpr *expr) {
// If we need to insert a force-unwrap for coercions of the form
// 'as T!', do so now.
if (hasForcedOptionalResult(expr)) {
auto *coerced = visitCoerceExpr(expr, None);
if (!coerced)
return nullptr;
return coerceImplicitlyUnwrappedOptionalToValue(
coerced, cs.getType(coerced)->getOptionalObjectType());
}
return visitCoerceExpr(expr, None);
}
Expr *visitCoerceExpr(CoerceExpr *expr, Optional<unsigned> choice) {
// Simplify and update the type we're coercing to.
assert(expr->getCastTypeRepr());
const auto toType = simplifyType(cs.getType(expr->getCastTypeRepr()));
expr->setCastType(toType);
cs.setType(expr->getCastTypeRepr(), toType);
// If this is a literal that got converted into constructor call
// lets put proper source information in place.
if (expr->isLiteralInit()) {
auto *literalInit = expr->getSubExpr();
if (auto *call = dyn_cast<CallExpr>(literalInit)) {
forEachExprInConstraintSystem(call->getFn(),
[&](Expr *subExpr) -> Expr * {
auto *TE = dyn_cast<TypeExpr>(subExpr);
if (!TE)
return subExpr;
auto type = cs.getInstanceType(TE);
assert(!type->hasError());
if (!type->isEqual(toType))
return subExpr;
return cs.cacheType(TypeExpr::createImplicitHack(
expr->getLoc(), toType, cs.getASTContext()));
});
}
if (auto *literal = dyn_cast<NumberLiteralExpr>(literalInit)) {
literal->setExplicitConversion();
} else {
literalInit->setImplicit(false);
}
cs.setType(expr, toType);
// Keep the coercion around, because it contains the source range
// for the original constructor call.
return expr;
}
// Turn the subexpression into an rvalue.
auto rvalueSub = cs.coerceToRValue(expr->getSubExpr());
expr->setSubExpr(rvalueSub);
// If we weren't explicitly told by the caller which disjunction choice,
// get it from the solution to determine whether we've picked a coercion
// or a bridging conversion.
auto *locator = cs.getConstraintLocator(expr);
if (!choice) {
choice = solution.getDisjunctionChoice(locator);
}
// Handle the coercion/bridging of the underlying subexpression, where
// optionality has been removed.
if (*choice == 0) {
// Convert the subexpression.
Expr *sub = expr->getSubExpr();
sub = solution.coerceToType(sub, toType, cs.getConstraintLocator(sub));
if (!sub)
return nullptr;
expr->setSubExpr(sub);
cs.setType(expr, toType);
return expr;
}
// Bridging conversion.
assert(*choice == 1 && "should be bridging");
// Handle optional bindings.
Expr *sub = handleOptionalBindings(expr->getSubExpr(), toType,
OptionalBindingsCastKind::Bridged,
[&](Expr *sub, Type toInstanceType) {
return buildObjCBridgeExpr(sub, toInstanceType, locator);
});
if (!sub) return nullptr;
expr->setSubExpr(sub);
cs.setType(expr, toType);
return expr;
}
// Rewrite ForcedCheckedCastExpr based on what the solver computed.
Expr *visitForcedCheckedCastExpr(ForcedCheckedCastExpr *expr) {
// The subexpression is always an rvalue.
auto sub = cs.coerceToRValue(expr->getSubExpr());
expr->setSubExpr(sub);
// Simplify and update the type we're casting to.
auto *const castTypeRepr = expr->getCastTypeRepr();
const auto fromType = cs.getType(sub);
auto toType = simplifyType(cs.getType(castTypeRepr));
if (hasForcedOptionalResult(expr))
toType = toType->getOptionalObjectType();
expr->setCastType(toType);
cs.setType(castTypeRepr, toType);
auto castContextKind =
SuppressDiagnostics ? CheckedCastContextKind::None
: CheckedCastContextKind::ForcedCast;
const auto castKind = TypeChecker::typeCheckCheckedCast(
fromType, toType, castContextKind, cs.DC, expr->getLoc(), sub,
castTypeRepr->getSourceRange());
switch (castKind) {
/// Invalid cast.
case CheckedCastKind::Unresolved:
return nullptr;
case CheckedCastKind::Coercion:
case CheckedCastKind::BridgingCoercion: {
expr->setCastKind(castKind);
cs.setType(expr, toType);
return expr;
}
// Valid casts.
case CheckedCastKind::ArrayDowncast:
case CheckedCastKind::DictionaryDowncast:
case CheckedCastKind::SetDowncast:
case CheckedCastKind::ValueCast:
expr->setCastKind(castKind);
break;
}
return handleOptionalBindingsForCast(expr, simplifyType(cs.getType(expr)),
OptionalBindingsCastKind::Forced);
}
Expr *visitConditionalCheckedCastExpr(ConditionalCheckedCastExpr *expr) {
// Simplify and update the type we're casting to.
auto *const castTypeRepr = expr->getCastTypeRepr();
const auto toType = simplifyType(cs.getType(castTypeRepr));
expr->setCastType(toType);
cs.setType(castTypeRepr, toType);
// If we need to insert a force-unwrap for coercions of the form
// 'as! T!', do so now.
if (hasForcedOptionalResult(expr)) {
auto *coerced = handleConditionalCheckedCastExpr(expr, castTypeRepr);
if (!coerced)
return nullptr;
return coerceImplicitlyUnwrappedOptionalToValue(
coerced, cs.getType(coerced)->getOptionalObjectType());
}
return handleConditionalCheckedCastExpr(expr, castTypeRepr);
}
Expr *handleConditionalCheckedCastExpr(ConditionalCheckedCastExpr *expr,
TypeRepr *castTypeRepr) {
assert(castTypeRepr &&
"cast requires TypeRepr; implicit casts are superfluous");
// The subexpression is always an rvalue.
auto &ctx = cs.getASTContext();
auto sub = cs.coerceToRValue(expr->getSubExpr());
expr->setSubExpr(sub);
// Simplify and update the type we're casting to.
const auto fromType = cs.getType(sub);
const auto toType = expr->getCastType();
bool isSubExprLiteral = isa<LiteralExpr>(sub);
auto castContextKind =
(SuppressDiagnostics || expr->isImplicit() || isSubExprLiteral)
? CheckedCastContextKind::None
: CheckedCastContextKind::ConditionalCast;
auto castKind = TypeChecker::typeCheckCheckedCast(
fromType, toType, castContextKind, cs.DC, expr->getLoc(), sub,
castTypeRepr->getSourceRange());
switch (castKind) {
// Invalid cast.
case CheckedCastKind::Unresolved:
// FIXME: This literal diagnostics needs to be revisited by a proposal
// to unify casting semantics for literals.
// https://bugs.swift.org/browse/SR-12093
if (isSubExprLiteral) {
auto protocol = TypeChecker::getLiteralProtocol(ctx, sub);
// Special handle for literals conditional checked cast when they can
// be statically coerced to the cast type.
if (protocol && TypeChecker::conformsToProtocol(
toType, protocol, cs.DC)) {
ctx.Diags
.diagnose(expr->getLoc(),
diag::literal_conditional_downcast_to_coercion,
toType);
} else {
ctx.Diags
.diagnose(expr->getLoc(), diag::downcast_to_unrelated, fromType,
toType)
.highlight(sub->getSourceRange())
.highlight(castTypeRepr->getSourceRange());
}
}
expr->setCastKind(CheckedCastKind::ValueCast);
break;
case CheckedCastKind::Coercion:
case CheckedCastKind::BridgingCoercion: {
expr->setCastKind(castKind);
cs.setType(expr, OptionalType::get(toType));
return expr;
}
// Valid casts.
case CheckedCastKind::ArrayDowncast:
case CheckedCastKind::DictionaryDowncast:
case CheckedCastKind::SetDowncast:
case CheckedCastKind::ValueCast:
expr->setCastKind(castKind);
break;
}
return handleOptionalBindingsForCast(expr, simplifyType(cs.getType(expr)),
OptionalBindingsCastKind::Conditional);
}
Expr *visitAssignExpr(AssignExpr *expr) {
// Convert the source to the simplified destination type.
auto destTy = simplifyType(cs.getType(expr->getDest()));
auto locator =
ConstraintLocatorBuilder(cs.getConstraintLocator(expr->getSrc()));
Expr *src = coerceToType(expr->getSrc(), destTy->getRValueType(), locator);
if (!src)
return nullptr;
expr->setSrc(src);
if (!SuppressDiagnostics) {
// If we're performing an assignment to a weak or unowned variable from
// a constructor call, emit a warning that the instance will be
// immediately deallocated.
diagnoseUnownedImmediateDeallocation(cs.getASTContext(), expr);
}
return expr;
}
Expr *visitDiscardAssignmentExpr(DiscardAssignmentExpr *expr) {
return simplifyExprType(expr);
}
Expr *visitUnresolvedPatternExpr(UnresolvedPatternExpr *expr) {
// If we end up here, we should have diagnosed somewhere else
// already.
Expr *simplified = simplifyExprType(expr);
// Invalidate 'VarDecl's inside the pattern.
expr->getSubPattern()->forEachVariable([](VarDecl *VD) {
VD->setInvalid();
});
if (!SuppressDiagnostics) {
auto &de = cs.getASTContext().Diags;
de.diagnose(simplified->getLoc(), diag::pattern_in_expr,
expr->getSubPattern()->getKind());
}
return simplified;
}
Expr *visitBindOptionalExpr(BindOptionalExpr *expr) {
return simplifyExprType(expr);
}
Expr *visitOptionalEvaluationExpr(OptionalEvaluationExpr *expr) {
Type optType = simplifyType(cs.getType(expr));
// If this is an optional chain that isn't chaining anything, and if the
// subexpression is already optional (not IUO), then this is a noop:
// reject it. This avoids confusion of the model (where the programmer
// thought it was doing something) and keeps pointless ?'s out of the
// code.
if (!SuppressDiagnostics) {
auto &de = cs.getASTContext().Diags;
if (auto *Bind = dyn_cast<BindOptionalExpr>(
expr->getSubExpr()->getSemanticsProvidingExpr())) {
if (cs.getType(Bind->getSubExpr())->isEqual(optType)) {
de.diagnose(expr->getLoc(), diag::optional_chain_noop, optType)
.fixItRemove(Bind->getQuestionLoc());
} else {
de.diagnose(expr->getLoc(), diag::optional_chain_isnt_chaining);
}
}
}
Expr *subExpr = coerceToType(expr->getSubExpr(), optType,
cs.getConstraintLocator(expr));
if (!subExpr) return nullptr;
expr->setSubExpr(subExpr);
cs.setType(expr, optType);
return expr;
}
Expr *visitForceValueExpr(ForceValueExpr *expr) {
// Check to see if we are forcing an
// ImplicitlyUnwrappedFunctionConversionExpr. This can happen
// in cases where we had a ForceValueExpr of an optional for a
// declaration for a function whose result type we need to
// implicitly force after applying. We need to hoist the function
// conversion above the ForceValueExpr, so that we may ultimately
// hoist it above the ApplyExpr where we will eventually rewrite the
// function conversion into a force of the result.
Expr *replacement = expr;
if (auto fnConv =
dyn_cast<ImplicitlyUnwrappedFunctionConversionExpr>(expr->getSubExpr())) {
auto fnConvSubExpr = fnConv->getSubExpr();
auto fnConvSubObjTy =
cs.getType(fnConvSubExpr)->getOptionalObjectType();
cs.setType(expr, fnConvSubObjTy);
expr->setSubExpr(fnConvSubExpr);
fnConv->setSubExpr(expr);
replacement = fnConv;
}
Type valueType = simplifyType(cs.getType(expr));
cs.setType(expr, valueType);
// Coerce the object type, if necessary.
auto subExpr = expr->getSubExpr();
if (auto objectTy = cs.getType(subExpr)->getOptionalObjectType()) {
if (objectTy && !objectTy->isEqual(valueType)) {
auto coercedSubExpr = coerceToType(subExpr,
OptionalType::get(valueType),
cs.getConstraintLocator(subExpr));
expr->setSubExpr(coercedSubExpr);
}
}
return replacement;
}
Expr *visitOpenExistentialExpr(OpenExistentialExpr *expr) {
llvm_unreachable("Already type-checked");
}
Expr *visitMakeTemporarilyEscapableExpr(MakeTemporarilyEscapableExpr *expr){
llvm_unreachable("Already type-checked");
}
Expr *visitKeyPathApplicationExpr(KeyPathApplicationExpr *expr){
// This should already be type-checked, but we may have had to re-
// check it for failure diagnosis.
return simplifyExprType(expr);
}
Expr *visitEnumIsCaseExpr(EnumIsCaseExpr *expr) {
// Should already be type-checked.
return simplifyExprType(expr);
}
Expr *visitLazyInitializerExpr(LazyInitializerExpr *expr) {
llvm_unreachable("Already type-checked");
}
Expr *visitEditorPlaceholderExpr(EditorPlaceholderExpr *E) {
simplifyExprType(E);
auto valueType = cs.getType(E);
assert(!valueType->hasUnresolvedType());
auto &ctx = cs.getASTContext();
// Synthesize a call to _undefined() of appropriate type.
FuncDecl *undefinedDecl = ctx.getUndefined();
if (!undefinedDecl) {
ctx.Diags.diagnose(E->getLoc(), diag::missing_undefined_runtime);
return nullptr;
}
DeclRefExpr *fnRef = new (ctx) DeclRefExpr(undefinedDecl, DeclNameLoc(),
/*Implicit=*/true);
fnRef->setFunctionRefKind(FunctionRefKind::SingleApply);
StringRef msg = "attempt to evaluate editor placeholder";
Expr *argExpr = new (ctx) StringLiteralExpr(msg, E->getLoc(),
/*implicit*/true);
Expr *callExpr = CallExpr::createImplicit(ctx, fnRef, { argExpr },
{ Identifier() });
auto resultTy = TypeChecker::typeCheckExpression(
callExpr, cs.DC, /*contextualInfo=*/{valueType, CTP_CannotFail});
assert(resultTy && "Conversion cannot fail!");
(void)resultTy;
cs.cacheExprTypes(callExpr);
E->setSemanticExpr(callExpr);
return E;
}
Expr *visitObjCSelectorExpr(ObjCSelectorExpr *E) {
// Dig out the reference to a declaration.
Expr *subExpr = E->getSubExpr();
ValueDecl *foundDecl = nullptr;
while (subExpr) {
// Declaration reference.
if (auto declRef = dyn_cast<DeclRefExpr>(subExpr)) {
foundDecl = declRef->getDecl();
break;
}
// Constructor reference.
if (auto ctorRef = dyn_cast<OtherConstructorDeclRefExpr>(subExpr)) {
foundDecl = ctorRef->getDecl();
break;
}
// Member reference.
if (auto memberRef = dyn_cast<MemberRefExpr>(subExpr)) {
foundDecl = memberRef->getMember().getDecl();
break;
}
// Dynamic member reference.
if (auto dynMemberRef = dyn_cast<DynamicMemberRefExpr>(subExpr)) {
foundDecl = dynMemberRef->getMember().getDecl();
break;
}
// Look through parentheses.
if (auto paren = dyn_cast<ParenExpr>(subExpr)) {
subExpr = paren->getSubExpr();
continue;
}
// Look through "a.b" to "b".
if (auto dotSyntax = dyn_cast<DotSyntaxBaseIgnoredExpr>(subExpr)) {
subExpr = dotSyntax->getRHS();
continue;
}
// Look through self-rebind expression.
if (auto rebindSelf = dyn_cast<RebindSelfInConstructorExpr>(subExpr)) {
subExpr = rebindSelf->getSubExpr();
continue;
}
// Look through optional binding within the monadic "?".
if (auto bind = dyn_cast<BindOptionalExpr>(subExpr)) {
subExpr = bind->getSubExpr();
continue;
}
// Look through optional evaluation of the monadic "?".
if (auto optEval = dyn_cast<OptionalEvaluationExpr>(subExpr)) {
subExpr = optEval->getSubExpr();
continue;
}
// Look through an implicit force-value.
if (auto force = dyn_cast<ForceValueExpr>(subExpr)) {
subExpr = force->getSubExpr();
continue;
}
// Look through implicit open-existential operations.
if (auto open = dyn_cast<OpenExistentialExpr>(subExpr)) {
if (open->isImplicit()) {
subExpr = open->getSubExpr();
continue;
}
break;
}
// Look to the referenced member in a self-application.
if (auto selfApply = dyn_cast<SelfApplyExpr>(subExpr)) {
subExpr = selfApply->getFn();
continue;
}
// Look through implicit conversions.
if (auto conversion = dyn_cast<ImplicitConversionExpr>(subExpr)) {
subExpr = conversion->getSubExpr();
continue;
}
// Look through explicit coercions.
if (auto coercion = dyn_cast<CoerceExpr>(subExpr)) {
subExpr = coercion->getSubExpr();
continue;
}
break;
}
if (!subExpr) return nullptr;
// If we didn't find any declaration at all, we're stuck.
auto &de = cs.getASTContext().Diags;
if (!foundDecl) {
de.diagnose(E->getLoc(), diag::expr_selector_no_declaration)
.highlight(subExpr->getSourceRange());
return E;
}
// Check whether we found an entity that #selector could refer to.
// If we found a method or initializer, check it.
AbstractFunctionDecl *method = nullptr;
if (auto func = dyn_cast<AbstractFunctionDecl>(foundDecl)) {
// Methods and initializers.
// If this isn't a method, complain.
if (!func->getDeclContext()->isTypeContext()) {
de.diagnose(E->getLoc(), diag::expr_selector_not_method,
func->getDeclContext()->isModuleScopeContext(),
func->getName())
.highlight(subExpr->getSourceRange());
de.diagnose(func, diag::decl_declared_here, func->getName());
return E;
}
// Check that we requested a method.
switch (E->getSelectorKind()) {
case ObjCSelectorExpr::Method:
break;
case ObjCSelectorExpr::Getter:
case ObjCSelectorExpr::Setter:
// Complain that we cannot ask for the getter or setter of a
// method.
de.diagnose(E->getModifierLoc(),
diag::expr_selector_expected_property,
E->getSelectorKind() == ObjCSelectorExpr::Setter,
foundDecl->getDescriptiveKind(), foundDecl->getName())
.fixItRemoveChars(E->getModifierLoc(),
E->getSubExpr()->getStartLoc());
// Update the AST to reflect the fix.
E->overrideObjCSelectorKind(ObjCSelectorExpr::Method, SourceLoc());
break;
}
// Note the method we're referring to.
method = func;
} else if (auto var = dyn_cast<VarDecl>(foundDecl)) {
// Properties.
// If this isn't a property on a type, complain.
if (!var->getDeclContext()->isTypeContext()) {
de.diagnose(E->getLoc(), diag::expr_selector_not_property,
isa<ParamDecl>(var), var->getName())
.highlight(subExpr->getSourceRange());
de.diagnose(var, diag::decl_declared_here, var->getName());
return E;
}
// Check that we requested a property getter or setter.
switch (E->getSelectorKind()) {
case ObjCSelectorExpr::Method: {
bool isSettable = var->isSettable(cs.DC) &&
var->isSetterAccessibleFrom(cs.DC);
auto primaryDiag =
de.diagnose(E->getLoc(), diag::expr_selector_expected_method,
isSettable, var->getName());
primaryDiag.highlight(subExpr->getSourceRange());
// The point at which we will insert the modifier.
SourceLoc modifierLoc = E->getSubExpr()->getStartLoc();
// If the property is settable, we don't know whether the
// user wanted the getter or setter. Provide notes for each.
if (isSettable) {
// Flush the primary diagnostic. We have notes to add.
primaryDiag.flush();
// Add notes for the getter and setter, respectively.
de.diagnose(modifierLoc, diag::expr_selector_add_modifier, false,
var->getName())
.fixItInsert(modifierLoc, "getter: ");
de.diagnose(modifierLoc, diag::expr_selector_add_modifier, true,
var->getName())
.fixItInsert(modifierLoc, "setter: ");
// Bail out now. We don't know what the user wanted, so
// don't fill in the details.
return E;
}
// The property is non-settable, so add "getter:".
primaryDiag.fixItInsert(modifierLoc, "getter: ");
E->overrideObjCSelectorKind(ObjCSelectorExpr::Getter, modifierLoc);
method = var->getOpaqueAccessor(AccessorKind::Get);
break;
}
case ObjCSelectorExpr::Getter:
method = var->getOpaqueAccessor(AccessorKind::Get);
break;
case ObjCSelectorExpr::Setter:
// Make sure we actually have a setter.
if (!var->isSettable(cs.DC)) {
de.diagnose(E->getLoc(), diag::expr_selector_property_not_settable,
var->getDescriptiveKind(), var->getName());
de.diagnose(var, diag::decl_declared_here, var->getName());
return E;
}
// Make sure the setter is accessible.
if (!var->isSetterAccessibleFrom(cs.DC)) {
de.diagnose(E->getLoc(),
diag::expr_selector_property_setter_inaccessible,
var->getDescriptiveKind(), var->getName());
de.diagnose(var, diag::decl_declared_here, var->getName());
return E;
}
method = var->getOpaqueAccessor(AccessorKind::Set);
break;
}
} else {
// Cannot reference with #selector.
de.diagnose(E->getLoc(), diag::expr_selector_no_declaration)
.highlight(subExpr->getSourceRange());
de.diagnose(foundDecl, diag::decl_declared_here,
foundDecl->getName());
return E;
}
assert(method && "Didn't find a method?");
// The declaration we found must be exposed to Objective-C.
if (!method->isObjC()) {
// If the method declaration lies in a protocol and we're providing
// a default implementation of the method through a protocol extension
// and using it as a selector, then bail out as adding @objc to the
// protocol might not be the right thing to do and could lead to
// problems.
if (auto protocolDecl = dyn_cast<ProtocolDecl>(foundDecl->getDeclContext())) {
de.diagnose(E->getLoc(), diag::expr_selector_cannot_be_used,
foundDecl->getBaseName(), protocolDecl->getName());
return E;
}
de.diagnose(E->getLoc(), diag::expr_selector_not_objc,
foundDecl->getDescriptiveKind(), foundDecl->getName())
.highlight(subExpr->getSourceRange());
de.diagnose(foundDecl, diag::make_decl_objc,
foundDecl->getDescriptiveKind())
.fixItInsert(foundDecl->getAttributeInsertionLoc(false), "@objc ");
return E;
} else if (auto attr = foundDecl->getAttrs().getAttribute<ObjCAttr>()) {
// If this attribute was inferred based on deprecated Swift 3 rules,
// complain.
if (attr->isSwift3Inferred() &&
cs.getASTContext().LangOpts.WarnSwift3ObjCInference ==
Swift3ObjCInferenceWarnings::Minimal) {
de.diagnose(E->getLoc(), diag::expr_selector_swift3_objc_inference,
foundDecl->getDescriptiveKind(), foundDecl->getName(),
foundDecl->getDeclContext()
->getSelfNominalTypeDecl()
->getName())
.highlight(subExpr->getSourceRange());
de.diagnose(foundDecl, diag::make_decl_objc,
foundDecl->getDescriptiveKind())
.fixItInsert(foundDecl->getAttributeInsertionLoc(false),
"@objc ");
}
}
// Note which method we're referencing.
E->setMethod(method);
return E;
}
Expr *visitKeyPathExpr(KeyPathExpr *E) {
if (E->isObjC()) {
cs.setType(E, cs.getType(E->getObjCStringLiteralExpr()));
return E;
}
simplifyExprType(E);
if (cs.getType(E)->hasError())
return E;
// If a component is already resolved, then all of them should be
// resolved, and we can let the expression be. This might happen when
// re-checking a failed system for diagnostics.
if (!E->getComponents().empty()
&& E->getComponents().front().isResolved()) {
assert([&]{
for (auto &c : E->getComponents())
if (!c.isResolved())
return false;
return true;
}());
return E;
}
SmallVector<KeyPathExpr::Component, 4> resolvedComponents;
// Resolve each of the components.
bool didOptionalChain = false;
bool isFunctionType = false;
Type baseTy, leafTy;
Type exprType = cs.getType(E);
if (auto fnTy = exprType->getAs<FunctionType>()) {
baseTy = fnTy->getParams()[0].getParameterType();
leafTy = fnTy->getResult();
isFunctionType = true;
} else {
auto keyPathTy = exprType->castTo<BoundGenericType>();
baseTy = keyPathTy->getGenericArgs()[0];
leafTy = keyPathTy->getGenericArgs()[1];
}
// Track the type of the current component. Once we finish projecting
// through each component of the key path, we should reach the leafTy.
auto componentTy = baseTy;
for (unsigned i : indices(E->getComponents())) {
auto &origComponent = E->getMutableComponents()[i];
// If there were unresolved types, we may end up with a null base for
// following components.
if (!componentTy) {
resolvedComponents.push_back(origComponent);
continue;
}
auto kind = origComponent.getKind();
auto locator = cs.getConstraintLocator(
E, LocatorPathElt::KeyPathComponent(i));
// Adjust the locator such that it includes any additional elements to
// point to the component's callee, e.g a SubscriptMember for a
// subscript component.
locator = cs.getCalleeLocator(locator);
bool isDynamicMember = false;
// If this is an unresolved link, make sure we resolved it.
if (kind == KeyPathExpr::Component::Kind::UnresolvedProperty ||
kind == KeyPathExpr::Component::Kind::UnresolvedSubscript) {
auto foundDecl = solution.getOverloadChoice(locator);
isDynamicMember =
foundDecl.choice.getKind() ==
OverloadChoiceKind::DynamicMemberLookup ||
foundDecl.choice.getKind() ==
OverloadChoiceKind::KeyPathDynamicMemberLookup;
// If this was a @dynamicMemberLookup property, then we actually
// form a subscript reference, so switch the kind.
if (isDynamicMember) {
kind = KeyPathExpr::Component::Kind::UnresolvedSubscript;
}
}
switch (kind) {
case KeyPathExpr::Component::Kind::UnresolvedProperty: {
buildKeyPathPropertyComponent(solution.getOverloadChoice(locator),
origComponent.getLoc(),
locator, resolvedComponents);
break;
}
case KeyPathExpr::Component::Kind::UnresolvedSubscript: {
ArrayRef<Identifier> subscriptLabels;
if (!isDynamicMember)
subscriptLabels = origComponent.getSubscriptLabels();
buildKeyPathSubscriptComponent(
solution.getOverloadChoice(locator),
origComponent.getLoc(), origComponent.getIndexExpr(),
subscriptLabels, locator, resolvedComponents);
break;
}
case KeyPathExpr::Component::Kind::OptionalChain: {
didOptionalChain = true;
// Chaining always forces the element to be an rvalue.
assert(!componentTy->hasUnresolvedType());
auto objectTy =
componentTy->getWithoutSpecifierType()->getOptionalObjectType();
assert(objectTy);
auto loc = origComponent.getLoc();
resolvedComponents.push_back(
KeyPathExpr::Component::forOptionalChain(objectTy, loc));
break;
}
case KeyPathExpr::Component::Kind::OptionalForce: {
// Handle force optional when it is the first component e.g.
// \String?.!.count
if (resolvedComponents.empty()) {
auto loc = origComponent.getLoc();
auto objectTy = componentTy->getOptionalObjectType();
assert(objectTy);
resolvedComponents.push_back(
KeyPathExpr::Component::forOptionalForce(objectTy, loc));
} else {
buildKeyPathOptionalForceComponent(resolvedComponents);
}
break;
}
case KeyPathExpr::Component::Kind::Invalid: {
auto component = origComponent;
component.setComponentType(leafTy);
resolvedComponents.push_back(component);
break;
}
case KeyPathExpr::Component::Kind::Identity: {
auto component = origComponent;
component.setComponentType(componentTy);
resolvedComponents.push_back(component);
break;
}
case KeyPathExpr::Component::Kind::Property:
case KeyPathExpr::Component::Kind::Subscript:
case KeyPathExpr::Component::Kind::OptionalWrap:
case KeyPathExpr::Component::Kind::TupleElement:
llvm_unreachable("already resolved");
break;
case KeyPathExpr::Component::Kind::DictionaryKey:
llvm_unreachable("DictionaryKey only valid in #keyPath");
break;
}
// Update "componentTy" with the result type of the last component.
assert(!resolvedComponents.empty());
componentTy = resolvedComponents.back().getComponentType();
}
// Wrap a non-optional result if there was chaining involved.
assert(!componentTy->hasUnresolvedType());
if (didOptionalChain && componentTy &&
!componentTy->getWithoutSpecifierType()->isEqual(leafTy)) {
assert(leafTy->getOptionalObjectType()->isEqual(
componentTy->getWithoutSpecifierType()));
auto component = KeyPathExpr::Component::forOptionalWrap(leafTy);
resolvedComponents.push_back(component);
componentTy = leafTy;
}
// Set the resolved components, and cache their types.
E->resolveComponents(cs.getASTContext(), resolvedComponents);
cs.cacheExprTypes(E);
// See whether there's an equivalent ObjC key path string we can produce
// for interop purposes.
checkAndSetObjCKeyPathString(E);
// The final component type ought to line up with the leaf type of the
// key path.
assert(!componentTy->hasUnresolvedType());
assert(componentTy->getWithoutSpecifierType()->isEqual(leafTy));
if (!isFunctionType)
return E;
// If we've gotten here, the user has used key path literal syntax to form
// a closure. The type checker has given E a function type to indicate
// this; we're going to change E's type to KeyPath<baseTy, leafTy> and
// then wrap it in a larger closure expression with the appropriate type.
// Compute KeyPath<baseTy, leafTy> and set E's type back to it.
auto kpDecl = cs.getASTContext().getKeyPathDecl();
auto keyPathTy =
BoundGenericType::get(kpDecl, nullptr, { baseTy, leafTy });
E->setType(keyPathTy);
cs.cacheType(E);
// To ensure side effects of the key path expression (mainly indices in
// subscripts) are only evaluated once, we construct an outer closure,
// which is immediately evaluated, and an inner closure, which it returns.
// The result looks like this:
//
// return "{ $kp$ in { $0[keyPath: $kp$] } }( \(E) )"
auto &ctx = cs.getASTContext();
auto discriminator = AutoClosureExpr::InvalidDiscriminator;
// The inner closure.
//
// let closure = "{ $0[keyPath: $kp$] }"
auto closureTy =
FunctionType::get({ FunctionType::Param(baseTy) }, leafTy);
auto closure = new (ctx)
AutoClosureExpr(/*set body later*/nullptr, leafTy,
discriminator, cs.DC);
auto param = new (ctx) ParamDecl(
SourceLoc(),
/*argument label*/ SourceLoc(), Identifier(),
/*parameter name*/ SourceLoc(), ctx.getIdentifier("$0"), closure);
param->setInterfaceType(baseTy->mapTypeOutOfContext());
param->setSpecifier(ParamSpecifier::Default);
param->setImplicit();
// The outer closure.
//
// let outerClosure = "{ $kp$ in \(closure) }"
auto outerClosureTy =
FunctionType::get({ FunctionType::Param(keyPathTy) }, closureTy);
auto outerClosure = new (ctx)
AutoClosureExpr(/*set body later*/nullptr, closureTy,
discriminator, cs.DC);
auto outerParam =
new (ctx) ParamDecl(SourceLoc(),
/*argument label*/ SourceLoc(), Identifier(),
/*parameter name*/ SourceLoc(),
ctx.getIdentifier("$kp$"), outerClosure);
outerParam->setInterfaceType(keyPathTy->mapTypeOutOfContext());
outerParam->setSpecifier(ParamSpecifier::Default);
outerParam->setImplicit();
// let paramRef = "$0"
auto *paramRef = new (ctx)
DeclRefExpr(param, DeclNameLoc(E->getLoc()), /*Implicit=*/true);
paramRef->setType(baseTy);
cs.cacheType(paramRef);
// let outerParamRef = "$kp$"
auto outerParamRef = new (ctx)
DeclRefExpr(outerParam, DeclNameLoc(E->getLoc()), /*Implicit=*/true);
outerParamRef->setType(keyPathTy);
cs.cacheType(outerParamRef);
// let application = "\(paramRef)[keyPath: \(outerParamRef)]"
auto *application = new (ctx)
KeyPathApplicationExpr(paramRef,
E->getStartLoc(), outerParamRef, E->getEndLoc(),
leafTy, /*implicit=*/true);
cs.cacheType(application);
// Finish up the inner closure.
closure->setParameterList(ParameterList::create(ctx, {param}));
closure->setBody(application);
closure->setType(closureTy);
cs.cacheType(closure);
// Finish up the outer closure.
outerClosure->setParameterList(ParameterList::create(ctx, {outerParam}));
outerClosure->setBody(closure);
outerClosure->setType(outerClosureTy);
cs.cacheType(outerClosure);
// let outerApply = "\( outerClosure )( \(E) )"
auto outerApply = CallExpr::createImplicit(ctx, outerClosure, {E}, {});
outerApply->setType(closureTy);
cs.cacheExprTypes(outerApply);
return coerceToType(outerApply, exprType, cs.getConstraintLocator(E));
}
void buildKeyPathOptionalForceComponent(
SmallVectorImpl<KeyPathExpr::Component> &components) {
assert(!components.empty());
// Unwrap the last component type, preserving @lvalue-ness.
auto optionalTy = components.back().getComponentType();
assert(!optionalTy->hasUnresolvedType());
Type objectTy;
if (auto lvalue = optionalTy->getAs<LValueType>()) {
objectTy = lvalue->getObjectType()->getOptionalObjectType();
objectTy = LValueType::get(objectTy);
} else {
objectTy = optionalTy->getOptionalObjectType();
}
assert(objectTy);
auto loc = components.back().getLoc();
components.push_back(
KeyPathExpr::Component::forOptionalForce(objectTy, loc));
}
void buildKeyPathPropertyComponent(
const SelectedOverload &overload, SourceLoc componentLoc,
ConstraintLocator *locator,
SmallVectorImpl<KeyPathExpr::Component> &components) {
auto resolvedTy = simplifyType(overload.openedType);
if (auto *property = overload.choice.getDeclOrNull()) {
// Key paths can only refer to properties currently.
auto varDecl = cast<VarDecl>(property);
// Key paths don't work with mutating-get properties.
assert(!varDecl->isGetterMutating());
// Key paths don't currently support static members.
// There is a fix which diagnoses such situation already.
assert(!varDecl->isStatic());
// Compute the concrete reference to the member.
auto ref = resolveConcreteDeclRef(property, locator);
components.push_back(
KeyPathExpr::Component::forProperty(ref, resolvedTy, componentLoc));
} else {
auto fieldIndex = overload.choice.getTupleIndex();
components.push_back(KeyPathExpr::Component::forTupleElement(
fieldIndex, resolvedTy, componentLoc));
}
if (shouldForceUnwrapResult(overload.choice, locator))
buildKeyPathOptionalForceComponent(components);
}
void buildKeyPathSubscriptComponent(
const SelectedOverload &overload,
SourceLoc componentLoc, Expr *indexExpr,
ArrayRef<Identifier> labels, ConstraintLocator *locator,
SmallVectorImpl<KeyPathExpr::Component> &components) {
auto subscript = cast<SubscriptDecl>(overload.choice.getDecl());
assert(!subscript->isGetterMutating());
// Compute substitutions to refer to the member.
auto ref = resolveConcreteDeclRef(subscript, locator);
// If this is a @dynamicMemberLookup reference to resolve a property
// through the subscript(dynamicMember:) member, restore the
// openedType and origComponent to its full reference as if the user
// wrote out the subscript manually.
bool forDynamicLookup =
overload.choice.getKind() ==
OverloadChoiceKind::DynamicMemberLookup ||
overload.choice.getKind() ==
OverloadChoiceKind::KeyPathDynamicMemberLookup;
if (forDynamicLookup) {
labels = cs.getASTContext().Id_dynamicMember;
auto indexType = getTypeOfDynamicMemberIndex(overload);
if (overload.choice.getKind() ==
OverloadChoiceKind::KeyPathDynamicMemberLookup) {
indexExpr = buildKeyPathDynamicMemberIndexExpr(
indexType->castTo<BoundGenericType>(), componentLoc, locator);
} else {
auto fieldName = overload.choice.getName().getBaseIdentifier().str();
indexExpr = buildDynamicMemberLookupIndexExpr(fieldName, componentLoc,
indexType);
}
}
auto subscriptType =
simplifyType(overload.openedType)->castTo<AnyFunctionType>();
auto resolvedTy = subscriptType->getResult();
// Coerce the indices to the type the subscript expects.
auto *newIndexExpr =
coerceCallArguments(indexExpr, subscriptType, ref,
/*applyExpr*/ nullptr, labels,
locator);
// We need to be able to hash the captured index values in order for
// KeyPath itself to be hashable, so check that all of the subscript
// index components are hashable and collect their conformances here.
SmallVector<ProtocolConformanceRef, 4> conformances;
auto hashable =
cs.getASTContext().getProtocol(KnownProtocolKind::Hashable);
auto fnType = overload.openedType->castTo<FunctionType>();
SmallVector<Identifier, 4> newLabels;
for (auto &param : fnType->getParams()) {
newLabels.push_back(param.getLabel());
auto indexType = simplifyType(param.getParameterType());
// Index type conformance to Hashable protocol has been
// verified by the solver, we just need to get it again
// with all of the generic parameters resolved.
auto hashableConformance =
TypeChecker::conformsToProtocol(indexType, hashable, cs.DC);
assert(hashableConformance);
conformances.push_back(hashableConformance);
}
auto comp = KeyPathExpr::Component::forSubscriptWithPrebuiltIndexExpr(
ref, newIndexExpr, cs.getASTContext().AllocateCopy(newLabels),
resolvedTy, componentLoc,
cs.getASTContext().AllocateCopy(conformances));
components.push_back(comp);
if (shouldForceUnwrapResult(overload.choice, locator))
buildKeyPathOptionalForceComponent(components);
}
Expr *visitKeyPathDotExpr(KeyPathDotExpr *E) {
llvm_unreachable("found KeyPathDotExpr in CSApply");
}
Expr *visitOneWayExpr(OneWayExpr *E) {
auto type = simplifyType(cs.getType(E));
return coerceToType(E->getSubExpr(), type, cs.getConstraintLocator(E));
}
Expr *visitTapExpr(TapExpr *E) {
auto type = simplifyType(cs.getType(E));
E->getVar()->setInterfaceType(type->mapTypeOutOfContext());
cs.setType(E, type);
E->setType(type);
return E;
}
/// Interface for ExprWalker
void walkToExprPre(Expr *expr) {
// If we have an apply, make a note of its callee locator prior to
// rewriting.
if (auto *apply = dyn_cast<ApplyExpr>(expr)) {
auto *calleeLoc = cs.getCalleeLocator(cs.getConstraintLocator(expr));
CalleeLocators[apply] = calleeLoc;
}
ExprStack.push_back(expr);
}
Expr *walkToExprPost(Expr *expr) {
Expr *result = visit(expr);
assert(expr == ExprStack.back());
ExprStack.pop_back();
return result;
}
void finalize() {
assert(ExprStack.empty());
assert(OpenedExistentials.empty());
auto &ctx = cs.getASTContext();
// Look at all of the suspicious optional injections
for (auto injection : SuspiciousOptionalInjections) {
auto *cast = findForcedDowncast(ctx, injection->getSubExpr());
if (!cast)
continue;
if (isa<ParenExpr>(injection->getSubExpr()))
continue;
ctx.Diags.diagnose(
injection->getLoc(), diag::inject_forced_downcast,
cs.getType(injection->getSubExpr())->getRValueType());
auto exclaimLoc = cast->getExclaimLoc();
ctx.Diags
.diagnose(exclaimLoc, diag::forced_to_conditional_downcast,
cs.getType(injection)->getOptionalObjectType())
.fixItReplace(exclaimLoc, "?");
ctx.Diags
.diagnose(cast->getStartLoc(), diag::silence_inject_forced_downcast)
.fixItInsert(cast->getStartLoc(), "(")
.fixItInsertAfter(cast->getEndLoc(), ")");
}
}
/// Diagnose an optional injection that is probably not what the
/// user wanted, because it comes from a forced downcast.
void diagnoseOptionalInjection(InjectIntoOptionalExpr *injection) {
// Check whether we have a forced downcast.
auto *cast =
findForcedDowncast(cs.getASTContext(), injection->getSubExpr());
if (!cast)
return;
SuspiciousOptionalInjections.push_back(injection);
}
};
} // end anonymous namespace
ConcreteDeclRef
Solution::resolveLocatorToDecl(ConstraintLocator *locator) const {
// Get the callee locator without looking through applies, ensuring we only
// return a decl for a direct reference.
auto *calleeLoc =
constraintSystem->getCalleeLocator(locator, /*lookThroughApply*/ false);
auto overload = getOverloadChoiceIfAvailable(calleeLoc);
if (!overload)
return ConcreteDeclRef();
return resolveConcreteDeclRef(overload->choice.getDeclOrNull(), locator);
}
/// Returns the concrete callee which 'owns' the default argument at a given
/// index. This looks through inheritance for inherited default args.
static ConcreteDeclRef getDefaultArgOwner(ConcreteDeclRef owner,
unsigned index) {
auto *param = getParameterAt(owner.getDecl(), index);
if (param->getDefaultArgumentKind() == DefaultArgumentKind::Inherited) {
return getDefaultArgOwner(owner.getOverriddenDecl(), index);
}
return owner;
}
static bool canPeepholeTupleConversion(Expr *expr,
ArrayRef<unsigned> sources) {
if (!isa<TupleExpr>(expr))
return false;
for (unsigned i = 0, e = sources.size(); i != e; ++i) {
if (sources[i] != i)
return false;
}
return true;
}
Expr *ExprRewriter::coerceTupleToTuple(Expr *expr,
TupleType *fromTuple,
TupleType *toTuple,
ConstraintLocatorBuilder locator,
ArrayRef<unsigned> sources) {
auto &ctx = cs.getASTContext();
// If the input expression is a tuple expression, we can convert it in-place.
if (canPeepholeTupleConversion(expr, sources)) {
auto *tupleExpr = cast<TupleExpr>(expr);
for (unsigned i = 0, e = tupleExpr->getNumElements(); i != e; ++i) {
auto *fromElt = tupleExpr->getElement(i);
// Actually convert the source element.
auto toEltType = toTuple->getElementType(i);
auto *toElt
= coerceToType(fromElt, toEltType,
locator.withPathElement(
LocatorPathElt::TupleElement(i)));
if (!toElt)
return nullptr;
tupleExpr->setElement(i, toElt);
}
tupleExpr->setType(toTuple);
cs.cacheType(tupleExpr);
return tupleExpr;
}
// Build a list of OpaqueValueExprs that matches the structure
// of expr's type.
//
// Each OpaqueValueExpr's type is equal to the type of the
// corresponding element of fromTuple.
SmallVector<OpaqueValueExpr *, 4> destructured;
for (unsigned i = 0, e = sources.size(); i != e; ++i) {
auto fromEltType = fromTuple->getElementType(i);
auto *opaqueElt =
new (ctx) OpaqueValueExpr(expr->getSourceRange(), fromEltType);
cs.cacheType(opaqueElt);
destructured.push_back(opaqueElt);
}
// Convert each OpaqueValueExpr to the correct type.
SmallVector<Expr *, 4> converted;
SmallVector<Identifier, 4> labels;
SmallVector<TupleTypeElt, 4> convertedElts;
bool anythingShuffled = false;
for (unsigned i = 0, e = sources.size(); i != e; ++i) {
unsigned source = sources[i];
auto *fromElt = destructured[source];
// Actually convert the source element.
auto toEltType = toTuple->getElementType(i);
auto toLabel = toTuple->getElement(i).getName();
// If we're shuffling positions and labels, we have to warn about this
// conversion.
if (i != sources[i] &&
fromTuple->getElement(i).getName() != toLabel)
anythingShuffled = true;
auto *toElt
= coerceToType(fromElt, toEltType,
locator.withPathElement(
LocatorPathElt::TupleElement(source)));
if (!toElt)
return nullptr;
converted.push_back(toElt);
labels.push_back(toLabel);
convertedElts.emplace_back(toEltType, toLabel, ParameterTypeFlags());
}
// Shuffling tuple elements is an anti-pattern worthy of a diagnostic. We
// will form the shuffle for now, but a future compiler should decline to
// do so and begin the process of removing them altogether.
if (anythingShuffled) {
cs.getASTContext().Diags.diagnose(
expr->getLoc(), diag::warn_reordering_tuple_shuffle_deprecated);
}
// Create the result tuple, written in terms of the destructured
// OpaqueValueExprs.
auto *result = TupleExpr::createImplicit(ctx, converted, labels);
result->setType(TupleType::get(convertedElts, ctx));
cs.cacheType(result);
// Create the tuple conversion.
return cs.cacheType(
DestructureTupleExpr::create(ctx, destructured, expr, result, toTuple));
}
static Type getMetatypeSuperclass(Type t) {
if (auto *metaTy = t->getAs<MetatypeType>())
return MetatypeType::get(getMetatypeSuperclass(
metaTy->getInstanceType()));
if (auto *metaTy = t->getAs<ExistentialMetatypeType>())
return ExistentialMetatypeType::get(getMetatypeSuperclass(
metaTy->getInstanceType()));
return t->getSuperclass();
}
Expr *ExprRewriter::coerceSuperclass(Expr *expr, Type toType) {
auto &ctx = cs.getASTContext();
auto fromType = cs.getType(expr);
auto fromInstanceType = fromType;
auto toInstanceType = toType;
while (fromInstanceType->is<AnyMetatypeType>() &&
toInstanceType->is<MetatypeType>()) {
fromInstanceType = fromInstanceType->castTo<AnyMetatypeType>()
->getInstanceType();
toInstanceType = toInstanceType->castTo<MetatypeType>()
->getInstanceType();
}
if (fromInstanceType->is<ArchetypeType>()) {
// Coercion from archetype to its (concrete) superclass.
auto superclass = getMetatypeSuperclass(fromType);
expr =
cs.cacheType(
new (ctx) ArchetypeToSuperExpr(expr, superclass));
if (!superclass->isEqual(toType))
return coerceSuperclass(expr, toType);
return expr;
}
if (fromInstanceType->isExistentialType()) {
// Coercion from superclass-constrained existential to its
// concrete superclass.
auto fromArchetype = OpenedArchetypeType::getAny(fromType);
auto *archetypeVal = cs.cacheType(new (ctx) OpaqueValueExpr(
expr->getSourceRange(), fromArchetype));
auto *result = coerceSuperclass(archetypeVal, toType);
return cs.cacheType(
new (ctx) OpenExistentialExpr(expr, archetypeVal, result,
toType));
}
// Coercion from subclass to superclass.
if (toType->is<MetatypeType>()) {
return cs.cacheType(
new (ctx) MetatypeConversionExpr(expr, toType));
}
return cs.cacheType(
new (ctx) DerivedToBaseExpr(expr, toType));
}
/// Collect the conformances for all the protocols of an existential type.
/// If the source type is also existential, we don't want to check conformance
/// because most protocols do not conform to themselves -- however we still
/// allow the conversion here, except the ErasureExpr ends up with trivial
/// conformances.
static ArrayRef<ProtocolConformanceRef>
collectExistentialConformances(Type fromType, Type toType,
DeclContext *DC) {
auto layout = toType->getExistentialLayout();
SmallVector<ProtocolConformanceRef, 4> conformances;
for (auto proto : layout.getProtocols()) {
conformances.push_back(TypeChecker::containsProtocol(
fromType, proto->getDecl(), DC));
}
return toType->getASTContext().AllocateCopy(conformances);
}
Expr *ExprRewriter::coerceExistential(Expr *expr, Type toType) {
Type fromType = cs.getType(expr);
Type fromInstanceType = fromType;
Type toInstanceType = toType;
// Look through metatypes
while (fromInstanceType->is<AnyMetatypeType>() &&
toInstanceType->is<ExistentialMetatypeType>()) {
fromInstanceType = fromInstanceType->castTo<AnyMetatypeType>()->getInstanceType();
toInstanceType = toInstanceType->castTo<ExistentialMetatypeType>()->getInstanceType();
}
ASTContext &ctx = cs.getASTContext();
auto conformances =
collectExistentialConformances(fromInstanceType, toInstanceType, cs.DC);
// For existential-to-existential coercions, open the source existential.
if (fromType->isAnyExistentialType()) {
fromType = OpenedArchetypeType::getAny(fromType);
auto *archetypeVal = cs.cacheType(
new (ctx) OpaqueValueExpr(expr->getSourceRange(), fromType));
auto *result = cs.cacheType(ErasureExpr::create(ctx, archetypeVal, toType,
conformances));
return cs.cacheType(
new (ctx) OpenExistentialExpr(expr, archetypeVal, result,
cs.getType(result)));
}
// Load tuples with lvalue elements.
if (auto tupleType = fromType->getAs<TupleType>()) {
if (tupleType->hasLValueType()) {
expr = cs.coerceToRValue(expr);
}
}
return cs.cacheType(ErasureExpr::create(ctx, expr, toType, conformances));
}
/// Given that the given expression is an implicit conversion added
/// to the target by coerceToType, find out how many OptionalEvaluationExprs
/// it includes and the target.
static unsigned getOptionalEvaluationDepth(Expr *expr, Expr *target) {
unsigned depth = 0;
while (true) {
// Look through sugar expressions.
expr = expr->getSemanticsProvidingExpr();
// If we find the target expression, we're done.
if (expr == target) return depth;
// If we see an optional evaluation, the depth goes up.
if (auto optEval = dyn_cast<OptionalEvaluationExpr>(expr)) {
++depth;
expr = optEval->getSubExpr();
// We have to handle any other expressions that can be introduced by
// coerceToType.
} else if (auto bind = dyn_cast<BindOptionalExpr>(expr)) {
expr = bind->getSubExpr();
} else if (auto force = dyn_cast<ForceValueExpr>(expr)) {
expr = force->getSubExpr();
} else if (auto open = dyn_cast<OpenExistentialExpr>(expr)) {
depth += getOptionalEvaluationDepth(open->getSubExpr(),
open->getOpaqueValue());
expr = open->getExistentialValue();
// Otherwise, look through implicit conversions.
} else {
expr = cast<ImplicitConversionExpr>(expr)->getSubExpr();
}
}
}
Expr *ExprRewriter::coerceOptionalToOptional(Expr *expr, Type toType,
ConstraintLocatorBuilder locator,
Optional<Pattern*> typeFromPattern) {
auto &ctx = cs.getASTContext();
Type fromType = cs.getType(expr);
TypeChecker::requireOptionalIntrinsics(ctx, expr->getLoc());
SmallVector<Type, 4> fromOptionals;
(void)fromType->lookThroughAllOptionalTypes(fromOptionals);
SmallVector<Type, 4> toOptionals;
(void)toType->lookThroughAllOptionalTypes(toOptionals);
assert(!toOptionals.empty());
assert(!fromOptionals.empty());
// If we are adding optionals but the types are equivalent up to the common
// depth, peephole the optional-to-optional conversion into a series of nested
// injections.
auto toDepth = toOptionals.size();
auto fromDepth = fromOptionals.size();
if (toDepth > fromDepth &&
toOptionals[toOptionals.size() - fromDepth]->isEqual(fromType)) {
auto diff = toDepth - fromDepth;
while (diff--) {
Type type = toOptionals[diff];
expr = cs.cacheType(new (ctx) InjectIntoOptionalExpr(expr, type));
diagnoseOptionalInjection(cast<InjectIntoOptionalExpr>(expr));
}
return expr;
}
Type fromValueType = fromType->getOptionalObjectType();
Type toValueType = toType->getOptionalObjectType();
// The depth we use here will get patched after we apply the coercion.
auto bindOptional =
new (ctx) BindOptionalExpr(expr, expr->getSourceRange().End,
/*depth*/ 0, fromValueType);
expr = cs.cacheType(bindOptional);
expr->setImplicit(true);
expr = coerceToType(expr, toValueType, locator, typeFromPattern);
if (!expr) return nullptr;
unsigned depth = getOptionalEvaluationDepth(expr, bindOptional);
bindOptional->setDepth(depth);
expr = cs.cacheType(new (ctx) InjectIntoOptionalExpr(expr, toType));
expr = cs.cacheType(new (ctx) OptionalEvaluationExpr(expr, toType));
expr->setImplicit(true);
return expr;
}
Expr *ExprRewriter::coerceImplicitlyUnwrappedOptionalToValue(Expr *expr, Type objTy) {
auto optTy = cs.getType(expr);
// Preserve l-valueness of the result.
if (optTy->is<LValueType>())
objTy = LValueType::get(objTy);
expr = new (cs.getASTContext()) ForceValueExpr(expr, expr->getEndLoc(),
/* forcedIUO=*/ true);
cs.setType(expr, objTy);
expr->setImplicit();
return expr;
}
/// Determine whether the given expression is a reference to an
/// unbound instance member of a type.
static bool isReferenceToMetatypeMember(ConstraintSystem &cs, Expr *expr) {
expr = expr->getSemanticsProvidingExpr();
if (auto dotIgnored = dyn_cast<DotSyntaxBaseIgnoredExpr>(expr))
return cs.getType(dotIgnored->getLHS())->is<AnyMetatypeType>();
if (auto dotSyntax = dyn_cast<DotSyntaxCallExpr>(expr))
return cs.getType(dotSyntax->getBase())->is<AnyMetatypeType>();
return false;
}
static bool hasCurriedSelf(ConstraintSystem &cs, ConcreteDeclRef callee,
ApplyExpr *apply) {
// If we do not have a callee, return false.
if (!callee) {
return false;
}
// Only calls to members of types can have curried 'self'.
auto calleeDecl = callee.getDecl();
if (!calleeDecl->getDeclContext()->isTypeContext()) {
return false;
}
// Would have `self`, if we're not applying it.
if (auto *call = dyn_cast<CallExpr>(apply)) {
if (!calleeDecl->isInstanceMember() ||
!isReferenceToMetatypeMember(cs, call->getDirectCallee())) {
return true;
}
return false;
}
// Operators have curried self.
if (isa<PrefixUnaryExpr>(apply) || isa<PostfixUnaryExpr>(apply) ||
isa<BinaryExpr>(apply)) {
return true;
}
// Otherwise, we have a normal application.
return false;
}
Expr *ExprRewriter::coerceCallArguments(
Expr *arg, AnyFunctionType *funcType,
ConcreteDeclRef callee,
ApplyExpr *apply,
ArrayRef<Identifier> argLabels,
ConstraintLocatorBuilder locator) {
auto &ctx = getConstraintSystem().getASTContext();
auto params = funcType->getParams();
// Local function to produce a locator to refer to the given parameter.
auto getArgLocator =
[&](unsigned argIdx, unsigned paramIdx,
ParameterTypeFlags flags) -> ConstraintLocatorBuilder {
return locator.withPathElement(
LocatorPathElt::ApplyArgToParam(argIdx, paramIdx, flags));
};
// Determine whether this application has curried self.
bool skipCurriedSelf = apply ? hasCurriedSelf(cs, callee, apply) : true;
// Determine the parameter bindings.
ParameterListInfo paramInfo(params, callee.getDecl(), skipCurriedSelf);
SmallVector<AnyFunctionType::Param, 8> args;
AnyFunctionType::decomposeInput(cs.getType(arg), args);
// If this application is an init(wrappedValue:) call that needs an injected
// wrapped value placeholder, the first non-defaulted argument must be
// wrapped in an OpaqueValueExpr.
bool shouldInjectWrappedValuePlaceholder =
target->shouldInjectWrappedValuePlaceholder(apply);
auto injectWrappedValuePlaceholder =
[&](Expr *arg, bool isAutoClosure = false) -> Expr * {
auto *placeholder = PropertyWrapperValuePlaceholderExpr::create(
ctx, arg->getSourceRange(), cs.getType(arg),
target->propertyWrapperHasInitialWrappedValue() ? arg : nullptr,
isAutoClosure);
cs.cacheType(placeholder);
cs.cacheType(placeholder->getOpaqueValuePlaceholder());
shouldInjectWrappedValuePlaceholder = false;
return placeholder;
};
// Quickly test if any further fix-ups for the argument types are necessary.
if (AnyFunctionType::equalParams(args, params) &&
!shouldInjectWrappedValuePlaceholder)
return arg;
// Apply labels to arguments.
AnyFunctionType::relabelParams(args, argLabels);
MatchCallArgumentListener listener;
auto unlabeledTrailingClosureIndex =
arg->getUnlabeledTrailingClosureIndexOfPackedArgument();
// Determine the trailing closure matching rule that was applied. This
// is only relevant for explicit calls and subscripts.
auto trailingClosureMatching = TrailingClosureMatching::Forward;
{
SmallVector<LocatorPathElt, 4> path;
auto anchor = locator.getLocatorParts(path);
if (!path.empty() && path.back().is<LocatorPathElt::ApplyArgument>() &&
!anchor.isExpr(ExprKind::UnresolvedDot)) {
auto locatorPtr = cs.getConstraintLocator(locator);
assert(solution.trailingClosureMatchingChoices.count(locatorPtr) == 1);
trailingClosureMatching = solution.trailingClosureMatchingChoices.find(
locatorPtr)->second;
}
}
auto callArgumentMatch = constraints::matchCallArguments(
args, params, paramInfo, unlabeledTrailingClosureIndex,
/*allowFixes=*/false, listener, trailingClosureMatching);
assert(callArgumentMatch && "Call arguments did not match up?");
auto parameterBindings = std::move(callArgumentMatch->parameterBindings);
// We should either have parentheses or a tuple.
auto *argTuple = dyn_cast<TupleExpr>(arg);
auto *argParen = dyn_cast<ParenExpr>(arg);
// FIXME: Eventually, we want to enforce that we have either argTuple or
// argParen here.
SourceLoc lParenLoc, rParenLoc;
if (argTuple) {
lParenLoc = argTuple->getLParenLoc();
rParenLoc = argTuple->getRParenLoc();
} else if (argParen) {
lParenLoc = argParen->getLParenLoc();
rParenLoc = argParen->getRParenLoc();
}
// Local function to extract the ith argument expression, which papers
// over some of the weirdness with tuples vs. parentheses.
auto getArg = [&](unsigned i) -> Expr * {
if (argTuple)
return argTuple->getElement(i);
assert(i == 0 && "Scalar only has a single argument");
if (argParen)
return argParen->getSubExpr();
return arg;
};
auto getLabelLoc = [&](unsigned i) -> SourceLoc {
if (argTuple)
return argTuple->getElementNameLoc(i);
assert(i == 0 && "Scalar only has a single argument");
return SourceLoc();
};
SmallVector<Expr *, 4> newArgs;
SmallVector<Identifier, 4> newLabels;
SmallVector<SourceLoc, 4> newLabelLocs;
SmallVector<AnyFunctionType::Param, 4> newParams;
for (unsigned paramIdx = 0, numParams = parameterBindings.size();
paramIdx != numParams; ++paramIdx) {
// Extract the parameter.
const auto &param = params[paramIdx];
newLabels.push_back(param.getLabel());
// Handle variadic parameters.
if (param.isVariadic()) {
assert(!param.isInOut());
SmallVector<Expr *, 4> variadicArgs;
// The first argument of this vararg parameter may have had a label;
// save its location.
auto &varargIndices = parameterBindings[paramIdx];
if (!varargIndices.empty())
newLabelLocs.push_back(getLabelLoc(varargIndices[0]));
else
newLabelLocs.push_back(SourceLoc());
// Convert the arguments.
for (auto argIdx : varargIndices) {
auto arg = getArg(argIdx);
auto argType = cs.getType(arg);
// If the argument type exactly matches, this just works.
if (argType->isEqual(param.getPlainType())) {
variadicArgs.push_back(arg);
continue;
}
// Convert the argument.
auto convertedArg = coerceToType(
arg, param.getPlainType(),
getArgLocator(argIdx, paramIdx, param.getParameterFlags()));
if (!convertedArg)
return nullptr;
// Add the converted argument.
variadicArgs.push_back(convertedArg);
}
SourceLoc start, end;
if (!variadicArgs.empty()) {
start = variadicArgs.front()->getStartLoc();
end = variadicArgs.back()->getEndLoc();
}
// Collect them into an ArrayExpr.
auto *arrayExpr = ArrayExpr::create(ctx, start, variadicArgs, {}, end,
param.getParameterType());
arrayExpr->setImplicit();
cs.cacheType(arrayExpr);
// Wrap the ArrayExpr in a VarargExpansionExpr.
auto *varargExpansionExpr = new (ctx)
VarargExpansionExpr(arrayExpr,
/*implicit=*/true, arrayExpr->getType());
cs.cacheType(varargExpansionExpr);
newArgs.push_back(varargExpansionExpr);
newParams.push_back(param);
continue;
}
// Handle default arguments.
if (parameterBindings[paramIdx].empty()) {
auto owner = getDefaultArgOwner(callee, paramIdx);
auto paramTy = param.getParameterType();
auto *defArg = new (ctx)
DefaultArgumentExpr(owner, paramIdx, arg->getStartLoc(), paramTy, dc);
cs.cacheType(defArg);
newArgs.push_back(defArg);
newParams.push_back(param);
newLabelLocs.push_back(SourceLoc());
continue;
}
// Otherwise, we have a plain old ordinary argument.
// Extract the argument used to initialize this parameter.
assert(parameterBindings[paramIdx].size() == 1);
unsigned argIdx = parameterBindings[paramIdx].front();
auto arg = getArg(argIdx);
auto argType = cs.getType(arg);
// Save the original label location.
newLabelLocs.push_back(getLabelLoc(argIdx));
// If the types exactly match, this is easy.
auto paramType = param.getOldType();
if (argType->isEqual(paramType) && !shouldInjectWrappedValuePlaceholder) {
newArgs.push_back(arg);
newParams.push_back(param);
continue;
}
Expr *convertedArg = nullptr;
auto argRequiresAutoClosureExpr = [&](const AnyFunctionType::Param &param,
Type argType) {
if (!param.isAutoClosure())
return false;
// Since it was allowed to pass function types to @autoclosure
// parameters in Swift versions < 5, it has to be handled as
// a regular function coversion by `coerceToType`.
if (isAutoClosureArgument(arg)) {
// In Swift >= 5 mode we only allow `@autoclosure` arguments
// to be used by value if parameter would return a function
// type (it just needs to get wrapped into autoclosure expr),
// otherwise argument must always form a call.
return cs.getASTContext().isSwiftVersionAtLeast(5);
}
return true;
};
if (argRequiresAutoClosureExpr(param, argType)) {
assert(!param.isInOut());
// If parameter is an autoclosure, we need to make sure that:
// - argument type is coerced to parameter result type
// - impilict autoclosure is created to wrap argument expression
// - new types are propagated to constraint system
auto *closureType = param.getPlainType()->castTo<FunctionType>();
auto argLoc = getArgLocator(argIdx, paramIdx, param.getParameterFlags());
arg = coerceToType(
arg, closureType->getResult(),
argLoc.withPathElement(ConstraintLocator::AutoclosureResult));
if (shouldInjectWrappedValuePlaceholder) {
// If init(wrappedValue:) takes an autoclosure, then we want
// the effect of autoclosure forwarding of the placeholder
// autoclosure. The only way to do this is to call the placeholder
// autoclosure when passing it to the init.
bool isDefaultWrappedValue =
target->propertyWrapperHasInitialWrappedValue();
auto *placeholder = injectWrappedValuePlaceholder(
cs.buildAutoClosureExpr(arg, closureType, isDefaultWrappedValue),
/*isAutoClosure=*/true);
arg = CallExpr::createImplicit(ctx, placeholder, {}, {});
arg->setType(closureType->getResult());
cs.cacheType(arg);
}
convertedArg = cs.buildAutoClosureExpr(arg, closureType);
} else {
convertedArg = coerceToType(
arg, paramType,
getArgLocator(argIdx, paramIdx, param.getParameterFlags()));
}
// Perform the wrapped value placeholder injection
if (shouldInjectWrappedValuePlaceholder)
convertedArg = injectWrappedValuePlaceholder(convertedArg);
if (!convertedArg)
return nullptr;
newArgs.push_back(convertedArg);
// Make an effort to preserve the sugared type of the argument in the
// case where there was no conversion, instead of using the parameter
// type.
newParams.emplace_back(cs.getType(convertedArg)->getInOutObjectType(),
param.getLabel(),
param.getParameterFlags());
}
assert(newArgs.size() == newParams.size());
assert(newArgs.size() == newLabels.size());
assert(newArgs.size() == newLabelLocs.size());
// This is silly. SILGen gets confused if a 'self' parameter is wrapped
// in a ParenExpr sometimes.
if (!argTuple && !argParen &&
(params[0].getValueOwnership() == ValueOwnership::Default ||
params[0].getValueOwnership() == ValueOwnership::InOut)) {
assert(newArgs.size() == 1);
assert(!unlabeledTrailingClosureIndex);
return newArgs[0];
}
// Rebuild the argument list, sharing as much structure as possible.
auto paramType = AnyFunctionType::composeInput(ctx, newParams,
/*canonicalVararg=*/false);
if (isa<ParenType>(paramType.getPointer())) {
if (argParen) {
// We already had a ParenExpr, so replace it's sub-expression.
argParen->setSubExpr(newArgs[0]);
} else {
bool isImplicit = arg->isImplicit();
arg = new (ctx) ParenExpr(
lParenLoc, newArgs[0], rParenLoc,
static_cast<bool>(unlabeledTrailingClosureIndex));
arg->setImplicit(isImplicit);
}
} else {
assert(isa<TupleType>(paramType.getPointer()));
if (argTuple && newArgs.size() == argTuple->getNumElements()) {
// The existing TupleExpr has the right number of elements,
// replace them.
for (unsigned i = 0, e = newArgs.size(); i != e; ++i) {
argTuple->setElement(i, newArgs[i]);
}
} else {
// Build a new TupleExpr, re-using source location information.
arg = TupleExpr::create(ctx, lParenLoc, rParenLoc, newArgs, newLabels,
newLabelLocs, unlabeledTrailingClosureIndex,
/*implicit=*/arg->isImplicit());
}
}
arg->setType(paramType);
return cs.cacheType(arg);
}
static bool isClosureLiteralExpr(Expr *expr) {
expr = expr->getSemanticsProvidingExpr();
return (isa<CaptureListExpr>(expr) || isa<ClosureExpr>(expr));
}
/// If the expression is an explicit closure expression (potentially wrapped in
/// IdentityExprs), change the type of the closure and identities to the
/// specified type and return true. Otherwise, return false with no effect.
static bool applyTypeToClosureExpr(ConstraintSystem &cs,
Expr *expr, Type toType) {
// Look through identity expressions, like parens.
if (auto IE = dyn_cast<IdentityExpr>(expr)) {
if (!applyTypeToClosureExpr(cs, IE->getSubExpr(), toType)) return false;
cs.setType(IE, toType);
return true;
}
// Look through capture lists.
if (auto CLE = dyn_cast<CaptureListExpr>(expr)) {
if (!applyTypeToClosureExpr(cs, CLE->getClosureBody(), toType)) return false;
cs.setType(CLE, toType);
return true;
}
// If we found an explicit ClosureExpr, update its type.
if (auto CE = dyn_cast<ClosureExpr>(expr)) {
cs.setType(CE, toType);
// If this closure isn't type-checked in its enclosing expression, write
// the type into the ClosureExpr directly here, since the visitor won't.
if (!shouldTypeCheckInEnclosingExpression(CE))
CE->setType(toType);
return true;
}
// Otherwise fail.
return false;
}
// Look through sugar and DotSyntaxBaseIgnoredExprs.
static Expr *
getSemanticExprForDeclOrMemberRef(Expr *expr) {
auto semanticExpr = expr->getSemanticsProvidingExpr();
while (auto ignoredBase = dyn_cast<DotSyntaxBaseIgnoredExpr>(semanticExpr)){
semanticExpr = ignoredBase->getRHS()->getSemanticsProvidingExpr();
}
return semanticExpr;
}
static void
maybeDiagnoseUnsupportedDifferentiableConversion(ConstraintSystem &cs,
Expr *expr,
AnyFunctionType *toType) {
ASTContext &ctx = cs.getASTContext();
Type fromType = cs.getType(expr);
auto fromFnType = fromType->getAs<AnyFunctionType>();
// Conversion between two different differentiable function types is not
// yet supported.
if (fromFnType->isDifferentiable() && toType->isDifferentiable() &&
fromFnType->getDifferentiabilityKind() !=
toType->getDifferentiabilityKind()) {
ctx.Diags.diagnose(expr->getLoc(),
diag::invalid_differentiable_function_conversion_expr);
return;
}
// Conversion from a non-`@differentiable` function to a `@differentiable` is
// only allowed from a closure expression or a declaration/member reference.
if (!fromFnType->isDifferentiable() && toType->isDifferentiable()) {
std::function<void(Expr *)> maybeDiagnoseFunctionRef;
maybeDiagnoseFunctionRef = [&](Expr *semanticExpr) {
if (auto *capture = dyn_cast<CaptureListExpr>(semanticExpr))
semanticExpr = capture->getClosureBody();
if (isa<ClosureExpr>(semanticExpr)) return;
if (auto *declRef = dyn_cast<DeclRefExpr>(semanticExpr)) {
if (isa<AbstractFunctionDecl>(declRef->getDecl())) return;
// If the referenced decl is a function parameter, the user may want
// to change the declaration to be a '@differentiable' closure. Emit a
// note with a fix-it.
if (auto *paramDecl = dyn_cast<ParamDecl>(declRef->getDecl())) {
ctx.Diags.diagnose(
expr->getLoc(),
diag::invalid_differentiable_function_conversion_expr);
if (paramDecl->getType()->is<AnyFunctionType>()) {
auto *typeRepr = paramDecl->getTypeRepr();
while (auto *attributed = dyn_cast<AttributedTypeRepr>(typeRepr))
typeRepr = attributed->getTypeRepr();
std::string attributeString = "@differentiable";
auto *funcTypeRepr = cast<FunctionTypeRepr>(typeRepr);
auto paramListLoc = funcTypeRepr->getArgsTypeRepr()->getStartLoc();
ctx.Diags.diagnose(paramDecl->getLoc(),
diag::invalid_differentiable_function_conversion_parameter,
attributeString)
.highlight(paramDecl->getTypeRepr()->getSourceRange())
.fixItInsert(paramListLoc, attributeString + " ");
}
return;
}
} else if (auto *memberRef = dyn_cast<MemberRefExpr>(semanticExpr)) {
if (isa<FuncDecl>(memberRef->getMember().getDecl())) return;
} else if (auto *dotSyntaxCall =
dyn_cast<DotSyntaxCallExpr>(semanticExpr)) {
// Recurse on the function expression.
auto *fnExpr = dotSyntaxCall->getFn()->getSemanticsProvidingExpr();
maybeDiagnoseFunctionRef(fnExpr);
return;
} else if (auto *autoclosureExpr = dyn_cast<AutoClosureExpr>(semanticExpr)) {
// Peer through curry thunks.
if (auto *unwrappedFnExpr = autoclosureExpr->getUnwrappedCurryThunkExpr()) {
maybeDiagnoseFunctionRef(unwrappedFnExpr);
return;
}
}
ctx.Diags.diagnose(expr->getLoc(),
diag::invalid_differentiable_function_conversion_expr);
};
maybeDiagnoseFunctionRef(getSemanticExprForDeclOrMemberRef(expr));
}
}
static void
maybeDiagnoseUnsupportedFunctionConversion(ConstraintSystem &cs, Expr *expr,
AnyFunctionType *toType) {
auto &de = cs.getASTContext().Diags;
Type fromType = cs.getType(expr);
auto fromFnType = fromType->getAs<AnyFunctionType>();
// Conversions to C function pointer type are limited. Since a C function
// pointer captures no context, we can only do the necessary thunking or
// codegen if the original function is a direct reference to a global function
// or context-free closure or local function.
if (toType->getRepresentation()
== AnyFunctionType::Representation::CFunctionPointer) {
// Can convert from an ABI-compatible C function pointer.
if (fromFnType
&& fromFnType->getRepresentation()
== AnyFunctionType::Representation::CFunctionPointer)
return;
// Can convert a decl ref to a global or local function that doesn't
// capture context. Look through ignored bases too.
// TODO: Look through static method applications to the type.
auto semanticExpr = getSemanticExprForDeclOrMemberRef(expr);
auto maybeDiagnoseFunctionRef = [&](FuncDecl *fn) {
// TODO: We could allow static (or class final) functions too by
// "capturing" the metatype in a thunk.
if (fn->getDeclContext()->isTypeContext()) {
de.diagnose(expr->getLoc(), diag::c_function_pointer_from_method);
} else if (fn->getGenericParams()) {
de.diagnose(expr->getLoc(),
diag::c_function_pointer_from_generic_function);
}
};
if (auto declRef = dyn_cast<DeclRefExpr>(semanticExpr)) {
if (auto fn = dyn_cast<FuncDecl>(declRef->getDecl())) {
return maybeDiagnoseFunctionRef(fn);
}
}
if (auto memberRef = dyn_cast<MemberRefExpr>(semanticExpr)) {
if (auto fn = dyn_cast<FuncDecl>(memberRef->getMember().getDecl())) {
return maybeDiagnoseFunctionRef(fn);
}
}
// Unwrap closures with explicit capture lists.
if (auto capture = dyn_cast<CaptureListExpr>(semanticExpr))
semanticExpr = capture->getClosureBody();
// Can convert a literal closure that doesn't capture context.
if (auto closure = dyn_cast<ClosureExpr>(semanticExpr))
return;
// Diagnose cases like:
// func f() { print(w) }; func g(_ : @convention(c) () -> ()) {}
// let k = f; g(k) // error
// func m() { let x = 0; g({ print(x) }) } // error
// (See also: [NOTE: diagnose-swift-to-c-convention-change])
de.diagnose(expr->getLoc(),
diag::invalid_c_function_pointer_conversion_expr);
}
}
/// Build the conversion of an element in a collection upcast.
static Expr *buildElementConversion(ExprRewriter &rewriter,
SourceRange srcRange, Type srcType,
Type destType, bool bridged,
ConstraintLocatorBuilder locator,
Expr *element) {
auto &cs = rewriter.getConstraintSystem();
if (bridged &&
TypeChecker::typeCheckCheckedCast(srcType, destType,
CheckedCastContextKind::None, cs.DC,
SourceLoc(), nullptr, SourceRange())
!= CheckedCastKind::Coercion) {
if (auto conversion =
rewriter.buildObjCBridgeExpr(element, destType, locator))
return conversion;
}
return rewriter.coerceToType(element, destType, locator);
}
static CollectionUpcastConversionExpr::ConversionPair
buildOpaqueElementConversion(ExprRewriter &rewriter, SourceRange srcRange,
Type srcCollectionType, Type destCollectionType,
bool bridged, ConstraintLocatorBuilder locator,
unsigned typeArgIndex) {
// We don't need this stuff unless we've got generalized casts.
Type srcType = srcCollectionType->castTo<BoundGenericType>()
->getGenericArgs()[typeArgIndex];
Type destType = destCollectionType->castTo<BoundGenericType>()
->getGenericArgs()[typeArgIndex];
// Build the conversion.
auto &cs = rewriter.getConstraintSystem();
ASTContext &ctx = cs.getASTContext();
auto opaque =
rewriter.cs.cacheType(new (ctx) OpaqueValueExpr(srcRange, srcType));
Expr *conversion = buildElementConversion(
rewriter, srcRange, srcType, destType, bridged,
locator.withPathElement(LocatorPathElt::GenericArgument(typeArgIndex)),
opaque);
return { opaque, conversion };
}
void ExprRewriter::peepholeArrayUpcast(ArrayExpr *expr, Type toType,
bool bridged, Type elementType,
ConstraintLocatorBuilder locator) {
// Update the type of the array literal.
cs.setType(expr, toType);
// FIXME: finish{Array,Dictionary}Expr invoke cacheExprTypes after forming
// the semantic expression for the dictionary literal, which will undo the
// type we set here if this dictionary literal is nested unless we update
// the expr type as well.
expr->setType(toType);
// Convert the elements.
ConstraintLocatorBuilder innerLocator =
locator.withPathElement(LocatorPathElt::GenericArgument(0));
for (auto &element : expr->getElements()) {
if (auto newElement = buildElementConversion(*this, expr->getLoc(),
cs.getType(element),
elementType,
bridged, innerLocator,
element)) {
element = newElement;
}
}
(void)finishArrayExpr(expr);
}
void ExprRewriter::peepholeDictionaryUpcast(DictionaryExpr *expr,
Type toType, bool bridged,
Type keyType, Type valueType,
ConstraintLocatorBuilder locator) {
// Update the type of the dictionary literal.
cs.setType(expr, toType);
// FIXME: finish{Array,Dictionary}Expr invoke cacheExprTypes after forming
// the semantic expression for the dictionary literal, which will undo the
// type we set here if this dictionary literal is nested unless we update
// the expr type as well.
expr->setType(toType);
ConstraintLocatorBuilder valueLocator =
locator.withPathElement(LocatorPathElt::GenericArgument(1));
// Convert the elements.
TupleTypeElt tupleTypeElts[2] = { keyType, valueType };
auto tupleType = TupleType::get(tupleTypeElts, cs.getASTContext());
for (auto element : expr->getElements()) {
if (auto tuple = dyn_cast<TupleExpr>(element)) {
auto key = tuple->getElement(0);
if (auto newKey = buildElementConversion(*this, expr->getLoc(),
cs.getType(key), keyType,
bridged, valueLocator, key))
tuple->setElement(0, newKey);
auto value = tuple->getElement(1);
if (auto newValue = buildElementConversion(*this, expr->getLoc(),
cs.getType(value), valueType,
bridged, valueLocator,
value)) {
tuple->setElement(1, newValue);
}
cs.setType(tuple, tupleType);
// FIXME: finish{Array,Dictionary}Expr invoke cacheExprTypes after forming
// the semantic expression for the dictionary literal, which will undo the
// type we set here if this dictionary literal is nested unless we update
// the expr type as well.
tuple->setType(tupleType);
}
}
(void)finishDictionaryExpr(expr);
}
bool ExprRewriter::peepholeCollectionUpcast(Expr *expr, Type toType,
bool bridged,
ConstraintLocatorBuilder locator) {
// Recur into parenthesized expressions.
if (auto paren = dyn_cast<ParenExpr>(expr)) {
// If we can't peephole the subexpression, we're done.
if (!peepholeCollectionUpcast(paren->getSubExpr(), toType, bridged,
locator))
return false;
// Update the type of this expression.
auto parenTy = ParenType::get(cs.getASTContext(),
cs.getType(paren->getSubExpr()));
cs.setType(paren, parenTy);
// FIXME: finish{Array,Dictionary}Expr invoke cacheExprTypes after forming
// the semantic expression for the dictionary literal, which will undo the
// type we set here if this dictionary literal is nested unless we update
// the expr type as well.
paren->setType(parenTy);
return true;
}
// Array literals.
if (auto arrayLiteral = dyn_cast<ArrayExpr>(expr)) {
if (Optional<Type> elementType = ConstraintSystem::isArrayType(toType)) {
peepholeArrayUpcast(arrayLiteral, toType, bridged, *elementType, locator);
return true;
}
if (Optional<Type> elementType = ConstraintSystem::isSetType(toType)) {
peepholeArrayUpcast(arrayLiteral, toType, bridged, *elementType, locator);
return true;
}
return false;
}
// Dictionary literals.
if (auto dictLiteral = dyn_cast<DictionaryExpr>(expr)) {
if (auto elementType = ConstraintSystem::isDictionaryType(toType)) {
peepholeDictionaryUpcast(dictLiteral, toType, bridged,
elementType->first, elementType->second,
locator);
return true;
}
return false;
}
return false;
}
Expr *ExprRewriter::buildCollectionUpcastExpr(
Expr *expr, Type toType,
bool bridged,
ConstraintLocatorBuilder locator) {
if (peepholeCollectionUpcast(expr, toType, bridged, locator))
return expr;
ASTContext &ctx = cs.getASTContext();
// Build the first value conversion.
auto conv =
buildOpaqueElementConversion(*this, expr->getLoc(), cs.getType(expr),
toType, bridged, locator, 0);
// For single-parameter collections, form the upcast.
if (ConstraintSystem::isArrayType(toType) ||
ConstraintSystem::isSetType(toType)) {
return cs.cacheType(
new (ctx) CollectionUpcastConversionExpr(expr, toType, {}, conv));
}
assert(ConstraintSystem::isDictionaryType(toType) &&
"Unhandled collection upcast");
// Build the second value conversion.
auto conv2 =
buildOpaqueElementConversion(*this, expr->getLoc(), cs.getType(expr),
toType, bridged, locator, 1);
return cs.cacheType(
new (ctx) CollectionUpcastConversionExpr(expr, toType, conv, conv2));
}
Expr *ExprRewriter::buildObjCBridgeExpr(Expr *expr, Type toType,
ConstraintLocatorBuilder locator) {
Type fromType = cs.getType(expr);
// Bridged collection casts always succeed, so we treat them as
// collection "upcasts".
if ((ConstraintSystem::isArrayType(fromType) &&
ConstraintSystem::isArrayType(toType)) ||
(ConstraintSystem::isDictionaryType(fromType) &&
ConstraintSystem::isDictionaryType(toType)) ||
(ConstraintSystem::isSetType(fromType) &&
ConstraintSystem::isSetType(toType))) {
return buildCollectionUpcastExpr(expr, toType, /*bridged=*/true, locator);
}
// Bridging from a Swift type to an Objective-C class type.
if (toType->isAnyObject() ||
(fromType->getRValueType()->isPotentiallyBridgedValueType() &&
(toType->isBridgeableObjectType() || toType->isExistentialType()))) {
// Bridging to Objective-C.
Expr *objcExpr = bridgeToObjectiveC(expr, toType);
if (!objcExpr)
return nullptr;
// We might have a coercion of a Swift type to a CF type toll-free
// bridged to Objective-C.
//
// FIXME: Ideally we would instead have already recorded a restriction
// when solving the constraint, and we wouldn't need to duplicate this
// part of coerceToType() here.
if (auto foreignClass = toType->getClassOrBoundGenericClass()) {
if (foreignClass->getForeignClassKind() ==
ClassDecl::ForeignKind::CFType) {
return cs.cacheType(new (cs.getASTContext())
ForeignObjectConversionExpr(objcExpr, toType));
}
}
return coerceToType(objcExpr, toType, locator);
}
// Bridging from an Objective-C class type to a Swift type.
return forceBridgeFromObjectiveC(expr, toType);
}
Expr *ConstraintSystem::addImplicitLoadExpr(Expr *expr) {
return TypeChecker::addImplicitLoadExpr(
getASTContext(), expr, [this](Expr *expr) { return getType(expr); },
[this](Expr *expr, Type type) { setType(expr, type); });
}
Expr *ExprRewriter::coerceToType(Expr *expr, Type toType,
ConstraintLocatorBuilder locator,
Optional<Pattern*> typeFromPattern) {
auto &ctx = cs.getASTContext();
// The type we're converting from.
Type fromType = cs.getType(expr);
// If the types are already equivalent, we don't have to do anything.
if (fromType->isEqual(toType))
return expr;
// If the solver recorded what we should do here, just do it immediately.
auto knownRestriction = solution.ConstraintRestrictions.find(
{ fromType->getCanonicalType(),
toType->getCanonicalType() });
if (knownRestriction != solution.ConstraintRestrictions.end()) {
switch (knownRestriction->second) {
case ConversionRestrictionKind::DeepEquality: {
assert(!toType->hasUnresolvedType());
// HACK: Fix problem related to Swift 4 mode (with assertions),
// since Swift 4 mode allows passing arguments with extra parens
// to parameters which don't expect them, it should be supported
// by "deep equality" type - Optional<T> e.g.
// ```swift
// func foo(_: (() -> Void)?) {}
// func bar() -> ((()) -> Void)? { return nil }
// foo(bar) // This expression should compile in Swift 3 mode
// ```
//
// See also: https://bugs.swift.org/browse/SR-6796
if (cs.getASTContext().isSwiftVersionAtLeast(4) &&
!cs.getASTContext().isSwiftVersionAtLeast(5)) {
auto obj1 = fromType->getOptionalObjectType();
auto obj2 = toType->getOptionalObjectType();
if (obj1 && obj2) {
auto *fn1 = obj1->getAs<AnyFunctionType>();
auto *fn2 = obj2->getAs<AnyFunctionType>();
if (fn1 && fn2) {
auto params1 = fn1->getParams();
auto params2 = fn2->getParams();
// This handles situations like argument: (()), parameter: ().
if (params1.size() == 1 && params2.empty()) {
auto tupleTy = params1.front().getOldType()->getAs<TupleType>();
if (tupleTy && tupleTy->getNumElements() == 0)
break;
}
}
}
}
auto &err = llvm::errs();
err << "fromType->getCanonicalType() = ";
fromType->getCanonicalType()->dump(err);
err << "toType->getCanonicalType() = ";
toType->getCanonicalType()->dump(err);
llvm_unreachable("Should be handled above");
}
case ConversionRestrictionKind::Superclass:
case ConversionRestrictionKind::ExistentialMetatypeToMetatype:
return coerceSuperclass(expr, toType);
case ConversionRestrictionKind::Existential:
case ConversionRestrictionKind::MetatypeToExistentialMetatype:
return coerceExistential(expr, toType);
case ConversionRestrictionKind::ClassMetatypeToAnyObject: {
assert(ctx.LangOpts.EnableObjCInterop &&
"metatypes can only be cast to objects w/ objc runtime!");
return cs.cacheType(new (ctx) ClassMetatypeToObjectExpr(expr, toType));
}
case ConversionRestrictionKind::ExistentialMetatypeToAnyObject: {
assert(ctx.LangOpts.EnableObjCInterop &&
"metatypes can only be cast to objects w/ objc runtime!");
return cs.cacheType(new (ctx)
ExistentialMetatypeToObjectExpr(expr, toType));
}
case ConversionRestrictionKind::ProtocolMetatypeToProtocolClass: {
return cs.cacheType(new (ctx) ProtocolMetatypeToObjectExpr(expr, toType));
}
case ConversionRestrictionKind::ValueToOptional: {
auto toGenericType = toType->castTo<BoundGenericType>();
assert(toGenericType->getDecl()->isOptionalDecl());
TypeChecker::requireOptionalIntrinsics(cs.getASTContext(),
expr->getLoc());
Type valueType = toGenericType->getGenericArgs()[0];
expr = coerceToType(expr, valueType, locator);
if (!expr) return nullptr;
auto *result =
cs.cacheType(new (ctx) InjectIntoOptionalExpr(expr, toType));
diagnoseOptionalInjection(result);
return result;
}
case ConversionRestrictionKind::OptionalToOptional:
return coerceOptionalToOptional(expr, toType, locator, typeFromPattern);
case ConversionRestrictionKind::ArrayUpcast: {
// Build the value conversion.
return buildCollectionUpcastExpr(expr, toType, /*bridged=*/false,
locator);
}
case ConversionRestrictionKind::HashableToAnyHashable: {
// We want to check conformance on the rvalue, as that's what has
// the Hashable conformance
expr = cs.coerceToRValue(expr);
// Find the conformance of the source type to Hashable.
auto hashable = ctx.getProtocol(KnownProtocolKind::Hashable);
auto conformance =
TypeChecker::conformsToProtocol(
cs.getType(expr), hashable, cs.DC);
assert(conformance && "must conform to Hashable");
return cs.cacheType(
new (ctx) AnyHashableErasureExpr(expr, toType, conformance));
}
case ConversionRestrictionKind::DictionaryUpcast: {
// Build the value conversion.
return buildCollectionUpcastExpr(expr, toType, /*bridged=*/false,
locator);
}
case ConversionRestrictionKind::SetUpcast: {
// Build the value conversion.
return buildCollectionUpcastExpr(expr, toType, /*bridged=*/false, locator);
}
case ConversionRestrictionKind::InoutToPointer: {
bool isOptional = false;
Type unwrappedTy = toType;
if (Type unwrapped = toType->getOptionalObjectType()) {
isOptional = true;
unwrappedTy = unwrapped;
}
PointerTypeKind pointerKind;
auto toEltType = unwrappedTy->getAnyPointerElementType(pointerKind);
assert(toEltType && "not a pointer type?"); (void) toEltType;
TypeChecker::requirePointerArgumentIntrinsics(ctx, expr->getLoc());
Expr *result =
cs.cacheType(new (ctx) InOutToPointerExpr(expr, unwrappedTy));
if (isOptional)
result = cs.cacheType(new (ctx) InjectIntoOptionalExpr(result, toType));
return result;
}
case ConversionRestrictionKind::ArrayToPointer: {
bool isOptional = false;
Type unwrappedTy = toType;
if (Type unwrapped = toType->getOptionalObjectType()) {
isOptional = true;
unwrappedTy = unwrapped;
}
TypeChecker::requirePointerArgumentIntrinsics(ctx, expr->getLoc());
Expr *result =
cs.cacheType(new (ctx) ArrayToPointerExpr(expr, unwrappedTy));
if (isOptional)
result = cs.cacheType(new (ctx) InjectIntoOptionalExpr(result, toType));
return result;
}
case ConversionRestrictionKind::StringToPointer: {
bool isOptional = false;
Type unwrappedTy = toType;
if (Type unwrapped = toType->getOptionalObjectType()) {
isOptional = true;
unwrappedTy = unwrapped;
}
TypeChecker::requirePointerArgumentIntrinsics(ctx, expr->getLoc());
Expr *result =
cs.cacheType(new (ctx) StringToPointerExpr(expr, unwrappedTy));
if (isOptional)
result = cs.cacheType(new (ctx) InjectIntoOptionalExpr(result, toType));
return result;
}
case ConversionRestrictionKind::PointerToPointer: {
TypeChecker::requirePointerArgumentIntrinsics(ctx, expr->getLoc());
Type unwrappedToTy = toType->getOptionalObjectType();
// Optional to optional.
if (Type unwrappedFromTy = cs.getType(expr)->getOptionalObjectType()) {
assert(unwrappedToTy && "converting optional to non-optional");
Expr *boundOptional = cs.cacheType(
new (ctx) BindOptionalExpr(expr, SourceLoc(),
/*depth*/ 0, unwrappedFromTy));
Expr *converted = cs.cacheType(
new (ctx) PointerToPointerExpr(boundOptional, unwrappedToTy));
Expr *rewrapped =
cs.cacheType(new (ctx) InjectIntoOptionalExpr(converted, toType));
return cs.cacheType(new (ctx)
OptionalEvaluationExpr(rewrapped, toType));
}
// Non-optional to optional.
if (unwrappedToTy) {
Expr *converted =
cs.cacheType(new (ctx) PointerToPointerExpr(expr, unwrappedToTy));
return cs.cacheType(new (ctx)
InjectIntoOptionalExpr(converted, toType));
}
// Non-optional to non-optional.
return cs.cacheType(new (ctx) PointerToPointerExpr(expr, toType));
}
case ConversionRestrictionKind::CFTollFreeBridgeToObjC: {
auto foreignClass = fromType->getClassOrBoundGenericClass();
auto objcType = foreignClass->getAttrs().getAttribute<ObjCBridgedAttr>()
->getObjCClass()->getDeclaredInterfaceType();
auto asObjCClass =
cs.cacheType(new (ctx) ForeignObjectConversionExpr(expr, objcType));
return coerceToType(asObjCClass, toType, locator);
}
case ConversionRestrictionKind::ObjCTollFreeBridgeToCF: {
auto foreignClass = toType->getClassOrBoundGenericClass();
auto objcType = foreignClass->getAttrs().getAttribute<ObjCBridgedAttr>()
->getObjCClass()->getDeclaredInterfaceType();
Expr *result = coerceToType(expr, objcType, locator);
if (!result)
return nullptr;
return cs.cacheType(new (ctx)
ForeignObjectConversionExpr(result, toType));
}
}
}
// Handle "from specific" coercions before "catch all" coercions.
auto desugaredFromType = fromType->getDesugaredType();
switch (desugaredFromType->getKind()) {
// Coercions from an lvalue: load or perform implicit address-of. We perform
// these coercions first because they are often the first step in a multi-step
// coercion.
case TypeKind::LValue: {
auto fromLValue = cast<LValueType>(desugaredFromType);
auto toIO = toType->getAs<InOutType>();
if (!toIO)
return coerceToType(cs.addImplicitLoadExpr(expr), toType, locator);
// In an 'inout' operator like "i += 1", the operand is converted from
// an implicit lvalue to an inout argument.
assert(toIO->getObjectType()->isEqual(fromLValue->getObjectType()));
return cs.cacheType(new (ctx) InOutExpr(expr->getStartLoc(), expr,
toIO->getObjectType(),
/*isImplicit*/ true));
}
// Coerce from a tuple to a tuple.
case TypeKind::Tuple: {
auto fromTuple = cast<TupleType>(desugaredFromType);
auto toTuple = toType->getAs<TupleType>();
if (!toTuple)
break;
if (fromTuple->hasLValueType() && !toTuple->hasLValueType())
return coerceToType(cs.coerceToRValue(expr), toType, locator);
SmallVector<unsigned, 4> sources;
if (!computeTupleShuffle(fromTuple, toTuple, sources)) {
return coerceTupleToTuple(expr, fromTuple, toTuple,
locator, sources);
}
break;
}
case TypeKind::PrimaryArchetype:
case TypeKind::OpenedArchetype:
case TypeKind::NestedArchetype:
case TypeKind::OpaqueTypeArchetype:
if (!cast<ArchetypeType>(desugaredFromType)->requiresClass())
break;
LLVM_FALLTHROUGH;
// Coercion from a subclass to a superclass.
//
// FIXME: Can we rig things up so that we always have a Superclass
// conversion restriction in this case?
case TypeKind::DynamicSelf:
case TypeKind::BoundGenericClass:
case TypeKind::Class: {
if (!toType->getClassOrBoundGenericClass())
break;
for (auto fromSuperClass = fromType->getSuperclass();
fromSuperClass;
fromSuperClass = fromSuperClass->getSuperclass()) {
if (fromSuperClass->isEqual(toType)) {
return coerceSuperclass(expr, toType);
}
}
break;
}
// Coercion from one function type to another, this produces a
// FunctionConversionExpr in its full generality.
case TypeKind::Function: {
auto fromFunc = cast<FunctionType>(desugaredFromType);
auto toFunc = toType->getAs<FunctionType>();
if (!toFunc)
break;
// Default argument generator must return escaping functions. Therefore, we
// leave an explicit escape to noescape cast here such that SILGen can skip
// the cast and emit a code for the escaping function.
bool isInDefaultArgumentContext = false;
if (auto initalizerCtx = dyn_cast<Initializer>(cs.DC))
isInDefaultArgumentContext = (initalizerCtx->getInitializerKind() ==
InitializerKind::DefaultArgument);
auto toEI = toFunc->getExtInfo();
assert(toType->is<FunctionType>());
// Handle implicit conversions between non-@differentiable and
// @differentiable functions.
{
auto fromEI = fromFunc->getExtInfo();
auto isFromDifferentiable = fromEI.isDifferentiable();
auto isToDifferentiable = toEI.isDifferentiable();
// Handle implicit conversion from @differentiable.
if (isFromDifferentiable && !isToDifferentiable) {
fromFunc = fromFunc->getWithoutDifferentiability()
->castTo<FunctionType>();
switch (fromEI.getDifferentiabilityKind()) {
// TODO: Ban `Normal` and `Forward` cases.
case DifferentiabilityKind::Normal:
case DifferentiabilityKind::Forward:
case DifferentiabilityKind::Reverse:
expr = cs.cacheType(new (ctx)
DifferentiableFunctionExtractOriginalExpr(expr, fromFunc));
break;
case DifferentiabilityKind::Linear:
expr = cs.cacheType(new (ctx)
LinearFunctionExtractOriginalExpr(expr, fromFunc));
break;
case DifferentiabilityKind::NonDifferentiable:
llvm_unreachable("Cannot be NonDifferentiable");
}
}
// Handle implicit conversion from non-@differentiable to @differentiable.
maybeDiagnoseUnsupportedDifferentiableConversion(cs, expr, toFunc);
if (!isFromDifferentiable && isToDifferentiable) {
auto newEI =
fromEI.intoBuilder()
.withDifferentiabilityKind(toEI.getDifferentiabilityKind())
.build();
fromFunc = FunctionType::get(toFunc->getParams(), fromFunc->getResult())
->withExtInfo(newEI)
->castTo<FunctionType>();
switch (toEI.getDifferentiabilityKind()) {
// TODO: Ban `Normal` and `Forward` cases.
case DifferentiabilityKind::Normal:
case DifferentiabilityKind::Forward:
case DifferentiabilityKind::Reverse:
expr = cs.cacheType(new (ctx)
DifferentiableFunctionExpr(expr, fromFunc));
break;
case DifferentiabilityKind::Linear:
expr = cs.cacheType(new (ctx) LinearFunctionExpr(expr, fromFunc));
break;
case DifferentiabilityKind::NonDifferentiable:
llvm_unreachable("Cannot be NonDifferentiable");
}
}
}
// If we have a ClosureExpr, then we can safely propagate the 'concurrent'
// bit to the closure without invalidating prior analysis.
auto fromEI = fromFunc->getExtInfo();
if (toEI.isConcurrent() && !fromEI.isConcurrent()) {
auto newFromFuncType = fromFunc->withExtInfo(fromEI.withConcurrent());
if (applyTypeToClosureExpr(cs, expr, newFromFuncType)) {
fromFunc = newFromFuncType->castTo<FunctionType>();
// Propagating the 'concurrent' bit might have satisfied the entire
// conversion. If so, we're done, otherwise keep converting.
if (fromFunc->isEqual(toType))
return expr;
}
}
// If we have a ClosureExpr, then we can safely propagate the 'no escape'
// bit to the closure without invalidating prior analysis.
fromEI = fromFunc->getExtInfo();
if (toEI.isNoEscape() && !fromEI.isNoEscape()) {
auto newFromFuncType = fromFunc->withExtInfo(fromEI.withNoEscape());
if (!isInDefaultArgumentContext &&
applyTypeToClosureExpr(cs, expr, newFromFuncType)) {
fromFunc = newFromFuncType->castTo<FunctionType>();
// Propagating the 'no escape' bit might have satisfied the entire
// conversion. If so, we're done, otherwise keep converting.
if (fromFunc->isEqual(toType))
return expr;
} else if (isInDefaultArgumentContext) {
// First apply the conversion *without* noescape attribute.
if (!newFromFuncType->isEqual(toType)) {
auto escapingToFuncTy =
toFunc->withExtInfo(toEI.withNoEscape(false));
maybeDiagnoseUnsupportedFunctionConversion(cs, expr, toFunc);
expr = cs.cacheType(
new (ctx) FunctionConversionExpr(expr, escapingToFuncTy));
}
// Apply an explict function conversion *only* for the escape to
// noescape conversion. This conversion will be stripped by the
// default argument generator. (We can't return a @noescape function)
auto newExpr =
cs.cacheType(new (ctx) FunctionConversionExpr(expr, toFunc));
return newExpr;
}
}
maybeDiagnoseUnsupportedFunctionConversion(cs, expr, toFunc);
return cs.cacheType(new (ctx) FunctionConversionExpr(expr, toType));
}
// Coercions from one metatype to another.
case TypeKind::Metatype: {
if (auto toMeta = toType->getAs<MetatypeType>())
return cs.cacheType(new (ctx) MetatypeConversionExpr(expr, toMeta));
LLVM_FALLTHROUGH;
}
// Coercions from metatype to objects.
case TypeKind::ExistentialMetatype: {
auto fromMeta = cast<AnyMetatypeType>(desugaredFromType);
if (toType->isAnyObject()) {
assert(cs.getASTContext().LangOpts.EnableObjCInterop
&& "metatype-to-object conversion requires objc interop");
if (fromMeta->is<MetatypeType>()) {
assert(fromMeta->getInstanceType()->mayHaveSuperclass()
&& "metatype-to-object input should be a class metatype");
return cs.cacheType(new (ctx) ClassMetatypeToObjectExpr(expr, toType));
}
if (fromMeta->is<ExistentialMetatypeType>()) {
assert(fromMeta->getInstanceType()->getCanonicalType()
->getExistentialLayout().requiresClass()
&& "metatype-to-object input should be a class metatype");
return cs.cacheType(new (ctx)
ExistentialMetatypeToObjectExpr(expr, toType));
}
llvm_unreachable("unhandled metatype kind");
}
if (auto toClass = toType->getClassOrBoundGenericClass()) {
if (toClass->getName() == cs.getASTContext().Id_Protocol
&& toClass->getModuleContext()->getName()
== cs.getASTContext().Id_ObjectiveC) {
assert(cs.getASTContext().LangOpts.EnableObjCInterop
&& "metatype-to-object conversion requires objc interop");
assert(fromMeta->is<MetatypeType>()
&& fromMeta->getInstanceType()->is<ProtocolType>()
&& "protocol-metatype-to-Protocol only works for single "
"protocols");
return cs.cacheType(new (ctx)
ProtocolMetatypeToObjectExpr(expr, toType));
}
}
break;
}
#define SUGARED_TYPE(Name, Parent) case TypeKind::Name:
#define BUILTIN_TYPE(Name, Parent) case TypeKind::Name:
#define UNCHECKED_TYPE(Name, Parent) case TypeKind::Name:
#define ARTIFICIAL_TYPE(Name, Parent) case TypeKind::Name:
#define TYPE(Name, Parent)
#include "swift/AST/TypeNodes.def"
case TypeKind::Error:
case TypeKind::InOut:
case TypeKind::Module:
case TypeKind::Enum:
case TypeKind::Struct:
case TypeKind::Protocol:
case TypeKind::ProtocolComposition:
case TypeKind::BoundGenericEnum:
case TypeKind::BoundGenericStruct:
case TypeKind::GenericFunction:
case TypeKind::GenericTypeParam:
case TypeKind::DependentMember:
break;
}
// "Catch all" coercions.
auto desugaredToType = toType->getDesugaredType();
switch (desugaredToType->getKind()) {
// Coercions from a type to an existential type.
case TypeKind::ExistentialMetatype:
case TypeKind::ProtocolComposition:
case TypeKind::Protocol:
return coerceExistential(expr, toType);
// Coercion to Optional<T>.
case TypeKind::BoundGenericEnum: {
auto toGenericType = cast<BoundGenericEnumType>(desugaredToType);
if (!toGenericType->getDecl()->isOptionalDecl())
break;
TypeChecker::requireOptionalIntrinsics(ctx, expr->getLoc());
if (cs.getType(expr)->getOptionalObjectType())
return coerceOptionalToOptional(expr, toType, locator, typeFromPattern);
Type valueType = toGenericType->getGenericArgs()[0];
expr = coerceToType(expr, valueType, locator);
if (!expr) return nullptr;
auto *result = cs.cacheType(new (ctx) InjectIntoOptionalExpr(expr, toType));
diagnoseOptionalInjection(result);
return result;
}
case TypeKind::BoundGenericStruct: {
auto toStruct = cast<BoundGenericStructType>(desugaredToType);
if (toStruct->getDecl() != ctx.getArrayDecl() &&
toStruct->getDecl() != ctx.getDictionaryDecl())
break;
if (toStruct->getDecl() == cs.getType(expr)->getAnyNominal())
return buildCollectionUpcastExpr(expr, toType, /*bridged=*/false,
locator);
break;
}
#define SUGARED_TYPE(Name, Parent) case TypeKind::Name:
#define BUILTIN_TYPE(Name, Parent) case TypeKind::Name:
#define UNCHECKED_TYPE(Name, Parent) case TypeKind::Name:
#define ARTIFICIAL_TYPE(Name, Parent) case TypeKind::Name:
#define TYPE(Name, Parent)
#include "swift/AST/TypeNodes.def"
case TypeKind::Error:
case TypeKind::Module:
case TypeKind::Tuple:
case TypeKind::Enum:
case TypeKind::Struct:
case TypeKind::Class:
case TypeKind::BoundGenericClass:
case TypeKind::Metatype:
case TypeKind::DynamicSelf:
case TypeKind::PrimaryArchetype:
case TypeKind::OpenedArchetype:
case TypeKind::NestedArchetype:
case TypeKind::OpaqueTypeArchetype:
case TypeKind::GenericTypeParam:
case TypeKind::DependentMember:
case TypeKind::Function:
case TypeKind::GenericFunction:
case TypeKind::LValue:
case TypeKind::InOut:
break;
}
assert(!fromType->hasUnresolvedType());
assert(!toType->hasUnresolvedType());
// Use an opaque type to abstract a value of the underlying concrete type.
if (toType->getAs<OpaqueTypeArchetypeType>()) {
return cs.cacheType(new (ctx) UnderlyingToOpaqueExpr(expr, toType));
}
llvm_unreachable("Unhandled coercion");
}
/// Detect whether an assignment to \c baseExpr.member in the given
/// decl context can potentially be initialization of a property wrapper.
static bool isPotentialPropertyWrapperInit(Expr *baseExpr,
ValueDecl *member,
DeclContext *UseDC) {
// Member is not a wrapped property
auto *VD = dyn_cast<VarDecl>(member);
if (!(VD && VD->hasAttachedPropertyWrapper()))
return false;
// Assignment to a wrapped property can only be re-written to
// initialization in an init.
auto *CD = dyn_cast<ConstructorDecl>(UseDC);
if (!CD)
return false;
// This is not an assignment on self
if (!baseExpr->isSelfExprOf(CD))
return false;
return true;
}
/// Adjust the given type to become the self type when referring to
/// the given member.
static Type adjustSelfTypeForMember(Expr *baseExpr,
Type baseTy, ValueDecl *member,
DeclContext *UseDC) {
assert(!baseTy->is<LValueType>());
auto inOutTy = baseTy->getAs<InOutType>();
if (!inOutTy)
return baseTy;
auto baseObjectTy = inOutTy->getObjectType();
if (isa<ConstructorDecl>(member))
return baseObjectTy;
if (auto func = dyn_cast<FuncDecl>(member)) {
// If 'self' is an inout type, turn the base type into an lvalue
// type with the same qualifiers.
if (func->isMutating())
return baseTy;
// Otherwise, return the rvalue type.
return baseObjectTy;
}
// If the base of the access is mutable, then we may be invoking a getter or
// setter that requires the base to be mutable.
auto *SD = cast<AbstractStorageDecl>(member);
bool isSettableFromHere =
SD->isSettable(UseDC) && SD->isSetterAccessibleFrom(UseDC);
// If neither the property's getter nor its setter are mutating,
// the base can be an rvalue unless the assignment is potentially
// initializing a property wrapper. If the assignment can be re-
// written to property wrapper initialization, the base type should
// be an lvalue.
if (!SD->isGetterMutating() &&
(!isSettableFromHere || !SD->isSetterMutating()) &&
!isPotentialPropertyWrapperInit(baseExpr, member, UseDC))
return baseObjectTy;
if (isa<SubscriptDecl>(member))
return baseTy;
return LValueType::get(baseObjectTy);
}
Expr *
ExprRewriter::coerceSelfArgumentToType(Expr *expr,
Type baseTy, ValueDecl *member,
ConstraintLocatorBuilder locator) {
Type toType = adjustSelfTypeForMember(expr, baseTy, member, dc);
// If our expression already has the right type, we're done.
Type fromType = cs.getType(expr);
if (fromType->isEqual(toType))
return expr;
// If we're coercing to an rvalue type, just do it.
auto toInOutTy = toType->getAs<InOutType>();
if (!toInOutTy)
return coerceToType(expr, toType, locator);
assert(fromType->is<LValueType>() && "Can only convert lvalues to inout");
auto &ctx = cs.getASTContext();
// Use InOutExpr to convert it to an explicit inout argument for the
// receiver.
return cs.cacheType(new (ctx) InOutExpr(expr->getStartLoc(), expr,
toInOutTy->getInOutObjectType(),
/*isImplicit*/ true));
}
Expr *ExprRewriter::convertLiteralInPlace(
LiteralExpr *literal, Type type, ProtocolDecl *protocol,
Identifier literalType, DeclName literalFuncName,
ProtocolDecl *builtinProtocol, DeclName builtinLiteralFuncName,
Diag<> brokenProtocolDiag, Diag<> brokenBuiltinProtocolDiag) {
// If coercing a literal to an unresolved type, we don't try to look up the
// witness members, just do it.
if (type->is<UnresolvedType>()) {
cs.setType(literal, type);
return literal;
}
// Check whether this literal type conforms to the builtin protocol. If so,
// initialize via the builtin protocol.
if (builtinProtocol) {
auto builtinConformance = TypeChecker::conformsToProtocol(
type, builtinProtocol, cs.DC);
if (builtinConformance) {
// Find the witness that we'll use to initialize the type via a builtin
// literal.
auto witness = builtinConformance.getWitnessByName(
type->getRValueType(), builtinLiteralFuncName);
if (!witness || !isa<AbstractFunctionDecl>(witness.getDecl()))
return nullptr;
// Form a reference to the builtin conversion function.
// Set the builtin initializer.
dyn_cast<BuiltinLiteralExpr>(literal)->setBuiltinInitializer(witness);
// The literal expression has this type.
cs.setType(literal, type);
return literal;
}
}
// This literal type must conform to the (non-builtin) protocol.
assert(protocol && "requirements should have stopped recursion");
auto conformance = TypeChecker::conformsToProtocol(type, protocol, cs.DC);
assert(conformance && "must conform to literal protocol");
// Dig out the literal type and perform a builtin literal conversion to it.
if (!literalType.empty()) {
// Extract the literal type.
Type builtinLiteralType =
conformance.getTypeWitnessByName(type, literalType);
if (builtinLiteralType->hasError())
return nullptr;
// Perform the builtin conversion.
if (!convertLiteralInPlace(literal, builtinLiteralType, nullptr,
Identifier(), DeclName(), builtinProtocol,
builtinLiteralFuncName, brokenProtocolDiag,
brokenBuiltinProtocolDiag))
return nullptr;
}
// Find the witness that we'll use to initialize the literal value.
auto witness =
conformance.getWitnessByName(type->getRValueType(), literalFuncName);
if (!witness || !isa<AbstractFunctionDecl>(witness.getDecl()))
return nullptr;
// Set the initializer.
literal->setInitializer(witness);
// The literal expression has this type.
cs.setType(literal, type);
return literal;
}
// Returns true if the given method and method type are a valid
// `@dynamicCallable` required `func dynamicallyCall` method.
static bool isValidDynamicCallableMethod(FuncDecl *method,
AnyFunctionType *methodType) {
auto &ctx = method->getASTContext();
if (method->getBaseIdentifier() != ctx.Id_dynamicallyCall)
return false;
if (methodType->getParams().size() != 1)
return false;
auto argumentLabel = methodType->getParams()[0].getLabel();
if (argumentLabel != ctx.Id_withArguments &&
argumentLabel != ctx.Id_withKeywordArguments)
return false;
return true;
}
// Build a reference to a `callAsFunction` method.
static Expr *buildCallAsFunctionMethodRef(
ExprRewriter &rewriter, ApplyExpr *apply, SelectedOverload selected,
ConstraintLocator *calleeLoc) {
assert(calleeLoc->isLastElement<LocatorPathElt::ImplicitCallAsFunction>());
assert(cast<FuncDecl>(selected.choice.getDecl())->isCallAsFunctionMethod());
// Create direct reference to `callAsFunction` method.
auto *fn = apply->getFn();
auto *arg = apply->getArg();
// HACK: Temporarily push the fn expr onto the expr stack to make sure we
// don't try to prematurely close an existential when applying the curried
// member ref. This can be removed once existential opening is refactored not
// to rely on the shape of the AST prior to rewriting.
rewriter.ExprStack.push_back(fn);
SWIFT_DEFER {
rewriter.ExprStack.pop_back();
};
auto *declRef = rewriter.buildMemberRef(
fn, /*dotLoc*/ SourceLoc(), selected, DeclNameLoc(arg->getStartLoc()),
calleeLoc, calleeLoc, /*implicit*/ true, AccessSemantics::Ordinary);
if (!declRef)
return nullptr;
declRef->setImplicit(apply->isImplicit());
return declRef;
}
// Resolve `@dynamicCallable` applications.
std::pair<Expr *, Expr *>
ExprRewriter::buildDynamicCallable(ApplyExpr *apply, SelectedOverload selected,
FuncDecl *method,
AnyFunctionType *methodType,
ConstraintLocatorBuilder loc) {
auto &ctx = cs.getASTContext();
auto *fn = apply->getFn();
TupleExpr *arg = dyn_cast<TupleExpr>(apply->getArg());
if (auto parenExpr = dyn_cast<ParenExpr>(apply->getArg()))
arg = TupleExpr::createImplicit(ctx, parenExpr->getSubExpr(), {});
// Get resolved `dynamicallyCall` method and verify it.
assert(isValidDynamicCallableMethod(method, methodType));
auto params = methodType->getParams();
auto argumentType = params[0].getParameterType();
// Determine which method was resolved: a `withArguments` method or a
// `withKeywordArguments` method.
auto argumentLabel = methodType->getParams()[0].getLabel();
bool useKwargsMethod = argumentLabel == ctx.Id_withKeywordArguments;
// HACK: Temporarily push the fn expr onto the expr stack to make sure we
// don't try to prematurely close an existential when applying the curried
// member ref. This can be removed once existential opening is refactored not
// to rely on the shape of the AST prior to rewriting.
ExprStack.push_back(fn);
SWIFT_DEFER {
ExprStack.pop_back();
};
// Construct expression referencing the `dynamicallyCall` method.
auto member = buildMemberRef(fn, SourceLoc(), selected,
DeclNameLoc(), loc, loc,
/*implicit=*/true, AccessSemantics::Ordinary);
// Construct argument to the method (either an array or dictionary
// expression).
Expr *argument = nullptr;
if (!useKwargsMethod) {
argument = ArrayExpr::create(ctx, SourceLoc(), arg->getElements(),
{}, SourceLoc());
cs.setType(argument, argumentType);
finishArrayExpr(cast<ArrayExpr>(argument));
} else {
auto dictLitProto =
ctx.getProtocol(KnownProtocolKind::ExpressibleByDictionaryLiteral);
auto conformance =
TypeChecker::conformsToProtocol(argumentType, dictLitProto, cs.DC);
auto keyType = conformance.getTypeWitnessByName(argumentType, ctx.Id_Key);
auto valueType =
conformance.getTypeWitnessByName(argumentType, ctx.Id_Value);
SmallVector<Identifier, 4> names;
SmallVector<Expr *, 4> dictElements;
for (unsigned i = 0, n = arg->getNumElements(); i < n; ++i) {
Expr *labelExpr =
new (ctx) StringLiteralExpr(arg->getElementName(i).get(),
arg->getElementNameLoc(i),
/*Implicit*/ true);
cs.setType(labelExpr, keyType);
handleStringLiteralExpr(cast<LiteralExpr>(labelExpr));
Expr *valueExpr = coerceToType(arg->getElement(i), valueType, loc);
assert(valueExpr && "Failed to coerce?");
Expr *pair = TupleExpr::createImplicit(ctx, {labelExpr, valueExpr}, {});
auto eltTypes = { TupleTypeElt(keyType), TupleTypeElt(valueType) };
cs.setType(pair, TupleType::get(eltTypes, ctx));
dictElements.push_back(pair);
}
argument = DictionaryExpr::create(ctx, SourceLoc(), dictElements, {},
SourceLoc());
cs.setType(argument, argumentType);
finishDictionaryExpr(cast<DictionaryExpr>(argument));
}
argument->setImplicit();
// Build the argument list expr.
argument = TupleExpr::createImplicit(ctx, {argument}, {argumentLabel});
cs.setType(argument,
TupleType::get({TupleTypeElt(argumentType, argumentLabel)}, ctx));
return std::make_pair(member, argument);
}
Expr *ExprRewriter::finishApply(ApplyExpr *apply, Type openedType,
ConstraintLocatorBuilder locator,
ConstraintLocatorBuilder calleeLocator) {
auto &ctx = cs.getASTContext();
auto *arg = apply->getArg();
auto *fn = apply->getFn();
auto finishApplyOfDeclWithSpecialTypeCheckingSemantics
= [&](ApplyExpr *apply,
ConcreteDeclRef declRef,
Type openedType) -> Expr* {
switch (TypeChecker::getDeclTypeCheckingSemantics(declRef.getDecl())) {
case DeclTypeCheckingSemantics::TypeOf: {
// Resolve into a DynamicTypeExpr.
auto arg = apply->getArg();
SmallVector<Identifier, 2> argLabelsScratch;
auto fnType = cs.getType(fn)->getAs<FunctionType>();
arg = coerceCallArguments(arg, fnType, declRef,
apply,
apply->getArgumentLabels(argLabelsScratch),
locator.withPathElement(
ConstraintLocator::ApplyArgument));
if (!arg) {
return nullptr;
}
if (auto tuple = dyn_cast<TupleExpr>(arg))
arg = tuple->getElements()[0];
auto replacement = new (ctx)
DynamicTypeExpr(apply->getFn()->getLoc(),
apply->getArg()->getStartLoc(),
arg,
apply->getArg()->getEndLoc(),
Type());
cs.setType(replacement, simplifyType(openedType));
return replacement;
}
case DeclTypeCheckingSemantics::WithoutActuallyEscaping: {
// Resolve into a MakeTemporarilyEscapableExpr.
auto arg = cast<TupleExpr>(apply->getArg());
assert(arg->getNumElements() == 2 && "should have two arguments");
auto nonescaping = arg->getElements()[0];
auto body = arg->getElements()[1];
auto bodyTy = cs.getType(body)->getWithoutSpecifierType();
auto bodyFnTy = bodyTy->castTo<FunctionType>();
auto escapableParams = bodyFnTy->getParams();
auto resultType = bodyFnTy->getResult();
// The body is immediately called, so is obviously noescape.
bodyFnTy = cast<FunctionType>(
bodyFnTy->withExtInfo(bodyFnTy->getExtInfo().withNoEscape()));
body = coerceToType(body, bodyFnTy, locator);
assert(body && "can't make nonescaping?!");
auto escapable = new (ctx)
OpaqueValueExpr(apply->getFn()->getSourceRange(), Type());
cs.setType(escapable, escapableParams[0].getOldType());
auto getType = [&](Expr *E) -> Type { return cs.getType(E); };
auto callSubExpr = CallExpr::createImplicit(ctx, body,
{escapable}, {}, getType);
cs.cacheSubExprTypes(callSubExpr);
cs.setType(callSubExpr->getArg(),
AnyFunctionType::composeInput(ctx,
escapableParams, false));
cs.setType(callSubExpr, resultType);
auto replacement = new (ctx)
MakeTemporarilyEscapableExpr(apply->getFn()->getLoc(),
apply->getArg()->getStartLoc(),
nonescaping,
callSubExpr,
apply->getArg()->getEndLoc(),
escapable,
apply);
cs.setType(replacement, resultType);
return replacement;
}
case DeclTypeCheckingSemantics::OpenExistential: {
// Resolve into an OpenExistentialExpr.
auto arg = cast<TupleExpr>(apply->getArg());
assert(arg->getNumElements() == 2 && "should have two arguments");
auto existential = cs.coerceToRValue(arg->getElements()[0]);
auto body = cs.coerceToRValue(arg->getElements()[1]);
auto bodyFnTy = cs.getType(body)->castTo<FunctionType>();
auto openedTy = getBaseType(bodyFnTy, /*wantsRValue*/ false);
auto resultTy = bodyFnTy->getResult();
// The body is immediately called, so is obviously noescape.
bodyFnTy = cast<FunctionType>(
bodyFnTy->withExtInfo(bodyFnTy->getExtInfo().withNoEscape()));
body = coerceToType(body, bodyFnTy, locator);
assert(body && "can't make nonescaping?!");
auto openedInstanceTy = openedTy;
auto existentialInstanceTy = cs.getType(existential);
if (auto metaTy = openedTy->getAs<MetatypeType>()) {
openedInstanceTy = metaTy->getInstanceType();
existentialInstanceTy = existentialInstanceTy
->castTo<ExistentialMetatypeType>()
->getInstanceType();
}
assert(openedInstanceTy->castTo<OpenedArchetypeType>()
->getOpenedExistentialType()
->isEqual(existentialInstanceTy));
auto opaqueValue =
new (ctx) OpaqueValueExpr(apply->getSourceRange(), openedTy);
cs.setType(opaqueValue, openedTy);
auto getType = [&](Expr *E) -> Type { return cs.getType(E); };
auto callSubExpr = CallExpr::createImplicit(ctx, body, {opaqueValue}, {}, getType);
cs.cacheSubExprTypes(callSubExpr);
cs.setType(callSubExpr, resultTy);
auto replacement = new (ctx)
OpenExistentialExpr(existential, opaqueValue, callSubExpr,
resultTy);
cs.setType(replacement, resultTy);
return replacement;
}
case DeclTypeCheckingSemantics::Normal:
return nullptr;
}
llvm_unreachable("Unhandled DeclTypeCheckingSemantics in switch.");
};
// Resolve the callee for the application if we have one.
ConcreteDeclRef callee;
auto *calleeLoc = cs.getConstraintLocator(calleeLocator);
auto overload = solution.getOverloadChoiceIfAvailable(calleeLoc);
if (overload) {
auto *decl = overload->choice.getDeclOrNull();
callee = resolveConcreteDeclRef(decl, calleeLoc);
}
// If this is an implicit call to a `callAsFunction` method, build the
// appropriate member reference.
if (cs.getType(fn)->getRValueType()->isCallableNominalType(dc)) {
fn = buildCallAsFunctionMethodRef(*this, apply, *overload, calleeLoc);
if (!fn)
return nullptr;
}
// Resolve a `@dynamicCallable` application.
auto applyFunctionLoc =
locator.withPathElement(ConstraintLocator::ApplyFunction);
if (auto selected = solution.getOverloadChoiceIfAvailable(
cs.getConstraintLocator(applyFunctionLoc))) {
auto *method = dyn_cast<FuncDecl>(selected->choice.getDecl());
auto methodType =
simplifyType(selected->openedType)->getAs<AnyFunctionType>();
if (method && methodType) {
// Handle a call to a @dynamicCallable method.
if (isValidDynamicCallableMethod(method, methodType))
std::tie(fn, arg) = buildDynamicCallable(
apply, *selected, method, methodType, applyFunctionLoc);
}
}
// The function is always an rvalue.
fn = cs.coerceToRValue(fn);
// Resolve applications of decls with special semantics.
if (auto declRef =
dyn_cast<DeclRefExpr>(getSemanticExprForDeclOrMemberRef(fn))) {
if (auto special =
finishApplyOfDeclWithSpecialTypeCheckingSemantics(apply,
declRef->getDeclRef(),
openedType)) {
return special;
}
}
bool unwrapResult = false;
if (auto *IUOFnTy = dyn_cast<ImplicitlyUnwrappedFunctionConversionExpr>(fn)) {
unwrapResult = true;
fn = IUOFnTy->getSubExpr();
}
// If we're applying a function that resulted from a covariant
// function conversion, strip off that conversion.
// FIXME: It would be nicer if we could build the ASTs properly in the
// first shot.
Type covariantResultType;
if (auto covariant = dyn_cast<CovariantFunctionConversionExpr>(fn)) {
// Strip off one layer of application from the covariant result.
covariantResultType
= cs.getType(covariant)->castTo<AnyFunctionType>()->getResult();
// Use the subexpression as the function.
fn = covariant->getSubExpr();
}
// An immediate application of a closure literal is always noescape.
if (isClosureLiteralExpr(fn)) {
if (auto fnTy = cs.getType(fn)->getAs<FunctionType>()) {
fnTy = cast<FunctionType>(
fnTy->withExtInfo(fnTy->getExtInfo().withNoEscape()));
fn = coerceToType(fn, fnTy, locator);
}
}
apply->setFn(fn);
// Check whether the argument is 'super'.
bool isSuper = apply->getArg()->isSuperExpr();
// For function application, convert the argument to the input type of
// the function.
SmallVector<Identifier, 2> argLabelsScratch;
if (auto fnType = cs.getType(fn)->getAs<FunctionType>()) {
arg = coerceCallArguments(arg, fnType, callee, apply,
apply->getArgumentLabels(argLabelsScratch),
locator.withPathElement(
ConstraintLocator::ApplyArgument));
if (!arg) {
return nullptr;
}
apply->setArg(arg);
cs.setType(apply, fnType->getResult());
apply->setIsSuper(isSuper);
solution.setExprTypes(apply);
Expr *result = TypeChecker::substituteInputSugarTypeForResult(apply);
cs.cacheExprTypes(result);
// If we have a covariant result type, perform the conversion now.
if (covariantResultType) {
if (covariantResultType->is<FunctionType>())
result = cs.cacheType(new (ctx) CovariantFunctionConversionExpr(
result, covariantResultType));
else
result = cs.cacheType(new (ctx) CovariantReturnConversionExpr(
result, covariantResultType));
}
// Try closing the existential, if there is one.
closeExistential(result, locator);
if (unwrapResult)
return forceUnwrapResult(result);
return result;
}
// FIXME: handle unwrapping everywhere else
assert(!unwrapResult);
assert(!cs.getType(fn)->is<UnresolvedType>());
// We have a type constructor.
auto metaTy = cs.getType(fn)->castTo<AnyMetatypeType>();
auto ty = metaTy->getInstanceType();
// If we're "constructing" a tuple type, it's simply a conversion.
if (auto tupleTy = ty->getAs<TupleType>()) {
return coerceToType(apply->getArg(), tupleTy, locator);
}
// We're constructing a value of nominal type. Look for the constructor or
// enum element to use.
auto *ctorLocator =
cs.getConstraintLocator(locator, {ConstraintLocator::ApplyFunction,
ConstraintLocator::ConstructorMember});
auto selected = solution.getOverloadChoice(ctorLocator);
assert(ty->getNominalOrBoundGenericNominal() || ty->is<DynamicSelfType>() ||
ty->isExistentialType() || ty->is<ArchetypeType>());
// Consider the constructor decl reference expr 'implicit', but the
// constructor call expr itself has the apply's 'implicitness'.
Expr *declRef = buildMemberRef(fn, /*dotLoc=*/SourceLoc(), selected,
DeclNameLoc(fn->getEndLoc()), locator,
ctorLocator, /*implicit=*/true,
AccessSemantics::Ordinary);
if (!declRef)
return nullptr;
declRef->setImplicit(apply->isImplicit());
apply->setFn(declRef);
// Tail-recur to actually call the constructor.
return finishApply(apply, openedType, locator, ctorLocator);
}
// Return the precedence-yielding parent of 'expr', along with the index of
// 'expr' as the child of that parent. The precedence-yielding parent is the
// nearest ancestor of 'expr' which imposes a minimum precedence on 'expr'.
// Right now that just means skipping over TupleExpr instances that only exist
// to hold arguments to binary operators.
static std::pair<Expr *, unsigned> getPrecedenceParentAndIndex(Expr *expr,
Expr *rootExpr)
{
auto parentMap = rootExpr->getParentMap();
auto it = parentMap.find(expr);
if (it == parentMap.end()) {
return { nullptr, 0 };
}
Expr *parent = it->second;
// Handle all cases where the answer isn't just going to be { parent, 0 }.
if (auto tuple = dyn_cast<TupleExpr>(parent)) {
// Get index of expression in tuple.
auto tupleElems = tuple->getElements();
auto elemIt = std::find(tupleElems.begin(), tupleElems.end(), expr);
assert(elemIt != tupleElems.end() && "expr not found in parent TupleExpr");
unsigned index = elemIt - tupleElems.begin();
it = parentMap.find(parent);
if (it != parentMap.end()) {
Expr *gparent = it->second;
// Was this tuple just constructed for a binop?
if (isa<BinaryExpr>(gparent)) {
return { gparent, index };
}
}
// Must be a tuple literal, function arg list, collection, etc.
return { parent, index };
} else if (auto ifExpr = dyn_cast<IfExpr>(parent)) {
unsigned index;
if (expr == ifExpr->getCondExpr()) {
index = 0;
} else if (expr == ifExpr->getThenExpr()) {
index = 1;
} else if (expr == ifExpr->getElseExpr()) {
index = 2;
} else {
llvm_unreachable("expr not found in parent IfExpr");
}
return { ifExpr, index };
} else if (auto assignExpr = dyn_cast<AssignExpr>(parent)) {
unsigned index;
if (expr == assignExpr->getSrc()) {
index = 0;
} else if (expr == assignExpr->getDest()) {
index = 1;
} else {
llvm_unreachable("expr not found in parent AssignExpr");
}
return { assignExpr, index };
}
return { parent, 0 };
}
/// Return true if, when replacing "<expr>" with "<expr> op <something>",
/// parentheses must be added around "<expr>" to allow the new operator
/// to bind correctly.
bool swift::exprNeedsParensInsideFollowingOperator(
DeclContext *DC, Expr *expr,
PrecedenceGroupDecl *followingPG) {
if (expr->isInfixOperator()) {
auto exprPG = TypeChecker::lookupPrecedenceGroupForInfixOperator(DC, expr);
if (!exprPG) return true;
return DC->getASTContext().associateInfixOperators(exprPG, followingPG)
!= Associativity::Left;
}
// We want to parenthesize a 'try?' on the LHS, but we don't care about
// capturing the new operator inside a 'try' or 'try!'.
if (isa<OptionalTryExpr>(expr))
return true;
return false;
}
/// Return true if, when replacing "<expr>" with "<expr> op <something>"
/// within the given root expression, parentheses must be added around
/// the new operator to prevent it from binding incorrectly in the
/// surrounding context.
bool swift::exprNeedsParensOutsideFollowingOperator(
DeclContext *DC, Expr *expr, Expr *rootExpr,
PrecedenceGroupDecl *followingPG) {
Expr *parent;
unsigned index;
std::tie(parent, index) = getPrecedenceParentAndIndex(expr, rootExpr);
if (!parent || isa<TupleExpr>(parent)) {
return false;
}
if (auto parenExp = dyn_cast<ParenExpr>(parent))
if (!parenExp->isImplicit())
return false;
if (parent->isInfixOperator()) {
auto parentPG = TypeChecker::lookupPrecedenceGroupForInfixOperator(DC,
parent);
if (!parentPG) return true;
// If the index is 0, this is on the LHS of the parent.
auto &Context = DC->getASTContext();
if (index == 0) {
return Context.associateInfixOperators(followingPG, parentPG)
!= Associativity::Left;
} else {
return Context.associateInfixOperators(parentPG, followingPG)
!= Associativity::Right;
}
}
return true;
}
bool swift::exprNeedsParensBeforeAddingNilCoalescing(DeclContext *DC,
Expr *expr) {
auto &ctx = DC->getASTContext();
auto asPG = TypeChecker::lookupPrecedenceGroup(
DC, ctx.Id_NilCoalescingPrecedence, SourceLoc())
.getSingle();
if (!asPG)
return true;
return exprNeedsParensInsideFollowingOperator(DC, expr, asPG);
}
bool swift::exprNeedsParensAfterAddingNilCoalescing(DeclContext *DC,
Expr *expr,
Expr *rootExpr) {
auto &ctx = DC->getASTContext();
auto asPG = TypeChecker::lookupPrecedenceGroup(
DC, ctx.Id_NilCoalescingPrecedence, SourceLoc())
.getSingle();
if (!asPG)
return true;
return exprNeedsParensOutsideFollowingOperator(DC, expr, rootExpr, asPG);
}
namespace {
class SetExprTypes : public ASTWalker {
const Solution &solution;
public:
explicit SetExprTypes(const Solution &solution)
: solution(solution) {}
Expr *walkToExprPost(Expr *expr) override {
auto &cs = solution.getConstraintSystem();
auto exprType = cs.getType(expr);
exprType = solution.simplifyType(exprType);
// assert((!expr->getType() || expr->getType()->isEqual(exprType)) &&
// "Mismatched types!");
assert(!exprType->hasTypeVariable() &&
"Should not write type variable into expression!");
assert(!exprType->hasPlaceholder() &&
"Should not write type placeholders into expression!");
expr->setType(exprType);
if (auto kp = dyn_cast<KeyPathExpr>(expr)) {
for (auto i : indices(kp->getComponents())) {
Type componentType;
if (cs.hasType(kp, i)) {
componentType = solution.simplifyType(cs.getType(kp, i));
assert(!componentType->hasTypeVariable() &&
"Should not write type variable into key-path component");
assert(!componentType->hasPlaceholder() &&
"Should not write type placeholder into key-path component");
kp->getMutableComponents()[i].setComponentType(componentType);
}
}
}
return expr;
}
/// Ignore statements.
std::pair<bool, Stmt *> walkToStmtPre(Stmt *stmt) override {
return { false, stmt };
}
/// Ignore declarations.
bool walkToDeclPre(Decl *decl) override { return false; }
};
class ExprWalker : public ASTWalker {
ExprRewriter &Rewriter;
SmallVector<ClosureExpr *, 4> ClosuresToTypeCheck;
SmallVector<std::pair<TapExpr *, DeclContext *>, 4> TapsToTypeCheck;
public:
ExprWalker(ExprRewriter &Rewriter) : Rewriter(Rewriter) { }
const SmallVectorImpl<ClosureExpr *> &getClosuresToTypeCheck() const {
return ClosuresToTypeCheck;
}
const SmallVectorImpl<std::pair<TapExpr *, DeclContext *>> &getTapsToTypeCheck() const {
return TapsToTypeCheck;
}
std::pair<bool, Expr *> walkToExprPre(Expr *expr) override {
// For closures, update the parameter types and check the body.
if (auto closure = dyn_cast<ClosureExpr>(expr)) {
rewriteFunction(closure);
return { false, closure };
}
if (auto tap = dyn_cast_or_null<TapExpr>(expr)) {
// We remember the DeclContext because the code to handle
// single-expression-body closures above changes it.
TapsToTypeCheck.push_back(std::make_pair(tap, Rewriter.dc));
}
if (auto captureList = dyn_cast<CaptureListExpr>(expr)) {
// Rewrite captures.
for (const auto &capture : captureList->getCaptureList()) {
(void)rewriteTarget(SolutionApplicationTarget(capture.Init));
}
}
Rewriter.walkToExprPre(expr);
return { true, expr };
}
Expr *walkToExprPost(Expr *expr) override {
return Rewriter.walkToExprPost(expr);
}
/// Ignore statements.
std::pair<bool, Stmt *> walkToStmtPre(Stmt *stmt) override {
return { false, stmt };
}
/// Ignore declarations.
bool walkToDeclPre(Decl *decl) override { return false; }
/// Rewrite the target, producing a new target.
Optional<SolutionApplicationTarget>
rewriteTarget(SolutionApplicationTarget target);
/// Rewrite the function for the given solution.
///
/// \returns true if an error occurred.
bool rewriteFunction(AnyFunctionRef fn) {
auto result = Rewriter.cs.applySolution(
Rewriter.solution, fn, Rewriter.dc,
[&](SolutionApplicationTarget target) {
auto resultTarget = rewriteTarget(target);
if (resultTarget) {
if (auto expr = resultTarget->getAsExpr())
Rewriter.solution.setExprTypes(expr);
}
return resultTarget;
});
switch (result) {
case SolutionApplicationToFunctionResult::Success: {
if (auto closure = dyn_cast_or_null<ClosureExpr>(
fn.getAbstractClosureExpr()))
TypeChecker::checkClosureAttributes(closure);
return false;
}
case SolutionApplicationToFunctionResult::Failure:
return true;
case SolutionApplicationToFunctionResult::Delay: {
if (!Rewriter.cs.Options
.contains(ConstraintSystemFlags::LeaveClosureBodyUnchecked)) {
auto closure = cast<ClosureExpr>(fn.getAbstractClosureExpr());
ClosuresToTypeCheck.push_back(closure);
}
return false;
}
}
}
};
} // end anonymous namespace
Expr *ConstraintSystem::coerceToRValue(Expr *expr) {
return TypeChecker::coerceToRValue(
getASTContext(), expr, [&](Expr *expr) { return getType(expr); },
[&](Expr *expr, Type type) { setType(expr, type); });
}
namespace {
/// Function object to compare source locations, putting invalid
/// locations at the end.
class CompareExprSourceLocs {
SourceManager &sourceMgr;
public:
explicit CompareExprSourceLocs(SourceManager &sourceMgr)
: sourceMgr(sourceMgr) { }
bool operator()(ASTNode lhs, ASTNode rhs) const {
if (static_cast<bool>(lhs) != static_cast<bool>(rhs)) {
return static_cast<bool>(lhs);
}
auto lhsLoc = getLoc(lhs);
auto rhsLoc = getLoc(rhs);
if (lhsLoc.isValid() != rhsLoc.isValid())
return lhsLoc.isValid();
return sourceMgr.isBeforeInBuffer(lhsLoc, rhsLoc);
}
};
}
/// Emit the fixes computed as part of the solution, returning true if we were
/// able to emit an error message, or false if none of the fixits worked out.
bool ConstraintSystem::applySolutionFixes(const Solution &solution) {
/// Collect the fixes on a per-expression basis.
llvm::SmallDenseMap<ASTNode, SmallVector<ConstraintFix *, 4>> fixesPerAnchor;
for (auto *fix : solution.Fixes) {
fixesPerAnchor[fix->getAnchor()].push_back(fix);
}
// Collect all of the expressions that have fixes, and sort them by
// source ordering.
SmallVector<ASTNode, 4> orderedAnchors;
for (const auto &fix : fixesPerAnchor) {
orderedAnchors.push_back(fix.getFirst());
}
std::sort(orderedAnchors.begin(), orderedAnchors.end(),
CompareExprSourceLocs(Context.SourceMgr));
// Walk over each of the expressions, diagnosing fixes.
bool diagnosedAnyErrors = false;
for (auto anchor : orderedAnchors) {
// Coalesce fixes with the same locator to avoid duplicating notes.
auto fixes = fixesPerAnchor[anchor];
using ConstraintFixVector = llvm::SmallVector<ConstraintFix *, 4>;
llvm::SmallMapVector<ConstraintLocator *,
llvm::SmallMapVector<FixKind, ConstraintFixVector, 4>, 4> aggregatedFixes;
for (auto *fix : fixes)
aggregatedFixes[fix->getLocator()][fix->getKind()].push_back(fix);
for (auto fixesPerLocator : aggregatedFixes) {
for (auto fixesPerKind : fixesPerLocator.second) {
auto fixes = fixesPerKind.second;
auto *primaryFix = fixes[0];
ArrayRef<ConstraintFix *> secondaryFixes{fixes.begin() + 1, fixes.end()};
auto diagnosed =
primaryFix->coalesceAndDiagnose(solution, secondaryFixes);
if (primaryFix->isWarning()) {
assert(diagnosed && "warnings should always be diagnosed");
(void)diagnosed;
} else {
diagnosedAnyErrors |= diagnosed;
}
}
}
}
return diagnosedAnyErrors;
}
/// For the initializer of an `async let`, wrap it in an autoclosure and then
/// a call to that autoclosure, so that the code for the child task is captured
/// entirely within the autoclosure. This captures the semantics of the
/// operation but not the timing, e.g., the call itself will actually occur
/// when one of the variables in the async let is referenced.
static Expr *wrapAsyncLetInitializer(
ConstraintSystem &cs, Expr *initializer, DeclContext *dc) {
// Form the autoclosure type. It is always 'async', and will be 'throws'.
Type initializerType = initializer->getType();
bool throws = TypeChecker::canThrow(initializer);
auto extInfo = ASTExtInfoBuilder()
.withAsync()
.withConcurrent()
.withThrows(throws)
.build();
// Form the autoclosure expression. The actual closure here encapsulates the
// child task.
auto closureType = FunctionType::get({ }, initializerType, extInfo);
ASTContext &ctx = dc->getASTContext();
Expr *autoclosureExpr = cs.buildAutoClosureExpr(
initializer, closureType, /*isDefaultWrappedValue=*/false,
/*isAsyncLetWrapper=*/true);
// Call the autoclosure so that the AST types line up. SILGen will ignore the
// actual calls and translate them into a different mechanism.
auto autoclosureCall = CallExpr::createImplicit(
ctx, autoclosureExpr, { }, { });
autoclosureCall->setType(initializerType);
autoclosureCall->setThrows(throws);
// For a throwing expression, wrap the call in a 'try'.
Expr *resultInit = autoclosureCall;
if (throws) {
resultInit = new (ctx) TryExpr(
SourceLoc(), resultInit, initializerType, /*implicit=*/true);
}
// Wrap the call in an 'await'.
resultInit = new (ctx) AwaitExpr(
SourceLoc(), resultInit, initializerType, /*implicit=*/true);
cs.cacheExprTypes(resultInit);
return resultInit;
}
/// Apply the given solution to the initialization target.
///
/// \returns the resulting initialization expression.
static Optional<SolutionApplicationTarget> applySolutionToInitialization(
Solution &solution, SolutionApplicationTarget target,
Expr *initializer) {
auto wrappedVar = target.getInitializationWrappedVar();
Type initType;
if (wrappedVar) {
initType = solution.getType(initializer);
} else {
initType = solution.getType(target.getInitializationPattern());
}
{
// Figure out what type the constraints decided on.
auto ty = solution.simplifyType(initType);
initType = ty->getRValueType()->reconstituteSugar(/*recursive =*/false);
}
// Convert the initializer to the type of the pattern.
auto &cs = solution.getConstraintSystem();
auto locator =
cs.getConstraintLocator(initializer, LocatorPathElt::ContextualType());
initializer = solution.coerceToType(initializer, initType, locator);
if (!initializer)
return None;
SolutionApplicationTarget resultTarget = target;
resultTarget.setExpr(initializer);
// Record the property wrapper type and note that the initializer has
// been subsumed by the backing property.
if (wrappedVar) {
ASTContext &ctx = cs.getASTContext();
wrappedVar->getParentPatternBinding()->setInitializerSubsumed(0);
ctx.setSideCachedPropertyWrapperBackingPropertyType(
wrappedVar, initType->mapTypeOutOfContext());
// Record the semantic initializer on the outermost property wrapper.
wrappedVar->getAttachedPropertyWrappers().front()
->setSemanticInit(initializer);
}
// Coerce the pattern to the type of the initializer.
TypeResolutionOptions options =
isa<EditorPlaceholderExpr>(initializer->getSemanticsProvidingExpr())
? TypeResolverContext::EditorPlaceholderExpr
: target.getInitializationPatternBindingDecl()
? TypeResolverContext::PatternBindingDecl
: TypeResolverContext::InExpression;
options |= TypeResolutionFlags::OverrideType;
// Determine the type of the pattern.
Type finalPatternType = initializer->getType();
if (wrappedVar) {
if (!finalPatternType->hasError() && !finalPatternType->is<TypeVariableType>())
finalPatternType = computeWrappedValueType(wrappedVar, finalPatternType);
}
if (finalPatternType->hasDependentMember())
return None;
finalPatternType = finalPatternType->reconstituteSugar(/*recursive =*/false);
// Apply the solution to the pattern as well.
auto contextualPattern = target.getContextualPattern();
if (auto coercedPattern = TypeChecker::coercePatternToType(
contextualPattern, finalPatternType, options)) {
resultTarget.setPattern(coercedPattern);
} else {
return None;
}
// For an async let, wrap the initializer appropriately to make it a child
// task.
if (auto patternBinding = target.getInitializationPatternBindingDecl()) {
if (patternBinding->isAsyncLet()) {
resultTarget.setExpr(
wrapAsyncLetInitializer(
cs, resultTarget.getAsExpr(), resultTarget.getDeclContext()));
}
}
return resultTarget;
}
/// Apply the given solution to the for-each statement target.
///
/// \returns the resulting initialization expression.
static Optional<SolutionApplicationTarget> applySolutionToForEachStmt(
Solution &solution, SolutionApplicationTarget target, Expr *sequence) {
auto resultTarget = target;
auto &forEachStmtInfo = resultTarget.getForEachStmtInfo();
// Simplify the various types.
forEachStmtInfo.elementType =
solution.simplifyType(forEachStmtInfo.elementType);
forEachStmtInfo.iteratorType =
solution.simplifyType(forEachStmtInfo.iteratorType);
forEachStmtInfo.initType =
solution.simplifyType(forEachStmtInfo.initType);
forEachStmtInfo.sequenceType =
solution.simplifyType(forEachStmtInfo.sequenceType);
// Coerce the sequence to the sequence type.
auto &cs = solution.getConstraintSystem();
auto locator = cs.getConstraintLocator(target.getAsExpr());
sequence = solution.coerceToType(
sequence, forEachStmtInfo.sequenceType, locator);
if (!sequence)
return None;
resultTarget.setExpr(sequence);
// Get the conformance of the sequence type to the Sequence protocol.
auto stmt = forEachStmtInfo.stmt;
auto sequenceProto = TypeChecker::getProtocol(
cs.getASTContext(), stmt->getForLoc(),
stmt->getAwaitLoc().isValid() ?
KnownProtocolKind::AsyncSequence : KnownProtocolKind::Sequence);
auto sequenceConformance = TypeChecker::conformsToProtocol(
forEachStmtInfo.sequenceType, sequenceProto, cs.DC);
assert(!sequenceConformance.isInvalid() &&
"Couldn't find sequence conformance");
// Coerce the pattern to the element type.
TypeResolutionOptions options(TypeResolverContext::ForEachStmt);
options |= TypeResolutionFlags::OverrideType;
// Apply the solution to the pattern as well.
auto contextualPattern = target.getContextualPattern();
if (auto coercedPattern = TypeChecker::coercePatternToType(
contextualPattern, forEachStmtInfo.initType, options)) {
resultTarget.setPattern(coercedPattern);
} else {
return None;
}
// Apply the solution to the filtering condition, if there is one.
auto dc = target.getDeclContext();
if (forEachStmtInfo.whereExpr) {
auto *boolDecl = dc->getASTContext().getBoolDecl();
assert(boolDecl);
Type boolType = boolDecl->getDeclaredInterfaceType();
assert(boolType);
SolutionApplicationTarget whereTarget(
forEachStmtInfo.whereExpr, dc, CTP_Condition, boolType,
/*isDiscarded=*/false);
auto newWhereTarget = cs.applySolution(solution, whereTarget);
if (!newWhereTarget)
return None;
forEachStmtInfo.whereExpr = newWhereTarget->getAsExpr();
}
// Invoke iterator() to get an iterator from the sequence.
ASTContext &ctx = cs.getASTContext();
VarDecl *iterator;
Type nextResultType = OptionalType::get(forEachStmtInfo.elementType);
{
// Create a local variable to capture the iterator.
std::string name;
if (auto np = dyn_cast_or_null<NamedPattern>(stmt->getPattern()))
name = "$"+np->getBoundName().str().str();
name += "$generator";
iterator = new (ctx) VarDecl(
/*IsStatic*/ false, VarDecl::Introducer::Var, stmt->getInLoc(),
ctx.getIdentifier(name), dc);
iterator->setInterfaceType(
forEachStmtInfo.iteratorType->mapTypeOutOfContext());
iterator->setImplicit();
auto genPat = new (ctx) NamedPattern(iterator);
genPat->setImplicit();
// TODO: test/DebugInfo/iteration.swift requires this extra info to
// be around.
PatternBindingDecl::createImplicit(
ctx, StaticSpellingKind::None, genPat,
new (ctx) OpaqueValueExpr(stmt->getInLoc(), nextResultType),
dc, /*VarLoc*/ stmt->getForLoc());
}
// Create the iterator variable.
auto *varRef = TypeChecker::buildCheckedRefExpr(
iterator, dc, DeclNameLoc(stmt->getInLoc()), /*implicit*/ true);
// Convert that Optional<Element> value to the type of the pattern.
auto optPatternType = OptionalType::get(forEachStmtInfo.initType);
if (!optPatternType->isEqual(nextResultType)) {
OpaqueValueExpr *elementExpr = new (ctx) OpaqueValueExpr(
stmt->getInLoc(), nextResultType->getOptionalObjectType(),
/*isPlaceholder=*/true);
Expr *convertElementExpr = elementExpr;
if (TypeChecker::typeCheckExpression(
convertElementExpr, dc,
/*contextualInfo=*/{forEachStmtInfo.initType, CTP_CoerceOperand})
.isNull()) {
return None;
}
elementExpr->setIsPlaceholder(false);
stmt->setElementExpr(elementExpr);
stmt->setConvertElementExpr(convertElementExpr);
}
// Write the result back into the AST.
stmt->setSequence(resultTarget.getAsExpr());
stmt->setPattern(resultTarget.getContextualPattern().getPattern());
stmt->setSequenceConformance(sequenceConformance);
stmt->setWhere(forEachStmtInfo.whereExpr);
stmt->setIteratorVar(iterator);
stmt->setIteratorVarRef(varRef);
return resultTarget;
}
Optional<SolutionApplicationTarget>
ExprWalker::rewriteTarget(SolutionApplicationTarget target) {
auto &solution = Rewriter.solution;
// Apply the solution to the target.
SolutionApplicationTarget result = target;
if (auto expr = target.getAsExpr()) {
Expr *rewrittenExpr = expr->walk(*this);
if (!rewrittenExpr)
return None;
/// Handle special cases for expressions.
switch (target.getExprContextualTypePurpose()) {
case CTP_Initialization: {
auto initResultTarget = applySolutionToInitialization(
solution, target, rewrittenExpr);
if (!initResultTarget)
return None;
result = *initResultTarget;
break;
}
case CTP_ForEachStmt: {
auto forEachResultTarget = applySolutionToForEachStmt(
solution, target, rewrittenExpr);
if (!forEachResultTarget)
return None;
result = *forEachResultTarget;
break;
}
case CTP_Unused:
case CTP_ReturnStmt:
case swift::CTP_ReturnSingleExpr:
case swift::CTP_YieldByValue:
case swift::CTP_YieldByReference:
case swift::CTP_ThrowStmt:
case swift::CTP_EnumCaseRawValue:
case swift::CTP_DefaultParameter:
case swift::CTP_AutoclosureDefaultParameter:
case swift::CTP_CalleeResult:
case swift::CTP_CallArgument:
case swift::CTP_ClosureResult:
case swift::CTP_ArrayElement:
case swift::CTP_DictionaryKey:
case swift::CTP_DictionaryValue:
case swift::CTP_CoerceOperand:
case swift::CTP_AssignSource:
case swift::CTP_SubscriptAssignSource:
case swift::CTP_Condition:
case swift::CTP_WrappedProperty:
case swift::CTP_ComposedPropertyWrapper:
case swift::CTP_CannotFail:
result.setExpr(rewrittenExpr);
break;
}
} else if (auto stmtCondition = target.getAsStmtCondition()) {
for (auto &condElement : *stmtCondition) {
switch (condElement.getKind()) {
case StmtConditionElement::CK_Availability:
continue;
case StmtConditionElement::CK_Boolean: {
auto condExpr = condElement.getBoolean();
auto finalCondExpr = condExpr->walk(*this);
if (!finalCondExpr)
return None;
// Load the condition if needed.
solution.setExprTypes(finalCondExpr);
if (finalCondExpr->getType()->hasLValueType()) {
ASTContext &ctx = solution.getConstraintSystem().getASTContext();
finalCondExpr = TypeChecker::addImplicitLoadExpr(ctx, finalCondExpr);
}
condElement.setBoolean(finalCondExpr);
continue;
}
case StmtConditionElement::CK_PatternBinding: {
ConstraintSystem &cs = solution.getConstraintSystem();
auto target = *cs.getSolutionApplicationTarget(&condElement);
auto resolvedTarget = rewriteTarget(target);
if (!resolvedTarget)
return None;
solution.setExprTypes(resolvedTarget->getAsExpr());
condElement.setInitializer(resolvedTarget->getAsExpr());
condElement.setPattern(resolvedTarget->getInitializationPattern());
continue;
}
}
}
return target;
} else if (auto caseLabelItem = target.getAsCaseLabelItem()) {
ConstraintSystem &cs = solution.getConstraintSystem();
auto info = *cs.getCaseLabelItemInfo(*caseLabelItem);
// Figure out the pattern type.
Type patternType = solution.simplifyType(solution.getType(info.pattern));
patternType = patternType->reconstituteSugar(/*recursive=*/false);
// Coerce the pattern to its appropriate type.
TypeResolutionOptions patternOptions(TypeResolverContext::InExpression);
patternOptions |= TypeResolutionFlags::OverrideType;
auto contextualPattern =
ContextualPattern::forRawPattern(info.pattern,
target.getDeclContext());
if (auto coercedPattern = TypeChecker::coercePatternToType(
contextualPattern, patternType, patternOptions)) {
(*caseLabelItem)->setPattern(coercedPattern, /*resolved=*/true);
} else {
return None;
}
// If there is a guard expression, coerce that.
if (auto guardExpr = info.guardExpr) {
guardExpr = guardExpr->walk(*this);
if (!guardExpr)
return None;
// FIXME: Feels like we could leverage existing code more.
Type boolType = cs.getASTContext().getBoolDecl()->getDeclaredInterfaceType();
guardExpr = solution.coerceToType(
guardExpr, boolType, cs.getConstraintLocator(info.guardExpr));
if (!guardExpr)
return None;
(*caseLabelItem)->setGuardExpr(guardExpr);
solution.setExprTypes(guardExpr);
}
return target;
} else if (auto patternBinding = target.getAsPatternBinding()) {
ConstraintSystem &cs = solution.getConstraintSystem();
for (unsigned index : range(patternBinding->getNumPatternEntries())) {
// Find the solution application target for this.
auto knownTarget = *cs.getSolutionApplicationTarget(
{patternBinding, index});
// Rewrite the target.
auto resultTarget = rewriteTarget(knownTarget);
if (!resultTarget)
return None;
patternBinding->setPattern(
index, resultTarget->getInitializationPattern(),
resultTarget->getDeclContext());
patternBinding->setInit(index, resultTarget->getAsExpr());
}
return target;
} else if (auto *wrappedVar = target.getAsUninitializedWrappedVar()) {
// Get the outermost wrapper type from the solution
auto outermostWrapper = wrappedVar->getAttachedPropertyWrappers().front();
auto backingType = solution.simplifyType(
solution.getType(outermostWrapper->getTypeRepr()));
auto &ctx = solution.getConstraintSystem().getASTContext();
ctx.setSideCachedPropertyWrapperBackingPropertyType(
wrappedVar, backingType->mapTypeOutOfContext());
return target;
} else {
auto fn = *target.getAsFunction();
if (rewriteFunction(fn))
return None;
result.setFunctionBody(fn.getBody());
}
// Follow-up tasks.
auto &cs = solution.getConstraintSystem();
if (auto resultExpr = result.getAsExpr()) {
Expr *expr = target.getAsExpr();
assert(expr && "Can't have expression result without expression target");
// We are supposed to use contextual type only if it is present and
// this expression doesn't represent the implicit return of the single
// expression function which got deduced to be `Never`.
Type convertType = target.getExprConversionType();
auto shouldCoerceToContextualType = [&]() {
return convertType &&
!target.isOptionalSomePatternInit() &&
!(solution.getType(resultExpr)->isUninhabited() &&
cs.getContextualTypePurpose(target.getAsExpr())
== CTP_ReturnSingleExpr);
};
// If we're supposed to convert the expression to some particular type,
// do so now.
if (shouldCoerceToContextualType()) {
resultExpr = Rewriter.coerceToType(resultExpr,
solution.simplifyType(convertType),
cs.getConstraintLocator(expr));
} else if (cs.getType(resultExpr)->hasLValueType() &&
!target.isDiscardedExpr()) {
// We referenced an lvalue. Load it.
resultExpr = Rewriter.coerceToType(
resultExpr,
cs.getType(resultExpr)->getRValueType(),
cs.getConstraintLocator(expr));
}
if (!resultExpr)
return None;
// For an @autoclosure default parameter type, add the autoclosure
// conversion.
if (FunctionType *autoclosureParamType =
target.getAsAutoclosureParamType()) {
resultExpr = cs.buildAutoClosureExpr(resultExpr, autoclosureParamType);
}
solution.setExprTypes(resultExpr);
result.setExpr(resultExpr);
if (cs.isDebugMode()) {
auto &log = llvm::errs();
log << "---Type-checked expression---\n";
resultExpr->dump(log);
log << "\n";
}
}
return result;
}
/// Apply a given solution to the expression, producing a fully
/// type-checked expression.
Optional<SolutionApplicationTarget> ConstraintSystem::applySolution(
Solution &solution, SolutionApplicationTarget target) {
// If any fixes needed to be applied to arrive at this solution, resolve
// them to specific expressions.
if (!solution.Fixes.empty()) {
if (shouldSuppressDiagnostics())
return None;
bool diagnosedErrorsViaFixes = applySolutionFixes(solution);
// If all of the available fixes would result in a warning,
// we can go ahead and apply this solution to AST.
if (!llvm::all_of(solution.Fixes, [](const ConstraintFix *fix) {
return fix->isWarning();
})) {
// If we already diagnosed any errors via fixes, that's it.
if (diagnosedErrorsViaFixes)
return None;
// If we didn't manage to diagnose anything well, so fall back to
// diagnosing mining the system to construct a reasonable error message.
diagnoseFailureFor(target);
return None;
}
}
// If there are no fixes recorded but score indicates that there
// should have been at least one, let's fail application and
// produce a fallback diagnostic to highlight the problem.
{
const auto &score = solution.getFixedScore();
if (score.Data[SK_Fix] > 0 || score.Data[SK_Hole] > 0) {
maybeProduceFallbackDiagnostic(target);
return None;
}
}
ExprRewriter rewriter(*this, solution, target, shouldSuppressDiagnostics());
ExprWalker walker(rewriter);
auto resultTarget = walker.rewriteTarget(target);
if (!resultTarget)
return None;
// Visit closures that have non-single expression bodies.
bool hadError = false;
for (auto *closure : walker.getClosuresToTypeCheck())
hadError |= TypeChecker::typeCheckClosureBody(closure);
// Tap expressions too; they should or should not be
// type-checked under the same conditions as closure bodies.
for (auto tuple : walker.getTapsToTypeCheck()) {
auto tap = std::get<0>(tuple);
auto tapDC = std::get<1>(tuple);
hadError |= TypeChecker::typeCheckTapBody(tap, tapDC);
}
// If any of them failed to type check, bail.
if (hadError)
return None;
rewriter.finalize();
return resultTarget;
}
Expr *Solution::coerceToType(Expr *expr, Type toType,
ConstraintLocator *locator,
Optional<Pattern*> typeFromPattern) {
auto &cs = getConstraintSystem();
ExprRewriter rewriter(cs, *this, None, /*suppressDiagnostics=*/false);
Expr *result = rewriter.coerceToType(expr, toType, locator, typeFromPattern);
if (!result)
return nullptr;
setExprTypes(result);
rewriter.finalize();
return result;
}
bool Solution::hasType(ASTNode node) const {
auto result = nodeTypes.find(node);
if (result != nodeTypes.end())
return true;
auto &cs = getConstraintSystem();
return cs.hasType(node);
}
Type Solution::getType(ASTNode node) const {
auto result = nodeTypes.find(node);
if (result != nodeTypes.end())
return result->second;
auto &cs = getConstraintSystem();
return cs.getType(node);
}
Type Solution::getResolvedType(ASTNode node) const {
return simplifyType(getType(node));
}
void Solution::setExprTypes(Expr *expr) const {
if (!expr)
return;
SetExprTypes SET(*this);
expr->walk(SET);
}
/// MARK: SolutionResult implementation.
SolutionResult SolutionResult::forSolved(Solution &&solution) {
SolutionResult result(Kind::Success);
void *memory = malloc(sizeof(Solution));
result.solutions = new (memory) Solution(std::move(solution));
result.numSolutions = 1;
return result;
}
SolutionResult SolutionResult::forAmbiguous(
MutableArrayRef<Solution> solutions) {
assert(solutions.size() > 1 && "Not actually ambiguous");
SolutionResult result(Kind::Ambiguous);
result.solutions =
(Solution *)malloc(sizeof(Solution) * solutions.size());
result.numSolutions = solutions.size();
std::uninitialized_copy(std::make_move_iterator(solutions.begin()),
std::make_move_iterator(solutions.end()),
result.solutions);
return result;
}
SolutionResult::~SolutionResult() {
assert((!requiresDiagnostic() || emittedDiagnostic) &&
"SolutionResult was destroyed without emitting a diagnostic");
for (unsigned i : range(numSolutions)) {
solutions[i].~Solution();
}
free(solutions);
}
const Solution &SolutionResult::getSolution() const {
assert(numSolutions == 1 && "Wrong number of solutions");
return solutions[0];
}
Solution &&SolutionResult::takeSolution() && {
assert(numSolutions == 1 && "Wrong number of solutions");
return std::move(solutions[0]);
}
ArrayRef<Solution> SolutionResult::getAmbiguousSolutions() const {
assert(getKind() == Ambiguous);
return makeArrayRef(solutions, numSolutions);
}
MutableArrayRef<Solution> SolutionResult::takeAmbiguousSolutions() && {
assert(getKind() == Ambiguous);
markAsDiagnosed();
return MutableArrayRef<Solution>(solutions, numSolutions);
}
SolutionApplicationTarget SolutionApplicationTarget::walk(ASTWalker &walker) {
switch (kind) {
case Kind::expression: {
SolutionApplicationTarget result = *this;
result.setExpr(getAsExpr()->walk(walker));
return result;
}
case Kind::function:
return SolutionApplicationTarget(
*getAsFunction(),
cast_or_null<BraceStmt>(getFunctionBody()->walk(walker)));
case Kind::stmtCondition:
for (auto &condElement : stmtCondition.stmtCondition) {
condElement = *condElement.walk(walker);
}
return *this;
case Kind::caseLabelItem:
if (auto newPattern =
caseLabelItem.caseLabelItem->getPattern()->walk(walker)) {
caseLabelItem.caseLabelItem->setPattern(
newPattern, caseLabelItem.caseLabelItem->isPatternResolved());
}
if (auto guardExpr = caseLabelItem.caseLabelItem->getGuardExpr()) {
if (auto newGuardExpr = guardExpr->walk(walker))
caseLabelItem.caseLabelItem->setGuardExpr(newGuardExpr);
}
return *this;
case Kind::patternBinding:
return *this;
case Kind::uninitializedWrappedVar:
return *this;
}
llvm_unreachable("invalid target kind");
}
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