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cf09a4e536008f4739f8c822fc9ea81188b55328
swift-mirror/lib/Sema/CSApply.cpp
Pavel Yaskevich cf09a4e536 [CSApply] Mark dynamic member lookup subscript expr and its argument as implicit 
These expressions are created to model an implicit call to dynamic
member lookup endpoint, which means both of them have to be implicit.
2019-04-09 19:12:10 -07:00

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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 "ConstraintSystem.h"
#include "CodeSynthesis.h"
#include "CSDiagnostics.h"
#include "MiscDiagnostics.h"
#include "TypeCheckProtocol.h"
#include "swift/AST/ASTVisitor.h"
#include "swift/AST/ASTWalker.h"
#include "swift/AST/ExistentialLayout.h"
#include "swift/AST/Initializer.h"
#include "swift/AST/GenericSignature.h"
#include "swift/AST/ParameterList.h"
#include "swift/AST/ProtocolConformance.h"
#include "swift/AST/SubstitutionMap.h"
#include "swift/Basic/StringExtras.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,
ConstraintLocatorBuilder locatorBuilder) const {
if (sig == nullptr)
return SubstitutionMap();
// Gather the substitutions from dependent types to concrete types.
auto locator = getConstraintSystem().getConstraintLocator(locatorBuilder);
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 &tc = getConstraintSystem().getTypeChecker();
auto lookupConformanceFn =
[&](CanType original, Type replacement, ProtocolDecl *protoType)
-> Optional<ProtocolConformanceRef> {
if (replacement->hasError() ||
isOpenedAnyObject(replacement) ||
replacement->is<GenericTypeParamType>()) {
return ProtocolConformanceRef(protoType);
}
return tc.conformsToProtocol(replacement, protoType,
getConstraintSystem().DC,
(ConformanceCheckFlags::InExpression|
ConformanceCheckFlags::Used));
};
return SubstitutionMap::get(sig,
QueryTypeSubstitutionMap{subs},
lookupConformanceFn);
}
/// Find a particular named function witness for a type that conforms to
/// the given protocol.
///
/// \param tc The type check we're using.
///
/// \param dc The context in which we need a witness.
///
/// \param type The type whose witness to find.
///
/// \param proto The protocol to which the type conforms.
///
/// \param name The name of the requirement.
///
/// \param diag The diagnostic to emit if the protocol definition doesn't
/// have a requirement with the given name.
///
/// \returns The named witness, or an empty ConcreteDeclRef if no witness
/// could be found.
ConcreteDeclRef findNamedWitnessImpl(
TypeChecker &tc, DeclContext *dc, Type type,
ProtocolDecl *proto, DeclName name,
Diag<> diag,
Optional<ProtocolConformanceRef> conformance = None) {
// Find the named requirement.
ValueDecl *requirement = nullptr;
for (auto member : proto->getMembers()) {
auto d = dyn_cast<ValueDecl>(member);
if (!d || !d->hasName())
continue;
if (d->getFullName().matchesRef(name)) {
requirement = d;
break;
}
}
if (!requirement || requirement->isInvalid()) {
tc.diagnose(proto->getLoc(), diag);
return nullptr;
}
// Find the member used to satisfy the named requirement.
if (!conformance) {
conformance = tc.conformsToProtocol(type, proto, dc,
ConformanceCheckFlags::InExpression);
if (!conformance)
return nullptr;
}
// For a type with dependent conformance, just return the requirement from
// the protocol. There are no protocol conformance tables.
if (!conformance->isConcrete()) {
auto subMap = SubstitutionMap::getProtocolSubstitutions(proto, type,
*conformance);
return ConcreteDeclRef(requirement, subMap);
}
auto concrete = conformance->getConcrete();
return concrete->getWitnessDeclRef(requirement, &tc);
}
static bool shouldAccessStorageDirectly(Expr *base, VarDecl *member,
DeclContext *DC) {
// This only matters for stored properties.
if (!member->hasStorage())
return false;
// ... referenced from constructors and destructors.
auto *AFD = dyn_cast<AbstractFunctionDecl>(DC);
if (AFD == nullptr)
return false;
if (!isa<ConstructorDecl>(AFD) && !isa<DestructorDecl>(AFD))
return false;
// ... via a "self.property" reference.
auto *DRE = dyn_cast<DeclRefExpr>(base);
if (DRE == nullptr)
return false;
if (AFD->getImplicitSelfDecl() != cast<DeclRefExpr>(base)->getDecl())
return false;
// Convenience initializers do not require special handling.
// FIXME: This is a language change -- for now, keep the old behavior
#if 0
if (auto *CD = dyn_cast<ConstructorDecl>(AFD))
if (!CD->isDesignatedInit())
return false;
#endif
// Ctor or dtor are for immediate class, not a derived class.
if (!AFD->getParent()->getDeclaredInterfaceType()->isEqual(
member->getDeclContext()->getDeclaredInterfaceType()))
return false;
// If the storage is resilient, we cannot access it directly at all.
if (member->isResilient(DC->getParentModule(),
DC->getResilienceExpansion()))
return false;
return true;
}
/// 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) {
// Properties that have storage and accessors are frequently accessed through
// accessors. However, in the init and destructor methods for the type
// immediately containing the property, accesses are done direct.
if (shouldAccessStorageDirectly(base, member, DC)) {
// Access this directly instead of going through (e.g.) observing or
// trivial accessors.
return AccessSemantics::DirectToStorage;
}
// 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(const Expr *E) {
return E->isTypeReference(
[&](const Expr *E) -> Type { return simplifyType(getType(E)); },
[&](const 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 ConstraintSystem::isStaticallyDerivedMetatype(const Expr *E) {
return E->isStaticallyDerivedMetatype(
[&](const Expr *E) -> Type { return simplifyType(getType(E)); },
[&](const Expr *E) -> bool { return isTypeReference(E); });
}
Type ConstraintSystem::getInstanceType(const TypeExpr *E) {
return E->getInstanceType([&](const Expr *E) -> bool { return hasType(E); },
[&](const Expr *E) -> Type { return getType(E); });
}
Type ConstraintSystem::getResultType(const AbstractClosureExpr *E) {
return E->getResultType([&](const 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;
}
}
// 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;
}
/// Form a type checked expression for the index of a @dynamicMemberLookup
/// subscript index parameter.
/// The index expression will have a tuple type of `(dynamicMember: T)`.
static Expr *buildDynamicMemberLookupIndexExpr(StringRef name, SourceLoc loc,
DeclContext *dc,
ConstraintSystem &cs) {
auto &ctx = cs.TC.Context;
// Build and type check the string literal index value to the specific
// string type expected by the subscript.
Expr *nameExpr = new (ctx) StringLiteralExpr(name, loc, /*implicit*/true);
(void)cs.TC.typeCheckExpression(nameExpr, dc);
cs.cacheExprTypes(nameExpr);
return nameExpr;
}
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;
const Solution &solution;
bool SuppressDiagnostics;
/// Recognize used conformances from an imported type when we must emit
/// the witness table.
///
/// This arises in _BridgedStoredNSError, where we wouldn't
/// otherwise pull in the witness table, causing dynamic casts to
/// perform incorrectly, and _ErrorCodeProtocol, where we need to
/// check for _BridgedStoredNSError conformances on the
/// corresponding ErrorType.
void checkForImportedUsedConformances(Type toType) {
cs.getTypeChecker().useBridgedNSErrorConformances(dc, toType);
}
/// 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.
/// \param locator Locator describing where this conversion occurs.
///
/// \return The coerced expression, whose type will be equivalent to
/// \c toType.
Expr *coerceSuperclass(Expr *expr, Type toType,
ConstraintLocatorBuilder locator);
/// 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.
/// \param locator Locator describing where this conversion occurs.
///
/// \return The coerced expression, whose type will be equivalent to
/// \c toType.
Expr *coerceExistential(Expr *expr, Type toType,
ConstraintLocatorBuilder locator);
/// 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();
}
public:
/// Build a reference to the given declaration.
Expr *buildDeclRef(OverloadChoice choice, DeclNameLoc loc, Type openedType,
ConstraintLocatorBuilder locator, bool implicit,
FunctionRefKind functionRefKind,
AccessSemantics semantics) {
auto *decl = choice.getDecl();
// Determine the declaration selected for this overloaded reference.
auto &ctx = cs.getASTContext();
// 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 openedFnType = openedType->castTo<FunctionType>();
auto simplifiedFnType
= simplifyType(openedFnType)->castTo<FunctionType>();
auto baseTy = getBaseType(simplifiedFnType);
// Handle operator requirements found in protocols.
if (auto proto = dyn_cast<ProtocolDecl>(decl->getDeclContext())) {
// If we don't have an archetype or existential, we have to call 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.
if (!baseTy->is<ArchetypeType>() && !baseTy->isAnyExistentialType()) {
auto &tc = cs.getTypeChecker();
auto conformance =
tc.conformsToProtocol(
baseTy, proto, cs.DC,
(ConformanceCheckFlags::InExpression|
ConformanceCheckFlags::Used));
if (conformance && conformance->isConcrete()) {
if (auto witness =
conformance->getConcrete()->getWitnessDecl(decl, &tc)) {
// Hack up an AST that we can type-check (independently) to get
// it into the right form.
// FIXME: the hop through 'getDecl()' is because
// SpecializedProtocolConformance doesn't substitute into
// witnesses' ConcreteDeclRefs.
Type expectedFnType = simplifiedFnType->getResult();
Expr *refExpr;
if (witness->getDeclContext()->isTypeContext()) {
Expr *base =
TypeExpr::createImplicitHack(loc.getBaseNameLoc(), baseTy,
ctx);
refExpr = new (ctx) MemberRefExpr(base, SourceLoc(), witness,
loc, /*Implicit=*/true);
} else {
auto declRefExpr = new (ctx) DeclRefExpr(witness, loc,
/*Implicit=*/false);
declRefExpr->setFunctionRefKind(functionRefKind);
refExpr = declRefExpr;
}
auto resultTy = tc.typeCheckExpression(
refExpr, cs.DC, TypeLoc::withoutLoc(expectedFnType),
CTP_CannotFail);
if (!resultTy)
return nullptr;
cs.cacheExprTypes(refExpr);
// Remove an outer function-conversion expression. This
// happens when we end up referring to a witness for a
// superclass conformance, and 'Self' differs.
if (auto fnConv = dyn_cast<FunctionConversionExpr>(refExpr))
refExpr = fnConv->getSubExpr();
return forceUnwrapIfExpected(refExpr, choice, locator);
}
}
}
}
// Build a reference to the protocol requirement.
Expr *base =
TypeExpr::createImplicitHack(loc.getBaseNameLoc(), baseTy, ctx);
cs.cacheExprTypes(base);
return buildMemberRef(base, openedType, SourceLoc(), choice, loc,
openedFnType->getResult(), locator, locator,
implicit, functionRefKind, semantics,
/*isDynamic=*/false);
}
SubstitutionMap substitutions;
// Due to a SILGen quirk, unqualified property references do not
// need substitutions.
if (!isa<VarDecl>(decl)) {
substitutions =
solution.computeSubstitutions(
decl->getInnermostDeclContext()->getGenericSignatureOfContext(),
locator);
}
auto type = solution.simplifyType(openedType);
auto declRefExpr =
new (ctx) DeclRefExpr(ConcreteDeclRef(decl, substitutions),
loc, implicit, semantics, type);
cs.cacheType(declRefExpr);
declRefExpr->setFunctionRefKind(functionRefKind);
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;
/// 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();
}
unsigned getNaturalArgumentCount(ValueDecl *member) {
if (isa<AbstractFunctionDecl>(member)) {
// For functions, close the existential once the function
// has been fully applied.
return 2;
} else {
// For storage, close the existential either when it's
// accessed (if it's an rvalue only) or when it is loaded or
// stored (if it's an lvalue).
assert(isa<AbstractStorageDecl>(member) &&
"unknown member when opening existential");
return 1;
}
}
/// 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) {
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;
}
// Invalid case -- direct call of a metatype. Has one less argument
// application because there's no ".init".
if (isa<ApplyExpr>(ExprStack.back()))
argCount--;
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?");
auto &tc = cs.getTypeChecker();
// 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 = getNaturalArgumentCount(member);
unsigned depth = ExprStack.size() - getArgCount(maxArgCount);
// 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 = tc.Context;
auto archetypeVal = new (ctx) OpaqueValueExpr(base->getLoc(), 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.
ConstraintSystem &innerCS = solution.getConstraintSystem();
auto &tc = innerCS.getTypeChecker();
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 (tc.Context) 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 (tc.Context) OpenExistentialExpr(
record.ExistentialValue,
record.OpaqueValue,
result, cs.getType(result));
cs.cacheType(result);
OpenedExistentials.pop_back();
return true;
}
/// Build a new member reference with the given base and member.
Expr *buildMemberRef(Expr *base, Type openedFullType, SourceLoc dotLoc,
OverloadChoice choice, DeclNameLoc memberLoc,
Type openedType, ConstraintLocatorBuilder locator,
ConstraintLocatorBuilder memberLocator, bool Implicit,
FunctionRefKind functionRefKind,
AccessSemantics semantics, bool isDynamic) {
ValueDecl *member = choice.getDecl();
auto &tc = cs.getTypeChecker();
auto &context = tc.Context;
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();
}
// Build a member reference.
SubstitutionMap substitutions =
solution.computeSubstitutions(
member->getInnermostDeclContext()->getGenericSignatureOfContext(),
memberLocator);
auto memberRef = ConcreteDeclRef(member, substitutions);
cs.TC.requestMemberLayout(member);
auto refTy = solution.simplifyType(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(functionRefKind);
auto *DSBI = cs.cacheType(new (context) DotSyntaxBaseIgnoredExpr(
base, dotLoc, ref, cs.getType(ref)));
return forceUnwrapIfExpected(DSBI, choice, memberLocator);
}
// 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.
auto knownOpened = solution.OpenedExistentialTypes.find(
getConstraintSystem().getConstraintLocator(
memberLocator));
bool openedExistential = false;
if (knownOpened != solution.OpenedExistentialTypes.end()) {
base = openExistentialReference(base, knownOpened->second, member);
baseTy = knownOpened->second;
selfTy = baseTy;
openedExistential = true;
}
// If this is a method whose result type is dynamic Self, or a
// construction, replace the result type with the actual object type.
Type dynamicSelfFnType;
if (!member->getDeclContext()->getSelfProtocolDecl()) {
if (auto func = dyn_cast<AbstractFunctionDecl>(member)) {
if ((isa<FuncDecl>(func) &&
cast<FuncDecl>(func)->hasDynamicSelf()) ||
(isa<ConstructorDecl>(func) &&
containerTy->getClassOrBoundGenericClass())) {
refTy = refTy->replaceCovariantResultType(containerTy, 2);
if (!baseTy->isEqual(containerTy)) {
dynamicSelfFnType = refTy->replaceCovariantResultType(baseTy, 2);
}
}
}
}
// 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);
}
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 = coerceObjectArgumentToType(
base, selfParamTy, member, semantics,
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->hasOpenedExistential(knownOpened->second)) {
refType = refType->eraseOpenedExistential(knownOpened->second);
}
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() &&
tc.Context.LangOpts.WarnSwift3ObjCInference
== Swift3ObjCInferenceWarnings::Minimal) {
tc.diagnose(memberLoc,
diag::expr_dynamic_lookup_swift3_objc_inference,
member->getDescriptiveKind(),
member->getFullName(),
member->getDeclContext()
->getSelfNominalTypeDecl()
->getName());
tc.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 types and properties, build member references.
if (isa<TypeDecl>(member) || isa<VarDecl>(member)) {
assert(!dynamicSelfFnType && "Converted type doesn't make sense here");
if (!baseIsInstance && member->isInstanceMember()) {
assert(memberLocator.getBaseLocator() &&
cs.UnevaluatedRootExprs.count(
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 memberRefExpr
= new (context) MemberRefExpr(base, dotLoc, memberRef,
memberLoc, Implicit, semantics);
memberRefExpr->setIsSuper(isSuper);
// Skip the synthesized 'self' input type of the opened type.
cs.setType(memberRefExpr, simplifyType(openedType));
Expr *result = memberRefExpr;
closeExistential(result, locator);
return forceUnwrapIfExpected(result, choice, memberLocator);
}
// Handle all other references.
auto declRefExpr = new (context) DeclRefExpr(memberRef, memberLoc,
Implicit, semantics);
declRefExpr->setFunctionRefKind(functionRefKind);
cs.setType(declRefExpr, refTy);
Expr *ref = declRefExpr;
// If the reference needs to be converted, do so now.
if (dynamicSelfFnType) {
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 (!baseIsInstance && member->isInstanceMember()) {
// 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);
}
/// Describes either a type or the name of a type to be resolved.
using TypeOrName = llvm::PointerUnion<Identifier, Type>;
/// 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(Expr *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.
Expr *finishApply(ApplyExpr *apply, Type openedType,
ConstraintLocatorBuilder locator);
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 a closure expression with a non-Void return type to a
/// contextual function type with a Void return type.
///
/// This operation cannot fail.
///
/// \param expr The closure expression to coerce.
///
/// \returns The coerced closure expression.
///
ClosureExpr *coerceClosureExprToVoid(ClosureExpr *expr);
/// Coerce a closure expression with a Never return type to a
/// contextual function type with some other return type.
///
/// This operation cannot fail.
///
/// \param expr The closure expression to coerce.
///
/// \returns The coerced closure expression.
///
ClosureExpr *coerceClosureExprFromNever(ClosureExpr *expr);
/// 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 apply The ApplyExpr that forms the call.
/// \param argLabels The argument labels provided for the call.
/// \param hasTrailingClosure Whether the last argument is a trailing
/// closure.
/// \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,
ApplyExpr *apply,
ArrayRef<Identifier> argLabels,
bool hasTrailingClosure,
ConstraintLocatorBuilder locator);
/// Coerce the given object 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 semantics The kind of access we've been asked to perform.
///
/// \param locator Locator used to describe where in this expression we are.
Expr *coerceObjectArgumentToType(Expr *expr,
Type baseTy, ValueDecl *member,
AccessSemantics semantics,
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,
Optional<SelectedOverload> selected = None) {
// Determine the declaration selected for this subscript operation.
if (!selected)
selected = solution.getOverloadChoiceIfAvailable(
cs.getConstraintLocator(
locator.withPathElement(
ConstraintLocator::SubscriptMember)));
// Handles situation where there was a solution available but it didn't
// have a proper overload selected from subscript call, might be because
// solver was allowed to return free or unresolved types, which can
// happen while running diagnostics on one of the expressions.
if (!selected.hasValue()) {
auto &tc = cs.TC;
auto baseType = cs.getType(base);
if (auto errorType = baseType->getAs<ErrorType>()) {
tc.diagnose(base->getLoc(), diag::cannot_subscript_base,
errorType->getOriginalType())
.highlight(base->getSourceRange());
} else {
tc.diagnose(base->getLoc(), diag::cannot_subscript_ambiguous_base)
.highlight(base->getSourceRange());
}
return nullptr;
}
// 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.withPathElement(ConstraintLocator::SubscriptMember)
.withPathElement(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 &&
!isa<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,
SelectedOverload &selected,
bool hasTrailingClosure,
ConstraintLocatorBuilder locator,
bool isImplicit, AccessSemantics semantics) {
auto choice = selected.choice;
// 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)) {
cs.TC.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 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());
cs.TC.requestMemberLayout(subscript);
auto &tc = cs.getTypeChecker();
auto baseTy = cs.getType(base)->getRValueType();
// 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 = isa<SubscriptExpr>(locator.getAnchor())
? ConstraintLocator::SubscriptMember
: ConstraintLocator::Member;
}
// If we opened up an existential when performing the subscript, open
// the base accordingly.
auto knownOpened = solution.OpenedExistentialTypes.find(
getConstraintSystem().getConstraintLocator(
locator.withPathElement(locatorKind)));
if (knownOpened != solution.OpenedExistentialTypes.end()) {
base = openExistentialReference(base, knownOpened->second, subscript);
baseTy = knownOpened->second;
}
// Figure out the index and result types.
Type resultTy;
if (choice.getKind() != OverloadChoiceKind::DynamicMemberLookup &&
choice.getKind() != OverloadChoiceKind::KeyPathDynamicMemberLookup) {
auto subscriptTy = simplifyType(selected.openedType);
auto *subscriptFnTy = subscriptTy->castTo<FunctionType>();
resultTy = subscriptFnTy->getResult();
// Coerce the index argument.
index = coerceCallArguments(index, subscriptFnTy, nullptr,
argLabels, hasTrailingClosure,
locator.withPathElement(
ConstraintLocator::ApplyArgument));
if (!index)
return nullptr;
} else {
// If this is a @dynamicMemberLookup, then the type of the selection is
// actually the property/result type. That's fine though, and we
// already have the index type adjusted to the correct type expected by
// the subscript.
resultTy = simplifyType(selected.openedType);
}
auto getType = [&](const Expr *E) -> Type {
return cs.getType(E);
};
// Form the subscript expression.
// Compute the substitutions used to reference the subscript.
SubstitutionMap substitutions =
solution.computeSubstitutions(
subscript->getInnermostDeclContext()->getGenericSignatureOfContext(),
locator.withPathElement(locatorKind));
ConcreteDeclRef subscriptRef(subscript, substitutions);
// Handle dynamic lookup.
if (choice.getKind() == OverloadChoiceKind::DeclViaDynamic ||
subscript->getAttrs().hasAttribute<OptionalAttr>()) {
base = coerceObjectArgumentToType(base, baseTy, subscript,
AccessSemantics::Ordinary, locator);
if (!base)
return nullptr;
// TODO: diagnose if semantics != AccessSemantics::Ordinary?
auto subscriptExpr = DynamicSubscriptExpr::create(tc.Context, base,
index, subscriptRef,
isImplicit, getType);
cs.setType(subscriptExpr, resultTy);
Expr *result = subscriptExpr;
closeExistential(result, locator);
return result;
}
// Convert the base.
auto openedFullFnType = selected.openedFullType->castTo<FunctionType>();
auto openedBaseType =
getBaseType(openedFullFnType, /*wantsRValue*/ false);
auto containerTy = solution.simplifyType(openedBaseType);
base = coerceObjectArgumentToType(
base, containerTy, subscript, AccessSemantics::Ordinary,
locator.withPathElement(ConstraintLocator::MemberRefBase));
if (!base)
return nullptr;
// Form the subscript expression.
auto subscriptExpr = SubscriptExpr::create(
tc.Context, base, index, subscriptRef, isImplicit, semantics, getType);
cs.setType(subscriptExpr, resultTy);
subscriptExpr->setIsSuper(isSuper);
Expr *result = subscriptExpr;
closeExistential(result, locator);
return result;
}
/// Build a new reference to another constructor.
Expr *buildOtherConstructorRef(Type openedFullType,
ConstructorDecl *ctor, Expr *base,
DeclNameLoc loc,
ConstraintLocatorBuilder locator,
bool implicit) {
auto &tc = cs.getTypeChecker();
auto &ctx = tc.Context;
// Compute the concrete reference.
SubstitutionMap substitutions =
solution.computeSubstitutions(ctor->getGenericSignature(), locator);
auto ref = ConcreteDeclRef(ctor, substitutions);
tc.requestMemberLayout(ctor);
// 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 = memberLoc->getAnchor();
KeyPathExpr::Component component;
// 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,
/*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::getKeyPathDynamicMember(keyPathTy->getAnyNominal()));
auto overload = solution.getOverloadChoice(componentLoc);
auto buildSubscriptComponent = [&](SourceLoc loc, Expr *indexExpr,
ArrayRef<Identifier> labels) {
// Save a reference to the component so we can do a post-pass to check
// the Hashable conformance of the indexes.
KeyPathSubscriptComponents.push_back({keyPath, 0});
return buildKeyPathSubscriptComponent(overload, loc, indexExpr, labels,
componentLoc);
};
auto getKeyPathComponentIndex =
[](ConstraintLocator *locator) -> unsigned {
for (const auto &elt : locator->getPath()) {
if (elt.getKind() == ConstraintLocator::KeyPathComponent)
return elt.getValue();
}
llvm_unreachable("no keypath component node");
};
// Looks like there is a chain of implicit `subscript(dynamicMember:)`
// calls necessary to resolve a member reference.
if (overload.choice.getKind() ==
OverloadChoiceKind::KeyPathDynamicMemberLookup) {
keyPath->resolveComponents(
ctx, buildSubscriptComponent(dotLoc, /*indexExpr=*/nullptr,
ctx.Id_dynamicMember));
return keyPath;
}
// 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 componentIdx = getKeyPathComponentIndex(memberLoc);
auto &origComponent = KPE->getComponents()[componentIdx];
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,
[&](const 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);
component = buildKeyPathPropertyComponent(overload, UDE->getLoc(),
componentLoc);
} 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());
}
Expr *trailingClosure = nullptr;
if (SE->hasTrailingClosure())
trailingClosure = arguments.back();
componentExpr = SubscriptExpr::create(
ctx, dotExpr, SE->getStartLoc(), arguments,
SE->getArgumentLabels(), SE->getArgumentLabelLocs(),
SE->getEndLoc(), trailingClosure,
SE->hasDecl() ? SE->getDecl() : ConcreteDeclRef(),
/*implicit=*/true, SE->getAccessSemantics());
}
component = buildSubscriptComponent(SE->getLoc(), SE->getIndex(),
SE->getArgumentLabels());
} else {
return nullptr;
}
assert(componentExpr);
componentExpr->setType(simplifyType(cs.getType(anchor)));
cs.cacheType(componentExpr);
keyPath->setParsedPath(componentExpr);
keyPath->resolveComponents(ctx, {component});
return keyPath;
}
/// Bridge the given value (which is an error type) to NSError.
Expr *bridgeErrorToObjectiveC(Expr *value) {
auto &tc = cs.getTypeChecker();
auto nsErrorDecl = tc.Context.getNSErrorDecl();
assert(nsErrorDecl && "Missing NSError?");
Type nsErrorType = nsErrorDecl->getDeclaredInterfaceType();
auto result = new (tc.Context) 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 &tc = cs.getTypeChecker();
auto result = new (tc.Context) 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 &tc = cs.getTypeChecker();
if (!conditional) {
auto result = new (tc.Context) BridgeFromObjCExpr(object, valueType);
return cs.cacheType(result);
}
// Find the _BridgedToObjectiveC protocol.
auto bridgedProto
= tc.Context.getProtocol(KnownProtocolKind::ObjectiveCBridgeable);
// Try to find the conformance of the value type to _BridgedToObjectiveC.
auto bridgedToObjectiveCConformance
= tc.conformsToProtocol(valueType,
bridgedProto,
cs.DC,
(ConformanceCheckFlags::InExpression|
ConformanceCheckFlags::Used));
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
? tc.Context.getConditionallyBridgeFromObjectiveCBridgeable()
: tc.Context.getForceBridgeFromObjectiveCBridgeable();
} else {
// Retrieve the bridging operation to be used if a static conformance
// to _BridgedToObjectiveC cannot be proven.
fn = conditional ? tc.Context.getConditionallyBridgeFromObjectiveC()
: tc.Context.getForceBridgeFromObjectiveC();
}
if (!fn) {
tc.diagnose(object->getLoc(), diag::missing_bridging_function,
conditional);
return nullptr;
}
tc.validateDecl(fn);
// 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 (tc.Context) 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);
}
TypeAliasDecl *MaxFloatTypeDecl = nullptr;
public:
ExprRewriter(ConstraintSystem &cs, const Solution &solution,
bool suppressDiagnostics)
: cs(cs), dc(cs.DC), solution(solution),
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 &tc = cs.getTypeChecker();
ProtocolDecl *protocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByIntegerLiteral);
ProtocolDecl *builtinProtocol
= tc.getProtocol(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 = tc.getDefaultType(protocol, dc)) {
if (defaultType->isEqual(type))
type = defaultType;
}
if (auto floatProtocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByFloatLiteral)) {
if (auto defaultFloatType = tc.getDefaultType(floatProtocol, dc)) {
if (defaultFloatType->isEqual(type))
type = defaultFloatType;
}
}
DeclName initName(tc.Context, DeclBaseName::createConstructor(),
{ tc.Context.Id_integerLiteral });
DeclName builtinInitName(tc.Context, DeclBaseName::createConstructor(),
{ tc.Context.Id_builtinIntegerLiteral });
auto *result = convertLiteralInPlace(
expr, type, protocol, tc.Context.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 &tc = cs.getTypeChecker();
auto *protocol = tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByNilLiteral);
// For type-sugar reasons, prefer the spelling of the default literal
// type.
auto type = simplifyType(cs.getType(expr));
if (auto defaultType = tc.getDefaultType(protocol, dc)) {
if (defaultType->isEqual(type))
type = defaultType;
}
// By far the most common 'nil' literal is for Optional<T>.none.
//
// Emit this case directly instead of calling Optional.init(nilLiteral:),
// since this generates more efficient SIL.
if (auto objectType = type->getOptionalObjectType()) {
auto *nilDecl = tc.Context.getOptionalNoneDecl();
tc.validateDecl(nilDecl);
if (!nilDecl->hasInterfaceType())
return nullptr;
auto genericSig =
nilDecl->getDeclContext()->getGenericSignatureOfContext();
SubstitutionMap subs =
SubstitutionMap::get(genericSig, llvm::makeArrayRef(objectType),
{ });
ConcreteDeclRef concreteDeclRef(nilDecl, subs);
auto nilType = FunctionType::get(
{FunctionType::Param(MetatypeType::get(type))}, type);
auto *nilRefExpr = new (tc.Context) DeclRefExpr(
concreteDeclRef, DeclNameLoc(expr->getLoc()),
/*implicit=*/true, AccessSemantics::Ordinary,
nilType);
cs.cacheType(nilRefExpr);
auto *typeExpr = TypeExpr::createImplicitHack(
expr->getLoc(),
type,
tc.Context);
cs.cacheType(typeExpr);
auto *callExpr = new (tc.Context) DotSyntaxCallExpr(
nilRefExpr, expr->getLoc(), typeExpr, type);
callExpr->setImplicit(true);
cs.cacheType(callExpr);
return callExpr;
}
DeclName initName(tc.Context, DeclBaseName::createConstructor(),
{ tc.Context.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 &tc = cs.getTypeChecker();
ProtocolDecl *protocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByFloatLiteral);
ProtocolDecl *builtinProtocol
= tc.getProtocol(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 = tc.getDefaultType(protocol, dc)) {
if (defaultType->isEqual(type))
type = defaultType;
}
// Find the maximum-sized builtin float type.
// FIXME: Cache name lookup.
if (!MaxFloatTypeDecl) {
SmallVector<ValueDecl *, 1> lookupResults;
tc.getStdlibModule(dc)->lookupValue(/*AccessPath=*/{},
tc.Context.Id_MaxBuiltinFloatType,
NLKind::QualifiedLookup,
lookupResults);
if (lookupResults.size() == 1)
MaxFloatTypeDecl = dyn_cast<TypeAliasDecl>(lookupResults.front());
}
if (!MaxFloatTypeDecl ||
!MaxFloatTypeDecl->hasInterfaceType() ||
!MaxFloatTypeDecl->getDeclaredInterfaceType()->is<BuiltinFloatType>()) {
tc.diagnose(expr->getLoc(), diag::no_MaxBuiltinFloatType_found);
return nullptr;
}
tc.validateDecl(MaxFloatTypeDecl);
auto maxType = MaxFloatTypeDecl->getUnderlyingTypeLoc().getType();
DeclName initName(tc.Context, DeclBaseName::createConstructor(),
{ tc.Context.Id_floatLiteral });
DeclName builtinInitName(tc.Context, DeclBaseName::createConstructor(),
{ tc.Context.Id_builtinFloatLiteral });
expr->setBuiltinType(maxType);
return convertLiteralInPlace(
expr, type, protocol, tc.Context.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 &tc = cs.getTypeChecker();
ProtocolDecl *protocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByBooleanLiteral);
ProtocolDecl *builtinProtocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByBuiltinBooleanLiteral);
if (!protocol || !builtinProtocol)
return nullptr;
auto type = simplifyType(cs.getType(expr));
DeclName initName(tc.Context, DeclBaseName::createConstructor(),
{ tc.Context.Id_booleanLiteral });
DeclName builtinInitName(tc.Context, DeclBaseName::createConstructor(),
{ tc.Context.Id_builtinBooleanLiteral });
return convertLiteralInPlace(
expr,
type,
protocol,
tc.Context.Id_BooleanLiteralType,
initName,
builtinProtocol,
builtinInitName,
diag::boolean_literal_broken_proto,
diag::builtin_boolean_literal_broken_proto);
}
Expr *handleStringLiteralExpr(LiteralExpr *expr) {
if (cs.getType(expr) && !cs.getType(expr)->hasTypeVariable())
return 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 &tc = cs.getTypeChecker();
bool isStringLiteral = true;
bool isGraphemeClusterLiteral = false;
ProtocolDecl *protocol = tc.getProtocol(
expr->getLoc(), KnownProtocolKind::ExpressibleByStringLiteral);
if (!tc.conformsToProtocol(type, protocol, cs.DC,
ConformanceCheckFlags::InExpression)) {
// If the type does not conform to ExpressibleByStringLiteral, it should
// be ExpressibleByExtendedGraphemeClusterLiteral.
protocol = tc.getProtocol(
expr->getLoc(),
KnownProtocolKind::ExpressibleByExtendedGraphemeClusterLiteral);
isStringLiteral = false;
isGraphemeClusterLiteral = true;
}
if (!tc.conformsToProtocol(type, protocol, cs.DC,
ConformanceCheckFlags::InExpression)) {
// ... or it should be ExpressibleByUnicodeScalarLiteral.
protocol = tc.getProtocol(
expr->getLoc(),
KnownProtocolKind::ExpressibleByUnicodeScalarLiteral);
isStringLiteral = false;
isGraphemeClusterLiteral = false;
}
// For type-sugar reasons, prefer the spelling of the default literal
// type.
if (auto defaultType = tc.getDefaultType(protocol, dc)) {
if (defaultType->isEqual(type))
type = defaultType;
}
ProtocolDecl *builtinProtocol;
Identifier literalType;
DeclName literalFuncName;
DeclName builtinLiteralFuncName;
Diag<> brokenProtocolDiag;
Diag<> brokenBuiltinProtocolDiag;
if (isStringLiteral) {
literalType = tc.Context.Id_StringLiteralType;
literalFuncName = DeclName(tc.Context, DeclBaseName::createConstructor(),
{ tc.Context.Id_stringLiteral });
builtinProtocol = tc.getProtocol(
expr->getLoc(),
KnownProtocolKind::ExpressibleByBuiltinStringLiteral);
builtinLiteralFuncName
= DeclName(tc.Context, DeclBaseName::createConstructor(),
{ tc.Context.Id_builtinStringLiteral,
tc.Context.getIdentifier("utf8CodeUnitCount"),
tc.Context.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 = tc.Context.Id_ExtendedGraphemeClusterLiteralType;
literalFuncName
= DeclName(tc.Context, DeclBaseName::createConstructor(),
{tc.Context.Id_extendedGraphemeClusterLiteral});
builtinLiteralFuncName
= DeclName(tc.Context, DeclBaseName::createConstructor(),
{ tc.Context.Id_builtinExtendedGraphemeClusterLiteral,
tc.Context.getIdentifier("utf8CodeUnitCount"),
tc.Context.getIdentifier("isASCII") });
builtinProtocol = tc.getProtocol(
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 = tc.Context.Id_UnicodeScalarLiteralType;
literalFuncName
= DeclName(tc.Context, DeclBaseName::createConstructor(),
{tc.Context.Id_unicodeScalarLiteral});
builtinLiteralFuncName
= DeclName(tc.Context, DeclBaseName::createConstructor(),
{tc.Context.Id_builtinUnicodeScalarLiteral});
builtinProtocol = tc.getProtocol(
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);
if (expr->getSemanticExpr() != nullptr) {
return expr;
}
auto &tc = cs.getTypeChecker();
auto loc = expr->getStartLoc();
auto buildProtocolInitCall =
[&](KnownProtocolKind protocolKind, Type type,
ArrayRef<Identifier> argLabels, ArrayRef<Expr *> args) -> Expr * {
auto proto = tc.getProtocol(loc, protocolKind);
assert(proto && "Missing string interpolation protocol?");
auto conformance =
tc.conformsToProtocol(type, proto, cs.DC,
ConformanceCheckFlags::InExpression);
assert(conformance && "string interpolation type conforms to protocol");
DeclName constrName(tc.Context, DeclBaseName::createConstructor(), argLabels);
Expr *base = TypeExpr::createImplicitHack(loc, type,
tc.Context);
Expr *semanticExpr = tc.callWitness(base, dc, proto, *conformance,
constrName, args,
diag::interpolation_broken_proto);
if (semanticExpr)
cs.cacheExprTypes(semanticExpr);
return semanticExpr;
};
auto associatedTypeArray =
tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByStringInterpolation)
->lookupDirect(tc.Context.Id_StringInterpolation);
if (associatedTypeArray.empty()) {
tc.diagnose(expr->getStartLoc(), diag::interpolation_broken_proto);
return nullptr;
}
auto associatedTypeDecl =
cast<AssociatedTypeDecl>(associatedTypeArray.front());
auto interpolationType =
simplifyType(DependentMemberType::get(openedType, associatedTypeDecl));
// interpolationInitCall = """
// StringInterpolationProtocol.init(
// literalCapacity: \(expr->getLiteralCapacity()),
// interpolationCount: \(expr->getInterpolationCount()))
// """
// Make the integer literals for the parameters.
Expr *literalCapacity =
IntegerLiteralExpr::createFromUnsigned(tc.Context,
expr->getLiteralCapacity());
cs.setType(literalCapacity, tc.getIntType(cs.DC));
literalCapacity =
handleIntegerLiteralExpr((LiteralExpr*)literalCapacity);
Expr *interpolationCount =
IntegerLiteralExpr::createFromUnsigned(tc.Context,
expr->getInterpolationCount());
cs.setType(interpolationCount, tc.getIntType(cs.DC));
interpolationCount =
handleIntegerLiteralExpr((LiteralExpr*)interpolationCount);
// Make the call itself.
auto interpolationInitCall =
buildProtocolInitCall(
KnownProtocolKind::StringInterpolationProtocol, interpolationType,
{ tc.Context.Id_literalCapacity, tc.Context.Id_interpolationCount },
{ literalCapacity, interpolationCount });
// appendingExpr = """
// _tap var \(expr->getBody()->getElement(0)) =
// \(interpolationInitCall) {
// \(expr->getBody())
// }
// """
auto appendingExpr = expr->getAppendingExpr();
appendingExpr->setSubExpr(interpolationInitCall);
// initStringInterpolationExpr = """
// ExpressibleByStringInterpolation.init(
// stringInterpolation: \(appendingExpr))
// """
auto initStringInterpolationExpr =
buildProtocolInitCall(
KnownProtocolKind::ExpressibleByStringInterpolation, type,
{ tc.Context.Id_stringInterpolation },
{ appendingExpr });
// Set that as the semantic expr.
expr->setSemanticExpr(initStringInterpolationExpr);
// And we're done!
return expr;
}
Expr *visitMagicIdentifierLiteralExpr(MagicIdentifierLiteralExpr *expr) {
switch (expr->getKind()) {
case MagicIdentifierLiteralExpr::File:
case MagicIdentifierLiteralExpr::Function:
return handleStringLiteralExpr(expr);
case MagicIdentifierLiteralExpr::Line:
case MagicIdentifierLiteralExpr::Column:
return handleIntegerLiteralExpr(expr);
case MagicIdentifierLiteralExpr::DSOHandle:
return expr;
}
llvm_unreachable("Unhandled MagicIdentifierLiteralExpr in switch.");
}
Expr *visitObjectLiteralExpr(ObjectLiteralExpr *expr) {
if (cs.getType(expr) && !cs.getType(expr)->hasTypeVariable())
return expr;
auto &ctx = cs.getASTContext();
auto &tc = cs.getTypeChecker();
// Figure out the type we're converting to.
auto openedType = cs.getType(expr);
auto type = simplifyType(openedType);
cs.setType(expr, type);
if (type->is<UnresolvedType>()) return expr;
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 = tc.getLiteralProtocol(expr);
assert(proto && "Missing object literal protocol?");
auto conformance =
tc.conformsToProtocol(conformingType, proto, cs.DC,
ConformanceCheckFlags::InExpression);
assert(conformance && "object literal type conforms to protocol");
Expr *base = TypeExpr::createImplicitHack(expr->getLoc(), conformingType,
ctx);
cs.cacheExprTypes(base);
SmallVector<Expr *, 4> args;
if (!isa<TupleExpr>(expr->getArg()))
return nullptr;
auto tupleArg = cast<TupleExpr>(expr->getArg());
for (auto elt : tupleArg->getElements()) {
cs.setExprTypes(elt);
args.push_back(elt);
}
DeclName constrName(tc.getObjectLiteralConstructorName(expr));
cs.cacheExprTypes(base);
cs.setExprTypes(base);
Expr *semanticExpr = tc.callWitness(base, dc, proto, *conformance,
constrName, args,
diag::object_literal_broken_proto);
if (semanticExpr)
cs.cacheExprTypes(semanticExpr);
expr->setSemanticExpr(semanticExpr);
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.getTypeChecker().Context;
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.getOverloadChoiceIfAvailable(locator);
if (!selected.hasValue()) {
auto *varDecl = cast<VarDecl>(expr->getDecl());
assert(varDecl->getType()->is<UnresolvedType>() &&
"should only happen for closure arguments in CSDiags");
cs.setType(expr, varDecl->getType());
return expr;
}
return buildDeclRef(selected->choice, expr->getNameLoc(),
selected->openedFullType, locator, expr->isImplicit(),
expr->getFunctionRefKind(),
expr->getAccessSemantics());
}
Expr *visitSuperRefExpr(SuperRefExpr *expr) {
simplifyExprType(expr);
return expr;
}
Expr *visitTypeExpr(TypeExpr *expr) {
auto toType = simplifyType(cs.getType(expr->getTypeLoc()));
expr->getTypeLoc().setType(toType);
cs.setType(expr, MetatypeType::get(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);
auto choice = selected.choice;
return buildDeclRef(choice, expr->getNameLoc(), selected.openedFullType,
locator, expr->isImplicit(),
choice.getFunctionRefKind(),
AccessSemantics::Ordinary);
}
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);
bool isDynamic
= selected.choice.getKind() == OverloadChoiceKind::DeclViaDynamic;
return buildMemberRef(
expr->getBase(), selected.openedFullType, expr->getDotLoc(),
selected.choice, expr->getNameLoc(), selected.openedType,
cs.getConstraintLocator(expr), memberLocator, expr->isImplicit(),
selected.choice.getFunctionRefKind(), expr->getAccessSemantics(),
isDynamic);
}
Expr *visitDynamicMemberRefExpr(DynamicMemberRefExpr *expr) {
llvm_unreachable("already type-checked?");
}
Expr *visitUnresolvedMemberExpr(UnresolvedMemberExpr *expr) {
// Dig out the type of the base, which will be the result type of this
// expression. 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->getRValueType()->is<UnresolvedType>()) {
cs.setType(expr, resultTy);
return expr;
}
Type baseTy = resultTy->getRValueType();
auto &tc = cs.getTypeChecker();
// Find the selected member.
auto memberLocator = cs.getConstraintLocator(
expr, ConstraintLocator::UnresolvedMember);
auto selected = solution.getOverloadChoice(memberLocator);
// If the member came by optional unwrapping, then unwrap the base type.
if (selected.choice.getKind()
== OverloadChoiceKind::DeclViaUnwrappedOptional) {
baseTy = baseTy->getOptionalObjectType();
assert(baseTy
&& "got unwrapped optional decl from non-optional base?!");
}
// The base expression is simply the metatype of the base type.
// FIXME: This location info is bogus.
auto base = TypeExpr::createImplicitHack(expr->getDotLoc(), baseTy,
tc.Context);
cs.cacheExprTypes(base);
// Build the member reference.
bool isDynamic
= selected.choice.getKind() == OverloadChoiceKind::DeclViaDynamic;
auto result = buildMemberRef(
base, selected.openedFullType, expr->getDotLoc(), selected.choice,
expr->getNameLoc(), selected.openedType,
cs.getConstraintLocator(expr), memberLocator, expr->isImplicit(),
selected.choice.getFunctionRefKind(), AccessSemantics::Ordinary,
isDynamic);
if (!result)
return nullptr;
auto getType = [&](const Expr *E) -> Type {
return cs.getType(E);
};
// If there was an argument, apply it.
if (auto arg = expr->getArgument()) {
ApplyExpr *apply = CallExpr::create(
tc.Context, result, arg, expr->getArgumentLabels(),
expr->getArgumentLabelLocs(), expr->hasTrailingClosure(),
/*implicit=*/expr->isImplicit(), Type(), getType);
result = finishApply(apply, Type(), cs.getConstraintLocator(expr));
// FIXME: Application could fail, because some of the solutions
// are not expressible in AST (yet?), like certain tuple-to-tuple
// conversions. Better solution here would be not to form solutions
// which couldn't be applied by e.g. detecting situations like that
// and inserting fixes early.
if (!result)
return nullptr;
}
// Check for ambiguous member if the base is an Optional
if (baseTy->getOptionalObjectType()) {
diagnoseAmbiguousNominalMember(baseTy, result);
}
return coerceToType(result, resultTy, cs.getConstraintLocator(expr));
}
/// Diagnose if the base type is optional, we're referring to a nominal
/// type member via the dot syntax and the member name matches
/// Optional<T>.{member name}
void diagnoseAmbiguousNominalMember(Type baseTy, Expr *result) {
if (auto baseTyUnwrapped = baseTy->lookThroughAllOptionalTypes()) {
// Return if the base type doesn't have a nominal type decl
if (!baseTyUnwrapped->getNominalOrBoundGenericNominal()) {
return;
}
// Otherwise, continue digging
if (auto DSCE = dyn_cast<DotSyntaxCallExpr>(result)) {
auto calledValue = DSCE->getCalledValue();
auto isOptional = false;
Identifier memberName;
// Try cast the assigned value to an enum case
//
// This will always succeed if the base is Optional<T> & the
// assigned case comes from Optional<T>
if (auto EED = dyn_cast<EnumElementDecl>(calledValue)) {
isOptional = EED->getParentEnum()->isOptionalDecl();
memberName = EED->getBaseName().getIdentifier();
}
// Return if the enum case doesn't come from Optional<T>
if (!isOptional) {
return;
}
// Look up the enum case in the unwrapped type to check if it exists
// as a member
auto baseTyNominalDecl = baseTyUnwrapped
->getNominalOrBoundGenericNominal();
auto &tc = cs.getTypeChecker();
auto results = tc.lookupMember(baseTyNominalDecl->getModuleContext(),
baseTyUnwrapped,
memberName,
defaultMemberLookupOptions);
// Lookup didn't find anything, so return
if (results.empty()) {
return;
}
if (auto member = results.front().getValueDecl()) {
// Lookup returned a member that is an instance member,
// so return
if (member->isInstanceMember()) {
return;
}
// Return if the member is an enum case w/ assoc values, as we only
// care (for now) about cases with no assoc values (like none)
if (auto EED = dyn_cast<EnumElementDecl>(member)) {
if (EED->hasAssociatedValues()) {
return;
}
}
// Emit a diagnostic with some fixits
auto baseTyName = baseTy->getCanonicalType().getString();
auto baseTyUnwrappedName = baseTyUnwrapped->getString();
auto loc = DSCE->getLoc();
auto startLoc = DSCE->getStartLoc();
tc.diagnose(loc, swift::diag::optional_ambiguous_case_ref,
baseTyName, baseTyUnwrappedName, memberName.str());
tc.diagnose(loc, swift::diag::optional_fixit_ambiguous_case_ref)
.fixItInsert(startLoc, "Optional");
tc.diagnose(loc, swift::diag::type_fixit_optional_ambiguous_case_ref,
baseTyUnwrappedName, memberName.str())
.fixItInsert(startLoc, baseTyUnwrappedName);
}
}
}
}
private:
/// A list of "suspicious" optional injections that come from
/// forced downcasts.
SmallVector<InjectIntoOptionalExpr *, 4> SuspiciousOptionalInjections;
public:
/// A list of optional injections that have been diagnosed.
llvm::SmallPtrSet<InjectIntoOptionalExpr *, 4> DiagnosedOptionalInjections;
private:
/// Create a member reference to the given constructor.
Expr *applyCtorRefExpr(Expr *expr, Expr *base, SourceLoc dotLoc,
DeclNameLoc nameLoc, bool implicit,
ConstraintLocator *ctorLocator,
OverloadChoice choice,
FunctionRefKind functionRefKind, Type openedType) {
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, openedType, dotLoc, choice, nameLoc, cs.getType(expr),
ConstraintLocatorBuilder(cs.getConstraintLocator(expr)),
ctorLocator, implicit, functionRefKind, AccessSemantics::Ordinary,
/*isDynamic=*/false);
}
// The subexpression must be either 'self' or 'super'.
if (!base->isSuperExpr()) {
// 'super' references have already been fully checked; handle the
// 'self' case below.
auto &tc = cs.getTypeChecker();
bool diagnoseBadInitRef = true;
auto arg = base->getSemanticsProvidingExpr();
if (auto dre = dyn_cast<DeclRefExpr>(arg)) {
if (dre->getDecl()->getFullName() == 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)
tc.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;
tc.diagnose(dotLoc, diag::bad_init_ref_base, hasSuper);
}
}
// Build a partial application of the delegated initializer.
Expr *ctorRef = buildOtherConstructorRef(openedType, ctor, base, nameLoc,
ctorLocator, implicit);
auto *call = new (cs.getASTContext()) DotSyntaxCallExpr(ctorRef, dotLoc,
base);
return finishApply(call, cs.getType(expr),
ConstraintLocatorBuilder(
cs.getConstraintLocator(expr)));
}
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)) {
auto choice = selected->choice;
return applyCtorRefExpr(
expr, base, dotLoc, nameLoc, implicit, ctorLocator, choice,
choice.getFunctionRefKind(), selected->openedFullType);
}
// Determine the declaration selected for this overloaded reference.
auto memberLocator = cs.getConstraintLocator(expr,
ConstraintLocator::Member);
auto selectedElt = solution.getOverloadChoiceIfAvailable(memberLocator);
if (!selectedElt) {
// If constraint solving resolved this to an UnresolvedType, then we're
// in an ambiguity tolerant mode used for diagnostic generation. Just
// leave this as whatever type of member reference it already is.
Type resultTy = simplifyType(cs.getType(expr));
cs.setType(expr, resultTy);
return expr;
}
auto selected = *selectedElt;
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);
cs.diagnoseDeprecatedConditionalConformanceOuterAccess(
UDE, selected.choice.getDecl());
return buildDeclRef(selected.choice, nameLoc, selected.openedFullType,
memberLocator, implicit,
selected.choice.getFunctionRefKind(),
AccessSemantics::Ordinary);
}
switch (selected.choice.getKind()) {
case OverloadChoiceKind::DeclViaBridge: {
base = cs.coerceToRValue(base);
// Look through an implicitly unwrapped optional.
auto baseTy = cs.getType(base);
auto &tc = cs.getTypeChecker();
auto &ctx = tc.Context;
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,
tc.Context);
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: {
bool isDynamic
= selected.choice.getKind() == OverloadChoiceKind::DeclViaDynamic;
return buildMemberRef(base, selected.openedFullType, dotLoc,
selected.choice, nameLoc, selected.openedType,
cs.getConstraintLocator(expr), memberLocator,
implicit, selected.choice.getFunctionRefKind(),
AccessSemantics::Ordinary, isDynamic);
}
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::BaseType:
return base;
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.");
}
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, dc, cs);
} 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.getTypeChecker().getLangOpts().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 *visitTupleExpr(TupleExpr *expr) {
return simplifyExprType(expr);
}
Expr *visitSubscriptExpr(SubscriptExpr *expr) {
auto *memberLocator =
cs.getConstraintLocator(expr, ConstraintLocator::SubscriptMember);
auto overload = solution.getOverloadChoiceIfAvailable(memberLocator);
if (overload && 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 &tc = cs.getTypeChecker();
ProtocolDecl *arrayProto
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByArrayLiteral);
assert(arrayProto && "type-checked array literal w/o protocol?!");
auto conformance =
tc.conformsToProtocol(arrayTy, arrayProto, cs.DC,
ConformanceCheckFlags::InExpression);
assert(conformance && "Type does not conform to protocol?");
DeclName name(tc.Context, DeclBaseName::createConstructor(),
{ tc.Context.Id_arrayLiteral });
ConcreteDeclRef witness =
findNamedWitnessImpl(tc, dc, arrayTy->getRValueType(), arrayProto,
name, diag::array_protocol_broken, conformance);
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 &tc = cs.getTypeChecker();
ProtocolDecl *dictionaryProto
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByDictionaryLiteral);
auto conformance =
tc.conformsToProtocol(dictionaryTy, dictionaryProto, cs.DC,
ConformanceCheckFlags::InExpression);
if (!conformance)
return nullptr;
// Call the witness that builds the dictionary literal.
// FIXME: callWitness() may end up re-doing some work we already did
// to convert the dictionary literal elements to the (key, value) tuple.
// It would be nicer to re-use them.
// FIXME: Cache the name.
// FIXME: This location info is bogus.
Expr *typeRef = TypeExpr::createImplicitHack(expr->getLoc(), dictionaryTy,
tc.Context);
cs.cacheExprTypes(typeRef);
DeclName name(tc.Context, DeclBaseName::createConstructor(),
{ tc.Context.Id_dictionaryLiteral });
// Restructure the argument to provide the appropriate labels in the
// tuple.
SmallVector<TupleTypeElt, 4> typeElements;
SmallVector<Identifier, 4> names;
bool first = true;
for (auto elt : expr->getElements()) {
if (first) {
typeElements.push_back(TupleTypeElt(cs.getType(elt),
tc.Context.Id_dictionaryLiteral));
names.push_back(tc.Context.Id_dictionaryLiteral);
first = false;
continue;
}
typeElements.push_back(cs.getType(elt));
names.push_back(Identifier());
}
Type argType = TupleType::get(typeElements, tc.Context);
assert(isa<TupleType>(argType.getPointer()));
Expr *arg =
TupleExpr::create(tc.Context, expr->getLBracketLoc(),
expr->getElements(),
names,
{ },
expr->getRBracketLoc(),
/*HasTrailingClosure=*/false,
/*Implicit=*/true,
argType);
cs.cacheExprTypes(arg);
cs.setExprTypes(typeRef);
cs.setExprTypes(arg);
Expr *result = tc.callWitness(typeRef, dc, dictionaryProto,
*conformance, name, arg,
diag::dictionary_protocol_broken);
if (!result)
return nullptr;
cs.cacheExprTypes(result);
expr->setSemanticExpr(result);
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) {
return buildSubscript(expr->getBase(), expr->getIndex(),
expr->getArgumentLabels(),
expr->hasTrailingClosure(),
cs.getConstraintLocator(expr),
expr->isImplicit(), AccessSemantics::Ordinary);
}
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) {
llvm_unreachable("Already type-checked");
}
Expr *visitDefaultArgumentExpr(DefaultArgumentExpr *expr) {
llvm_unreachable("Already type-checked");
}
Expr *visitCallerDefaultArgumentExpr(CallerDefaultArgumentExpr *expr) {
llvm_unreachable("Already type-checked");
}
Expr *visitApplyExpr(ApplyExpr *expr) {
return finishApply(expr, cs.getType(expr),
ConstraintLocatorBuilder(
cs.getConstraintLocator(expr)));
}
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->getFailability() == OTK_None) {
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->getAttrs().hasAttribute<ImplicitlyUnwrappedOptionalAttr>();
// If we're suppressing diagnostics, just fail.
if (isError && SuppressDiagnostics)
return nullptr;
auto &tc = cs.getTypeChecker();
auto &ctx = tc.Context;
if (isError) {
if (auto *optTry = dyn_cast<OptionalTryExpr>(unwrappedSubExpr)) {
tc.diagnose(optTry->getTryLoc(),
diag::delegate_chain_nonoptional_to_optional_try,
isChaining);
tc.diagnose(optTry->getTryLoc(), diag::init_delegate_force_try)
.fixItReplace({optTry->getTryLoc(), optTry->getQuestionLoc()},
"try!");
tc.diagnose(inCtor->getLoc(), diag::init_propagate_failure)
.fixItInsertAfter(inCtor->getLoc(), "?");
} else {
// Give the user the option of adding '!' or making the enclosing
// initializer failable.
tc.diagnose(otherCtorRef->getLoc(),
diag::delegate_chain_nonoptional_to_optional,
isChaining, ctor->getFullName());
tc.diagnose(otherCtorRef->getLoc(), diag::init_force_unwrap)
.fixItInsertAfter(expr->getEndLoc(), "!");
tc.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 &tc = cs.getTypeChecker();
auto toType = simplifyType(cs.getType(expr->getCastTypeLoc()));
auto sub = cs.coerceToRValue(expr->getSubExpr());
checkForImportedUsedConformances(toType);
expr->setSubExpr(sub);
// Set the type we checked against.
expr->getCastTypeLoc().setType(toType);
auto fromType = cs.getType(sub);
auto castContextKind =
SuppressDiagnostics ? CheckedCastContextKind::None
: CheckedCastContextKind::IsExpr;
auto castKind = tc.typeCheckCheckedCast(
fromType, toType, castContextKind, cs.DC,
expr->getLoc(), sub,
expr->getCastTypeLoc().getSourceRange());
switch (castKind) {
case CheckedCastKind::Unresolved:
expr->setCastKind(CheckedCastKind::ValueCast);
break;
case CheckedCastKind::Coercion:
case CheckedCastKind::BridgingCoercion:
// Check is trivially true.
tc.diagnose(expr->getLoc(), diag::isa_is_always_true, "is");
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) {
tc.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 (!tc.Context.getBoolBuiltinInitDecl()) {
tc.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 toOptType = OptionalType::get(toType);
ConditionalCheckedCastExpr *cast
= new (tc.Context) ConditionalCheckedCastExpr(
sub, expr->getLoc(), SourceLoc(),
TypeLoc::withoutLoc(toType));
cs.setType(cast, toOptType);
cs.setType(cast->getCastTypeLoc(), toType);
if (expr->isImplicit())
cast->setImplicit();
// Type-check this conditional case.
Expr *result = handleConditionalCheckedCastExpr(cast, true);
if (!result)
return nullptr;
// Extract a Bool from the resulting expression.
return solution.convertOptionalToBool(result,
cs.getConstraintLocator(expr));
}
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 &tc = cs.getTypeChecker();
tc.diagnose(cast->getLoc(), diag::conditional_downcast_foreign,
destValueType);
ConcreteDeclRef refDecl = sub->getReferencedDecl();
if (refDecl) {
tc.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 &tc = cs.getTypeChecker();
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 || (tc.Context.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 : reversed(destOptionalInjections)) {
result =
cs.cacheType(new (tc.Context) InjectIntoOptionalExpr(result,
destType));
}
return result;
};
// There's nothing special to do if the operand isn't optional
// and we don't need any bridging.
if (srcOptionals.empty()) {
Expr *result = buildInnerOperation(subExpr, finalResultType);
if (!result) return nullptr;
return addFinalOptionalInjections(result);
}
// The result type (without the final optional) is a subtype of
// the operand type, so it will never have a higher depth.
assert(destOptionals.size() - destExtraOptionals <= srcOptionals.size());
// 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 (tc.Context) ForceValueExpr(subExpr, fakeQuestionLoc);
cs.setType(subExpr, valueType);
subExpr->setImplicit(true);
continue;
}
subExpr =
cs.cacheType(new (tc.Context) 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 (tc.Context) 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 (tc.Context) InjectIntoOptionalExpr(result,
destType));
result =
cs.cacheType(new (tc.Context) OptionalEvaluationExpr(result,
destType));
}
// Otherwise, we just need to capture the failure-depth binding.
} else if (!forceExtraSourceOptionals) {
result =
cs.cacheType(new (tc.Context) OptionalEvaluationExpr(result,
finalResultType));
}
return addFinalOptionalInjections(result);
}
bool hasForcedOptionalResult(ExplicitCastExpr *expr) {
auto *TR = expr->getCastTypeLoc().getTypeRepr();
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 the type we're casting to.
auto toType = simplifyType(cs.getType(expr->getCastTypeLoc()));
expr->getCastTypeLoc().setType(toType);
checkForImportedUsedConformances(toType);
auto &tc = cs.getTypeChecker();
// 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)) {
call->getFn()->forEachChildExpr([&](Expr *subExpr) -> Expr * {
auto *TE = dyn_cast<TypeExpr>(subExpr);
if (!TE)
return subExpr;
auto type = TE->getInstanceType(
[&](const Expr *expr) { return cs.hasType(expr); },
[&](const Expr *expr) { return cs.getType(expr); });
assert(!type->hasError());
if (!type->isEqual(toType))
return subExpr;
return cs.cacheType(new (tc.Context)
TypeExpr(expr->getCastTypeLoc()));
});
}
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();
cs.setExprTypes(sub);
if (tc.convertToType(sub, toType, cs.DC))
return nullptr;
cs.cacheExprTypes(sub);
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) {
// Simplify the type we're casting to.
auto toType = simplifyType(cs.getType(expr->getCastTypeLoc()));
if (hasForcedOptionalResult(expr))
toType = toType->getOptionalObjectType();
expr->getCastTypeLoc().setType(toType);
checkForImportedUsedConformances(toType);
// The subexpression is always an rvalue.
auto &tc = cs.getTypeChecker();
auto sub = cs.coerceToRValue(expr->getSubExpr());
expr->setSubExpr(sub);
auto castContextKind =
SuppressDiagnostics ? CheckedCastContextKind::None
: CheckedCastContextKind::ForcedCast;
auto fromType = cs.getType(sub);
auto castKind = tc.typeCheckCheckedCast(
fromType, toType, castContextKind, cs.DC,
expr->getLoc(), sub,
expr->getCastTypeLoc().getSourceRange());
switch (castKind) {
/// Invalid cast.
case CheckedCastKind::Unresolved:
return nullptr;
case CheckedCastKind::Coercion:
case CheckedCastKind::BridgingCoercion: {
if (SuppressDiagnostics)
return nullptr;
if (cs.getType(sub)->isEqual(toType)) {
tc.diagnose(expr->getLoc(), diag::forced_downcast_noop, toType)
.fixItRemove(SourceRange(expr->getLoc(),
expr->getCastTypeLoc().getSourceRange().End));
} else {
tc.diagnose(expr->getLoc(), diag::forced_downcast_coercion,
cs.getType(sub), toType)
.fixItReplace(SourceRange(expr->getLoc(), expr->getExclaimLoc()),
"as");
}
// Transmute the checked cast into a coercion expression.
auto *result = new (tc.Context) CoerceExpr(sub, expr->getLoc(),
expr->getCastTypeLoc());
cs.setType(result, toType);
cs.setType(result->getCastTypeLoc(), toType);
unsigned disjunctionChoice =
(castKind == CheckedCastKind::Coercion ? 0 : 1);
return visitCoerceExpr(result, disjunctionChoice);
}
// 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) {
// 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);
if (!coerced)
return nullptr;
return coerceImplicitlyUnwrappedOptionalToValue(
coerced, cs.getType(coerced)->getOptionalObjectType());
}
return handleConditionalCheckedCastExpr(expr);
}
Expr *handleConditionalCheckedCastExpr(ConditionalCheckedCastExpr *expr,
bool isInsideIsExpr = false) {
// Simplify the type we're casting to.
auto toType = simplifyType(cs.getType(expr->getCastTypeLoc()));
checkForImportedUsedConformances(toType);
expr->getCastTypeLoc().setType(toType);
// The subexpression is always an rvalue.
auto &tc = cs.getTypeChecker();
auto sub = cs.coerceToRValue(expr->getSubExpr());
expr->setSubExpr(sub);
auto castContextKind =
(SuppressDiagnostics || isInsideIsExpr)
? CheckedCastContextKind::None
: CheckedCastContextKind::ConditionalCast;
auto fromType = cs.getType(sub);
auto castKind = tc.typeCheckCheckedCast(
fromType, toType, castContextKind, cs.DC,
expr->getLoc(), sub,
expr->getCastTypeLoc().getSourceRange());
switch (castKind) {
/// Invalid cast.
case CheckedCastKind::Unresolved:
expr->setCastKind(CheckedCastKind::ValueCast);
break;
case CheckedCastKind::Coercion:
case CheckedCastKind::BridgingCoercion: {
if (SuppressDiagnostics)
return nullptr;
tc.diagnose(expr->getLoc(), diag::conditional_downcast_coercion,
cs.getType(sub), toType);
// Transmute the checked cast into a coercion expression.
auto *coerce = new (tc.Context) CoerceExpr(sub, expr->getLoc(),
expr->getCastTypeLoc());
cs.setType(coerce, toType);
cs.setType(coerce->getCastTypeLoc(), toType);
unsigned disjunctionChoice =
(castKind == CheckedCastKind::Coercion ? 0 : 1);
Expr *result = visitCoerceExpr(coerce, disjunctionChoice);
if (!result)
return nullptr;
// Wrap the result in an optional. Mark the optional injection as
// explicit, because the user did in fact write the '?' as part of
// 'as?', even though it wasn't necessary.
result = new (tc.Context) InjectIntoOptionalExpr(
result,
OptionalType::get(toType));
result->setImplicit(false);
return cs.cacheType(result);
}
// 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.getTypeChecker(), 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);
if (!SuppressDiagnostics
&& !cs.getType(simplified)->is<UnresolvedType>()) {
cs.TC.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)
if (auto *Bind = dyn_cast<BindOptionalExpr>(
expr->getSubExpr()->getSemanticsProvidingExpr())) {
if (cs.getType(Bind->getSubExpr())->isEqual(optType))
cs.TC.diagnose(expr->getLoc(), diag::optional_chain_noop,
optType).fixItRemove(Bind->getQuestionLoc());
else
cs.TC.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) {
// Since `LazyInitializerExpr` should always have a type set,
// there is no need to do anything here.
assert(cs.getType(expr)->isEqual(expr->getSubExpr()->getType()));
return expr;
}
Expr *visitEditorPlaceholderExpr(EditorPlaceholderExpr *E) {
simplifyExprType(E);
auto valueType = cs.getType(E);
auto &tc = cs.getTypeChecker();
auto &ctx = tc.Context;
// Synthesize a call to _undefined() of appropriate type.
FuncDecl *undefinedDecl = ctx.getUndefinedDecl();
if (!undefinedDecl) {
tc.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 = tc.typeCheckExpression(
callExpr, cs.DC, TypeLoc::withoutLoc(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 &tc = cs.getTypeChecker();
if (!foundDecl) {
tc.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()) {
tc.diagnose(E->getLoc(), diag::expr_selector_not_method,
func->getDeclContext()->isModuleScopeContext(),
func->getFullName())
.highlight(subExpr->getSourceRange());
tc.diagnose(func, diag::decl_declared_here, func->getFullName());
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.
tc.diagnose(E->getModifierLoc(),
diag::expr_selector_expected_property,
E->getSelectorKind() == ObjCSelectorExpr::Setter,
foundDecl->getDescriptiveKind(),
foundDecl->getFullName())
.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.
maybeAddAccessorsToStorage(var);
// If this isn't a property on a type, complain.
if (!var->getDeclContext()->isTypeContext()) {
tc.diagnose(E->getLoc(), diag::expr_selector_not_property,
isa<ParamDecl>(var), var->getFullName())
.highlight(subExpr->getSourceRange());
tc.diagnose(var, diag::decl_declared_here, var->getFullName());
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 =
tc.diagnose(E->getLoc(), diag::expr_selector_expected_method,
isSettable, var->getFullName());
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.
tc.diagnose(modifierLoc, diag::expr_selector_add_modifier,
false, var->getFullName())
.fixItInsert(modifierLoc, "getter: ");
tc.diagnose(modifierLoc, diag::expr_selector_add_modifier,
true, var->getFullName())
.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->getGetter();
break;
}
case ObjCSelectorExpr::Getter:
method = var->getGetter();
break;
case ObjCSelectorExpr::Setter:
// Make sure we actually have a setter.
if (!var->isSettable(cs.DC)) {
tc.diagnose(E->getLoc(), diag::expr_selector_property_not_settable,
var->getDescriptiveKind(), var->getFullName());
tc.diagnose(var, diag::decl_declared_here, var->getFullName());
return E;
}
// Make sure the setter is accessible.
if (!var->isSetterAccessibleFrom(cs.DC)) {
tc.diagnose(E->getLoc(),
diag::expr_selector_property_setter_inaccessible,
var->getDescriptiveKind(), var->getFullName());
tc.diagnose(var, diag::decl_declared_here, var->getFullName());
return E;
}
method = var->getSetter();
break;
}
} else {
// Cannot reference with #selector.
tc.diagnose(E->getLoc(), diag::expr_selector_no_declaration)
.highlight(subExpr->getSourceRange());
tc.diagnose(foundDecl, diag::decl_declared_here,
foundDecl->getFullName());
return E;
}
assert(method && "Didn't find a method?");
// The declaration we found must be exposed to Objective-C.
tc.validateDecl(method);
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())) {
tc.diagnose(E->getLoc(), diag::expr_selector_cannot_be_used,
foundDecl->getBaseName(), protocolDecl->getFullName());
return E;
}
tc.diagnose(E->getLoc(), diag::expr_selector_not_objc,
foundDecl->getDescriptiveKind(), foundDecl->getFullName())
.highlight(subExpr->getSourceRange());
tc.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() &&
tc.Context.LangOpts.WarnSwift3ObjCInference
== Swift3ObjCInferenceWarnings::Minimal) {
tc.diagnose(E->getLoc(), diag::expr_selector_swift3_objc_inference,
foundDecl->getDescriptiveKind(), foundDecl->getFullName(),
foundDecl->getDeclContext()
->getSelfNominalTypeDecl()
->getName())
.highlight(subExpr->getSourceRange());
tc.diagnose(foundDecl, diag::make_decl_objc,
foundDecl->getDescriptiveKind())
.fixItInsert(foundDecl->getAttributeInsertionLoc(false),
"@objc ");
}
}
// Note which method we're referencing.
E->setMethod(method);
return E;
}
private:
// Key path components we need to
SmallVector<std::pair<KeyPathExpr *, unsigned>, 4>
KeyPathSubscriptComponents;
public:
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;
auto keyPathTy = cs.getType(E)->castTo<BoundGenericType>();
Type baseTy = keyPathTy->getGenericArgs()[0];
Type leafTy = keyPathTy->getGenericArgs()[1];
// We do not allow keypaths to go through AnyObject
if (baseTy->isAnyObject()) {
auto rootTyRepr = E->getRootType();
cs.TC.diagnose(rootTyRepr->getLoc(),
diag::expr_swift_keypath_invalid_component)
.highlight(rootTyRepr->getSourceRange());
return nullptr;
}
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 (!baseTy) {
resolvedComponents.push_back(origComponent);
continue;
}
auto getObjectType = [](Type optionalTy) -> Type {
Type objectTy;
if (auto lvalue = optionalTy->getAs<LValueType>()) {
objectTy = lvalue->getObjectType()->getOptionalObjectType();
if (optionalTy->hasUnresolvedType() && !objectTy) {
objectTy = optionalTy;
}
objectTy = LValueType::get(objectTy);
} else {
objectTy = optionalTy->getOptionalObjectType();
if (optionalTy->hasUnresolvedType() && !objectTy) {
objectTy = optionalTy;
}
}
assert(objectTy);
return objectTy;
};
auto kind = origComponent.getKind();
Optional<SelectedOverload> foundDecl;
auto locator = cs.getConstraintLocator(
E, ConstraintLocator::PathElement::getKeyPathComponent(i));
if (kind == KeyPathExpr::Component::Kind::UnresolvedSubscript) {
locator =
cs.getConstraintLocator(locator,
ConstraintLocator::SubscriptMember);
}
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) {
foundDecl = solution.getOverloadChoiceIfAvailable(locator);
// Leave the component unresolved if the overload was not resolved.
if (foundDecl) {
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;
}
}
}
KeyPathExpr::Component component;
switch (kind) {
case KeyPathExpr::Component::Kind::UnresolvedProperty: {
// If we couldn't resolve the component, leave it alone.
if (!foundDecl) {
component = origComponent;
break;
}
component = buildKeyPathPropertyComponent(
*foundDecl, origComponent.getLoc(), locator);
baseTy = component.getComponentType();
resolvedComponents.push_back(component);
if (shouldForceUnwrapResult(foundDecl->choice, locator)) {
auto objectTy = getObjectType(baseTy);
auto loc = origComponent.getLoc();
component = KeyPathExpr::Component::forOptionalForce(objectTy, loc);
baseTy = component.getComponentType();
resolvedComponents.push_back(component);
}
break;
}
case KeyPathExpr::Component::Kind::UnresolvedSubscript: {
// Leave the component unresolved if the overload was not resolved.
if (!foundDecl) {
component = origComponent;
break;
}
ArrayRef<Identifier> subscriptLabels;
if (!isDynamicMember)
subscriptLabels = origComponent.getSubscriptLabels();
component = buildKeyPathSubscriptComponent(
*foundDecl, origComponent.getLoc(), origComponent.getIndexExpr(),
subscriptLabels, locator);
// Save a reference to the component so we can do a post-pass to check
// the Hashable conformance of the indexes.
KeyPathSubscriptComponents.push_back({E, resolvedComponents.size()});
baseTy = component.getComponentType();
resolvedComponents.push_back(component);
if (shouldForceUnwrapResult(foundDecl->choice, locator)) {
auto objectTy = getObjectType(baseTy);
auto loc = origComponent.getLoc();
component = KeyPathExpr::Component::forOptionalForce(objectTy, loc);
baseTy = component.getComponentType();
resolvedComponents.push_back(component);
}
break;
}
case KeyPathExpr::Component::Kind::OptionalChain: {
didOptionalChain = true;
// Chaining always forces the element to be an rvalue.
auto objectTy =
baseTy->getWithoutSpecifierType()->getOptionalObjectType();
if (baseTy->hasUnresolvedType() && !objectTy) {
objectTy = baseTy;
}
assert(objectTy);
auto loc = origComponent.getLoc();
component = KeyPathExpr::Component::forOptionalChain(objectTy, loc);
baseTy = component.getComponentType();
resolvedComponents.push_back(component);
break;
}
case KeyPathExpr::Component::Kind::OptionalForce: {
auto objectTy = getObjectType(baseTy);
auto loc = origComponent.getLoc();
component = KeyPathExpr::Component::forOptionalForce(objectTy, loc);
baseTy = component.getComponentType();
resolvedComponents.push_back(component);
break;
}
case KeyPathExpr::Component::Kind::Invalid:
component = origComponent;
component.setComponentType(leafTy);
baseTy = component.getComponentType();
resolvedComponents.push_back(component);
break;
case KeyPathExpr::Component::Kind::Identity:
component = origComponent;
component.setComponentType(baseTy);
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");
}
}
// Wrap a non-optional result if there was chaining involved.
if (didOptionalChain &&
baseTy &&
!baseTy->hasUnresolvedType() &&
!baseTy->getWithoutSpecifierType()->isEqual(leafTy)) {
assert(leafTy->getOptionalObjectType()->isEqual(
baseTy->getWithoutSpecifierType()));
auto component = KeyPathExpr::Component::forOptionalWrap(leafTy);
resolvedComponents.push_back(component);
baseTy = leafTy;
}
E->resolveComponents(cs.getASTContext(), resolvedComponents);
// See whether there's an equivalent ObjC key path string we can produce
// for interop purposes.
if (cs.getASTContext().LangOpts.EnableObjCInterop) {
SmallString<64> compatStringBuf;
if (buildObjCKeyPathString(E, 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.getType(E));
E->setObjCStringLiteralExpr(stringExpr);
}
}
// The final component type ought to line up with the leaf type of the
// key path.
assert(!baseTy || baseTy->hasUnresolvedType()
|| baseTy->getWithoutSpecifierType()->isEqual(leafTy));
return E;
}
KeyPathExpr::Component
buildKeyPathPropertyComponent(const SelectedOverload &overload,
SourceLoc componentLoc,
ConstraintLocator *locator) {
if (overload.choice.isDecl()) {
auto property = overload.choice.getDecl();
// Key paths can only refer to properties currently.
if (!isa<VarDecl>(property)) {
cs.TC.diagnose(componentLoc, diag::expr_keypath_not_property,
property->getDescriptiveKind(),
property->getFullName());
} else {
// Key paths don't work with mutating-get properties.
auto varDecl = cast<VarDecl>(property);
if (varDecl->isGetterMutating()) {
cs.TC.diagnose(componentLoc, diag::expr_keypath_mutating_getter,
property->getFullName());
}
// Key paths don't currently support static members.
if (varDecl->isStatic()) {
cs.TC.diagnose(componentLoc, diag::expr_keypath_static_member,
property->getFullName());
}
}
cs.TC.requestMemberLayout(property);
auto dc = property->getInnermostDeclContext();
// Compute substitutions to refer to the member.
SubstitutionMap subs = solution.computeSubstitutions(
dc->getGenericSignatureOfContext(), locator);
auto resolvedTy = overload.openedType;
resolvedTy = simplifyType(resolvedTy);
auto ref = ConcreteDeclRef(property, subs);
return KeyPathExpr::Component::forProperty(ref, resolvedTy,
componentLoc);
}
auto fieldIndex = overload.choice.getTupleIndex();
auto resolvedTy = overload.openedType;
resolvedTy = simplifyType(resolvedTy);
return KeyPathExpr::Component::forTupleElement(fieldIndex, resolvedTy,
componentLoc);
}
KeyPathExpr::Component buildKeyPathSubscriptComponent(
SelectedOverload &overload, SourceLoc componentLoc, Expr *indexExpr,
ArrayRef<Identifier> labels, ConstraintLocator *locator) {
auto subscript = cast<SubscriptDecl>(overload.choice.getDecl());
if (subscript->isGetterMutating()) {
cs.TC.diagnose(componentLoc, diag::expr_keypath_mutating_getter,
subscript->getFullName());
}
cs.TC.requestMemberLayout(subscript);
auto dc = subscript->getInnermostDeclContext();
auto indexType = AnyFunctionType::composeInput(
cs.TC.Context,
subscript->getInterfaceType()->castTo<AnyFunctionType>()->getParams(),
/*canonicalVararg=*/false);
SubstitutionMap subs;
if (auto sig = dc->getGenericSignatureOfContext()) {
// Compute substitutions to refer to the member.
subs = solution.computeSubstitutions(sig, locator);
indexType = indexType.subst(subs);
}
// 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.
if (overload.choice.getKind() ==
OverloadChoiceKind::DynamicMemberLookup ||
overload.choice.getKind() ==
OverloadChoiceKind::KeyPathDynamicMemberLookup) {
overload.openedType =
overload.openedFullType->castTo<AnyFunctionType>()->getResult();
labels = cs.getASTContext().Id_dynamicMember;
if (overload.choice.getKind() ==
OverloadChoiceKind::KeyPathDynamicMemberLookup) {
auto indexType = getTypeOfDynamicMemberIndex(overload);
indexExpr = buildKeyPathDynamicMemberIndexExpr(
indexType->castTo<BoundGenericType>(), componentLoc, locator);
} else {
auto fieldName = overload.choice.getName().getBaseIdentifier().str();
indexExpr = buildDynamicMemberLookupIndexExpr(fieldName, componentLoc,
dc, cs);
}
}
auto subscriptType =
simplifyType(overload.openedType)->castTo<AnyFunctionType>();
auto resolvedTy = subscriptType->getResult();
auto ref = ConcreteDeclRef(subscript, subs);
// Coerce the indices to the type the subscript expects.
auto *newIndexExpr =
coerceCallArguments(indexExpr, subscriptType,
/*applyExpr*/ nullptr, labels,
/*hasTrailingClosure*/ false, locator);
return KeyPathExpr::Component::forSubscriptWithPrebuiltIndexExpr(
ref, newIndexExpr, labels, resolvedTy, componentLoc, {});
}
Expr *visitKeyPathDotExpr(KeyPathDotExpr *E) {
llvm_unreachable("found KeyPathDotExpr in CSApply");
}
Expr *visitTapExpr(TapExpr *E) {
auto type = simplifyType(cs.getType(E));
E->getVar()->setType(type);
E->getVar()->setInterfaceType(type->mapTypeOutOfContext());
cs.setType(E, type);
E->setType(type);
return E;
}
/// Interface for ExprWalker
void walkToExprPre(Expr *expr) {
ExprStack.push_back(expr);
}
Expr *walkToExprPost(Expr *expr) {
Expr *result = visit(expr);
// Mark any _ObjectiveCBridgeable conformances as 'used'.
if (result) {
useObjectiveCBridgeableConformances(cs.DC, cs.getType(result));
}
assert(expr == ExprStack.back());
ExprStack.pop_back();
return result;
}
void finalize(Expr *&result) {
assert(ExprStack.empty());
assert(OpenedExistentials.empty());
auto &tc = cs.getTypeChecker();
// Look at all of the suspicious optional injections
for (auto injection : SuspiciousOptionalInjections) {
// If we already diagnosed this injection, we're done.
if (DiagnosedOptionalInjections.count(injection)) {
continue;
}
auto *cast = findForcedDowncast(tc.Context, injection->getSubExpr());
if (!cast)
continue;
if (isa<ParenExpr>(injection->getSubExpr()))
continue;
tc.diagnose(injection->getLoc(), diag::inject_forced_downcast,
cs.getType(injection->getSubExpr())->getRValueType());
auto exclaimLoc = cast->getExclaimLoc();
tc.diagnose(exclaimLoc, diag::forced_to_conditional_downcast,
cs.getType(injection)->getOptionalObjectType())
.fixItReplace(exclaimLoc, "?");
tc.diagnose(cast->getStartLoc(), diag::silence_inject_forced_downcast)
.fixItInsert(cast->getStartLoc(), "(")
.fixItInsertAfter(cast->getEndLoc(), ")");
}
// Look at key path subscript components to verify that they're hashable.
for (auto componentRef : KeyPathSubscriptComponents) {
auto &component = componentRef.first
->getMutableComponents()[componentRef.second];
// 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, 2> hashables;
bool allIndexesHashable = true;
ArrayRef<TupleTypeElt> indexTypes;
TupleTypeElt singleIndexTypeBuf;
if (auto tup = cs.getType(component.getIndexExpr())
->getAs<TupleType>()) {
indexTypes = tup->getElements();
} else {
singleIndexTypeBuf = cs.getType(component.getIndexExpr());
indexTypes = singleIndexTypeBuf;
}
auto hashable =
cs.getASTContext().getProtocol(KnownProtocolKind::Hashable);
auto equatable =
cs.getASTContext().getProtocol(KnownProtocolKind::Equatable);
for (auto indexType : indexTypes) {
auto conformance =
cs.TC.conformsToProtocol(indexType.getType(), hashable,
cs.DC,
(ConformanceCheckFlags::Used|
ConformanceCheckFlags::InExpression));
if (!conformance) {
cs.TC.diagnose(component.getIndexExpr()->getLoc(),
diag::expr_keypath_subscript_index_not_hashable,
indexType.getType());
allIndexesHashable = false;
continue;
}
hashables.push_back(*conformance);
// FIXME: Hashable implies Equatable, but we need to make sure the
// Equatable conformance is forced into existence during type checking
// so that it's available for SILGen.
auto eqConformance =
cs.TC.conformsToProtocol(indexType.getType(), equatable,
cs.DC,
(ConformanceCheckFlags::Used|
ConformanceCheckFlags::InExpression));
assert(eqConformance.hasValue());
(void)eqConformance;
}
if (allIndexesHashable) {
component.setSubscriptIndexHashableConformances(hashables);
}
}
// Set the final types on the expression.
cs.setExprTypes(result);
}
/// 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 &tc = cs.getTypeChecker();
auto *cast = findForcedDowncast(tc.Context, injection->getSubExpr());
if (!cast)
return;
SuspiciousOptionalInjections.push_back(injection);
}
};
} // end anonymous namespace
/// Resolve a locator to the specific declaration it references, if possible.
///
/// \param cs The constraint system in which the locator will be resolved.
///
/// \param locator The locator to resolve.
///
/// \param findOvlChoice A function that searches for the overload choice
/// associated with the given locator, or an empty optional if there is no such
/// overload.
///
/// \returns the decl to which the locator resolved.
///
static ConcreteDeclRef resolveLocatorToDecl(
ConstraintSystem &cs, ConstraintLocator *locator,
llvm::function_ref<Optional<SelectedOverload>(ConstraintLocator *)>
findOvlChoice,
llvm::function_ref<ConcreteDeclRef(ValueDecl *decl, Type openedType,
ConstraintLocator *declLocator)>
getConcreteDeclRef) {
assert(locator && "Null locator");
if (!locator->getAnchor())
return ConcreteDeclRef();
auto anchor = locator->getAnchor();
// Unwrap any specializations, constructor calls, implicit conversions, and
// '.'s.
// FIXME: This is brittle.
do {
if (auto specialize = dyn_cast<UnresolvedSpecializeExpr>(anchor)) {
anchor = specialize->getSubExpr();
continue;
}
if (auto implicit = dyn_cast<ImplicitConversionExpr>(anchor)) {
anchor = implicit->getSubExpr();
continue;
}
if (auto identity = dyn_cast<IdentityExpr>(anchor)) {
anchor = identity->getSubExpr();
continue;
}
if (auto tryExpr = dyn_cast<AnyTryExpr>(anchor)) {
if (isa<OptionalTryExpr>(tryExpr))
break;
anchor = tryExpr->getSubExpr();
continue;
}
if (auto selfApply = dyn_cast<SelfApplyExpr>(anchor)) {
anchor = selfApply->getFn();
continue;
}
if (auto dotSyntax = dyn_cast<DotSyntaxBaseIgnoredExpr>(anchor)) {
anchor = dotSyntax->getRHS();
continue;
}
if (auto *OEE = dyn_cast<OpenExistentialExpr>(anchor)) {
anchor = OEE->getSubExpr();
continue;
}
break;
} while (true);
// Simple case: direct reference to a declaration.
if (auto dre = dyn_cast<DeclRefExpr>(anchor))
return dre->getDeclRef();
// Simple case: direct reference to a declaration.
if (auto mre = dyn_cast<MemberRefExpr>(anchor))
return mre->getMember();
if (auto ctorRef = dyn_cast<OtherConstructorDeclRefExpr>(anchor))
return ctorRef->getDeclRef();
if (isa<OverloadedDeclRefExpr>(anchor) ||
isa<UnresolvedDeclRefExpr>(anchor)) {
// Overloaded and unresolved cases: find the resolved overload.
auto anchorLocator = cs.getConstraintLocator(anchor);
if (auto selected = findOvlChoice(anchorLocator)) {
if (selected->choice.isDecl())
return getConcreteDeclRef(selected->choice.getDecl(),
selected->openedType,
anchorLocator);
}
}
if (isa<UnresolvedMemberExpr>(anchor)) {
// Unresolved member: find the resolved overload.
auto anchorLocator = cs.getConstraintLocator(anchor,
ConstraintLocator::UnresolvedMember);
if (auto selected = findOvlChoice(anchorLocator)) {
if (selected->choice.isDecl())
return getConcreteDeclRef(selected->choice.getDecl(),
selected->openedType,
anchorLocator);
}
}
if (isa<UnresolvedDotExpr>(anchor)) {
// Unresolved member: find the resolved overload.
auto anchorLocator = cs.getConstraintLocator(anchor,
ConstraintLocator::Member);
if (auto selected = findOvlChoice(anchorLocator)) {
if (selected->choice.isDecl())
return getConcreteDeclRef(selected->choice.getDecl(),
selected->openedType,
anchorLocator);
}
}
if (auto subscript = dyn_cast<SubscriptExpr>(anchor)) {
// Subscript expressions may have a declaration. If so, use it.
if (subscript->hasDecl())
return subscript->getDecl();
// Otherwise, find the resolved overload.
auto anchorLocator =
cs.getConstraintLocator(anchor, ConstraintLocator::SubscriptMember);
if (auto selected = findOvlChoice(anchorLocator)) {
if (selected->choice.isDecl())
return getConcreteDeclRef(selected->choice.getDecl(),
selected->openedType,
anchorLocator);
}
}
if (auto subscript = dyn_cast<DynamicSubscriptExpr>(anchor)) {
// Dynamic subscripts are always resolved.
return subscript->getMember();
}
return ConcreteDeclRef();
}
ConcreteDeclRef Solution::resolveLocatorToDecl(
ConstraintLocator *locator) const {
auto &cs = getConstraintSystem();
// Simplify the locator.
SourceRange range;
locator = simplifyLocator(cs, locator, range);
// If we didn't map down to a specific expression, we can't handle a default
// argument.
if (!locator->getAnchor() || !locator->getPath().empty())
return nullptr;
if (auto resolved
= ::resolveLocatorToDecl(cs, locator,
[&](ConstraintLocator *locator) -> Optional<SelectedOverload> {
auto known = overloadChoices.find(locator);
if (known == overloadChoices.end()) {
return None;
}
return known->second;
},
[&](ValueDecl *decl, Type openedType, ConstraintLocator *locator)
-> ConcreteDeclRef {
SubstitutionMap subs =
computeSubstitutions(
decl->getInnermostDeclContext()
->getGenericSignatureOfContext(),
locator);
return ConcreteDeclRef(decl, subs);
})) {
return resolved;
}
return ConcreteDeclRef();
}
/// Given a constraint locator, find the declaration reference
/// to the callee, it is a call to a declaration.
static ConcreteDeclRef
findCalleeDeclRef(ConstraintSystem &cs, const Solution &solution,
ConstraintLocator *locator) {
if (locator->getPath().empty() || !locator->getAnchor())
return nullptr;
// If the locator points to a function application, find the function itself.
if (locator->getPath().back().getKind() == ConstraintLocator::ApplyArgument) {
assert(locator->getPath().back().getNewSummaryFlags() == 0 &&
"ApplyArgument adds no flags");
SmallVector<LocatorPathElt, 4> newPath;
newPath.append(locator->getPath().begin(), locator->getPath().end()-1);
unsigned newFlags = locator->getSummaryFlags();
newPath.push_back(ConstraintLocator::ApplyFunction);
assert(newPath.back().getNewSummaryFlags() == 0 &&
"added element that changes the flags?");
locator = cs.getConstraintLocator(locator->getAnchor(), newPath, newFlags);
}
return solution.resolveLocatorToDecl(locator);
}
/// Produce the caller-side default argument for this default argument, or
/// null if the default argument will be provided by the callee.
static std::pair<Expr *, DefaultArgumentKind>
getCallerDefaultArg(ConstraintSystem &cs, DeclContext *dc,
SourceLoc loc, ConcreteDeclRef &owner,
unsigned index) {
auto &tc = cs.getTypeChecker();
const auto *param = getParameterAt(cast<ValueDecl>(owner.getDecl()), index);
Expr *init = nullptr;
switch (param->getDefaultArgumentKind()) {
case DefaultArgumentKind::None:
llvm_unreachable("No default argument here?");
case DefaultArgumentKind::StoredProperty:
case DefaultArgumentKind::Normal:
return {nullptr, param->getDefaultArgumentKind()};
case DefaultArgumentKind::Inherited:
// Update the owner to reflect inheritance here.
owner = owner.getOverriddenDecl();
return getCallerDefaultArg(cs, dc, loc, owner, index);
case DefaultArgumentKind::Column:
init = new (tc.Context) MagicIdentifierLiteralExpr(
MagicIdentifierLiteralExpr::Column, loc,
/*implicit=*/true);
break;
case DefaultArgumentKind::File:
init = new (tc.Context) MagicIdentifierLiteralExpr(
MagicIdentifierLiteralExpr::File, loc,
/*implicit=*/true);
break;
case DefaultArgumentKind::Line:
init = new (tc.Context) MagicIdentifierLiteralExpr(
MagicIdentifierLiteralExpr::Line, loc,
/*implicit=*/true);
break;
case DefaultArgumentKind::Function:
init = new (tc.Context) MagicIdentifierLiteralExpr(
MagicIdentifierLiteralExpr::Function, loc,
/*implicit=*/true);
break;
case DefaultArgumentKind::DSOHandle:
init = new (tc.Context) MagicIdentifierLiteralExpr(
MagicIdentifierLiteralExpr::DSOHandle, loc,
/*implicit=*/true);
break;
case DefaultArgumentKind::NilLiteral:
init = new (tc.Context) NilLiteralExpr(loc, /*Implicit=*/true);
break;
case DefaultArgumentKind::EmptyArray:
init = ArrayExpr::create(tc.Context, loc, {}, {}, loc);
init->setImplicit();
break;
case DefaultArgumentKind::EmptyDictionary:
init = DictionaryExpr::create(tc.Context, loc, {}, {}, loc);
init->setImplicit();
break;
}
// Convert the literal to the appropriate type.
auto defArgType = owner.getDecl()->getDeclContext()->mapTypeIntoContext(
param->getInterfaceType());
auto resultTy =
tc.typeCheckParameterDefault(init, dc, defArgType,
/*isAutoClosure=*/param->isAutoClosure(),
/*canFail=*/false);
assert(resultTy && "Conversion cannot fail");
(void)resultTy;
cs.cacheExprTypes(init);
return {init, param->getDefaultArgumentKind()};
}
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 &tc = cs.getTypeChecker();
// 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::getTupleElement(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 (tc.Context) OpaqueValueExpr(expr->getLoc(),
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;
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();
auto *toElt
= coerceToType(fromElt, toEltType,
locator.withPathElement(
LocatorPathElt::getTupleElement(source)));
if (!toElt)
return nullptr;
converted.push_back(toElt);
labels.push_back(toLabel);
convertedElts.emplace_back(toEltType, toLabel, ParameterTypeFlags());
}
// Create the result tuple, written in terms of the destructured
// OpaqueValueExprs.
auto *result = TupleExpr::createImplicit(tc.Context, converted, labels);
result->setType(TupleType::get(convertedElts, tc.Context));
cs.cacheType(result);
// Create the tuple conversion.
return
cs.cacheType(DestructureTupleExpr::create(tc.Context,
destructured, expr, result,
toTuple));
}
static Type getMetatypeSuperclass(Type t, TypeChecker &tc) {
if (auto *metaTy = t->getAs<MetatypeType>())
return MetatypeType::get(getMetatypeSuperclass(
metaTy->getInstanceType(),
tc));
if (auto *metaTy = t->getAs<ExistentialMetatypeType>())
return ExistentialMetatypeType::get(getMetatypeSuperclass(
metaTy->getInstanceType(),
tc));
return t->getSuperclass();
}
Expr *ExprRewriter::coerceSuperclass(Expr *expr, Type toType,
ConstraintLocatorBuilder locator) {
auto &tc = cs.getTypeChecker();
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, tc);
expr =
cs.cacheType(
new (tc.Context) ArchetypeToSuperExpr(expr, superclass));
if (!superclass->isEqual(toType))
return coerceSuperclass(expr, toType, locator);
return expr;
}
if (fromInstanceType->isExistentialType()) {
// Coercion from superclass-constrained existential to its
// concrete superclass.
auto fromArchetype = OpenedArchetypeType::getAny(fromType);
auto *archetypeVal =
cs.cacheType(
new (tc.Context) OpaqueValueExpr(expr->getLoc(),
fromArchetype));
auto *result = coerceSuperclass(archetypeVal, toType, locator);
return cs.cacheType(
new (tc.Context) OpenExistentialExpr(expr, archetypeVal, result,
toType));
}
// Coercion from subclass to superclass.
if (toType->is<MetatypeType>()) {
return cs.cacheType(
new (tc.Context) MetatypeConversionExpr(expr, toType));
}
return cs.cacheType(
new (tc.Context) 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(TypeChecker &tc, Type fromType, Type toType,
DeclContext *DC) {
auto layout = toType->getExistentialLayout();
SmallVector<ProtocolConformanceRef, 4> conformances;
for (auto proto : layout.getProtocols()) {
conformances.push_back(
*tc.containsProtocol(fromType, proto->getDecl(), DC,
(ConformanceCheckFlags::InExpression|
ConformanceCheckFlags::Used)));
}
return tc.Context.AllocateCopy(conformances);
}
Expr *ExprRewriter::coerceExistential(Expr *expr, Type toType,
ConstraintLocatorBuilder locator) {
auto &tc = solution.getConstraintSystem().getTypeChecker();
Type fromType = cs.getType(expr);
Type fromInstanceType = fromType;
Type toInstanceType = toType;
// Look through metatypes
while ((fromInstanceType->is<UnresolvedType>() ||
fromInstanceType->is<AnyMetatypeType>()) &&
toInstanceType->is<ExistentialMetatypeType>()) {
if (!fromInstanceType->is<UnresolvedType>())
fromInstanceType = fromInstanceType->castTo<AnyMetatypeType>()->getInstanceType();
toInstanceType = toInstanceType->castTo<ExistentialMetatypeType>()->getInstanceType();
}
ASTContext &ctx = tc.Context;
auto conformances =
collectExistentialConformances(tc, 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->getLoc(),
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 &tc = cs.getTypeChecker();
Type fromType = cs.getType(expr);
tc.requireOptionalIntrinsics(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 (tc.Context) 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 (tc.Context) 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 (tc.Context) InjectIntoOptionalExpr(expr, toType));
expr = cs.cacheType(new (tc.Context) OptionalEvaluationExpr(expr, toType));
expr->setImplicit(true);
return expr;
}
Expr *ExprRewriter::coerceImplicitlyUnwrappedOptionalToValue(Expr *expr, Type objTy) {
auto optTy = cs.getType(expr);
// Coerce to an r-value.
if (optTy->is<LValueType>())
objTy = LValueType::get(objTy);
expr = new (cs.getTypeChecker().Context) 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,
ApplyExpr *apply,
ArrayRef<Identifier> argLabels,
bool hasTrailingClosure,
ConstraintLocatorBuilder locator) {
auto &tc = getConstraintSystem().getTypeChecker();
auto params = funcType->getParams();
// Local function to produce a locator to refer to the given parameter.
auto getArgLocator = [&](unsigned argIdx, unsigned paramIdx)
-> ConstraintLocatorBuilder {
return locator.withPathElement(
LocatorPathElt::getApplyArgToParam(argIdx, paramIdx));
};
bool matchCanFail =
llvm::any_of(params, [](const AnyFunctionType::Param &param) {
return param.getPlainType()->hasUnresolvedType();
});
// Find the callee declaration.
ConcreteDeclRef callee =
findCalleeDeclRef(cs, solution, cs.getConstraintLocator(locator));
// Determine whether this application has curried self.
bool skipCurriedSelf = apply ? hasCurriedSelf(cs, callee, apply) : true;
// Determine the parameter bindings.
SmallBitVector defaultMap
= computeDefaultMap(params, callee.getDecl(), skipCurriedSelf);
SmallVector<AnyFunctionType::Param, 8> args;
AnyFunctionType::decomposeInput(cs.getType(arg), args);
// Quickly test if any further fix-ups for the argument types are necessary.
if (AnyFunctionType::equalParams(args, params))
return arg;
// Apply labels to arguments.
AnyFunctionType::relabelParams(args, argLabels);
MatchCallArgumentListener listener;
SmallVector<ParamBinding, 4> parameterBindings;
bool failed = constraints::matchCallArguments(args, params,
defaultMap,
hasTrailingClosure,
/*allowFixes=*/false, listener,
parameterBindings);
assert((matchCanFail || !failed) && "Call arguments did not match up?");
(void)failed;
(void)matchCanFail;
// 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));
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(tc.Context,
start,
variadicArgs,
{}, end,
param.getParameterType());
arrayExpr->setImplicit();
cs.cacheType(arrayExpr);
// Wrap the ArrayExpr in a VarargExpansionExpr.
auto *varargExpansionExpr =
new (tc.Context) 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()) {
Expr *defArg;
DefaultArgumentKind defArgKind;
std::tie(defArg, defArgKind) = getCallerDefaultArg(cs, dc, arg->getLoc(),
callee, paramIdx);
// If we have a caller-side default argument, just add the magic literal
// expression to our argument list.
if (defArg) {
defArg =
new (tc.Context) CallerDefaultArgumentExpr(defArg,
arg->getStartLoc(),
param.getParameterType());
// Otherwise, create a call of the default argument generator.
} else {
defArg =
new (tc.Context) DefaultArgumentExpr(callee, paramIdx,
arg->getStartLoc(),
param.getParameterType());
}
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)) {
newArgs.push_back(arg);
newParams.push_back(param);
continue;
}
auto isAutoClosureArg = [](Expr *arg) -> bool {
if (auto *DRE = dyn_cast<DeclRefExpr>(arg)) {
if (auto *PD = dyn_cast<ParamDecl>(DRE->getDecl()))
return PD->isAutoClosure();
}
return false;
};
Expr *convertedArg = nullptr;
// 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 (param.isAutoClosure() && (!argType->is<FunctionType>() ||
!isAutoClosureArg(arg))) {
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>();
arg = coerceToType(
arg, closureType->getResult(),
locator.withPathElement(ConstraintLocator::AutoclosureResult));
convertedArg = cs.TC.buildAutoClosureExpr(dc, arg, closureType);
cs.cacheExprTypes(convertedArg);
} else {
convertedArg =
coerceToType(arg, paramType, getArgLocator(argIdx, paramIdx));
}
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(!hasTrailingClosure);
return newArgs[0];
}
// Rebuild the argument list, sharing as much structure as possible.
auto paramType = AnyFunctionType::composeInput(tc.Context, 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 {
arg = new (tc.Context) ParenExpr(lParenLoc,
newArgs[0],
rParenLoc,
hasTrailingClosure);
arg->setImplicit();
}
} 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(tc.Context, lParenLoc,
newArgs, newLabels, newLabelLocs,
rParenLoc,
hasTrailingClosure,
/*implicit=*/true);
}
}
arg->setType(paramType);
return cs.cacheType(arg);
}
static ClosureExpr *getClosureLiteralExpr(Expr *expr) {
expr = expr->getSemanticsProvidingExpr();
if (auto *captureList = dyn_cast<CaptureListExpr>(expr))
return captureList->getClosureBody();
if (auto *closure = dyn_cast<ClosureExpr>(expr))
return closure;
return nullptr;
}
/// 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 is not a single-expression closure, write the type into the
// ClosureExpr directly here, since the visitor won't.
if (!CE->hasSingleExpressionBody())
CE->setType(toType);
return true;
}
// Otherwise fail.
return false;
}
ClosureExpr *ExprRewriter::coerceClosureExprToVoid(ClosureExpr *closureExpr) {
auto &tc = cs.getTypeChecker();
// Re-write the single-expression closure to return '()'
assert(closureExpr->hasSingleExpressionBody());
// A single-expression body contains a single return statement
// prior to this transformation.
auto member = closureExpr->getBody()->getElement(0);
if (member.is<Stmt *>()) {
auto returnStmt = cast<ReturnStmt>(member.get<Stmt *>());
auto singleExpr = returnStmt->getResult();
auto voidExpr =
cs.cacheType(
TupleExpr::createEmpty(tc.Context,
singleExpr->getStartLoc(),
singleExpr->getEndLoc(),
/*implicit*/true));
returnStmt->setResult(voidExpr);
// For l-value types, reset to the object type. This might not be strictly
// necessary any more, but it's probably still a good idea.
if (cs.getType(singleExpr)->is<LValueType>())
cs.setType(singleExpr,
cs.getType(singleExpr)->getWithoutSpecifierType());
cs.setExprTypes(singleExpr);
tc.checkIgnoredExpr(singleExpr);
SmallVector<ASTNode, 2> elements;
elements.push_back(singleExpr);
elements.push_back(returnStmt);
auto braceStmt = BraceStmt::create(tc.Context,
closureExpr->getStartLoc(),
elements,
closureExpr->getEndLoc(),
/*implicit*/true);
closureExpr->setImplicit();
closureExpr->setBody(braceStmt, /*isSingleExpression*/true);
}
// Finally, compute the proper type for the closure.
auto fnType = cs.getType(closureExpr)->getAs<FunctionType>();
auto newClosureType = FunctionType::get(
fnType->getParams(), tc.Context.TheEmptyTupleType, fnType->getExtInfo());
cs.setType(closureExpr, newClosureType);
return closureExpr;
}
ClosureExpr *ExprRewriter::coerceClosureExprFromNever(ClosureExpr *closureExpr) {
auto &tc = cs.getTypeChecker();
// Re-write the single-expression closure to drop the 'return'.
assert(closureExpr->hasSingleExpressionBody());
// A single-expression body contains a single return statement
// prior to this transformation.
auto member = closureExpr->getBody()->getElement(0);
if (member.is<Stmt *>()) {
auto returnStmt = cast<ReturnStmt>(member.get<Stmt *>());
auto singleExpr = returnStmt->getResult();
cs.setExprTypes(singleExpr);
tc.checkIgnoredExpr(singleExpr);
SmallVector<ASTNode, 1> elements;
elements.push_back(singleExpr);
auto braceStmt = BraceStmt::create(tc.Context,
closureExpr->getStartLoc(),
elements,
closureExpr->getEndLoc(),
/*implicit*/true);
closureExpr->setImplicit();
closureExpr->setBody(braceStmt, /*isSingleExpression*/true);
}
return closureExpr;
}
// 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
maybeDiagnoseUnsupportedFunctionConversion(ConstraintSystem &cs, Expr *expr,
AnyFunctionType *toType) {
auto &tc = cs.getTypeChecker();
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()) {
tc.diagnose(expr->getLoc(),
diag::c_function_pointer_from_method);
} else if (fn->getGenericParams()) {
tc.diagnose(expr->getLoc(),
diag::c_function_pointer_from_generic_function);
} else {
tc.maybeDiagnoseCaptures(expr, fn);
}
};
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)) {
tc.maybeDiagnoseCaptures(expr, closure);
return;
}
tc.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,
SourceLoc srcLoc,
Type srcType,
Type destType,
bool bridged,
ConstraintLocatorBuilder locator,
Expr *element) {
auto &cs = rewriter.getConstraintSystem();
auto &tc = rewriter.getConstraintSystem().getTypeChecker();
if (bridged &&
tc.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,
SourceLoc srcLoc,
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(srcLoc, srcType));
Expr *conversion =
buildElementConversion(rewriter, srcLoc, srcType, destType, bridged,
locator.withPathElement(
ConstraintLocator::PathElement::getGenericArgument(
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(
ConstraintLocator::PathElement::getGenericArgument(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(
ConstraintLocator::PathElement::getGenericArgument(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) {
auto &tc = cs.getTypeChecker();
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 (tc.Context) ForeignObjectConversionExpr(objcExpr, toType));
}
}
return coerceToType(objcExpr, toType, locator);
}
// Bridging from an Objective-C class type to a Swift type.
return forceBridgeFromObjectiveC(expr, toType);
}
static Expr *addImplicitLoadExpr(ConstraintSystem &cs, Expr *expr) {
auto &tc = cs.getTypeChecker();
return tc.addImplicitLoadExpr(
expr, [&cs](Expr *expr) { return cs.getType(expr); },
[&cs](Expr *expr, Type type) { cs.setType(expr, type); });
}
Expr *ExprRewriter::coerceToType(Expr *expr, Type toType,
ConstraintLocatorBuilder locator,
Optional<Pattern*> typeFromPattern) {
auto &tc = cs.getTypeChecker();
// 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: {
if (toType->hasUnresolvedType())
break;
// 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;
}
}
}
}
llvm_unreachable("Should be handled above");
}
case ConversionRestrictionKind::Superclass:
case ConversionRestrictionKind::ExistentialMetatypeToMetatype:
return coerceSuperclass(expr, toType, locator);
case ConversionRestrictionKind::Existential:
case ConversionRestrictionKind::MetatypeToExistentialMetatype:
return coerceExistential(expr, toType, locator);
case ConversionRestrictionKind::ClassMetatypeToAnyObject: {
assert(tc.getLangOpts().EnableObjCInterop
&& "metatypes can only be cast to objects w/ objc runtime!");
return cs.cacheType(
new (tc.Context) ClassMetatypeToObjectExpr(expr, toType));
}
case ConversionRestrictionKind::ExistentialMetatypeToAnyObject: {
assert(tc.getLangOpts().EnableObjCInterop
&& "metatypes can only be cast to objects w/ objc runtime!");
return cs.cacheType(
new (tc.Context) ExistentialMetatypeToObjectExpr(expr, toType));
}
case ConversionRestrictionKind::ProtocolMetatypeToProtocolClass: {
return cs.cacheType(
new (tc.Context) ProtocolMetatypeToObjectExpr(expr, toType));
}
case ConversionRestrictionKind::ValueToOptional: {
auto toGenericType = toType->castTo<BoundGenericType>();
assert(toGenericType->getDecl()->isOptionalDecl());
tc.requireOptionalIntrinsics(expr->getLoc());
Type valueType = toGenericType->getGenericArgs()[0];
expr = coerceToType(expr, valueType, locator);
if (!expr) return nullptr;
auto *result =
cs.cacheType(new (tc.Context) 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 = tc.Context.getProtocol(KnownProtocolKind::Hashable);
auto conformance =
tc.conformsToProtocol(
cs.getType(expr), hashable, cs.DC,
(ConformanceCheckFlags::InExpression |
ConformanceCheckFlags::Used));
assert(conformance && "must conform to Hashable");
return cs.cacheType(
new (tc.Context) 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;
tc.requirePointerArgumentIntrinsics(expr->getLoc());
Expr *result =
cs.cacheType(new (tc.Context) InOutToPointerExpr(expr, unwrappedTy));
if (isOptional)
result = cs.cacheType(new (tc.Context)
InjectIntoOptionalExpr(result, toType));
return result;
}
case ConversionRestrictionKind::ArrayToPointer: {
bool isOptional = false;
Type unwrappedTy = toType;
if (Type unwrapped = toType->getOptionalObjectType()) {
isOptional = true;
unwrappedTy = unwrapped;
}
tc.requirePointerArgumentIntrinsics(expr->getLoc());
Expr *result =
cs.cacheType(new (tc.Context) ArrayToPointerExpr(expr, unwrappedTy));
if (isOptional)
result = cs.cacheType(new (tc.Context)
InjectIntoOptionalExpr(result, toType));
return result;
}
case ConversionRestrictionKind::StringToPointer: {
bool isOptional = false;
Type unwrappedTy = toType;
if (Type unwrapped = toType->getOptionalObjectType()) {
isOptional = true;
unwrappedTy = unwrapped;
}
tc.requirePointerArgumentIntrinsics(expr->getLoc());
Expr *result =
cs.cacheType(new (tc.Context) StringToPointerExpr(expr, unwrappedTy));
if (isOptional)
result = cs.cacheType(new (tc.Context)
InjectIntoOptionalExpr(result, toType));
return result;
}
case ConversionRestrictionKind::PointerToPointer: {
tc.requirePointerArgumentIntrinsics(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 (tc.Context) BindOptionalExpr(expr, SourceLoc(),
/*depth*/ 0, unwrappedFromTy));
Expr *converted = cs.cacheType(new (tc.Context) PointerToPointerExpr(
boundOptional, unwrappedToTy));
Expr *rewrapped = cs.cacheType(
new (tc.Context) InjectIntoOptionalExpr(converted, toType));
return cs.cacheType(new (tc.Context)
OptionalEvaluationExpr(rewrapped, toType));
}
// Non-optional to optional.
if (unwrappedToTy) {
Expr *converted = cs.cacheType(
new (tc.Context) PointerToPointerExpr(expr, unwrappedToTy));
return cs.cacheType(new (tc.Context)
InjectIntoOptionalExpr(converted, toType));
}
// Non-optional to non-optional.
return cs.cacheType(new (tc.Context) PointerToPointerExpr(expr, toType));
}
case ConversionRestrictionKind::CFTollFreeBridgeToObjC: {
auto foreignClass = fromType->getClassOrBoundGenericClass();
auto objcType = foreignClass->getAttrs().getAttribute<ObjCBridgedAttr>()
->getObjCClass()->getDeclaredInterfaceType();
auto asObjCClass = cs.cacheType(
new (tc.Context) 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 (tc.Context)
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(addImplicitLoadExpr(cs, 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 (tc.Context) 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:
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, locator);
}
}
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>());
// If we have a ClosureExpr, then we can safely propagate the 'no escape'
// bit to the closure without invalidating prior analysis.
auto 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 (tc.Context) 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 (tc.Context)
FunctionConversionExpr(expr, toFunc));
return newExpr;
}
}
maybeDiagnoseUnsupportedFunctionConversion(cs, expr, toFunc);
return cs.cacheType(new (tc.Context)
FunctionConversionExpr(expr, toType));
}
// Coercions from one metatype to another.
case TypeKind::Metatype: {
if (auto toMeta = toType->getAs<MetatypeType>())
return cs.cacheType(new(tc.Context) 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 (tc.Context) 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 (tc.Context) 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 (tc.Context) 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, locator);
// Coercion to Optional<T>.
case TypeKind::BoundGenericEnum: {
auto toGenericType = cast<BoundGenericEnumType>(desugaredToType);
if (!toGenericType->getDecl()->isOptionalDecl())
break;
tc.requireOptionalIntrinsics(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 (tc.Context) InjectIntoOptionalExpr(expr, toType));
diagnoseOptionalInjection(result);
return result;
}
#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::BoundGenericStruct:
case TypeKind::Metatype:
case TypeKind::DynamicSelf:
case TypeKind::PrimaryArchetype:
case TypeKind::OpenedArchetype:
case TypeKind::NestedArchetype:
case TypeKind::GenericTypeParam:
case TypeKind::DependentMember:
case TypeKind::Function:
case TypeKind::GenericFunction:
case TypeKind::LValue:
case TypeKind::InOut:
break;
}
// Unresolved types come up in diagnostics for lvalue and inout types.
if (fromType->hasUnresolvedType() || toType->hasUnresolvedType())
return cs.cacheType(new (tc.Context)
UnresolvedTypeConversionExpr(expr, toType));
llvm_unreachable("Unhandled coercion");
}
/// Adjust the given type to become the self type when referring to
/// the given member.
static Type adjustSelfTypeForMember(Type baseTy, ValueDecl *member,
AccessSemantics semantics,
DeclContext *UseDC) {
auto baseObjectTy = baseTy->getWithoutSpecifierType();
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 InOutType::get(baseObjectTy);
// 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.
if (!SD->isGetterMutating()
&& (!isSettableFromHere || !SD->isSetterMutating()))
return baseObjectTy;
// If we're calling an accessor, keep the base as an inout type, because the
// getter may be mutating.
auto strategy = SD->getAccessStrategy(semantics,
isSettableFromHere
? AccessKind::ReadWrite
: AccessKind::Read,
UseDC->getParentModule(),
UseDC->getResilienceExpansion());
if (baseTy->is<InOutType>() && strategy.getKind() != AccessStrategy::Storage)
return InOutType::get(baseObjectTy);
// Accesses to non-function members in value types are done through an @lvalue
// type.
if (baseTy->is<InOutType>())
return LValueType::get(baseObjectTy);
// Accesses to members in values of reference type (classes, metatypes) are
// always done through a the reference to self. Accesses to value types with
// a non-mutable self are also done through the base type.
return baseTy;
}
Expr *
ExprRewriter::coerceObjectArgumentToType(Expr *expr,
Type baseTy, ValueDecl *member,
AccessSemantics semantics,
ConstraintLocatorBuilder locator) {
Type toType = adjustSelfTypeForMember(baseTy, member, semantics, 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.getTypeChecker().Context;
// 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(Expr *literal,
Type type,
ProtocolDecl *protocol,
Identifier literalType,
DeclName literalFuncName,
ProtocolDecl *builtinProtocol,
DeclName builtinLiteralFuncName,
Diag<> brokenProtocolDiag,
Diag<> brokenBuiltinProtocolDiag) {
auto &tc = cs.getTypeChecker();
auto getType = [&](const Expr *E) -> Type {
return cs.getType(E);
};
auto setType = [&](Expr *E, Type Ty) {
cs.setType(E, Ty);
};
// 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>()) {
// Instead of updating the literal expr in place, allocate a new node. This
// avoids issues where Builtin types end up on expr nodes and pollute
// diagnostics.
literal = cast<LiteralExpr>(literal)->shallowClone(tc.Context, setType,
getType);
// The literal expression has this type.
cs.setType(literal, type);
return literal;
}
// Check whether this literal type conforms to the builtin protocol. If so,
// initialize via the builtin protocol.
Optional<ProtocolConformanceRef> builtinConformance;
if (builtinProtocol &&
(builtinConformance =
tc.conformsToProtocol(type, builtinProtocol, cs.DC,
ConformanceCheckFlags::InExpression))) {
// Find the witness that we'll use to initialize the type via a builtin
// literal.
auto witness = findNamedWitnessImpl(
tc, dc, type->getRValueType(), builtinProtocol,
builtinLiteralFuncName, brokenBuiltinProtocolDiag,
*builtinConformance);
if (!witness || !isa<AbstractFunctionDecl>(witness.getDecl()))
return nullptr;
// Form a reference to the builtin conversion function.
// Set the builtin initializer.
if (auto stringLiteral = dyn_cast<StringLiteralExpr>(literal))
stringLiteral->setBuiltinInitializer(witness);
else if (auto booleanLiteral = dyn_cast<BooleanLiteralExpr>(literal))
booleanLiteral->setBuiltinInitializer(witness);
else if (auto numberLiteral = dyn_cast<NumberLiteralExpr>(literal))
numberLiteral->setBuiltinInitializer(witness);
else {
cast<MagicIdentifierLiteralExpr>(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 = tc.conformsToProtocol(type, protocol, cs.DC,
ConformanceCheckFlags::InExpression);
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 = tc.getWitnessType(type, protocol, *conformance,
literalType,
brokenProtocolDiag);
if (!builtinLiteralType)
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 = findNamedWitnessImpl(
tc, dc, type->getRValueType(), protocol,
literalFuncName, brokenProtocolDiag,
conformance);
if (!witness || !isa<AbstractFunctionDecl>(witness.getDecl()))
return nullptr;
// Set the initializer.
if (auto nilLiteral = dyn_cast<NilLiteralExpr>(literal))
nilLiteral->setInitializer(witness);
else if (auto stringLiteral = dyn_cast<StringLiteralExpr>(literal))
stringLiteral->setInitializer(witness);
else if (auto booleanLiteral = dyn_cast<BooleanLiteralExpr>(literal))
booleanLiteral->setInitializer(witness);
else if (auto numberLiteral = dyn_cast<NumberLiteralExpr>(literal))
numberLiteral->setInitializer(witness);
else
cast<MagicIdentifierLiteralExpr>(literal)->setInitializer(witness);
// The literal expression has this type.
cs.setType(literal, type);
return literal;
}
// Resolve @dynamicCallable applications.
static Expr *finishApplyDynamicCallable(ConstraintSystem &cs,
const Solution &solution,
ApplyExpr *apply,
ConstraintLocatorBuilder locator) {
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.
auto loc = locator.withPathElement(ConstraintLocator::ApplyFunction);
auto selected = solution.getOverloadChoice(cs.getConstraintLocator(loc));
auto *method = dyn_cast<FuncDecl>(selected.choice.getDecl());
auto methodType = selected.openedType->castTo<AnyFunctionType>();
assert(method->getName() == ctx.Id_dynamicallyCall &&
"Expected 'dynamicallyCall' method");
assert(methodType->getParams().size() == 1 &&
"Expected 'dynamicallyCall' method with one parameter");
auto argumentLabel = methodType->getParams()[0].getLabel();
assert((argumentLabel == ctx.Id_withArguments ||
argumentLabel == ctx.Id_withKeywordArguments) &&
"Expected 'dynamicallyCall' method argument label 'withArguments' or "
"'withKeywordArguments'");
// Determine which method was resolved: a `withArguments` method or a
// `withKeywordArguments` method.
bool useKwargsMethod = argumentLabel == ctx.Id_withKeywordArguments;
// Construct expression referencing the `dynamicallyCall` method.
Expr *member =
new (ctx) MemberRefExpr(fn, fn->getEndLoc(), ConcreteDeclRef(method),
DeclNameLoc(method->getNameLoc()),
/*Implicit*/ true);
// Construct argument to the method (either an array or dictionary
// expression).
Expr *argument = nullptr;
if (!useKwargsMethod) {
argument = ArrayExpr::create(ctx, SourceLoc(), arg->getElements(),
{}, SourceLoc());
} else {
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);
Expr *pair =
TupleExpr::createImplicit(ctx, { labelExpr, arg->getElement(i) }, {});
dictElements.push_back(pair);
}
argument = DictionaryExpr::create(ctx, SourceLoc(), dictElements, {},
SourceLoc());
}
argument->setImplicit();
// Construct call to the `dynamicallyCall` method.
Expr *result = CallExpr::createImplicit(ctx, member, argument,
{ argumentLabel });
cs.TC.typeCheckExpression(result, cs.DC);
cs.cacheExprTypes(result);
return result;
}
Expr *ExprRewriter::finishApply(ApplyExpr *apply, Type openedType,
ConstraintLocatorBuilder locator) {
TypeChecker &tc = cs.getTypeChecker();
auto fn = apply->getFn();
bool hasTrailingClosure =
isa<CallExpr>(apply) && cast<CallExpr>(apply)->hasTrailingClosure();
auto finishApplyOfDeclWithSpecialTypeCheckingSemantics
= [&](ApplyExpr *apply,
ValueDecl *decl,
Type openedType) -> Expr* {
switch (cs.TC.getDeclTypeCheckingSemantics(decl)) {
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,
apply,
apply->getArgumentLabels(argLabelsScratch),
hasTrailingClosure,
locator.withPathElement(
ConstraintLocator::ApplyArgument));
if (!arg) {
return nullptr;
}
if (auto tuple = dyn_cast<TupleExpr>(arg))
arg = tuple->getElements()[0];
auto replacement = new (tc.Context)
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 (tc.Context)
OpaqueValueExpr(apply->getFn()->getLoc(), Type());
cs.setType(escapable, escapableParams[0].getOldType());
auto getType = [&](const Expr *E) -> Type {
return cs.getType(E);
};
auto callSubExpr = CallExpr::createImplicit(tc.Context, body,
{escapable}, {}, getType);
cs.cacheSubExprTypes(callSubExpr);
cs.setType(callSubExpr->getArg(),
AnyFunctionType::composeInput(tc.Context,
escapableParams, false));
cs.setType(callSubExpr, resultType);
auto replacement = new (tc.Context)
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 (tc.Context)
OpaqueValueExpr(apply->getLoc(), openedTy);
cs.setType(opaqueValue, openedTy);
auto getType = [&](const Expr *E) -> Type {
return cs.getType(E);
};
auto callSubExpr = CallExpr::createImplicit(tc.Context, body, {opaqueValue}, {}, getType);
cs.cacheSubExprTypes(callSubExpr);
cs.setType(callSubExpr, resultTy);
auto replacement = new (tc.Context)
OpenExistentialExpr(existential, opaqueValue, callSubExpr,
resultTy);
cs.setType(replacement, resultTy);
return replacement;
}
case DeclTypeCheckingSemantics::Normal:
return nullptr;
}
llvm_unreachable("Unhandled DeclTypeCheckingSemantics in switch.");
};
// 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->getDecl(),
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 (getClosureLiteralExpr(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>()) {
auto origArg = apply->getArg();
Expr *arg = coerceCallArguments(origArg, fnType,
apply,
apply->getArgumentLabels(argLabelsScratch),
hasTrailingClosure,
locator.withPathElement(
ConstraintLocator::ApplyArgument));
if (!arg) {
return nullptr;
}
apply->setArg(arg);
cs.setType(apply, fnType->getResult());
apply->setIsSuper(isSuper);
cs.setExprTypes(apply);
Expr *result = tc.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 (tc.Context) CovariantFunctionConversionExpr(
result, covariantResultType));
else
result = cs.cacheType(new (tc.Context) CovariantReturnConversionExpr(
result, covariantResultType));
}
// Try closing the existential, if there is one.
closeExistential(result, locator);
// Extract all arguments.
auto *CEA = arg;
// The argument is either a ParenExpr or TupleExpr.
ArrayRef<Expr *> arguments;
SmallVector<Expr *, 1> Scratch;
if (auto *TE = dyn_cast<TupleExpr>(CEA))
arguments = TE->getElements();
else if (auto *PE = dyn_cast<ParenExpr>(CEA)) {
Scratch.push_back(PE->getSubExpr());
arguments = makeArrayRef(Scratch);
}
else {
Scratch.push_back(apply->getArg());
arguments = makeArrayRef(Scratch);
}
for (auto arg: arguments) {
bool isNoEscape = false;
while (1) {
if (auto AFT = cs.getType(arg)->getAs<AnyFunctionType>()) {
isNoEscape = isNoEscape || AFT->isNoEscape();
}
if (auto conv = dyn_cast<ImplicitConversionExpr>(arg))
arg = conv->getSubExpr();
else if (auto *PE = dyn_cast<ParenExpr>(arg))
arg = PE->getSubExpr();
else
break;
}
if (!isNoEscape) {
if (auto DRE = dyn_cast<DeclRefExpr>(arg))
if (auto FD = dyn_cast<FuncDecl>(DRE->getDecl())) {
tc.addEscapingFunctionAsArgument(FD, apply);
}
}
}
if (unwrapResult)
return forceUnwrapResult(result);
return result;
}
// FIXME: handle unwrapping everywhere else
assert(!unwrapResult);
// If this is an UnresolvedType in the system, preserve it.
if (cs.getType(fn)->is<UnresolvedType>()) {
cs.setType(apply, cs.getType(fn));
return apply;
}
// We have a type constructor.
if (auto metaTy = cs.getType(fn)->getAs<AnyMetatypeType>()) {
auto ty = metaTy->getInstanceType();
// If we're "constructing" a tuple type, it's simply a conversion.
if (auto tupleTy = ty->getAs<TupleType>()) {
// FIXME: Need an AST to represent this properly.
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.withPathElement(ConstraintLocator::ApplyFunction)
.withPathElement(ConstraintLocator::ConstructorMember));
auto selected = solution.getOverloadChoiceIfAvailable(ctorLocator);
if (!selected) {
assert(ty->hasError() || ty->hasUnresolvedType());
cs.setType(apply, ty);
return apply;
}
assert(ty->getNominalOrBoundGenericNominal() || ty->is<DynamicSelfType>() ||
ty->isExistentialType() || ty->is<ArchetypeType>());
// We have the constructor.
auto choice = selected->choice;
// Consider the constructor decl reference expr 'implicit', but the
// constructor call expr itself has the apply's 'implicitness'.
bool isDynamic = choice.getKind() == OverloadChoiceKind::DeclViaDynamic;
Expr *declRef = buildMemberRef(fn, selected->openedFullType,
/*dotLoc=*/SourceLoc(), choice,
DeclNameLoc(fn->getEndLoc()),
selected->openedType, locator, ctorLocator,
/*Implicit=*/true,
choice.getFunctionRefKind(),
AccessSemantics::Ordinary, isDynamic);
if (!declRef)
return nullptr;
declRef->setImplicit(apply->isImplicit());
apply->setFn(declRef);
// Tail-recur to actually call the constructor.
return finishApply(apply, openedType, locator);
}
// Handle @dynamicCallable applications.
// At this point, all other ApplyExpr cases have been handled.
return finishApplyDynamicCallable(cs, solution, apply, locator);
}
// 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(
TypeChecker &TC, DeclContext *DC, Expr *expr,
PrecedenceGroupDecl *followingPG) {
if (expr->isInfixOperator()) {
auto exprPG = TC.lookupPrecedenceGroupForInfixOperator(DC, expr);
if (!exprPG) return true;
return TC.Context.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(
TypeChecker &TC, 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 = TC.lookupPrecedenceGroupForInfixOperator(DC, parent);
if (!parentPG) return true;
// If the index is 0, this is on the LHS of the parent.
if (index == 0) {
return TC.Context.associateInfixOperators(followingPG, parentPG)
!= Associativity::Left;
} else {
return TC.Context.associateInfixOperators(parentPG, followingPG)
!= Associativity::Right;
}
}
return true;
}
bool swift::exprNeedsParensBeforeAddingNilCoalescing(TypeChecker &TC,
DeclContext *DC,
Expr *expr) {
auto asPG =
TC.lookupPrecedenceGroup(DC, DC->getASTContext().Id_NilCoalescingPrecedence,
SourceLoc());
if (!asPG) return true;
return exprNeedsParensInsideFollowingOperator(TC, DC, expr, asPG);
}
bool swift::exprNeedsParensAfterAddingNilCoalescing(TypeChecker &TC,
DeclContext *DC,
Expr *expr,
Expr *rootExpr) {
auto asPG =
TC.lookupPrecedenceGroup(DC, DC->getASTContext().Id_NilCoalescingPrecedence,
SourceLoc());
if (!asPG) return true;
return exprNeedsParensOutsideFollowingOperator(TC, DC, expr, rootExpr, asPG);
}
namespace {
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)) {
Rewriter.simplifyExprType(expr);
auto &cs = Rewriter.getConstraintSystem();
auto &tc = cs.getTypeChecker();
// Coerce the pattern, in case we resolved something.
auto fnType = cs.getType(closure)->castTo<FunctionType>();
auto *params = closure->getParameters();
tc.coerceParameterListToType(params, closure, fnType);
// Require layout of dependent types that could be used to materialize
// metadata types/conformances during IRGen.
tc.requestRequiredNominalTypeLayoutForParameters(params);
// If this is a single-expression closure, convert the expression
// in the body to the result type of the closure.
if (closure->hasSingleExpressionBody()) {
// Enter the context of the closure when type-checking the body.
llvm::SaveAndRestore<DeclContext *> savedDC(Rewriter.dc, closure);
Expr *body = closure->getSingleExpressionBody()->walk(*this);
if (!body)
return { false, nullptr };
if (body != closure->getSingleExpressionBody())
closure->setSingleExpressionBody(body);
if (body) {
// A single-expression closure with a non-Void expression type
// coerces to a Void-returning function type.
if (fnType->getResult()->isVoid() && !cs.getType(body)->isVoid()) {
closure = Rewriter.coerceClosureExprToVoid(closure);
// A single-expression closure with a Never expression type
// coerces to any other function type.
} else if (cs.getType(body)->isUninhabited()) {
closure = Rewriter.coerceClosureExprFromNever(closure);
} else {
body = Rewriter.coerceToType(body,
fnType->getResult(),
cs.getConstraintLocator(
closure,
ConstraintLocator::ClosureResult));
if (!body)
return { false, nullptr };
closure->setSingleExpressionBody(body);
}
}
} else {
// For other closures, type-check the body once we've finished with
// the expression.
cs.setExprTypes(closure);
ClosuresToTypeCheck.push_back(closure);
}
tc.ClosuresWithUncomputedCaptures.push_back(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));
}
Rewriter.walkToExprPre(expr);
return { true, expr };
}
Expr *walkToExprPost(Expr *expr) override {
Expr *result = Rewriter.walkToExprPost(expr);
auto &cs = Rewriter.getConstraintSystem();
if (result && cs.hasType(result))
Rewriter.checkForImportedUsedConformances(cs.getType(result));
return result;
}
/// Ignore statements.
std::pair<bool, Stmt *> walkToStmtPre(Stmt *stmt) override {
return { false, stmt };
}
/// Ignore declarations.
bool walkToDeclPre(Decl *decl) override { return false; }
};
} // end anonymous namespace
Expr *ConstraintSystem::coerceToRValue(Expr *expr) {
auto &tc = getTypeChecker();
return tc.coerceToRValue(expr,
[&](Expr *expr) {
return getType(expr);
},
[&](Expr *expr, Type type) {
setType(expr, type);
});
}
/// 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(Expr *E, const Solution &solution) {
llvm::SmallDenseMap<Expr *, SmallVector<const ConstraintFix *, 4>>
fixesPerExpr;
applySolution(solution);
for (auto *fix : solution.Fixes)
fixesPerExpr[fix->getAnchor()].push_back(fix);
auto diagnoseExprFailures = [&](Expr *expr) -> bool {
auto fixes = fixesPerExpr.find(expr);
if (fixes == fixesPerExpr.end())
return false;
bool diagnosedError = false;
for (const auto *fix : fixes->second) {
auto diagnosed = fix->diagnose(E);
if (fix->isWarning()) {
assert(diagnosed && "warnings should always be diagnosed");
(void)diagnosed;
} else {
diagnosedError |= diagnosed;
}
}
return diagnosedError;
};
bool diagnosedError = false;
E->forEachChildExpr([&](Expr *subExpr) -> Expr * {
// Diagnose root expression at the end to
// preserve ordering.
if (subExpr != E)
diagnosedError |= diagnoseExprFailures(subExpr);
return subExpr;
});
diagnosedError |= diagnoseExprFailures(E);
return diagnosedError;
}
/// Apply a given solution to the expression, producing a fully
/// type-checked expression.
Expr *ConstraintSystem::applySolution(Solution &solution, Expr *expr,
Type convertType,
bool discardedExpr,
bool skipClosures) {
// If any fixes needed to be applied to arrive at this solution, resolve
// them to specific expressions.
if (!solution.Fixes.empty()) {
if (shouldSuppressDiagnostics())
return nullptr;
bool diagnosedErrorsViaFixes = applySolutionFixes(expr, 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 nullptr;
// If we didn't manage to diagnose anything well, so fall back to
// diagnosing mining the system to construct a reasonable error message.
diagnoseFailureForExpr(expr);
return nullptr;
}
}
// Mark any normal conformances used in this solution as "used".
for (auto &e : solution.Conformances)
TC.markConformanceUsed(e.second, DC);
ExprRewriter rewriter(*this, solution, shouldSuppressDiagnostics());
ExprWalker walker(rewriter);
// Apply the solution to the expression.
auto result = expr->walk(walker);
if (!result)
return nullptr;
// If we're re-typechecking an expression for diagnostics, don't
// visit closures that have non-single expression bodies.
if (!skipClosures) {
auto &tc = getTypeChecker();
bool hadError = false;
for (auto *closure : walker.getClosuresToTypeCheck())
hadError |= tc.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 |= tc.typeCheckTapBody(tap, tapDC);
}
// If any of them failed to type check, bail.
if (hadError)
return nullptr;
}
// If we're supposed to convert the expression to some particular type,
// do so now.
if (convertType) {
result = rewriter.coerceToType(result, convertType,
getConstraintLocator(expr));
if (!result)
return nullptr;
} else if (getType(result)->hasLValueType() && !discardedExpr) {
// We referenced an lvalue. Load it.
result = rewriter.coerceToType(result, getType(result)->getRValueType(),
getConstraintLocator(expr));
}
if (result)
rewriter.finalize(result);
return result;
}
Expr *Solution::coerceToType(Expr *expr, Type toType,
ConstraintLocator *locator,
bool ignoreTopLevelInjection,
Optional<Pattern*> typeFromPattern) const {
auto &cs = getConstraintSystem();
ExprRewriter rewriter(cs, *this, /*suppressDiagnostics=*/false);
Expr *result = rewriter.coerceToType(expr, toType, locator, typeFromPattern);
if (!result)
return nullptr;
// If we were asked to ignore top-level optional injections, mark
// the top-level injection (if any) as "diagnosed".
if (ignoreTopLevelInjection) {
if (auto injection = dyn_cast<InjectIntoOptionalExpr>(
result->getSemanticsProvidingExpr())) {
rewriter.DiagnosedOptionalInjections.insert(injection);
}
}
rewriter.finalize(result);
return result;
}
// Determine whether this is a variadic witness.
static bool isVariadicWitness(AbstractFunctionDecl *afd) {
for (auto param : *afd->getParameters())
if (param->isVariadic())
return true;
return false;
}
static bool argumentNamesMatch(Type argTy, ArrayRef<Identifier> names) {
auto tupleType = argTy->getAs<TupleType>();
if (!tupleType)
return names.size() == 1 && names[0].empty();
if (tupleType->getNumElements() != names.size())
return false;
for (unsigned i = 0, n = tupleType->getNumElements(); i != n; ++i) {
if (tupleType->getElement(i).getName() != names[i])
return false;
}
return true;
}
Expr *TypeChecker::callWitness(Expr *base, DeclContext *dc,
ProtocolDecl *protocol,
ProtocolConformanceRef conformance,
DeclName name,
ArrayRef<Expr *> arguments,
Diag<> brokenProtocolDiag) {
// Construct an empty constraint system and solution.
ConstraintSystem cs(*this, dc, ConstraintSystemOptions());
for (auto *arg : arguments)
cs.cacheType(arg);
// Find the witness we need to use.
auto type = base->getType();
assert(!type->hasTypeVariable() &&
"Building call to witness with unresolved base type!");
if (auto metaType = type->getAs<AnyMetatypeType>())
type = metaType->getInstanceType();
auto witness = findNamedWitnessImpl(
*this, dc, type->getRValueType(), protocol,
name, brokenProtocolDiag);
if (!witness || !isa<AbstractFunctionDecl>(witness.getDecl()))
return nullptr;
auto *witnessFn = cast<AbstractFunctionDecl>(witness.getDecl());
// Form a syntactic expression that describes the reference to the
// witness.
// FIXME: Egregious hack.
auto unresolvedDot = new (Context) UnresolvedDotExpr(
base, SourceLoc(),
witness.getDecl()->getFullName(),
DeclNameLoc(base->getEndLoc()),
/*Implicit=*/true);
unresolvedDot->setFunctionRefKind(FunctionRefKind::SingleApply);
auto dotLocator = cs.getConstraintLocator(unresolvedDot);
// Form a reference to the witness itself.
Type openedFullType, openedType;
std::tie(openedFullType, openedType)
= cs.getTypeOfMemberReference(base->getType(), witness.getDecl(), dc,
/*isDynamicResult=*/false,
FunctionRefKind::DoubleApply,
dotLocator);
auto getType = [&](const Expr *E) -> Type {
return cs.getType(E);
};
// Form the call argument.
// FIXME: Standardize all callers to always provide all argument names,
// rather than hack around this.
CallExpr *call;
auto argLabels = witness.getDecl()->getFullName().getArgumentNames();
if (arguments.size() == 1 &&
(isVariadicWitness(witnessFn) ||
argumentNamesMatch(cs.getType(arguments[0]), argLabels))) {
call = CallExpr::create(Context, unresolvedDot, arguments[0], {}, {},
/*hasTrailingClosure=*/false,
/*implicit=*/true, Type(), getType);
} else {
// The tuple should have the source range enclosing its arguments unless
// they are invalid or there are no arguments.
SourceLoc TupleStartLoc = base->getStartLoc();
SourceLoc TupleEndLoc = base->getEndLoc();
if (!arguments.empty()) {
SourceLoc AltStartLoc = arguments.front()->getStartLoc();
SourceLoc AltEndLoc = arguments.back()->getEndLoc();
if (AltStartLoc.isValid() && AltEndLoc.isValid()) {
TupleStartLoc = AltStartLoc;
TupleEndLoc = AltEndLoc;
}
}
call = CallExpr::create(Context, unresolvedDot, TupleStartLoc, arguments,
argLabels, {}, TupleEndLoc,
/*trailingClosure=*/nullptr,
/*implicit=*/true, getType);
}
cs.cacheSubExprTypes(call);
// Extract the arguments.
SmallVector<AnyFunctionType::Param, 8> args;
AnyFunctionType::decomposeInput(cs.getType(call->getArg()), args);
// Add the conversion from the argument to the function parameter type.
auto openedFuncType = openedType->castTo<FunctionType>();
::matchCallArguments(
cs, args, openedFuncType->getParams(),
cs.getConstraintLocator(call, ConstraintLocator::ApplyArgument));
// Solve the system.
SmallVector<Solution, 1> solutions;
cs.cacheExprTypes(call);
// If the system failed to produce a solution, post any available diagnostics.
if (cs.solve(call, solutions) || solutions.size() != 1) {
cs.salvage(solutions, base);
return nullptr;
}
Solution &solution = solutions.front();
ExprRewriter rewriter(cs, solution,
/*suppressDiagnostics=*/false);
auto choice =
OverloadChoice(openedFullType, witnessFn, FunctionRefKind::SingleApply);
auto memberRef = rewriter.buildMemberRef(
base, openedFullType, base->getStartLoc(), choice,
DeclNameLoc(base->getEndLoc()), openedType, dotLocator, dotLocator,
/*Implicit=*/true, FunctionRefKind::SingleApply,
AccessSemantics::Ordinary,
/*isDynamic=*/false);
call->setFn(memberRef);
// Call the witness.
Expr *result = rewriter.finishApply(call, openedType,
cs.getConstraintLocator(call));
if (!result)
return nullptr;
rewriter.finalize(result);
return result;
}
Expr *Solution::convertOptionalToBool(Expr *expr,
ConstraintLocator *locator) const {
auto &cs = getConstraintSystem();
auto &tc = cs.getTypeChecker();
tc.requireOptionalIntrinsics(expr->getLoc());
// Match the optional value against its `Some` case.
auto &ctx = tc.Context;
auto isSomeExpr = new (ctx) EnumIsCaseExpr(expr, ctx.getOptionalSomeDecl());
auto boolDecl = ctx.getBoolDecl();
if (!boolDecl) {
tc.diagnose(SourceLoc(), diag::broken_bool);
}
cs.setType(isSomeExpr, boolDecl ? boolDecl->getDeclaredType() : Type());
return isSomeExpr;
}
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