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swift-mirror/lib/Sema/CSApply.cpp
Doug Gregor 85ba4fe40f [AST] Narrow TypeSubstitutionMap to SubstitutableType keys. 
Type substitution works on a fairly narrow set of types: generic type
parameters (to, e.g., use a generic) and archetypes (to map out of a
generic context). Historically, it was also used with
DependentMemberTypes, but recent refactoring to eliminate witness
markers eliminate that code path.

Therefore, narrow TypeSubstitutionMap's keys to SubstitutableType,
which covers archetypes and generic type parameters. NFC
2016-11-15 11:34:09 -08:00

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//===--- CSApply.cpp - Constraint Application -----------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://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 "swift/AST/ArchetypeBuilder.h"
#include "swift/AST/ASTVisitor.h"
#include "swift/AST/ASTWalker.h"
#include "swift/Basic/StringExtras.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/SaveAndRestore.h"
using namespace swift;
using namespace constraints;
/// \brief Get a substitution corresponding to the type witness.
/// Inspired by ProtocolConformance::getTypeWitnessByName.
const Substitution *
getTypeWitnessByName(ProtocolConformance *conformance,
Identifier name,
LazyResolver *resolver) {
// Find the named requirement.
AssociatedTypeDecl *assocType = nullptr;
auto members = conformance->getProtocol()->lookupDirect(name);
for (auto member : members) {
assocType = dyn_cast<AssociatedTypeDecl>(member);
if (assocType)
break;
}
if (!assocType)
return nullptr;
assert(conformance && "Missing conformance information");
return &conformance->getTypeWitness(assocType, resolver);
}
/// \brief 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<ArchetypeType>();
if (!archetype)
return false;
auto existential = archetype->getOpenedExistentialType();
if (!existential)
return false;
SmallVector<ProtocolDecl *, 2> protocols;
existential->isExistentialType(protocols);
return protocols.size() == 1 &&
protocols[0]->isSpecificProtocol(KnownProtocolKind::AnyObject);
}
Type Solution::computeSubstitutions(
Type origType, DeclContext *dc,
Type openedType,
ConstraintLocator *locator,
SmallVectorImpl<Substitution> &result) const {
auto &tc = getConstraintSystem().getTypeChecker();
// Gather the substitutions from dependent types to concrete types.
auto openedTypes = OpenedTypes.find(locator);
assert(openedTypes != OpenedTypes.end() && "Missing opened type information");
TypeSubstitutionMap subs;
for (const auto &opened : openedTypes->second) {
subs[opened.first->castTo<GenericTypeParamType>()] =
getFixedType(opened.second);
}
// Produce the concrete form of the opened type.
Type type = simplifyType(tc, openedType);
auto mod = getConstraintSystem().DC->getParentModule();
GenericSignature *sig;
if (auto genericFn = origType->getAs<GenericFunctionType>()) {
sig = genericFn->getGenericSignature();
} else {
sig = dc->getGenericSignatureOfContext();
}
auto lookupConformanceFn =
[&](CanType original, Type replacement, ProtocolType *protoType)
-> ProtocolConformanceRef {
auto conformance = tc.conformsToProtocol(
replacement,
protoType->getDecl(),
getConstraintSystem().DC,
(ConformanceCheckFlags::InExpression|
ConformanceCheckFlags::Used));
(void)isOpenedAnyObject;
assert((conformance ||
replacement->hasError() ||
isOpenedAnyObject(replacement) ||
replacement->is<GenericTypeParamType>()) &&
"Constraint system missed a conformance?");
// Put an abstract conformance in place if we don't already have one.
// FIXME: Feels like a hack
if (!conformance &&
(replacement->hasDependentProtocolConformances() ||
replacement->hasError()))
conformance = ProtocolConformanceRef(protoType->getDecl());
assert(conformance->isConcrete() ||
replacement->hasError() ||
replacement->hasDependentProtocolConformances());
return *conformance;
};
sig->getSubstitutions(*mod, subs, lookupConformanceFn, result);
return type;
}
/// \brief 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 nullptr if no witness could be found.
template <typename DeclTy>
static DeclTy *findNamedWitnessImpl(
TypeChecker &tc, DeclContext *dc, Type type,
ProtocolDecl *proto, DeclName name,
Diag<> diag,
Optional<ProtocolConformanceRef> conformance = None) {
// Find the named requirement.
DeclTy *requirement = nullptr;
for (auto member : proto->getMembers()) {
auto d = dyn_cast<DeclTy>(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 (type->hasDependentProtocolConformances()) {
return requirement;
}
if (!conformance->isConcrete()) return nullptr;
auto concrete = conformance->getConcrete();
// FIXME: Dropping substitutions here.
return cast_or_null<DeclTy>(concrete->getWitness(requirement, &tc).getDecl());
}
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()->getDeclaredTypeOfContext()->getCanonicalType() !=
member->getDeclContext()->getDeclaredTypeOfContext()->getCanonicalType())
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)) {
// The storage better not be resilient.
assert(member->hasFixedLayout(DC->getParentModule(),
DC->getResilienceExpansion()) &&
"Designated initializers and destructors of resilient types "
"cannot be @_transparent or defined in extensions");
// Access this directly instead of going through (e.g.) observing or
// trivial accessors.
return AccessSemantics::DirectToStorage;
}
// Check for property behavior initializations.
if (auto *AFD_DC = dyn_cast<AbstractFunctionDecl>(DC)) {
if (member->hasBehaviorNeedingInitialization() &&
// In a ctor.
isa<ConstructorDecl>(AFD_DC) &&
// Ctor is for immediate class, not a derived class.
AFD_DC->getParent()->getDeclaredTypeOfContext()->getCanonicalType() ==
member->getDeclContext()->getDeclaredTypeOfContext()->getCanonicalType() &&
// Is a "self.property" reference.
isa<DeclRefExpr>(base) &&
AFD_DC->getImplicitSelfDecl() == cast<DeclRefExpr>(base)->getDecl()) {
// Do definite initialization analysis to handle this property.
return AccessSemantics::BehaviorInitialization;
}
}
// If the value is always directly accessed from this context, do it.
return member->getAccessSemanticsFromContext(DC);
}
namespace {
/// \brief 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;
bool SkipClosures;
/// 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);
}
/// \brief 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.
///
/// \param variadicArgs The source indices that are mapped to the variadic
/// parameter of the resulting tuple, as provided by \c computeTupleShuffle.
///
/// \param typeFromPattern Optionally, the caller can specify the pattern
/// from where the toType is derived, so that we can deliver better fixit.
Expr *coerceTupleToTuple(Expr *expr, TupleType *fromTuple,
TupleType *toTuple,
ConstraintLocatorBuilder locator,
SmallVectorImpl<int> &sources,
SmallVectorImpl<unsigned> &variadicArgs,
Optional<Pattern*> typeFromPattern = None);
/// \brief Coerce the given scalar value to the given tuple type.
///
/// \param expr The expression to be coerced.
/// \param toTuple The tuple type to which the expression will be coerced.
/// \param toScalarIdx The index of the scalar field within the tuple type
/// \c toType.
/// \param locator Locator describing where this conversion occurs.
///
/// \returns The coerced expression, whose type will be equivalent to
/// \c toTuple.
Expr *coerceScalarToTuple(Expr *expr, TupleType *toTuple,
int toScalarIdx,
ConstraintLocatorBuilder locator);
/// \brief 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);
/// \brief 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);
/// \brief 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,
ConstraintLocatorBuilder locator);
public:
/// \brief Build a reference to the given declaration.
Expr *buildDeclRef(ValueDecl *decl, DeclNameLoc loc, Type openedType,
ConstraintLocatorBuilder locator,
bool specialized, bool implicit,
FunctionRefKind functionRefKind,
AccessSemantics semantics) {
// 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 = simplifiedFnType->getInput()->getRValueInstanceType();
// 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 witnessRef =
conformance->getConcrete()->getWitness(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;
ValueDecl *witness = witnessRef.getDecl();
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;
}
if (tc.typeCheckExpression(refExpr, cs.DC,
TypeLoc::withoutLoc(expectedFnType),
CTP_CannotFail))
return nullptr;
// 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 refExpr;
}
}
}
}
// Build a reference to the protocol requirement.
Expr *base = TypeExpr::createImplicitHack(loc.getBaseNameLoc(), baseTy,
ctx);
return buildMemberRef(base, openedType, SourceLoc(), decl,
loc, openedFnType->getResult(),
locator, locator, implicit, functionRefKind,
semantics, /*isDynamic=*/false);
}
// If this is a declaration with generic function type, build a
// specialized reference to it.
if (auto genericFn
= decl->getInterfaceType()->getAs<GenericFunctionType>()) {
auto dc = decl->getInnermostDeclContext();
SmallVector<Substitution, 4> substitutions;
auto type = solution.computeSubstitutions(
genericFn, dc, openedType,
getConstraintSystem().getConstraintLocator(locator),
substitutions);
auto declRefExpr =
new (ctx) DeclRefExpr(ConcreteDeclRef(ctx, decl, substitutions),
loc, implicit, semantics, type);
declRefExpr->setFunctionRefKind(functionRefKind);
return declRefExpr;
}
auto type = simplifyType(openedType);
// If we've ended up trying to assign an inout type here, it means we're
// missing an ampersand in front of the ref.
if (auto inoutType = type->getAs<InOutType>()) {
auto &tc = cs.getTypeChecker();
tc.diagnose(loc.getBaseNameLoc(), diag::missing_address_of,
inoutType->getInOutObjectType())
.fixItInsert(loc.getBaseNameLoc(), "&");
return nullptr;
}
auto declRefExpr = new (ctx) DeclRefExpr(decl, loc, implicit, semantics,
type);
declRefExpr->setFunctionRefKind(functionRefKind);
return declRefExpr;
}
/// Describes an opened existential that has not yet been closed.
struct OpenedExistential {
/// The archetype describing this opened existential.
ArchetypeType *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 (auto func = dyn_cast<AbstractFunctionDecl>(member)) {
// For functions, close the existential once the function
// has been fully applied.
return func->getNumParameterLists();
} 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 memberRef = dyn_cast<MemberRefExpr>(expr)) {
return memberRef->getBase();
} else if (auto dynMemberRef = dyn_cast<DynamicMemberRefExpr>(expr)) {
return dynMemberRef->getBase();
} else if (auto subscriptRef = dyn_cast<SubscriptExpr>(expr)) {
return subscriptRef->getBase();
} else if (auto dynSubscriptRef = dyn_cast<DynamicSubscriptExpr>(expr)) {
return dynSubscriptRef->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;
}
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, ArchetypeType *archetype,
ValueDecl *member) {
assert(archetype && "archetype not already opened?");
auto &tc = cs.getTypeChecker();
// Dig out the base type.
auto baseTy = base->getType();
// 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) ||
isMetatype || baseTy->isClassExistentialType())) {
base = tc.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);
// 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, bool force=false) {
if (OpenedExistentials.empty())
return false;
auto &record = OpenedExistentials.back();
assert(record.Depth <= ExprStack.size() - 1);
if (!force && record.Depth < ExprStack.size() - 1)
return false;
// If we had a return type of 'Self', erase it.
ConstraintSystem &cs = solution.getConstraintSystem();
auto &tc = cs.getTypeChecker();
auto resultTy = result->getType();
if (resultTy->hasOpenedExistential(record.Archetype)) {
Type erasedTy = resultTy->eraseOpenedExistential(
cs.DC->getParentModule(),
record.Archetype);
result = coerceToType(result, erasedTy, nullptr);
}
// If the opaque value has an l-value access kind, then
// the OpenExistentialExpr isn't making a derived l-value, which
// means this is our only chance to propagate the l-value access kind
// down to the original existential value. Otherwise, propagateLVAK
// will handle this.
if (record.OpaqueValue->hasLValueAccessKind())
record.ExistentialValue->propagateLValueAccessKind(
record.OpaqueValue->getLValueAccessKind());
// Form the open-existential expression.
result = new (tc.Context) OpenExistentialExpr(
record.ExistentialValue,
record.OpaqueValue,
result);
OpenedExistentials.pop_back();
return true;
}
/// Is the given function a constructor of a class or protocol?
/// Such functions are subject to DynamicSelf manipulations.
///
/// We want to avoid taking the DynamicSelf paths for other
/// constructors for two reasons:
/// - it's an unnecessary cost
/// - optionality preservation has a problem with constructors on
/// optional types
static bool isPolymorphicConstructor(AbstractFunctionDecl *fn) {
if (!isa<ConstructorDecl>(fn))
return false;
auto *parent =
fn->getParent()->getAsGenericTypeOrGenericTypeExtensionContext();
return parent && (isa<ClassDecl>(parent) || isa<ProtocolDecl>(parent));
}
/// \brief Build a new member reference with the given base and member.
Expr *buildMemberRef(Expr *base, Type openedFullType, SourceLoc dotLoc,
ValueDecl *member, DeclNameLoc memberLoc,
Type openedType, ConstraintLocatorBuilder locator,
ConstraintLocatorBuilder memberLocator,
bool Implicit, FunctionRefKind functionRefKind,
AccessSemantics semantics, bool isDynamic) {
auto &tc = cs.getTypeChecker();
auto &context = tc.Context;
bool isSuper = base->isSuperExpr();
Type baseTy = base->getType()->getRValueType();
// Explicit member accesses are permitted to implicitly look
// through ImplicitlyUnwrappedOptional<T>.
if (!Implicit) {
if (auto objTy = cs.lookThroughImplicitlyUnwrappedOptionalType(baseTy)) {
base = coerceImplicitlyUnwrappedOptionalToValue(base, objTy, locator);
baseTy = objTy;
}
}
// Figure out the actual base type, and whether we have an instance of
// that type or its metatype.
bool baseIsInstance = true;
if (auto baseMeta = baseTy->getAs<AnyMetatypeType>()) {
baseIsInstance = false;
baseTy = baseMeta->getInstanceType();
// If the member is a constructor, verify that it can be legally
// referenced from this base.
if (auto ctor = dyn_cast<ConstructorDecl>(member)) {
if (!tc.diagnoseInvalidDynamicConstructorReferences(base, memberLoc,
baseMeta, ctor, SuppressDiagnostics))
return nullptr;
}
}
// Produce a reference to the member, the type of the container it
// resides in, and the type produced by the reference itself.
Type containerTy;
ConcreteDeclRef memberRef;
Type refTy;
Type dynamicSelfFnType;
if (member->getInterfaceType()->is<GenericFunctionType>() ||
openedFullType->hasTypeVariable()) {
// We require substitutions. Figure out what they are.
// Figure out the declaration context where we'll get the generic
// parameters.
auto dc = member->getInnermostDeclContext();
// Build a reference to the generic member.
SmallVector<Substitution, 4> substitutions;
refTy = solution.computeSubstitutions(
member->getInterfaceType(),
dc,
openedFullType,
getConstraintSystem().getConstraintLocator(memberLocator),
substitutions);
memberRef = ConcreteDeclRef(context, member, substitutions);
if (auto openedFullFnType = openedFullType->getAs<FunctionType>()) {
auto openedBaseType = openedFullFnType->getInput()
->getRValueInstanceType();
containerTy = solution.simplifyType(tc, openedBaseType);
}
} else {
// No substitutions required; the declaration reference is simple.
containerTy = member->getDeclContext()->getDeclaredTypeOfContext();
memberRef = member;
refTy = openedFullType;
}
// 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;
containerTy = 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.
if (auto func = dyn_cast<AbstractFunctionDecl>(member)) {
if ((isa<FuncDecl>(func) &&
(cast<FuncDecl>(func)->hasDynamicSelf() ||
(openedExistential &&
cast<FuncDecl>(func)->hasArchetypeSelf()))) ||
isPolymorphicConstructor(func)) {
refTy = refTy->replaceCovariantResultType(containerTy,
func->getNumParameterLists());
dynamicSelfFnType = refTy->replaceCovariantResultType(
baseTy,
func->getNumParameterLists());
if (openedExistential) {
// Replace the covariant result type in the opened type. We need to
// handle dynamic member references, which wrap the function type
// in an optional.
OptionalTypeKind optKind;
if (auto optObject = openedType->getAnyOptionalObjectType(optKind))
openedType = optObject;
openedType = openedType->replaceCovariantResultType(
baseTy,
func->getNumParameterLists()-1);
if (optKind != OptionalTypeKind::OTK_None)
openedType = OptionalType::get(optKind, openedType);
}
// If the type after replacing DynamicSelf with the provided base
// type is no different, we don't need to perform a conversion here.
if (refTy->isEqual(dynamicSelfFnType))
dynamicSelfFnType = nullptr;
}
}
// 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");
assert(!dynamicSelfFnType && "No reference type to convert to");
auto ref = new (context) DeclRefExpr(memberRef, memberLoc, Implicit);
ref->setType(refTy);
ref->setFunctionRefKind(functionRefKind);
return new (context) DotSyntaxBaseIgnoredExpr(base, dotLoc, ref);
}
// Otherwise, we're referring to a member of a type.
// Is it an archetype member?
bool isDependentConformingRef
= isa<ProtocolDecl>(member->getDeclContext()) &&
baseTy->hasDependentProtocolConformances();
// 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.
Type selfTy;
if (isDependentConformingRef)
selfTy = baseTy;
else
selfTy = containerTy;
// If the base is already an lvalue with the right base type, we can
// pass it as an inout qualified type.
if (selfTy->isEqual(baseTy))
if (base->getType()->is<LValueType>())
selfTy = InOutType::get(selfTy);
base = coerceObjectArgumentToType(
base, selfTy, member, semantics,
locator.withPathElement(ConstraintLocator::MemberRefBase));
} else {
// Convert the base to an rvalue of the appropriate metatype.
base = coerceToType(base,
MetatypeType::get(isDependentConformingRef
? baseTy
: containerTy),
locator.withPathElement(
ConstraintLocator::MemberRefBase));
if (!base)
return nullptr;
base = tc.coerceToRValue(base);
}
assert(base && "Unable to convert base?");
// Handle dynamic references.
if (isDynamic || member->getAttrs().hasAttribute<OptionalAttr>()) {
base = tc.coerceToRValue(base);
if (!base) return nullptr;
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(
cs.DC->getParentModule(),
knownOpened->second);
}
ref->setType(refType);
closeExistential(ref, /*force=*/openedExistential);
return ref;
}
// 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 = base->getType()->getRValueInstanceType();
base = new (context) UnevaluatedInstanceExpr(base, baseInstanceTy);
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.
memberRefExpr->setType(simplifyType(openedType));
Expr *result = memberRefExpr;
closeExistential(result);
return result;
}
// Handle all other references.
auto declRefExpr = new (context) DeclRefExpr(memberRef, memberLoc,
Implicit, semantics);
declRefExpr->setFunctionRefKind(functionRefKind);
declRefExpr->setType(refTy);
Expr *ref = declRefExpr;
// If the reference needs to be converted, do so now.
if (dynamicSelfFnType) {
ref = new (context) CovariantFunctionConversionExpr(ref,
dynamicSelfFnType);
}
ApplyExpr *apply;
if (isa<ConstructorDecl>(member)) {
// FIXME: Provide type annotation.
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);
closeExistential(result, /*force=*/openedExistential);
return result;
} else {
assert((!baseIsInstance || member->isInstanceMember()) &&
"can't call a static method on an instance");
apply = new (context) DotSyntaxCallExpr(ref, dotLoc, base);
if (Implicit) {
apply->setImplicit();
}
}
return finishApply(apply, openedType, locator);
}
/// \brief Describes either a type or the name of a type to be resolved.
typedef llvm::PointerUnion<Identifier, Type> TypeOrName;
/// \brief 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 openedType The literal type as it was opened in the type system.
///
/// \param protocol The protocol that describes the literal requirement.
///
/// \param literalType Either the name of the associated type in
/// \c protocol that describes the argument type of the conversion function
/// (\c literalFuncName) or the argument type itself.
///
/// \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 builtinLiteralType Either the name of the associated type in
/// \c builtinProtocol that describes the argument type of the builtin
/// conversion function (\c builtinLiteralFuncName) or the argument type
/// itself.
///
/// \param builtinLiteralFuncName The name of the conversion function
/// requirement in \c builtinProtocol.
///
/// \param isBuiltinArgType Function that determines whether the given
/// type is acceptable as the argument type for the builtin conversion.
///
/// \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 *convertLiteral(Expr *literal,
Type type,
Type openedType,
ProtocolDecl *protocol,
TypeOrName literalType,
DeclName literalFuncName,
ProtocolDecl *builtinProtocol,
TypeOrName builtinLiteralType,
DeclName builtinLiteralFuncName,
bool (*isBuiltinArgType)(Type),
Diag<> brokenProtocolDiag,
Diag<> brokenBuiltinProtocolDiag);
/// \brief 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);
/// \brief 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:
/// \brief Retrieve the overload choice associated with the given
/// locator.
SelectedOverload getOverloadChoice(ConstraintLocator *locator) {
return *getOverloadChoiceIfAvailable(locator);
}
/// \brief Retrieve the overload choice associated with the given
/// locator.
Optional<SelectedOverload>
getOverloadChoiceIfAvailable(ConstraintLocator *locator) {
auto known = solution.overloadChoices.find(locator);
if (known != solution.overloadChoices.end())
return known->second;
return None;
}
/// \brief Simplify the given type by substituting all occurrences of
/// type variables for their fixed types.
Type simplifyType(Type type) {
return solution.simplifyType(cs.getTypeChecker(), type);
}
public:
/// \brief 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);
/// \brief 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);
/// \brief 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);
using LevelTy = llvm::PointerEmbeddedInt<unsigned, 2>;
/// \brief 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 paramType The parameter type.
/// \param applyOrLevel For function applications, the ApplyExpr that forms
/// the call. Otherwise, a specific level describing which parameter level
/// we're applying.
/// \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, Type paramType,
llvm::PointerUnion<ApplyExpr *, LevelTy> applyOrLevel,
ArrayRef<Identifier> argLabels,
bool hasTrailingClosure,
ConstraintLocatorBuilder locator);
/// \brief 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:
/// \brief 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) {
// Determine the declaration selected for this subscript operation.
auto selected = getOverloadChoice(
cs.getConstraintLocator(
locator.withPathElement(
ConstraintLocator::SubscriptMember)));
auto choice = selected.choice;
auto subscript = cast<SubscriptDecl>(choice.getDecl());
auto &tc = cs.getTypeChecker();
auto baseTy = base->getType()->getRValueType();
// Check whether the base is 'super'.
bool isSuper = base->isSuperExpr();
// Handle accesses that implicitly look through ImplicitlyUnwrappedOptional<T>.
if (auto objTy = cs.lookThroughImplicitlyUnwrappedOptionalType(baseTy)) {
base = coerceImplicitlyUnwrappedOptionalToValue(base, objTy, locator);
baseTy = base->getType();
}
// Figure out the index and result types.
auto containerTy
= subscript->getDeclContext()->getDeclaredTypeOfContext();
auto subscriptTy = simplifyType(selected.openedType);
auto indexTy = subscriptTy->castTo<AnyFunctionType>()->getInput();
auto resultTy = subscriptTy->castTo<AnyFunctionType>()->getResult();
// If we opened up an existential when performing the subscript, open
// the base accordingly.
auto knownOpened = solution.OpenedExistentialTypes.find(
getConstraintSystem().getConstraintLocator(
locator.withPathElement(
ConstraintLocator::SubscriptMember)));
if (knownOpened != solution.OpenedExistentialTypes.end()) {
base = openExistentialReference(base, knownOpened->second, subscript);
baseTy = knownOpened->second;
containerTy = baseTy;
}
// Coerce the index argument.
index = coerceCallArguments(
index, indexTy, LevelTy(1), argLabels,
hasTrailingClosure,
locator.withPathElement(ConstraintLocator::SubscriptIndex));
if (!index)
return nullptr;
// Form the subscript expression.
// Handle dynamic lookup.
if (selected.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, subscript,
isImplicit);
subscriptExpr->setType(resultTy);
Expr *result = subscriptExpr;
closeExistential(result);
return result;
}
// Handle subscripting of generics.
if (subscript->getDeclContext()->isGenericContext()) {
auto dc = subscript->getDeclContext();
// Compute the substitutions used to reference the subscript.
SmallVector<Substitution, 4> substitutions;
solution.computeSubstitutions(
subscript->getInterfaceType(),
dc,
selected.openedFullType,
getConstraintSystem().getConstraintLocator(
locator.withPathElement(ConstraintLocator::SubscriptMember)),
substitutions);
// Convert the base.
auto openedFullFnType = selected.openedFullType->castTo<FunctionType>();
auto openedBaseType = openedFullFnType->getInput();
containerTy = solution.simplifyType(tc, openedBaseType);
base = coerceObjectArgumentToType(
base, containerTy, subscript, AccessSemantics::Ordinary,
locator.withPathElement(ConstraintLocator::MemberRefBase));
if (!base)
return nullptr;
// Form the generic subscript expression.
auto subscriptExpr
= SubscriptExpr::create(tc.Context, base, index,
ConcreteDeclRef(tc.Context, subscript,
substitutions),
isImplicit,
semantics);
subscriptExpr->setType(resultTy);
subscriptExpr->setIsSuper(isSuper);
Expr *result = subscriptExpr;
closeExistential(result);
return result;
}
Type selfTy = containerTy;
if (selfTy->isEqual(baseTy) && !selfTy->hasReferenceSemantics())
if (base->getType()->is<LValueType>())
selfTy = InOutType::get(selfTy);
// Coerce the base to the container type.
base = coerceObjectArgumentToType(base, selfTy, subscript,
AccessSemantics::Ordinary, locator);
if (!base)
return nullptr;
// Form a normal subscript.
auto *subscriptExpr
= SubscriptExpr::create(tc.Context, base, index, subscript,
isImplicit, semantics);
subscriptExpr->setType(resultTy);
subscriptExpr->setIsSuper(isSuper);
Expr *result = subscriptExpr;
closeExistential(result);
return result;
}
/// \brief Build a new reference to another constructor.
Expr *buildOtherConstructorRef(Type openedFullType,
ConstructorDecl *ctor, DeclNameLoc loc,
ConstraintLocatorBuilder locator,
bool implicit) {
auto &tc = cs.getTypeChecker();
auto &ctx = tc.Context;
// Compute the concrete reference.
ConcreteDeclRef ref;
Type resultTy;
if (ctor->getInitializerInterfaceType()->is<GenericFunctionType>()) {
// Compute the reference to the generic constructor.
SmallVector<Substitution, 4> substitutions;
resultTy = solution.computeSubstitutions(
ctor->getInterfaceType(),
ctor,
openedFullType,
getConstraintSystem().getConstraintLocator(locator),
substitutions);
ref = ConcreteDeclRef(ctx, ctor, substitutions);
} else {
Type containerTy = ctor->getDeclContext()->getDeclaredTypeOfContext();
resultTy = openedFullType->replaceCovariantResultType(
containerTy, ctor->getNumParameterLists());
ref = ConcreteDeclRef(ctor);
}
// The constructor was opened with the allocating type, not the
// initializer type. Map the former into the latter.
auto resultFnTy = resultTy->castTo<FunctionType>();
auto selfTy = resultFnTy->getInput()->getRValueInstanceType();
if (!selfTy->hasReferenceSemantics())
selfTy = InOutType::get(selfTy);
resultTy = FunctionType::get(selfTy, resultFnTy->getResult(),
resultFnTy->getExtInfo());
// Build the constructor reference.
return new (ctx) OtherConstructorDeclRefExpr(ref, loc, implicit,
resultTy);
}
/// Bridge the given value (which is an error type) to NSError.
Expr *bridgeErrorToObjectiveC(Expr *value) {
auto &tc = cs.getTypeChecker();
// Use _bridgeErrorToNSError to convert to an NSError.
auto fn = tc.Context.getBridgeErrorToNSError(&tc);
SourceLoc loc = value->getLoc();
if (!fn) {
tc.diagnose(loc, diag::missing_nserror_bridging_function);
return nullptr;
}
tc.validateDecl(fn);
ConcreteDeclRef fnDeclRef(fn);
auto fnRef = new (tc.Context) DeclRefExpr(fnDeclRef, DeclNameLoc(loc),
/*Implicit=*/true);
fnRef->setType(fn->getInterfaceType());
fnRef->setFunctionRefKind(FunctionRefKind::SingleApply);
Expr *call = CallExpr::createImplicit(tc.Context, fnRef, { value }, { });
if (tc.typeCheckExpressionShallow(call, dc))
return nullptr;
// The return type of _bridgeErrorToNSError is formally
// 'AnyObject' to avoid stdlib-to-Foundation dependencies, but it's
// really NSError. Abuse CovariantReturnConversionExpr to fix this.
auto nsErrorDecl = tc.Context.getNSErrorDecl();
assert(nsErrorDecl && "Missing NSError?");
Type nsErrorType = nsErrorDecl->getDeclaredInterfaceType();
return new (tc.Context) CovariantReturnConversionExpr(call,
nsErrorType);
}
/// 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) {
// TODO: It would be nicer to represent this as a special AST node
// instead of inlining the bridging calls in the AST. Doing so would
// simplify the AST and make it easier for SILGen to peephole bridging
// conversions.
auto &tc = cs.getTypeChecker();
// Find the _ObjectiveCBridgeable protocol.
auto bridgedProto
= tc.Context.getProtocol(KnownProtocolKind::ObjectiveCBridgeable);
// Find the conformance of the value type to _ObjectiveCBridgeable.
Type valueType = value->getType()->getRValueType();
if (auto conformance =
tc.conformsToProtocol(valueType, bridgedProto, cs.DC,
(ConformanceCheckFlags::InExpression|
ConformanceCheckFlags::Used))) {
// Form the call.
return tc.callWitness(value, cs.DC, bridgedProto, *conformance,
tc.Context.Id_bridgeToObjectiveC,
{ }, diag::broken_bridged_to_objc_protocol);
}
// If there is an Error conformance, try bridging as an error.
if (tc.isConvertibleTo(valueType,
tc.Context.getProtocol(KnownProtocolKind::Error)
->getDeclaredType(),
cs.DC))
return bridgeErrorToObjectiveC(value);
// Fall back to universal bridging.
auto bridgeAnything = tc.Context.getBridgeAnythingToObjectiveC(&tc);
value = tc.coerceToRValue(value);
auto valueSub = Substitution(valueType, {});
auto bridgeAnythingRef = ConcreteDeclRef(tc.Context, bridgeAnything,
valueSub);
auto valueParenTy = ParenType::get(tc.Context, value->getType());
auto bridgeTy = tc.Context.getProtocol(KnownProtocolKind::AnyObject)
->getDeclaredType();
auto bridgeFnTy = FunctionType::get(valueParenTy, bridgeTy);
// FIXME: Wrap in ParenExpr to prevent bogus "tuple passed as argument"
// errors.
auto valueParen = new (tc.Context) ParenExpr(SourceLoc(),
value,
SourceLoc(),
/*trailing closure*/ false);
valueParen->setImplicit();
valueParen->setType(valueParenTy);
auto fnRef = new (tc.Context) DeclRefExpr(bridgeAnythingRef,
DeclNameLoc(),
/*implicit*/ true,
AccessSemantics::Ordinary,
bridgeFnTy);
fnRef->setFunctionRefKind(FunctionRefKind::SingleApply);
Expr *call = CallExpr::createImplicit(tc.Context, fnRef, valueParen,
{ Identifier() });
call->setType(bridgeTy);
return call;
}
/// 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();
// 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) {
// 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)
: tc.Context.getForceBridgeFromObjectiveCBridgeable(&tc);
} else {
// Retrieve the bridging operation to be used if a static conformance
// to _BridgedToObjectiveC cannot be proven.
fn = conditional ? tc.Context.getConditionallyBridgeFromObjectiveC(&tc)
: tc.Context.getForceBridgeFromObjectiveC(&tc);
}
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 Conformances =
tc.Context.AllocateUninitialized<ProtocolConformanceRef>(
bridgedToObjectiveCConformance ? 1 : 0);
if (bridgedToObjectiveCConformance) {
Conformances[0] = *bridgedToObjectiveCConformance;
}
auto fnGenericParams
= fn->getGenericSignatureOfContext()->getGenericParams();
Substitution Subs[1] = {
Substitution(valueType, Conformances)
};
ConcreteDeclRef fnSpecRef(tc.Context, fn, Subs);
auto fnRef = new (tc.Context) DeclRefExpr(fnSpecRef,
DeclNameLoc(
object->getStartLoc()),
/*Implicit=*/true);
fnRef->setFunctionRefKind(FunctionRefKind::SingleApply);
TypeSubstitutionMap subMap;
auto genericParam = fnGenericParams[0];
subMap[genericParam->getCanonicalType()->castTo<SubstitutableType>()]
= valueType;
fnRef->setType(fn->getInterfaceType().subst(dc->getParentModule(), subMap,
None));
// Form the arguments.
Expr *args[2] = {
object,
new (tc.Context) DotSelfExpr(
TypeExpr::createImplicitHack(object->getLoc(),
valueType,
tc.Context),
object->getLoc(), object->getLoc(),
MetatypeType::get(valueType))
};
args[1]->setImplicit();
// Form the call and type-check it.
Expr *call = CallExpr::createImplicit(tc.Context, fnRef, args,
{ Identifier(), Identifier() });
if (tc.typeCheckExpressionShallow(call, dc))
return nullptr;
return call;
}
/// 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 *MaxIntegerTypeDecl = nullptr;
TypeAliasDecl *MaxFloatTypeDecl = nullptr;
public:
ExprRewriter(ConstraintSystem &cs, const Solution &solution,
bool suppressDiagnostics, bool skipClosures)
: cs(cs), dc(cs.DC), solution(solution),
SuppressDiagnostics(suppressDiagnostics),
SkipClosures(skipClosures) { }
ConstraintSystem &getConstraintSystem() const { return cs; }
/// \brief 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(expr->getType());
expr->setType(toType);
return expr;
}
Expr *visitErrorExpr(ErrorExpr *expr) {
// Do nothing with error expressions.
return expr;
}
Expr *visitCodeCompletionExpr(CodeCompletionExpr *expr) {
// Do nothing with code completion expressions.
return expr;
}
Expr *handleIntegerLiteralExpr(LiteralExpr *expr) {
// If the literal has been assigned a builtin integer type,
// don't mess with it.
if (expr->getType()->is<BuiltinIntegerType>())
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(expr->getType());
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;
}
}
// Find the maximum-sized builtin integer type.
if (!MaxIntegerTypeDecl) {
SmallVector<ValueDecl *, 1> lookupResults;
tc.getStdlibModule(dc)->lookupValue(/*filter=*/{},
tc.Context.Id_MaxBuiltinIntegerType,
NLKind::QualifiedLookup,
lookupResults);
if (lookupResults.size() == 1) {
MaxIntegerTypeDecl = dyn_cast<TypeAliasDecl>(lookupResults.front());
tc.validateDecl(MaxIntegerTypeDecl);
}
}
if (!MaxIntegerTypeDecl ||
!MaxIntegerTypeDecl->hasUnderlyingType() ||
!MaxIntegerTypeDecl->getUnderlyingType()->is<BuiltinIntegerType>()) {
tc.diagnose(expr->getLoc(), diag::no_MaxBuiltinIntegerType_found);
return nullptr;
}
tc.validateDecl(MaxIntegerTypeDecl);
auto maxType = MaxIntegerTypeDecl->getUnderlyingType();
DeclName initName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_integerLiteral });
DeclName builtinInitName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_builtinIntegerLiteral });
return convertLiteral(
expr,
type,
expr->getType(),
protocol,
tc.Context.Id_IntegerLiteralType,
initName,
builtinProtocol,
maxType,
builtinInitName,
nullptr,
diag::integer_literal_broken_proto,
diag::builtin_integer_literal_broken_proto);
}
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(expr->getType());
if (auto defaultType = tc.getDefaultType(protocol, dc)) {
if (defaultType->isEqual(type))
type = defaultType;
}
DeclName initName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_nilLiteral });
return convertLiteral(expr, type, expr->getType(), protocol,
Identifier(), initName,
nullptr, Identifier(),
Identifier(),
[] (Type type) -> bool {
return false;
},
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 (expr->getType()->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(expr->getType());
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(/*filter=*/{},
tc.Context.Id_MaxBuiltinFloatType,
NLKind::QualifiedLookup,
lookupResults);
if (lookupResults.size() == 1)
MaxFloatTypeDecl = dyn_cast<TypeAliasDecl>(lookupResults.front());
}
if (!MaxFloatTypeDecl ||
!MaxFloatTypeDecl->hasUnderlyingType() ||
!MaxFloatTypeDecl->getUnderlyingType()->is<BuiltinFloatType>()) {
tc.diagnose(expr->getLoc(), diag::no_MaxBuiltinFloatType_found);
return nullptr;
}
tc.validateDecl(MaxFloatTypeDecl);
auto maxType = MaxFloatTypeDecl->getUnderlyingType();
DeclName initName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_floatLiteral });
DeclName builtinInitName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_builtinFloatLiteral });
return convertLiteral(
expr,
type,
expr->getType(),
protocol,
tc.Context.Id_FloatLiteralType,
initName,
builtinProtocol,
maxType,
builtinInitName,
nullptr,
diag::float_literal_broken_proto,
diag::builtin_float_literal_broken_proto);
}
Expr *visitBooleanLiteralExpr(BooleanLiteralExpr *expr) {
if (expr->getType() && expr->getType()->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(expr->getType());
DeclName initName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_booleanLiteral });
DeclName builtinInitName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_builtinBooleanLiteral });
return convertLiteral(
expr,
type,
expr->getType(),
protocol,
tc.Context.Id_BooleanLiteralType,
initName,
builtinProtocol,
Type(BuiltinIntegerType::get(BuiltinIntegerWidth::fixed(1),
tc.Context)),
builtinInitName,
nullptr,
diag::boolean_literal_broken_proto,
diag::builtin_boolean_literal_broken_proto);
}
Expr *handleStringLiteralExpr(LiteralExpr *expr) {
if (expr->getType() && !expr->getType()->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(expr->getType());
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) {
// If the string contains only ASCII, force a UTF8 representation
bool forceASCII = stringLiteral != nullptr;
if (forceASCII) {
for (auto c: stringLiteral->getValue()) {
if (c & (1 << 7)) {
forceASCII = false;
break;
}
}
}
literalType = tc.Context.Id_StringLiteralType;
literalFuncName = DeclName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_stringLiteral });
// If the string contains non-ASCII and the type can handle
// UTF-16 string literals, prefer them.
builtinProtocol = tc.getProtocol(
expr->getLoc(),
KnownProtocolKind::ExpressibleByBuiltinUTF16StringLiteral);
if (!forceASCII &&
tc.conformsToProtocol(type, builtinProtocol, cs.DC,
ConformanceCheckFlags::InExpression)) {
builtinLiteralFuncName
= DeclName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_builtinUTF16StringLiteral,
tc.Context.getIdentifier("utf16CodeUnitCount") });
if (stringLiteral)
stringLiteral->setEncoding(StringLiteralExpr::UTF16);
else
magicLiteral->setStringEncoding(StringLiteralExpr::UTF16);
} else {
// Otherwise, fall back to UTF-8.
builtinProtocol = tc.getProtocol(
expr->getLoc(),
KnownProtocolKind::ExpressibleByBuiltinStringLiteral);
builtinLiteralFuncName
= DeclName(tc.Context, tc.Context.Id_init,
{ 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, tc.Context.Id_init,
{tc.Context.Id_extendedGraphemeClusterLiteral});
builtinLiteralFuncName
= DeclName(tc.Context, tc.Context.Id_init,
{ 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, tc.Context.Id_init,
{tc.Context.Id_unicodeScalarLiteral});
builtinLiteralFuncName
= DeclName(tc.Context, tc.Context.Id_init,
{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 = expr->getType();
auto type = simplifyType(openedType);
expr->setType(type);
// Find the string interpolation protocol we need.
auto &tc = cs.getTypeChecker();
auto interpolationProto
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByStringInterpolation);
assert(interpolationProto && "Missing string interpolation protocol?");
DeclName name(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_stringInterpolation });
auto member
= findNamedWitnessImpl<ConstructorDecl>(
tc, dc, type,
interpolationProto, name,
diag::interpolation_broken_proto);
DeclName segmentName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_stringInterpolationSegment });
auto segmentMember
= findNamedWitnessImpl<ConstructorDecl>(
tc, dc, type, interpolationProto, segmentName,
diag::interpolation_broken_proto);
if (!member || !segmentMember)
return nullptr;
// Build a reference to the init(stringInterpolation:) initializer.
// FIXME: This location info is bogus.
auto typeRef = TypeExpr::createImplicitHack(expr->getStartLoc(),
type, tc.Context);
Expr *memberRef =
new (tc.Context) MemberRefExpr(typeRef,
expr->getStartLoc(),
member,
DeclNameLoc(expr->getStartLoc()),
/*Implicit=*/true);
bool failed = tc.typeCheckExpressionShallow(memberRef, cs.DC);
assert(!failed && "Could not reference string interpolation witness");
(void)failed;
// Create a tuple containing all of the segments.
SmallVector<Expr *, 4> segments;
SmallVector<TupleTypeElt, 4> typeElements;
SmallVector<Identifier, 4> names;
unsigned index = 0;
ConstraintLocatorBuilder locatorBuilder(cs.getConstraintLocator(expr));
for (auto segment : expr->getSegments()) {
auto locator = cs.getConstraintLocator(
locatorBuilder.withPathElement(
LocatorPathElt::getInterpolationArgument(index++)));
// Find the initializer we chose.
auto choice = getOverloadChoice(locator);
auto memberRef = buildMemberRef(
typeRef, choice.openedFullType,
segment->getStartLoc(), choice.choice.getDecl(),
DeclNameLoc(segment->getStartLoc()),
choice.openedType,
locator, locator, /*Implicit=*/true,
choice.choice.getFunctionRefKind(),
AccessSemantics::Ordinary,
/*isDynamic=*/false);
ApplyExpr *apply =
CallExpr::createImplicit(
tc.Context, memberRef,
{ segment },
{ tc.Context.Id_stringInterpolationSegment });
auto converted = finishApply(apply, openedType, locatorBuilder);
if (!converted)
return nullptr;
segments.push_back(converted);
if (index == 1) {
names.push_back(tc.Context.Id_stringInterpolation);
} else {
names.push_back(Identifier());
}
}
// Call the init(stringInterpolation:) initializer with the arguments.
ApplyExpr *apply = CallExpr::createImplicit(tc.Context, memberRef,
segments, names);
expr->setSemanticExpr(finishApply(apply, openedType, locatorBuilder));
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;
}
}
Expr *visitObjectLiteralExpr(ObjectLiteralExpr *expr) {
if (expr->getType() && !expr->getType()->hasTypeVariable())
return expr;
auto &ctx = cs.getASTContext();
auto &tc = cs.getTypeChecker();
// Figure out the type we're converting to.
auto openedType = expr->getType();
auto type = simplifyType(openedType);
expr->setType(type);
if (type->is<UnresolvedType>()) return expr;
Type conformingType = type;
if (auto baseType = conformingType->getAnyOptionalObjectType()) {
// 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);
SmallVector<Expr *, 4> args;
if (!isa<TupleExpr>(expr->getArg()))
return nullptr;
auto tupleArg = cast<TupleExpr>(expr->getArg());
for (auto elt : tupleArg->getElements())
args.push_back(elt);
DeclName constrName(tc.getObjectLiteralConstructorName(expr));
Expr *semanticExpr = tc.callWitness(base, dc, proto, *conformance,
constrName, args,
diag::object_literal_broken_proto);
expr->setSemanticExpr(semanticExpr);
return expr;
}
Expr *visitDeclRefExpr(DeclRefExpr *expr) {
auto locator = cs.getConstraintLocator(expr);
// Find the overload choice used for this declaration reference.
auto selected = getOverloadChoiceIfAvailable(locator);
if (!selected.hasValue()) {
assert(expr->getDecl()->getType()->is<UnresolvedType>() &&
"should only happen for closure arguments in CSDiags");
expr->setType(expr->getDecl()->getType());
return expr;
}
auto choice = selected->choice;
auto decl = choice.getDecl();
// FIXME: Cannibalize the existing DeclRefExpr rather than allocating a
// new one?
return buildDeclRef(decl, expr->getNameLoc(), selected->openedFullType,
locator, expr->isSpecialized(),
expr->isImplicit(),
expr->getFunctionRefKind(),
expr->getAccessSemantics());
}
Expr *visitSuperRefExpr(SuperRefExpr *expr) {
simplifyExprType(expr);
return expr;
}
Expr *visitTypeExpr(TypeExpr *expr) {
auto toType = simplifyType(expr->getTypeLoc().getType());
expr->getTypeLoc().setType(toType, /*validated=*/true);
expr->setType(MetatypeType::get(toType));
return expr;
}
Expr *visitOtherConstructorDeclRefExpr(OtherConstructorDeclRefExpr *expr) {
assert(!expr->getDeclRef().isSpecialized());
expr->setType(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 = getOverloadChoice(locator);
auto choice = selected.choice;
auto decl = choice.getDecl();
return buildDeclRef(decl, expr->getNameLoc(), selected.openedFullType,
locator, expr->isSpecialized(), 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.
if (auto DRE = dyn_cast<DeclRefExpr>(expr->getSubExpr())) {
assert(DRE->getGenericArgs().empty() ||
DRE->getGenericArgs().size() == expr->getUnresolvedParams().size());
if (DRE->getGenericArgs().empty()) {
SmallVector<TypeRepr *, 8> GenArgs;
for (auto TL : expr->getUnresolvedParams())
GenArgs.push_back(TL.getTypeRepr());
DRE->setGenericArgs(GenArgs);
}
}
return expr->getSubExpr();
}
Expr *visitMemberRefExpr(MemberRefExpr *expr) {
auto memberLocator = cs.getConstraintLocator(expr,
ConstraintLocator::Member);
auto selected = getOverloadChoice(memberLocator);
bool isDynamic
= selected.choice.getKind() == OverloadChoiceKind::DeclViaDynamic;
return buildMemberRef(expr->getBase(),
selected.openedFullType,
expr->getDotLoc(),
selected.choice.getDecl(), 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(expr->getType());
if (resultTy->getRValueType()->is<UnresolvedType>()) {
expr->setType(resultTy);
return expr;
}
Type baseTy = resultTy->getRValueType();
auto &tc = cs.getTypeChecker();
// Find the selected member.
auto memberLocator = cs.getConstraintLocator(
expr, ConstraintLocator::UnresolvedMember);
auto selected = getOverloadChoice(memberLocator);
auto member = selected.choice.getDecl();
// If the member came by optional unwrapping, then unwrap the base type.
if (selected.choice.getKind()
== OverloadChoiceKind::DeclViaUnwrappedOptional) {
baseTy = baseTy->getAnyOptionalObjectType();
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);
// Build the member reference.
bool isDynamic
= selected.choice.getKind() == OverloadChoiceKind::DeclViaDynamic;
auto result = buildMemberRef(base,
selected.openedFullType,
expr->getDotLoc(), member,
expr->getNameLoc(),
selected.openedType,
cs.getConstraintLocator(expr),
memberLocator,
expr->isImplicit(),
selected.choice.getFunctionRefKind(),
AccessSemantics::Ordinary,
isDynamic);
if (!result)
return nullptr;
// 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=*/false);
result = finishApply(apply, Type(), cs.getConstraintLocator(expr));
}
result = coerceToType(result, resultTy, cs.getConstraintLocator(expr));
return result;
}
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,
ConstructorDecl *ctor,
FunctionRefKind functionRefKind,
Type openedType) {
// If the subexpression is a metatype, build a direct reference to the
// constructor.
if (base->getType()->is<AnyMetatypeType>()) {
return buildMemberRef(base, openedType, dotLoc, ctor, nameLoc,
expr->getType(),
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()->getName() == cs.getASTContext().Id_self) {
// We have a reference to 'self'.
diagnoseBadInitRef = false;
// Make sure the reference to 'self' occurs within an initializer.
if (!dyn_cast_or_null<ConstructorDecl>(
cs.DC->getInnermostMethodContext())) {
if (!SuppressDiagnostics)
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 nominalType
= func->getDeclContext()->getDeclaredTypeOfContext()) {
if (auto classDecl = nominalType->getClassOrBoundGenericClass()) {
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, nameLoc,
ctorLocator, implicit);
auto *call = new (cs.getASTContext()) DotSyntaxCallExpr(ctorRef, dotLoc,
base);
return finishApply(call, expr->getType(),
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 = getOverloadChoiceIfAvailable(ctorLocator)) {
auto choice = selected->choice;
auto *ctor = cast<ConstructorDecl>(choice.getDecl());
return applyCtorRefExpr(expr, base, dotLoc, nameLoc, implicit,
ctorLocator, ctor, choice.getFunctionRefKind(),
selected->openedFullType);
}
// Determine the declaration selected for this overloaded reference.
auto memberLocator = cs.getConstraintLocator(expr,
ConstraintLocator::Member);
auto selectedElt = 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(expr->getType());
expr->setType(resultTy);
return expr;
}
auto selected = *selectedElt;
switch (selected.choice.getKind()) {
case OverloadChoiceKind::DeclViaBridge: {
// Look through an implicitly unwrapped optional.
auto baseTy = base->getType()->getRValueType();
if (auto objTy = cs.lookThroughImplicitlyUnwrappedOptionalType(baseTy)){
base = coerceImplicitlyUnwrappedOptionalToValue(base, objTy,
cs.getConstraintLocator(base));
baseTy = base->getType()->getRValueType();
}
if (auto baseMetaTy = baseTy->getAs<MetatypeType>()) {
auto &tc = cs.getTypeChecker();
auto &ctx = tc.Context;
auto classTy = ctx.getBridgedToObjC(cs.DC,
baseMetaTy->getInstanceType());
// FIXME: We're dropping side effects in the base here!
base = TypeExpr::createImplicitHack(base->getLoc(), classTy,
tc.Context);
} else {
// Bridge the base to its corresponding Objective-C object.
base = bridgeToObjectiveC(base);
}
// Fall through to build the member reference.
SWIFT_FALLTHROUGH;
}
case OverloadChoiceKind::Decl:
case OverloadChoiceKind::DeclViaUnwrappedOptional:
case OverloadChoiceKind::DeclViaDynamic: {
bool isDynamic
= selected.choice.getKind() == OverloadChoiceKind::DeclViaDynamic;
auto member = buildMemberRef(base,
selected.openedFullType,
dotLoc,
selected.choice.getDecl(),
nameLoc,
selected.openedType,
cs.getConstraintLocator(expr),
memberLocator,
implicit,
selected.choice.getFunctionRefKind(),
AccessSemantics::Ordinary,
isDynamic);
return member;
}
case OverloadChoiceKind::TupleIndex: {
auto baseTy = base->getType()->getRValueType();
if (auto objTy = cs.lookThroughImplicitlyUnwrappedOptionalType(baseTy)){
base = coerceImplicitlyUnwrappedOptionalToValue(base, objTy,
cs.getConstraintLocator(base));
}
Type toType = simplifyType(expr->getType());
// 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.
baseTy = base->getType();
if (!toType->isLValueType() && baseTy->isLValueType())
base = coerceToType(base, baseTy->getRValueType(), cs.getConstraintLocator(base));
return new (cs.getASTContext()) TupleElementExpr(base, dotLoc,
selected.choice.getTupleIndex(),
nameLoc.getBaseNameLoc(), toType);
}
case OverloadChoiceKind::BaseType: {
// FIXME: Losing ".0" sugar here.
return base;
}
case OverloadChoiceKind::TypeDecl:
llvm_unreachable("Nonsensical overload choice");
}
}
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) {
expr->setType(expr->getSubExpr()->getType());
return expr;
}
Expr *visitAnyTryExpr(AnyTryExpr *expr) {
expr->setType(expr->getSubExpr()->getType());
return expr;
}
Expr *visitOptionalTryExpr(OptionalTryExpr *expr) {
return simplifyExprType(expr);
}
Expr *visitParenExpr(ParenExpr *expr) {
auto &ctx = cs.getASTContext();
expr->setType(ParenType::get(ctx, expr->getSubExpr()->getType()));
return expr;
}
Expr *visitTupleExpr(TupleExpr *expr) {
return simplifyExprType(expr);
}
Expr *visitSubscriptExpr(SubscriptExpr *expr) {
return buildSubscript(expr->getBase(), expr->getIndex(),
expr->getArgumentLabels(),
expr->hasTrailingClosure(),
cs.getConstraintLocator(expr),
expr->isImplicit(),
expr->getAccessSemantics());
}
Expr *visitArrayExpr(ArrayExpr *expr) {
Type openedType = expr->getType();
Type arrayTy = simplifyType(openedType);
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?");
// Call the witness that builds the array literal.
// FIXME: callWitness() may end up re-doing some work we already did
// to convert the array literal elements to the element type. It would
// be nicer to re-use them.
// FIXME: This location info is bogus.
Expr *typeRef = TypeExpr::createImplicitHack(expr->getLoc(),
arrayTy, tc.Context);
DeclName name(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_arrayLiteral });
// 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(elt->getType(),
tc.Context.Id_arrayLiteral));
names.push_back(tc.Context.Id_arrayLiteral);
first = false;
continue;
}
typeElements.push_back(elt->getType());
names.push_back(Identifier());
}
Type argType = TupleType::get(typeElements, tc.Context);
Expr *arg = TupleExpr::create(tc.Context, SourceLoc(),
expr->getElements(),
names,
{ },
SourceLoc(), /*HasTrailingClosure=*/false,
/*Implicit=*/true,
argType);
Expr *result = tc.callWitness(typeRef, dc, arrayProto, *conformance,
name, arg, diag::array_protocol_broken);
if (!result)
return nullptr;
expr->setSemanticExpr(result);
expr->setType(arrayTy);
// If the array element type was defaulted, note that in the expression.
if (solution.DefaultedConstraints.count(cs.getConstraintLocator(expr)))
expr->setIsTypeDefaulted();
return expr;
}
Expr *visitDictionaryExpr(DictionaryExpr *expr) {
Type openedType = expr->getType();
Type dictionaryTy = simplifyType(openedType);
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);
DeclName name(tc.Context, tc.Context.Id_init,
{ 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(elt->getType(),
tc.Context.Id_dictionaryLiteral));
names.push_back(tc.Context.Id_dictionaryLiteral);
first = false;
continue;
}
typeElements.push_back(elt->getType());
names.push_back(Identifier());
}
Type argType = TupleType::get(typeElements, tc.Context);
Expr *arg = TupleExpr::create(tc.Context, expr->getLBracketLoc(),
expr->getElements(),
names,
{ },
expr->getRBracketLoc(),
/*HasTrailingClosure=*/false,
/*Implicit=*/false,
argType);
Expr *result = tc.callWitness(typeRef, dc, dictionaryProto,
*conformance, name, arg,
diag::dictionary_protocol_broken);
if (!result)
return nullptr;
expr->setSemanticExpr(result);
expr->setType(dictionaryTy);
// 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) {
// Handle accesses that implicitly look through ImplicitlyUnwrappedOptional<T>.
auto base = expr->getBase();
auto baseTy = base->getType()->getRValueType();
if (auto objTy = cs.lookThroughImplicitlyUnwrappedOptionalType(baseTy)) {
base = coerceImplicitlyUnwrappedOptionalToValue(base, objTy,
cs.getConstraintLocator(base));
expr->setBase(base);
}
simplifyExprType(expr);
return expr;
}
Expr *visitCaptureListExpr(CaptureListExpr *expr) {
// The type of the capture list is the type of the closure contained
// inside it.
expr->setType(expr->getClosureBody()->getType());
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) {
// The default assumption is that inouts are read-write. It's easier
// to do this unconditionally here and then overwrite in the exception
// case (when we turn the inout into an UnsafePointer) than to try to
// discover that we're in that case right now.
if (!expr->getSubExpr()->getType()->is<UnresolvedType>())
expr->getSubExpr()->propagateLValueAccessKind(AccessKind::ReadWrite);
auto objectTy = expr->getSubExpr()->getType()->getRValueType();
// The type is simply inout of whatever the lvalue's object type was.
expr->setType(InOutType::get(objectTy));
return expr;
}
Expr *visitDynamicTypeExpr(DynamicTypeExpr *expr) {
auto &tc = cs.getTypeChecker();
Expr *base = expr->getBase();
base = tc.coerceToRValue(base);
if (!base) return nullptr;
expr->setBase(base);
return simplifyExprType(expr);
}
Expr *visitOpaqueValueExpr(OpaqueValueExpr *expr) {
llvm_unreachable("Already type-checked");
}
Expr *visitApplyExpr(ApplyExpr *expr) {
return finishApply(expr, expr->getType(),
ConstraintLocatorBuilder(
cs.getConstraintLocator(expr)));
}
Expr *visitRebindSelfInConstructorExpr(RebindSelfInConstructorExpr *expr) {
// A non-failable initializer cannot delegate to a failable
// initializer.
OptionalTypeKind calledOTK;
Expr *unwrappedSubExpr = expr->getSubExpr()->getSemanticsProvidingExpr();
Type valueTy
= unwrappedSubExpr->getType()->getAnyOptionalObjectType(calledOTK);
auto inCtor = cast<ConstructorDecl>(cs.DC->getInnermostMethodContext());
if (calledOTK != OTK_None && inCtor->getFailability() == OTK_None) {
bool isError = (calledOTK == OTK_Optional);
// If we're suppressing diagnostics, just fail.
if (isError && SuppressDiagnostics)
return nullptr;
bool isChaining;
auto *otherCtorRef = expr->getCalledConstructor(isChaining);
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.
ConstructorDecl *ctor = otherCtorRef->getDecl();
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());
newSub->setType(valueTy);
newSub->setImplicit();
expr->setSubExpr(newSub);
}
return expr;
}
Expr *visitIfExpr(IfExpr *expr) {
auto resultTy = simplifyType(expr->getType());
expr->setType(resultTy);
// Convert the condition to a logic value.
auto cond
= solution.convertBooleanTypeToBuiltinI1(expr->getCondExpr(),
cs.getConstraintLocator(expr));
if (!cond) {
expr->getCondExpr()->setType(ErrorType::get(resultTy));
} else {
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(expr->getCastTypeLoc().getType());
auto sub = tc.coerceToRValue(expr->getSubExpr());
if (!sub)
return nullptr;
checkForImportedUsedConformances(toType);
expr->setSubExpr(sub);
// Set the type we checked against.
expr->getCastTypeLoc().setType(toType, /*validated=*/true);
auto fromType = sub->getType();
auto castKind = tc.typeCheckCheckedCast(
fromType, toType, cs.DC,
expr->getLoc(),
sub->getSourceRange(),
expr->getCastTypeLoc().getSourceRange(),
[&](Type commonTy) -> bool {
return tc.convertToType(sub, commonTy, cs.DC);
},
SuppressDiagnostics);
switch (castKind) {
case CheckedCastKind::Unresolved:
// Invalid type check.
return nullptr;
case CheckedCastKind::Coercion:
// 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:
case CheckedCastKind::BridgeFromObjectiveC:
// Valid checks.
expr->setCastKind(castKind);
break;
}
// SIL-generation magically turns this into a Bool; make sure it can.
if (!cs.getASTContext().getGetBoolDecl(&cs.getTypeChecker())) {
tc.diagnose(expr->getLoc(), diag::bool_intrinsics_not_found);
// Continue anyway.
}
// Dig through the optionals in the from/to types.
SmallVector<Type, 2> fromOptionals;
fromType->lookThroughAllAnyOptionalTypes(fromOptionals);
SmallVector<Type, 2> toOptionals;
toType->lookThroughAllAnyOptionalTypes(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));
cast->setType(toOptType);
if (expr->isImplicit())
cast->setImplicit();
// Type-check this conditional case.
Expr *result = visitConditionalCheckedCastExpr(cast);
if (!result)
return nullptr;
// Extract a Bool from the resulting expression.
return solution.convertOptionalToBool(result,
cs.getConstraintLocator(expr));
}
return expr;
}
/// Handle optional operands and results in an explicit cast.
Expr *handleOptionalBindings(ExplicitCastExpr *cast,
Type finalResultType,
bool conditionalCast) {
auto &tc = cs.getTypeChecker();
unsigned destExtraOptionals = conditionalCast ? 1 : 0;
// 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.
Expr *subExpr = cast->getSubExpr();
Type srcType = subExpr->getType();
SmallVector<Type, 4> srcOptionals;
srcType = srcType->lookThroughAllAnyOptionalTypes(srcOptionals);
SmallVector<Type, 4> destOptionals;
auto destValueType
= finalResultType->lookThroughAllAnyOptionalTypes(destOptionals);
// Complain about conditional casts to foreign class types; they can't
// actually be conditionally checked.
if (conditionalCast) {
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;
tc.diagnose(cast->getLoc(), diag::conditional_downcast_foreign,
destValueType);
}
}
}
// There's nothing special to do if the operand isn't optional
// and we don't need any bridging.
if (srcOptionals.empty()) {
cast->setType(finalResultType);
return cast;
}
// 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.
if (conditionalCast) {
assert(!destOptionals.empty() &&
"result of checked cast is not an optional type");
cast->setType(destOptionals.back());
} else {
cast->setType(destValueType);
}
// 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 (!conditionalCast) {
// For a forced cast, force the required optionals.
subExpr = new (tc.Context) ForceValueExpr(subExpr, fakeQuestionLoc);
subExpr->setType(valueType);
subExpr->setImplicit(true);
continue;
}
subExpr = new (tc.Context) BindOptionalExpr(subExpr, fakeQuestionLoc,
depth, valueType);
subExpr->setImplicit(true);
}
cast->setSubExpr(subExpr);
// If we're casting to an optional type, we need to capture the
// final M bindings.
Expr *result = cast;
if (destOptionals.size() > destExtraOptionals) {
if (conditionalCast) {
// 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 = new (tc.Context) BindOptionalExpr(result, cast->getEndLoc(),
failureDepth,
destValueType);
result->setImplicit(true);
}
for (unsigned i = destOptionals.size(); i != 0; --i) {
Type destType = destOptionals[i-1];
result = new (tc.Context) InjectIntoOptionalExpr(result, destType);
result = new (tc.Context) OptionalEvaluationExpr(result, destType);
}
// Otherwise, we just need to capture the failure-depth binding.
} else if (conditionalCast) {
result = new (tc.Context) OptionalEvaluationExpr(result,
finalResultType);
}
return result;
}
Expr *visitCoerceExpr(CoerceExpr *expr) {
// Simplify the type we're casting to.
auto toType = simplifyType(expr->getCastTypeLoc().getType());
expr->getCastTypeLoc().setType(toType, /*validated=*/true);
checkForImportedUsedConformances(toType);
// Determine whether we performed a coercion or downcast.
if (cs.shouldAttemptFixes()) {
auto locator = cs.getConstraintLocator(expr);
unsigned choice = solution.getDisjunctionChoice(locator);
(void) choice;
assert(choice == 0 &&
"checked cast branch of disjunction should have resulted in Fix");
}
auto &tc = cs.getTypeChecker();
auto sub = tc.coerceToRValue(expr->getSubExpr());
// The subexpression is always an rvalue.
if (!sub)
return nullptr;
// Convert the subexpression.
if (tc.convertToType(sub, toType, cs.DC))
return nullptr;
expr->setSubExpr(sub);
expr->setType(toType);
return expr;
}
Expr *visitForcedCheckedCastExpr(ForcedCheckedCastExpr *expr) {
// Simplify the type we're casting to.
auto toType = simplifyType(expr->getCastTypeLoc().getType());
expr->getCastTypeLoc().setType(toType, /*validated=*/true);
checkForImportedUsedConformances(toType);
// The subexpression is always an rvalue.
auto &tc = cs.getTypeChecker();
auto sub = tc.coerceToRValue(expr->getSubExpr());
if (!sub)
return nullptr;
expr->setSubExpr(sub);
auto fromType = sub->getType();
auto castKind = tc.typeCheckCheckedCast(
fromType, toType, cs.DC,
expr->getLoc(),
sub->getSourceRange(),
expr->getCastTypeLoc().getSourceRange(),
[&](Type commonTy) -> bool {
return tc.convertToType(sub, commonTy,
cs.DC);
},
SuppressDiagnostics);
switch (castKind) {
/// Invalid cast.
case CheckedCastKind::Unresolved:
return nullptr;
case CheckedCastKind::Coercion: {
if (SuppressDiagnostics)
return nullptr;
if (sub->getType()->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,
sub->getType(), toType)
.fixItReplace(SourceRange(expr->getLoc(), expr->getExclaimLoc()),
"as");
}
// Convert the subexpression.
bool failed = tc.convertToType(sub, toType, cs.DC);
(void)failed;
assert(!failed && "Not convertible?");
// Transmute the checked cast into a coercion expression.
Expr *result = new (tc.Context) CoerceExpr(sub, expr->getLoc(),
expr->getCastTypeLoc());
// The result type is the type we're converting to.
result->setType(toType);
return result;
}
// Valid casts.
case CheckedCastKind::ArrayDowncast:
case CheckedCastKind::DictionaryDowncast:
case CheckedCastKind::SetDowncast:
case CheckedCastKind::ValueCast:
case CheckedCastKind::BridgeFromObjectiveC:
expr->setCastKind(castKind);
break;
}
return handleOptionalBindings(expr, simplifyType(expr->getType()),
/*conditionalCast=*/false);
}
Expr *visitConditionalCheckedCastExpr(ConditionalCheckedCastExpr *expr) {
// Simplify the type we're casting to.
auto toType = simplifyType(expr->getCastTypeLoc().getType());
checkForImportedUsedConformances(toType);
expr->getCastTypeLoc().setType(toType, /*validated=*/true);
// The subexpression is always an rvalue.
auto &tc = cs.getTypeChecker();
auto sub = tc.coerceToRValue(expr->getSubExpr());
if (!sub)
return nullptr;
expr->setSubExpr(sub);
auto fromType = sub->getType();
auto castKind = tc.typeCheckCheckedCast(
fromType, toType, cs.DC,
expr->getLoc(),
sub->getSourceRange(),
expr->getCastTypeLoc().getSourceRange(),
[&](Type commonTy) -> bool {
return tc.convertToType(sub, commonTy,
cs.DC);
},
SuppressDiagnostics);
switch (castKind) {
/// Invalid cast.
case CheckedCastKind::Unresolved:
return nullptr;
case CheckedCastKind::Coercion: {
if (SuppressDiagnostics)
return nullptr;
tc.diagnose(expr->getLoc(), diag::conditional_downcast_coercion,
sub->getType(), toType);
// Convert the subexpression.
bool failed = tc.convertToType(sub, toType, cs.DC);
(void)failed;
assert(!failed && "Not convertible?");
// Transmute the checked cast into a coercion expression.
Expr *result = new (tc.Context) CoerceExpr(sub, expr->getLoc(),
expr->getCastTypeLoc());
// The result type is the type we're converting to.
result->setType(toType);
// Wrap the result in an optional.
return new (tc.Context) InjectIntoOptionalExpr(
result,
OptionalType::get(toType));
}
// Valid casts.
case CheckedCastKind::ArrayDowncast:
case CheckedCastKind::DictionaryDowncast:
case CheckedCastKind::SetDowncast:
case CheckedCastKind::ValueCast:
case CheckedCastKind::BridgeFromObjectiveC:
expr->setCastKind(castKind);
break;
}
return handleOptionalBindings(expr, simplifyType(expr->getType()),
/*conditionalCast=*/true);
}
Expr *visitAssignExpr(AssignExpr *expr) {
// Compute the type to which the source must be converted to allow
// assignment to the destination.
//
// FIXME: This is also computed when the constraint system is set up.
auto destTy = cs.computeAssignDestType(expr->getDest(), expr->getLoc());
if (!destTy)
return nullptr;
expr->getDest()->propagateLValueAccessKind(AccessKind::Write);
// Convert the source to the simplified destination type.
auto locator =
ConstraintLocatorBuilder(cs.getConstraintLocator(expr->getSrc()));
Expr *src = coerceToType(expr->getSrc(), destTy, locator);
if (!src)
return nullptr;
expr->setSrc(src);
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.
if (!SuppressDiagnostics) {
cs.TC.diagnose(expr->getLoc(), diag::pattern_in_expr,
expr->getSubPattern()->getKind());
}
return expr;
}
Expr *visitBindOptionalExpr(BindOptionalExpr *expr) {
Type valueType = simplifyType(expr->getType());
expr->setType(valueType);
return expr;
}
Expr *visitOptionalEvaluationExpr(OptionalEvaluationExpr *expr) {
Type optType = simplifyType(expr->getType());
// 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 (Bind->getSubExpr()->getType()->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);
expr->setType(optType);
return expr;
}
Expr *visitForceValueExpr(ForceValueExpr *expr) {
Type valueType = simplifyType(expr->getType());
expr->setType(valueType);
// Coerce the object type, if necessary.
auto subExpr = expr->getSubExpr();
if (auto objectTy = subExpr->getType()->getAnyOptionalObjectType()) {
if (objectTy && !objectTy->isEqual(valueType)) {
auto coercedSubExpr = coerceToType(subExpr,
OptionalType::get(valueType),
cs.getConstraintLocator(subExpr));
expr->setSubExpr(coercedSubExpr);
}
}
return expr;
}
Expr *visitOpenExistentialExpr(OpenExistentialExpr *expr) {
llvm_unreachable("Already type-checked");
}
Expr *visitEnumIsCaseExpr(EnumIsCaseExpr *expr) {
// Should already be type-checked.
Type valueType = simplifyType(expr->getType());
expr->setType(valueType);
return expr;
}
Expr *visitEditorPlaceholderExpr(EditorPlaceholderExpr *E) {
Type valueType = simplifyType(E->getType());
E->setType(valueType);
auto &tc = cs.getTypeChecker();
auto &ctx = tc.Context;
// Synthesize a call to _undefined() of appropriate type.
FuncDecl *undefinedDecl = ctx.getUndefinedDecl(&tc);
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() });
bool invalid = tc.typeCheckExpression(callExpr, cs.DC,
TypeLoc::withoutLoc(valueType),
CTP_CannotFail);
(void) invalid;
assert(!invalid && "conversion cannot fail");
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.
// 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();
// Make sure we have the accessors.
tc.synthesizeAccessorsForStorage(var,
/*wantMaterializeForSet=*/false);
// 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.
if (!method->isObjC()) {
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;
}
// Note which method we're referencing.
E->setMethod(method);
return E;
}
Expr *visitObjCKeyPathExpr(ObjCKeyPathExpr *E) {
if (auto semanticE = E->getSemanticExpr())
E->setType(semanticE->getType());
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) {
auto &tc = cs.getTypeChecker();
tc.useObjectiveCBridgeableConformances(cs.DC, result->getType());
}
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,
injection->getSubExpr()->getType()->getRValueType());
auto exclaimLoc = cast->getExclaimLoc();
tc.diagnose(exclaimLoc, diag::forced_to_conditional_downcast,
injection->getType()->getAnyOptionalObjectType())
.fixItReplace(exclaimLoc, "?");
tc.diagnose(cast->getStartLoc(), diag::silence_inject_forced_downcast)
.fixItInsert(cast->getStartLoc(), "(")
.fixItInsertAfter(cast->getEndLoc(), ")");
}
}
/// Diagnose an optional injection that is probably not what the
/// user wanted, because it comes from a forced downcast.
void diagnoseOptionalInjection(InjectIntoOptionalExpr *injection) {
// Don't diagnose when we're injecting into
auto toOptionalType = injection->getType();
if (toOptionalType->getImplicitlyUnwrappedOptionalObjectType())
return;
// 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);
}
};
}
/// 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,
std::function<Optional<SelectedOverload>(ConstraintLocator *)> findOvlChoice,
std::function<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;
}
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 {
if (decl->getInnermostDeclContext()->isGenericContext()) {
SmallVector<Substitution, 4> subs;
computeSubstitutions(
decl->getType(),
decl->getInnermostDeclContext(),
openedType, locator, subs);
return ConcreteDeclRef(cs.getASTContext(), decl, subs);
}
return decl;
})) {
return resolved;
}
return ConcreteDeclRef();
}
/// \brief 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.
bool isSubscript =
locator->getPath().back().getKind() == ConstraintLocator::SubscriptIndex;
if (locator->getPath().back().getKind() == ConstraintLocator::ApplyArgument ||
isSubscript) {
assert(locator->getPath().back().getNewSummaryFlags() == 0 &&
"ApplyArgument/SubscriptIndex adds no flags");
SmallVector<LocatorPathElt, 4> newPath;
newPath.append(locator->getPath().begin(), locator->getPath().end()-1);
unsigned newFlags = locator->getSummaryFlags();
// If we have an interpolation argument, dig out the constructor if we
// can.
// FIXME: This representation is actually quite awful
if (newPath.size() == 1 &&
newPath[0].getKind() == ConstraintLocator::InterpolationArgument) {
newPath.push_back(ConstraintLocator::ConstructorMember);
locator = cs.getConstraintLocator(locator->getAnchor(), newPath, newFlags);
auto known = solution.overloadChoices.find(locator);
if (known != solution.overloadChoices.end()) {
auto &choice = known->second.choice;
if (choice.getKind() == OverloadChoiceKind::Decl)
return cast<AbstractFunctionDecl>(choice.getDecl());
}
return nullptr;
} else if (isSubscript) {
newPath.push_back(ConstraintLocator::SubscriptMember);
} else {
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);
}
static bool
shouldApplyAddingLabelFixit(TuplePattern *tuplePattern, TupleType *fromTuple,
TupleType *toTuple,
std::vector<std::pair<SourceLoc, std::string>> &locInsertPairs) {
std::vector<TuplePattern*> patternParts;
std::vector<TupleType*> fromParts;
std::vector<TupleType*> toParts;
patternParts.push_back(tuplePattern);
fromParts.push_back(fromTuple);
toParts.push_back(toTuple);
while (!patternParts.empty()) {
TuplePattern *curPattern = patternParts.back();
TupleType *curFrom = fromParts.back();
TupleType *curTo = toParts.back();
patternParts.pop_back();
fromParts.pop_back();
toParts.pop_back();
unsigned n = curPattern->getElements().size();
if (curFrom->getElements().size() != n ||
curTo->getElements().size() != n)
return false;
for (unsigned i = 0; i < n; i++) {
Pattern* subPat = curPattern->getElement(i).getPattern();
const TupleTypeElt &subFrom = curFrom->getElement(i);
const TupleTypeElt &subTo = curTo->getElement(i);
if ((subFrom.getType()->getKind() == TypeKind::Tuple) ^
(subTo.getType()->getKind() == TypeKind::Tuple))
return false;
auto addLabelFunc = [&]() {
if (subFrom.getName().empty() && !subTo.getName().empty()) {
llvm::SmallString<8> Name;
Name.append(subTo.getName().str());
Name.append(": ");
locInsertPairs.push_back({subPat->getStartLoc(), Name.str()});
}
};
if (auto subFromTuple = subFrom.getType()->getAs<TupleType>()) {
fromParts.push_back(subFromTuple);
toParts.push_back(subTo.getType()->getAs<TupleType>());
patternParts.push_back(static_cast<TuplePattern*>(subPat));
addLabelFunc();
} else if (subFrom.getType()->isEqual(subTo.getType())) {
addLabelFunc();
} else
return false;
}
}
return true;
}
/// 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(TypeChecker &tc, DeclContext *dc,
SourceLoc loc, ConcreteDeclRef &owner,
unsigned index) {
auto ownerFn = cast<AbstractFunctionDecl>(owner.getDecl());
auto defArg = ownerFn->getDefaultArg(index);
Expr *init = nullptr;
switch (defArg.first) {
case DefaultArgumentKind::None:
llvm_unreachable("No default argument here?");
case DefaultArgumentKind::Normal:
return {nullptr, defArg.first};
case DefaultArgumentKind::Inherited:
// Update the owner to reflect inheritance here.
owner = ownerFn->getOverriddenDecl();
return getCallerDefaultArg(tc, 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::Nil:
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.
bool invalid = tc.typeCheckExpression(init, dc,
TypeLoc::withoutLoc(defArg.second),
CTP_CannotFail);
assert(!invalid && "conversion cannot fail");
(void)invalid;
return {init, defArg.first};
}
static Expr *lookThroughIdentityExprs(Expr *expr) {
while (true) {
if (auto ident = dyn_cast<IdentityExpr>(expr)) {
expr = ident->getSubExpr();
} else if (auto anyTry = dyn_cast<AnyTryExpr>(expr)) {
if (isa<OptionalTryExpr>(anyTry))
return expr;
expr = anyTry->getSubExpr();
} else {
return expr;
}
}
}
/// Rebuild the ParenTypes for the given expression, whose underlying expression
/// should be set to the given type. This has to apply to exactly the same
/// levels of sugar that were stripped off by lookThroughIdentityExprs.
static Type rebuildIdentityExprs(ASTContext &ctx, Expr *expr, Type type) {
if (auto paren = dyn_cast<ParenExpr>(expr)) {
type = rebuildIdentityExprs(ctx, paren->getSubExpr(), type);
paren->setType(ParenType::get(ctx, type));
return paren->getType();
}
if (auto ident = dyn_cast<IdentityExpr>(expr)) {
type = rebuildIdentityExprs(ctx, ident->getSubExpr(), type);
ident->setType(type);
return ident->getType();
}
if (auto ident = dyn_cast<AnyTryExpr>(expr)) {
if (isa<OptionalTryExpr>(ident))
return type;
type = rebuildIdentityExprs(ctx, ident->getSubExpr(), type);
ident->setType(type);
return ident->getType();
}
return type;
}
Expr *ExprRewriter::coerceTupleToTuple(Expr *expr, TupleType *fromTuple,
TupleType *toTuple,
ConstraintLocatorBuilder locator,
SmallVectorImpl<int> &sources,
SmallVectorImpl<unsigned> &variadicArgs,
Optional<Pattern*> typeFromPattern){
auto &tc = cs.getTypeChecker();
// Capture the tuple expression, if there is one.
Expr *innerExpr = lookThroughIdentityExprs(expr);
TupleExpr *fromTupleExpr = dyn_cast<TupleExpr>(innerExpr);
/// Check each of the tuple elements in the destination.
bool hasVariadic = false;
unsigned variadicParamIdx = toTuple->getNumElements();
bool anythingShuffled = false;
bool hasInits = false;
SmallVector<TupleTypeElt, 4> toSugarFields;
SmallVector<TupleTypeElt, 4> fromTupleExprFields(
fromTuple->getElements().size());
SmallVector<Expr *, 2> callerDefaultArgs;
ConcreteDeclRef callee =
findCalleeDeclRef(cs, solution, cs.getConstraintLocator(locator));
for (unsigned i = 0, n = toTuple->getNumElements(); i != n; ++i) {
const auto &toElt = toTuple->getElement(i);
auto toEltType = toElt.getType();
// If we're default-initializing this member, there's nothing to do.
if (sources[i] == TupleShuffleExpr::DefaultInitialize) {
anythingShuffled = true;
hasInits = true;
toSugarFields.push_back(toElt);
// Create a caller-side default argument, if we need one.
if (auto defArg = getCallerDefaultArg(tc, dc, expr->getLoc(),
callee, i).first) {
callerDefaultArgs.push_back(defArg);
sources[i] = TupleShuffleExpr::CallerDefaultInitialize;
}
continue;
}
// If this is the variadic argument, note it.
if (sources[i] == TupleShuffleExpr::Variadic) {
assert(!hasVariadic && "two variadic parameters?");
toSugarFields.push_back(toElt);
hasVariadic = true;
variadicParamIdx = i;
anythingShuffled = true;
continue;
}
// If the source and destination index are different, we'll be shuffling.
if ((unsigned)sources[i] != i) {
anythingShuffled = true;
}
// We're matching one element to another. If the types already
// match, there's nothing to do.
const auto &fromElt = fromTuple->getElement(sources[i]);
auto fromEltType = fromElt.getType();
if (fromEltType->isEqual(toEltType)) {
// Get the sugared type directly from the tuple expression, if there
// is one.
if (fromTupleExpr)
fromEltType = fromTupleExpr->getElement(sources[i])->getType();
toSugarFields.push_back(toElt.getWithType(fromEltType));
fromTupleExprFields[sources[i]] = fromElt;
continue;
}
// We need to convert the source element to the destination type.
if (!fromTupleExpr) {
// FIXME: Lame! We can't express this in the AST.
auto anchorExpr = locator.getBaseLocator()->getAnchor();
InFlightDiagnostic diag = tc.diagnose(anchorExpr->getLoc(),
diag::tuple_conversion_not_expressible,
fromTuple, toTuple);
if (typeFromPattern) {
std::vector<std::pair<SourceLoc, std::string>> locInsertPairs;
TuplePattern *tupleP = dyn_cast<TuplePattern>(typeFromPattern.getValue());
if (tupleP && shouldApplyAddingLabelFixit(tupleP, toTuple, fromTuple,
locInsertPairs)) {
for (auto &Pair : locInsertPairs) {
diag.fixItInsert(Pair.first, Pair.second);
}
}
}
return nullptr;
}
// Actually convert the source element.
auto convertedElt
= coerceToType(fromTupleExpr->getElement(sources[i]), toEltType,
locator.withPathElement(
LocatorPathElt::getTupleElement(sources[i])));
if (!convertedElt)
return nullptr;
fromTupleExpr->setElement(sources[i], convertedElt);
// Record the sugared field name.
toSugarFields.push_back(toElt.getWithType(convertedElt->getType()));
fromTupleExprFields[sources[i]] =
fromElt.getWithType(convertedElt->getType());
}
// Convert all of the variadic arguments to the destination type.
ArraySliceType *arrayType = nullptr;
if (hasVariadic) {
Type toEltType = toTuple->getElements()[variadicParamIdx].getVarargBaseTy();
for (int fromFieldIdx : variadicArgs) {
const auto &fromElt = fromTuple->getElement(fromFieldIdx);
Type fromEltType = fromElt.getType();
// If the source and destination types match, there's nothing to do.
if (toEltType->isEqual(fromEltType)) {
fromTupleExprFields[fromFieldIdx] = fromElt;
continue;
}
// We need to convert the source element to the destination type.
if (!fromTupleExpr) {
// FIXME: Lame! We can't express this in the AST.
tc.diagnose(expr->getLoc(),
diag::tuple_conversion_not_expressible,
fromTuple, toTuple);
return nullptr;
}
// Actually convert the source element.
auto convertedElt = coerceToType(
fromTupleExpr->getElement(fromFieldIdx),
toEltType,
locator.withPathElement(
LocatorPathElt::getTupleElement(fromFieldIdx)));
if (!convertedElt)
return nullptr;
fromTupleExpr->setElement(fromFieldIdx, convertedElt);
fromTupleExprFields[fromFieldIdx] =
fromElt.getWithType(convertedElt->getType());
}
// Find the appropriate injection function.
if (tc.requireArrayLiteralIntrinsics(expr->getStartLoc()))
return nullptr;
arrayType = cast<ArraySliceType>(
toTuple->getElements()[variadicParamIdx].getType().getPointer());
}
// Compute the updated 'from' tuple type, since we may have
// performed some conversions in place.
Type fromTupleType = TupleType::get(fromTupleExprFields, tc.Context);
if (fromTupleExpr) {
fromTupleExpr->setType(fromTupleType);
// Update the types of parentheses around the tuple expression.
rebuildIdentityExprs(cs.getASTContext(), expr, fromTupleType);
}
// Compute the re-sugared tuple type.
Type toSugarType = hasInits? toTuple
: TupleType::get(toSugarFields, tc.Context);
// If we don't have to shuffle anything, we're done.
if (!anythingShuffled && fromTupleExpr) {
fromTupleExpr->setType(toSugarType);
// Update the types of parentheses around the tuple expression.
rebuildIdentityExprs(cs.getASTContext(), expr, toSugarType);
return expr;
}
// Create the tuple shuffle.
ArrayRef<int> mapping = tc.Context.AllocateCopy(sources);
auto callerDefaultArgsCopy = tc.Context.AllocateCopy(callerDefaultArgs);
auto shuffle = new (tc.Context) TupleShuffleExpr(
expr, mapping,
TupleShuffleExpr::SourceIsTuple,
callee,
tc.Context.AllocateCopy(variadicArgs),
callerDefaultArgsCopy,
toSugarType);
shuffle->setVarargsArrayType(arrayType);
return shuffle;
}
Expr *ExprRewriter::coerceScalarToTuple(Expr *expr, TupleType *toTuple,
int toScalarIdx,
ConstraintLocatorBuilder locator) {
auto &tc = solution.getConstraintSystem().getTypeChecker();
// If the destination type is variadic, compute the injection function to use.
Type arrayType = nullptr;
const auto &lastField = toTuple->getElements().back();
if (lastField.isVararg()) {
// Find the appropriate injection function.
arrayType = cast<ArraySliceType>(lastField.getType().getPointer());
if (tc.requireArrayLiteralIntrinsics(expr->getStartLoc()))
return nullptr;
}
// If we're initializing the varargs list, use its base type.
const auto &field = toTuple->getElement(toScalarIdx);
Type toScalarType;
if (field.isVararg())
toScalarType = field.getVarargBaseTy();
else
toScalarType = field.getType();
// Coerce the expression to the scalar type.
expr = coerceToType(expr, toScalarType,
locator.withPathElement(
ConstraintLocator::ScalarToTuple));
if (!expr)
return nullptr;
// Preserve the sugar of the scalar field.
// FIXME: This doesn't work if the type has default values because they fail
// to canonicalize.
SmallVector<TupleTypeElt, 4> sugarFields;
bool hasInit = false;
int i = 0;
for (auto &field : toTuple->getElements()) {
if (i == toScalarIdx) {
if (field.isVararg()) {
assert(expr->getType()->isEqual(field.getVarargBaseTy()) &&
"scalar field is not equivalent to dest vararg field?!");
sugarFields.push_back(field);
}
else {
assert(expr->getType()->isEqual(field.getType()) &&
"scalar field is not equivalent to dest tuple field?!");
sugarFields.push_back(field.getWithType(expr->getType()));
}
// Record the
} else {
sugarFields.push_back(field);
}
++i;
}
// Compute the elements of the resulting tuple.
SmallVector<int, 4> elements;
SmallVector<unsigned, 1> variadicArgs;
SmallVector<Expr*, 4> callerDefaultArgs;
ConcreteDeclRef callee =
findCalleeDeclRef(cs, solution, cs.getConstraintLocator(locator));
i = 0;
for (auto &field : toTuple->getElements()) {
if (field.isVararg()) {
elements.push_back(TupleShuffleExpr::Variadic);
if (i == toScalarIdx) {
variadicArgs.push_back(i);
++i;
continue;
}
}
// This is the scalar field, so act like we're shuffling the 0th element.
assert(i == toScalarIdx);
elements.push_back(0);
++i;
}
Type destSugarTy = hasInit? toTuple
: TupleType::get(sugarFields, tc.Context);
return new (tc.Context) TupleShuffleExpr(expr,
tc.Context.AllocateCopy(elements),
TupleShuffleExpr::SourceIsScalar,
callee,
tc.Context.AllocateCopy(variadicArgs),
tc.Context.AllocateCopy(callerDefaultArgs),
destSugarTy);
}
/// 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) {
SmallVector<ProtocolDecl *, 4> protocols;
toType->getAnyExistentialTypeProtocols(protocols);
SmallVector<ProtocolConformanceRef, 4> conformances;
for (auto proto : protocols) {
conformances.push_back(
*tc.containsProtocol(fromType, proto, 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 = expr->getType();
// Handle existential coercions that implicitly look through ImplicitlyUnwrappedOptional<T>.
if (auto ty = cs.lookThroughImplicitlyUnwrappedOptionalType(fromType)) {
expr = coerceImplicitlyUnwrappedOptionalToValue(expr, ty, locator);
fromType = expr->getType();
assert(!fromType->is<AnyMetatypeType>());
// FIXME: Hack. We shouldn't try to coerce existential when there is no
// existential upcast to perform.
if (fromType->isEqual(toType))
return expr;
}
Type fromInstanceType = fromType;
Type toInstanceType = toType;
// Look through metatypes
while (fromInstanceType->is<AnyMetatypeType>() &&
toInstanceType->is<ExistentialMetatypeType>()) {
fromInstanceType = fromInstanceType->castTo<AnyMetatypeType>()->getInstanceType();
toInstanceType = toInstanceType->castTo<ExistentialMetatypeType>()->getInstanceType();
}
ASTContext &ctx = tc.Context;
auto conformances =
collectExistentialConformances(tc, fromInstanceType, toInstanceType, cs.DC);
// For existential-to-existential coercions, open the source existential.
if (fromType->isAnyExistentialType()) {
fromType = ArchetypeType::getAnyOpened(fromType);
auto archetypeVal = new (ctx) OpaqueValueExpr(expr->getLoc(), fromType);
auto result = new (ctx) ErasureExpr(archetypeVal, toType, conformances);
return new (ctx) OpenExistentialExpr(expr, archetypeVal, result);
}
return new (ctx) ErasureExpr(expr, toType, conformances);
}
static unsigned getOptionalBindDepth(const BoundGenericType *bgt) {
if (bgt->getDecl()->classifyAsOptionalType()) {
auto tyarg = bgt->getGenericArgs()[0];
unsigned innerDepth = 0;
if (auto wrappedBGT = dyn_cast<BoundGenericType>(tyarg->
getCanonicalType())) {
innerDepth = getOptionalBindDepth(wrappedBGT);
}
return 1 + innerDepth;
}
return 0;
}
static Type getOptionalBaseType(const Type &type) {
if (auto bgt = dyn_cast<BoundGenericType>(type->
getCanonicalType())) {
if (bgt->getDecl()->classifyAsOptionalType()) {
return getOptionalBaseType(bgt->getGenericArgs()[0]);
}
}
return type;
}
Expr *ExprRewriter::coerceOptionalToOptional(Expr *expr, Type toType,
ConstraintLocatorBuilder locator,
Optional<Pattern*> typeFromPattern) {
auto &tc = cs.getTypeChecker();
Type fromType = expr->getType();
auto fromGenericType = fromType->castTo<BoundGenericType>();
auto toGenericType = toType->castTo<BoundGenericType>();
assert(fromGenericType->getDecl()->classifyAsOptionalType());
assert(toGenericType->getDecl()->classifyAsOptionalType());
tc.requireOptionalIntrinsics(expr->getLoc());
Type fromValueType = fromGenericType->getGenericArgs()[0];
Type toValueType = toGenericType->getGenericArgs()[0];
// If the option kinds are the same, and the wrapped types are the same,
// but the arities are different, we can peephole the optional-to-optional
// conversion into a series of nested injections.
auto toDepth = getOptionalBindDepth(toGenericType);
auto fromDepth = getOptionalBindDepth(fromGenericType);
if (toDepth > fromDepth) {
auto toBaseType = getOptionalBaseType(toGenericType);
auto fromBaseType = getOptionalBaseType(fromGenericType);
if ((toGenericType->getDecl() == fromGenericType->getDecl()) &&
toBaseType->isEqual(fromBaseType)) {
auto diff = toDepth - fromDepth;
auto isIUO = fromGenericType->getDecl()->
classifyAsOptionalType() == OTK_ImplicitlyUnwrappedOptional;
while (diff) {
const Type &t = expr->getType();
const Type &wrapped = isIUO ?
Type(ImplicitlyUnwrappedOptionalType::get(t)) :
Type(OptionalType::get(t));
expr = new (tc.Context) InjectIntoOptionalExpr(expr, wrapped);
diagnoseOptionalInjection(cast<InjectIntoOptionalExpr>(expr));
diff--;
}
return expr;
}
}
expr = new (tc.Context) BindOptionalExpr(expr, expr->getSourceRange().End,
/*depth*/ 0, fromValueType);
expr->setImplicit(true);
expr = coerceToType(expr, toValueType, locator, typeFromPattern);
if (!expr) return nullptr;
expr = new (tc.Context) InjectIntoOptionalExpr(expr, toType);
expr = new (tc.Context) OptionalEvaluationExpr(expr, toType);
expr->setImplicit(true);
return expr;
}
Expr *ExprRewriter::coerceImplicitlyUnwrappedOptionalToValue(Expr *expr, Type objTy,
ConstraintLocatorBuilder locator) {
auto optTy = expr->getType();
// Coerce to an r-value.
if (optTy->is<LValueType>())
objTy = LValueType::get(objTy);
expr = new (cs.getTypeChecker().Context) ForceValueExpr(expr,
expr->getEndLoc());
expr->setType(objTy);
expr->setImplicit();
return expr;
}
/// Determine whether the given expression is a reference to an
/// unbound instance member of a type.
static bool isReferenceToMetatypeMember(Expr *expr) {
expr = expr->getSemanticsProvidingExpr();
if (auto dotIgnored = dyn_cast<DotSyntaxBaseIgnoredExpr>(expr))
return dotIgnored->getLHS()->getType()->is<AnyMetatypeType>();
if (auto dotSyntax = dyn_cast<DotSyntaxCallExpr>(expr))
return dotSyntax->getBase()->getType()->is<AnyMetatypeType>();
return false;
}
Expr *ExprRewriter::coerceCallArguments(
Expr *arg, Type paramType,
llvm::PointerUnion<ApplyExpr *, LevelTy> applyOrLevel,
ArrayRef<Identifier> argLabels,
bool hasTrailingClosure,
ConstraintLocatorBuilder locator) {
bool allParamsMatch = arg->getType()->isEqual(paramType);
// Find the callee declaration.
ConcreteDeclRef callee =
findCalleeDeclRef(cs, solution, cs.getConstraintLocator(locator));
// Determine the level,
unsigned level = 0;
if (applyOrLevel.is<LevelTy>()) {
// Level specified by caller.
level = applyOrLevel.get<LevelTy>();
} else if (callee) {
// Determine the level based on the application itself.
auto apply = applyOrLevel.get<ApplyExpr *>();
// Only calls to members of types can have level > 0.
auto calleeDecl = callee.getDecl();
if (calleeDecl->getDeclContext()->isTypeContext()) {
// Level 1 if we're not applying "self".
if (auto call = dyn_cast<CallExpr>(apply)) {
if (!calleeDecl->isInstanceMember() ||
!isReferenceToMetatypeMember(call->getDirectCallee()))
level = 1;
} else if (isa<PrefixUnaryExpr>(apply) ||
isa<PostfixUnaryExpr>(apply) ||
isa<BinaryExpr>(apply)) {
level = 1;
}
}
}
// Determine the parameter bindings.
auto params = decomposeParamType(paramType, callee.getDecl(), level);
auto args = decomposeArgType(arg->getType(), argLabels);
// Quickly test if any further fix-ups for the argument types are necessary.
// FIXME: This hack is only necessary to work around some problems we have
// for inferring the type of an unresolved member reference expression in
// an optional context. We should seek a more holistic fix for this.
if (allParamsMatch &&
(params.size() == args.size())) {
if (auto argTuple = dyn_cast<TupleExpr>(arg)) {
auto argElts = argTuple->getElements();
for (size_t i = 0; i < params.size(); i++) {
if (auto dotExpr = dyn_cast<DotSyntaxCallExpr>(argElts[i])) {
auto paramTy = params[i].Ty->getLValueOrInOutObjectType();
auto argTy = dotExpr->getType()->getLValueOrInOutObjectType();
if (!paramTy->isEqual(argTy)) {
allParamsMatch = false;
break;
}
}
}
}
}
if (allParamsMatch)
return arg;
MatchCallArgumentListener listener;
SmallVector<ParamBinding, 4> parameterBindings;
bool failed = constraints::matchCallArguments(args, params,
hasTrailingClosure,
/*allowFixes=*/false, listener,
parameterBindings);
assert(!failed && "Call arguments did not match up?");
(void)failed;
// We should either have parentheses or a tuple.
TupleExpr *argTuple = dyn_cast<TupleExpr>(arg);
ParenExpr *argParen = dyn_cast<ParenExpr>(arg);
// FIXME: Eventually, we want to enforce that we have either argTuple or
// argParen here.
// 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;
};
// Local function to extract the ith argument label, which papers over some
// of the weirdness with tuples vs. parentheses.
auto getArgLabel = [&](unsigned i) -> Identifier {
if (argTuple)
return argTuple->getElementName(i);
assert(i == 0 && "Scalar only has a single argument");
return Identifier();
};
// Local function to produce a locator to refer to the ith element of the
// argument tuple.
auto getArgLocator = [&](unsigned argIdx, unsigned paramIdx)
-> ConstraintLocatorBuilder {
return locator.withPathElement(
LocatorPathElt::getApplyArgToParam(argIdx, paramIdx));
};
auto &tc = getConstraintSystem().getTypeChecker();
bool anythingShuffled = false;
SmallVector<TupleTypeElt, 4> toSugarFields;
SmallVector<TupleTypeElt, 4> fromTupleExprFields(
argTuple? argTuple->getNumElements() : 1);
SmallVector<Expr*, 4> fromTupleExpr(argTuple? argTuple->getNumElements() : 1);
SmallVector<unsigned, 4> variadicArgs;
SmallVector<Expr *, 2> callerDefaultArgs;
Type sliceType = nullptr;
SmallVector<int, 4> sources;
for (unsigned paramIdx = 0, numParams = parameterBindings.size();
paramIdx != numParams; ++paramIdx) {
// Extract the parameter.
const auto &param = params[paramIdx];
// Handle variadic parameters.
if (param.isVariadic()) {
// Find the appropriate injection function.
if (tc.requireArrayLiteralIntrinsics(arg->getStartLoc()))
return nullptr;
// Record this parameter.
auto paramBaseType = param.Ty;
assert(sliceType.isNull() && "Multiple variadic parameters?");
sliceType = tc.getArraySliceType(arg->getLoc(), paramBaseType);
toSugarFields.push_back(
TupleTypeElt(sliceType, param.Label, param.parameterFlags));
anythingShuffled = true;
sources.push_back(TupleShuffleExpr::Variadic);
// Convert the arguments.
for (auto argIdx : parameterBindings[paramIdx]) {
auto arg = getArg(argIdx);
auto argType = arg->getType();
variadicArgs.push_back(argIdx);
// If the argument type exactly matches, this just works.
if (argType->isEqual(paramBaseType)) {
fromTupleExprFields[argIdx] = TupleTypeElt(argType,
getArgLabel(argIdx));
fromTupleExpr[argIdx] = arg;
continue;
}
// Convert the argument.
auto convertedArg = coerceToType(arg, paramBaseType,
getArgLocator(argIdx, paramIdx));
if (!convertedArg)
return nullptr;
// Add the converted argument.
fromTupleExpr[argIdx] = convertedArg;
fromTupleExprFields[argIdx] = TupleTypeElt(convertedArg->getType(),
getArgLabel(argIdx));
}
continue;
}
// If we are using a default argument, handle it now.
if (parameterBindings[paramIdx].empty()) {
// Create a caller-side default argument, if we need one.
Expr *defArg;
DefaultArgumentKind defArgKind;
std::tie(defArg, defArgKind) = getCallerDefaultArg(tc, dc, arg->getLoc(),
callee, paramIdx);
// Note that we'll be doing a shuffle involving default arguments.
anythingShuffled = true;
toSugarFields.push_back(TupleTypeElt(
param.isVariadic()
? tc.getArraySliceType(arg->getLoc(),
param.Ty)
: param.Ty,
param.Label,
param.parameterFlags));
if (defArg) {
callerDefaultArgs.push_back(defArg);
sources.push_back(TupleShuffleExpr::CallerDefaultInitialize);
} else {
sources.push_back(TupleShuffleExpr::DefaultInitialize);
}
continue;
}
// Extract the argument used to initialize this parameter.
assert(parameterBindings[paramIdx].size() == 1);
unsigned argIdx = parameterBindings[paramIdx].front();
auto arg = getArg(argIdx);
auto argType = arg->getType();
// If the argument and parameter indices differ, or if the names differ,
// this is a shuffle.
sources.push_back(argIdx);
if (argIdx != paramIdx || getArgLabel(argIdx) != param.Label) {
anythingShuffled = true;
}
// If the types exactly match, this is easy.
auto paramType = param.Ty;
if (argType->isEqual(paramType)) {
toSugarFields.push_back(
TupleTypeElt(argType, param.Label, param.parameterFlags));
fromTupleExprFields[argIdx] =
TupleTypeElt(paramType, param.Label, param.parameterFlags);
fromTupleExpr[argIdx] = arg;
continue;
}
// Convert the argument.
auto convertedArg = coerceToType(arg, paramType,
getArgLocator(argIdx, paramIdx));
if (!convertedArg)
return nullptr;
// Add the converted argument.
fromTupleExpr[argIdx] = convertedArg;
fromTupleExprFields[argIdx] = TupleTypeElt(
convertedArg->getType(), getArgLabel(argIdx), param.parameterFlags);
toSugarFields.push_back(
TupleTypeElt(argType, param.Label, param.parameterFlags));
}
// Compute a new 'arg', from the bits we have. We have three cases: the
// scalar case, the paren case, and the tuple literal case.
if (!argTuple && !argParen) {
assert(fromTupleExpr.size() == 1 && fromTupleExpr[0]);
arg = fromTupleExpr[0];
} else if (argParen) {
// If the element changed, rebuild a new ParenExpr.
assert(fromTupleExpr.size() == 1 && fromTupleExpr[0]);
if (fromTupleExpr[0] != argParen->getSubExpr()) {
bool argParenImplicit = argParen->isImplicit();
argParen = new (tc.Context) ParenExpr(argParen->getLParenLoc(),
fromTupleExpr[0],
argParen->getRParenLoc(),
argParen->hasTrailingClosure(),
fromTupleExpr[0]->getType());
if (argParenImplicit) {
argParen->setImplicit();
}
arg = argParen;
} else {
// coerceToType may have updated the element type of the ParenExpr in
// place. If so, propagate the type out to the ParenExpr as well.
argParen->setType(fromTupleExpr[0]->getType());
}
} else {
assert(argTuple);
bool anyChanged = false;
for (unsigned i = 0, e = argTuple->getNumElements(); i != e; ++i)
if (fromTupleExpr[i] != argTuple->getElement(i)) {
anyChanged = true;
break;
}
// If anything about the TupleExpr changed, rebuild a new one.
Type argTupleType = TupleType::get(fromTupleExprFields, tc.Context);
if (anyChanged || !argTuple->getType()->isEqual(argTupleType)) {
auto EltNames = argTuple->getElementNames();
auto EltNameLocs = argTuple->getElementNameLocs();
argTuple = TupleExpr::create(tc.Context, argTuple->getLParenLoc(),
fromTupleExpr, EltNames, EltNameLocs,
argTuple->getRParenLoc(),
argTuple->hasTrailingClosure(),
argTuple->isImplicit(),
argTupleType);
arg = argTuple;
}
}
// If we don't have to shuffle anything, we're done.
if (arg->getType()->isEqual(paramType))
return arg;
// If we came from a scalar, create a scalar-to-tuple conversion.
auto isSourceScalar = TupleShuffleExpr::SourceIsScalar_t(argTuple == nullptr);
// Create the tuple shuffle.
ArrayRef<int> mapping = tc.Context.AllocateCopy(sources);
auto callerDefaultArgsCopy = tc.Context.AllocateCopy(callerDefaultArgs);
auto shuffle = new (tc.Context) TupleShuffleExpr(
arg, mapping,
isSourceScalar,
callee,
tc.Context.AllocateCopy(variadicArgs),
callerDefaultArgsCopy,
paramType);
shuffle->setVarargsArrayType(sliceType);
return shuffle;
}
/// 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(Expr *expr, Type toType) {
// Look through identity expressions, like parens.
if (auto IE = dyn_cast<IdentityExpr>(expr)) {
if (!applyTypeToClosureExpr(IE->getSubExpr(), toType)) return false;
IE->setType(toType);
return true;
}
// If we found an explicit ClosureExpr, update its type.
if (auto CE = dyn_cast<ClosureExpr>(expr)) {
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 = 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 (singleExpr->getType()->getAs<LValueType>())
singleExpr->setType(singleExpr->getType()->getLValueOrInOutObjectType());
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 = closureExpr->getType()->getAs<FunctionType>();
Type inputType = fnType->getInput();
auto newClosureType = FunctionType::get(inputType,
tc.Context.TheEmptyTupleType,
fnType->getExtInfo());
closureExpr->setType(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();
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;
}
static void
maybeDiagnoseUnsupportedFunctionConversion(TypeChecker &tc, Expr *expr,
AnyFunctionType *toType) {
Type fromType = expr->getType();
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 = expr->getSemanticsProvidingExpr();
while (auto ignoredBase = dyn_cast<DotSyntaxBaseIgnoredExpr>(semanticExpr)){
semanticExpr = ignoredBase->getRHS()->getSemanticsProvidingExpr();
}
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);
}
}
static CollectionUpcastConversionExpr::ConversionPair
buildElementConversion(ExprRewriter &rewriter,
SourceLoc srcLoc,
Type srcCollectionType,
Type destCollectionType,
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.
ASTContext &ctx = rewriter.getConstraintSystem().getASTContext();
auto opaque = new (ctx) OpaqueValueExpr(srcLoc, srcType);
auto conversion =
rewriter.coerceToType(opaque, destType,
locator.withPathElement(
ConstraintLocator::PathElement::getGenericArgument(typeArgIndex)));
return { opaque, conversion };
}
Expr *ExprRewriter::coerceToType(Expr *expr, Type toType,
ConstraintLocatorBuilder locator,
Optional<Pattern*> typeFromPattern) {
auto &tc = cs.getTypeChecker();
// The type we're converting from.
Type fromType = expr->getType();
// 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::TupleToTuple: {
auto fromTuple = fromType->castTo<TupleType>();
auto toTuple = toType->castTo<TupleType>();
SmallVector<int, 4> sources;
SmallVector<unsigned, 4> variadicArgs;
bool failed = computeTupleShuffle(fromTuple, toTuple,
sources, variadicArgs);
assert(!failed && "Couldn't convert tuple to tuple?");
(void)failed;
return coerceTupleToTuple(expr, fromTuple, toTuple, locator, sources,
variadicArgs, typeFromPattern);
}
case ConversionRestrictionKind::ScalarToTuple: {
auto toTuple = toType->castTo<TupleType>();
return coerceScalarToTuple(expr, toTuple,
toTuple->getElementForScalarInit(), locator);
}
case ConversionRestrictionKind::TupleToScalar: {
// If this was a single-element tuple expression, reach into that
// subexpression.
// FIXME: This is a hack to deal with @lvalue-ness issues. It loses
// source information.
if (auto fromTupleExpr = dyn_cast<TupleExpr>(expr)) {
if (fromTupleExpr->getNumElements() == 1) {
return coerceToType(fromTupleExpr->getElement(0), toType,
locator.withPathElement(
LocatorPathElt::getTupleElement(0)));
}
}
// Extract the element.
auto fromTuple = fromType->castTo<TupleType>();
expr = new (cs.getASTContext()) TupleElementExpr(
expr,
expr->getLoc(),
0,
expr->getLoc(),
fromTuple->getElementType(0));
expr->setImplicit(true);
// Coerce the element to the expected type.
return coerceToType(expr, toType,
locator.withPathElement(
LocatorPathElt::getTupleElement(0)));
}
case ConversionRestrictionKind::DeepEquality:
llvm_unreachable("Equality handled above");
case ConversionRestrictionKind::Superclass: {
// Coercion from archetype to its (concrete) superclass.
if (auto fromArchetype = fromType->getAs<ArchetypeType>()) {
expr = new (tc.Context) ArchetypeToSuperExpr(
expr,
fromArchetype->getSuperclass());
// If we are done succeeded, use the coerced result.
if (expr->getType()->isEqual(toType)) {
return expr;
}
fromType = expr->getType();
}
// Coercion from subclass to superclass.
return new (tc.Context) DerivedToBaseExpr(expr, toType);
}
case ConversionRestrictionKind::LValueToRValue: {
if (toType->is<TupleType>() || fromType->is<TupleType>())
break;
// Load from the lvalue.
expr->propagateLValueAccessKind(AccessKind::Read);
expr = new (tc.Context) LoadExpr(expr, fromType->getRValueType());
// Coerce the result.
return coerceToType(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 new (tc.Context) ClassMetatypeToObjectExpr(expr, toType);
}
case ConversionRestrictionKind::ExistentialMetatypeToAnyObject: {
assert(tc.getLangOpts().EnableObjCInterop
&& "metatypes can only be cast to objects w/ objc runtime!");
return new (tc.Context) ExistentialMetatypeToObjectExpr(expr, toType);
}
case ConversionRestrictionKind::ProtocolMetatypeToProtocolClass: {
return new (tc.Context) ProtocolMetatypeToObjectExpr(expr, toType);
}
case ConversionRestrictionKind::ValueToOptional: {
auto toGenericType = toType->castTo<BoundGenericType>();
assert(toGenericType->getDecl()->classifyAsOptionalType());
tc.requireOptionalIntrinsics(expr->getLoc());
Type valueType = toGenericType->getGenericArgs()[0];
expr = coerceToType(expr, valueType, locator);
if (!expr) return nullptr;
auto *result = new (tc.Context) InjectIntoOptionalExpr(expr, toType);
diagnoseOptionalInjection(result);
return result;
}
case ConversionRestrictionKind::OptionalToImplicitlyUnwrappedOptional:
case ConversionRestrictionKind::ImplicitlyUnwrappedOptionalToOptional:
case ConversionRestrictionKind::OptionalToOptional:
return coerceOptionalToOptional(expr, toType, locator, typeFromPattern);
case ConversionRestrictionKind::ForceUnchecked: {
auto valueTy = fromType->getImplicitlyUnwrappedOptionalObjectType();
assert(valueTy);
expr = coerceImplicitlyUnwrappedOptionalToValue(expr, valueTy, locator);
return coerceToType(expr, toType, locator);
}
case ConversionRestrictionKind::ArrayUpcast: {
// Look through implicitly unwrapped optionals.
if (auto objTy= cs.lookThroughImplicitlyUnwrappedOptionalType(fromType)) {
expr = coerceImplicitlyUnwrappedOptionalToValue(expr, objTy, locator);
}
// Build the value conversion.
auto conv = buildElementConversion(*this, expr->getLoc(), expr->getType(),
toType, locator, 0);
// Form the upcast.
return new (tc.Context) CollectionUpcastConversionExpr(expr, toType,
{}, conv);
}
case ConversionRestrictionKind::HashableToAnyHashable: {
// Look through implicitly unwrapped optionals.
if (auto objTy
= cs.lookThroughImplicitlyUnwrappedOptionalType(expr->getType())) {
expr = coerceImplicitlyUnwrappedOptionalToValue(expr, objTy, locator);
}
// We want to check conformance on the rvalue, as that's what has
// the Hashable conformance
expr = tc.coerceToRValue(expr);
// Find the conformance of the source type to Hashable.
auto hashable = tc.Context.getProtocol(KnownProtocolKind::Hashable);
auto conformance =
tc.conformsToProtocol(expr->getType(), hashable, cs.DC,
(ConformanceCheckFlags::InExpression |
ConformanceCheckFlags::Used));
assert(conformance && "must conform to Hashable");
return new (tc.Context) AnyHashableErasureExpr(expr, toType,
*conformance);
}
case ConversionRestrictionKind::DictionaryUpcast: {
// Look through implicitly unwrapped optionals.
if (auto objTy
= cs.lookThroughImplicitlyUnwrappedOptionalType(expr->getType())) {
expr = coerceImplicitlyUnwrappedOptionalToValue(expr, objTy, locator);
}
// Build the key and value conversions.
auto keyConv = buildElementConversion(
*this, expr->getLoc(), expr->getType(), toType, locator, 0);
auto valueConv = buildElementConversion(
*this, expr->getLoc(), expr->getType(), toType, locator, 1);
// If the source key and value types are object types, this is an upcast.
// Otherwise, it's bridged.
Type sourceKey, sourceValue;
std::tie(sourceKey, sourceValue) = *cs.isDictionaryType(expr->getType());
return new (tc.Context) CollectionUpcastConversionExpr(expr, toType,
keyConv,
valueConv);
}
case ConversionRestrictionKind::SetUpcast: {
// Look through implicitly unwrapped optionals.
if (auto objTy
= cs.lookThroughImplicitlyUnwrappedOptionalType(expr->getType())) {
expr = coerceImplicitlyUnwrappedOptionalToValue(expr, objTy, locator);
}
// Build the value conversion.
auto conv = buildElementConversion(*this, expr->getLoc(), expr->getType(),
toType, locator, 0);
return new (tc.Context) CollectionUpcastConversionExpr(expr, toType,
{}, conv);
}
case ConversionRestrictionKind::InoutToPointer: {
OptionalTypeKind optionalKind;
Type unwrappedTy = toType;
if (Type unwrapped = toType->getAnyOptionalObjectType(optionalKind))
unwrappedTy = unwrapped;
PointerTypeKind pointerKind;
auto toEltType = unwrappedTy->getAnyPointerElementType(pointerKind);
assert(toEltType && "not a pointer type?"); (void) toEltType;
if (pointerKind == PTK_UnsafePointer) {
// Overwrite the l-value access kind to be read-only if we're
// converting to a non-mutable pointer type.
cast<InOutExpr>(expr->getValueProvidingExpr())->getSubExpr()
->propagateLValueAccessKind(AccessKind::Read, /*overwrite*/ true);
}
tc.requirePointerArgumentIntrinsics(expr->getLoc());
Expr *result = new (tc.Context) InOutToPointerExpr(expr, unwrappedTy);
if (optionalKind != OTK_None)
result = new (tc.Context) InjectIntoOptionalExpr(result, toType);
return result;
}
case ConversionRestrictionKind::ArrayToPointer: {
OptionalTypeKind optionalKind;
Type unwrappedTy = toType;
if (Type unwrapped = toType->getAnyOptionalObjectType(optionalKind))
unwrappedTy = unwrapped;
tc.requirePointerArgumentIntrinsics(expr->getLoc());
Expr *result = new (tc.Context) ArrayToPointerExpr(expr, unwrappedTy);
if (optionalKind != OTK_None)
result = new (tc.Context) InjectIntoOptionalExpr(result, toType);
return result;
}
case ConversionRestrictionKind::StringToPointer: {
OptionalTypeKind optionalKind;
Type unwrappedTy = toType;
if (Type unwrapped = toType->getAnyOptionalObjectType(optionalKind))
unwrappedTy = unwrapped;
tc.requirePointerArgumentIntrinsics(expr->getLoc());
Expr *result = new (tc.Context) StringToPointerExpr(expr, unwrappedTy);
if (optionalKind != OTK_None)
result = new (tc.Context) InjectIntoOptionalExpr(result, toType);
return result;
}
case ConversionRestrictionKind::PointerToPointer: {
tc.requirePointerArgumentIntrinsics(expr->getLoc());
Type unwrappedToTy = toType->getAnyOptionalObjectType();
// Optional to optional.
if (Type unwrappedFromTy = expr->getType()->getAnyOptionalObjectType()) {
assert(unwrappedToTy && "converting optional to non-optional");
Expr *boundOptional =
new (tc.Context) BindOptionalExpr(expr, SourceLoc(), /*depth*/0,
unwrappedFromTy);
Expr *converted =
new (tc.Context) PointerToPointerExpr(boundOptional, unwrappedToTy);
Expr *rewrapped =
new (tc.Context) InjectIntoOptionalExpr(converted, toType);
return new (tc.Context) OptionalEvaluationExpr(rewrapped, toType);
}
// Non-optional to optional.
if (unwrappedToTy) {
Expr *converted =
new (tc.Context) PointerToPointerExpr(expr, unwrappedToTy);
return new (tc.Context) InjectIntoOptionalExpr(converted, toType);
}
// Non-optional to non-optional.
return new (tc.Context) PointerToPointerExpr(expr, toType);
}
case ConversionRestrictionKind::BridgeToObjC: {
Expr *objcExpr = bridgeToObjectiveC(expr);
if (!objcExpr)
return nullptr;
return coerceToType(objcExpr, toType, locator);
}
case ConversionRestrictionKind::BridgeFromObjC:
return forceBridgeFromObjectiveC(expr, toType);
case ConversionRestrictionKind::CFTollFreeBridgeToObjC: {
auto foreignClass = fromType->getClassOrBoundGenericClass();
auto objcType = foreignClass->getAttrs().getAttribute<ObjCBridgedAttr>()
->getObjCClass()->getDeclaredInterfaceType();
auto asObjCClass = 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 new (tc.Context) ForeignObjectConversionExpr(result, toType);
}
}
}
// Tuple-to-scalar conversion.
if (auto fromTuple = fromType->getAs<TupleType>()) {
if (fromTuple->getNumElements() == 1 &&
!fromTuple->getElement(0).isVararg() &&
!toType->is<TupleType>()) {
expr = new (cs.getASTContext()) TupleElementExpr(
expr,
expr->getLoc(),
0,
expr->getLoc(),
fromTuple->getElementType(0));
expr->setImplicit(true);
}
}
// 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.
if (auto fromLValue = fromType->getAs<LValueType>()) {
if (auto *toIO = toType->getAs<InOutType>()) {
(void)toIO;
// In an 'inout' operator like "++i", the operand is converted from
// an implicit lvalue to an inout argument.
assert(toIO->getObjectType()->isEqual(fromLValue->getObjectType()));
expr->propagateLValueAccessKind(AccessKind::ReadWrite);
return new (tc.Context) InOutExpr(expr->getStartLoc(), expr,
toType, /*isImplicit*/true);
}
// If we're actually turning this into an lvalue tuple element, don't
// load.
bool performLoad = true;
if (auto toTuple = toType->getAs<TupleType>()) {
int scalarIdx = toTuple->getElementForScalarInit();
if (scalarIdx >= 0 &&
toTuple->getElementType(scalarIdx)->is<InOutType>())
performLoad = false;
}
if (performLoad) {
// Load from the lvalue.
expr->propagateLValueAccessKind(AccessKind::Read);
expr = new (tc.Context) LoadExpr(expr, fromLValue->getObjectType());
// Coerce the result.
return coerceToType(expr, toType, locator);
}
}
// Coercions to tuple type.
if (auto toTuple = toType->getAs<TupleType>()) {
// Coerce from a tuple to a tuple.
if (auto fromTuple = fromType->getAs<TupleType>()) {
SmallVector<int, 4> sources;
SmallVector<unsigned, 4> variadicArgs;
if (!computeTupleShuffle(fromTuple, toTuple, sources, variadicArgs)) {
return coerceTupleToTuple(expr, fromTuple, toTuple,
locator, sources, variadicArgs);
}
}
// Coerce scalar to tuple.
int toScalarIdx = toTuple->getElementForScalarInit();
if (toScalarIdx != -1) {
return coerceScalarToTuple(expr, toTuple, toScalarIdx, locator);
}
}
// Coercion from a subclass to a superclass.
if (fromType->mayHaveSuperclass() &&
toType->getClassOrBoundGenericClass()) {
for (auto fromSuperClass = tc.getSuperClassOf(fromType);
fromSuperClass;
fromSuperClass = tc.getSuperClassOf(fromSuperClass)) {
if (fromSuperClass->isEqual(toType)) {
// Coercion from archetype to its (concrete) superclass.
if (auto fromArchetype = fromType->getAs<ArchetypeType>()) {
expr = new (tc.Context) ArchetypeToSuperExpr(
expr,
fromArchetype->getSuperclass());
// If we succeeded, use the coerced result.
if (expr->getType()->isEqual(toType))
return expr;
}
// Coercion from subclass to superclass.
return new (tc.Context) DerivedToBaseExpr(expr, toType);
}
}
}
// Coercions to function type.
if (auto toFunc = toType->getAs<FunctionType>()) {
// Coercion to an autoclosure type produces an implicit closure.
// FIXME: The type checker is more lenient, and allows @autoclosures to
// be subtypes of non-@autoclosures, which is bogus.
if (toFunc->isAutoClosure()) {
// Convert the value to the expected result type of the function.
expr = coerceToType(expr, toFunc->getResult(),
locator.withPathElement(ConstraintLocator::Load));
// We'll set discriminator values on all the autoclosures in a
// later pass.
auto discriminator = AutoClosureExpr::InvalidDiscriminator;
auto closure = new (tc.Context) AutoClosureExpr(expr, toType,
discriminator, dc);
closure->setParameterList(ParameterList::createEmpty(tc.Context));
// Compute the capture list, now that we have analyzed the expression.
tc.ClosuresWithUncomputedCaptures.push_back(closure);
return closure;
}
// Coercion from one function type to another, this produces a
// FunctionConversionExpr in its full generality.
if (auto fromFunc = fromType->getAs<FunctionType>()) {
// If toType is a NoEscape or NoReturn function type and the expression is
// a ClosureExpr, propagate these bits onto the ClosureExpr. Do not
// *remove* any bits that are already on the closure though.
// Note that in this case, we do not want to propagate the 'throws' bit
// to the closure type, as the closure has already been analyzed for
// throwing subexpressions. We also don't want to change the convention
// of the original closure.
auto fromEI = fromFunc->getExtInfo(), toEI = toFunc->getExtInfo();
if (toEI.isNoEscape() && !fromEI.isNoEscape()) {
swift::AnyFunctionType::ExtInfo newEI(fromEI.getRepresentation(),
toEI.isAutoClosure(),
toEI.isNoEscape() | fromEI.isNoEscape(),
toEI.throws() & fromEI.throws());
auto newToType = FunctionType::get(fromFunc->getInput(),
fromFunc->getResult(), newEI);
if (applyTypeToClosureExpr(expr, newToType)) {
fromFunc = newToType;
// Propagating the bits in might have satisfied the entire
// conversion. If so, we're done, otherwise keep converting.
if (fromFunc->isEqual(toType))
return expr;
}
}
maybeDiagnoseUnsupportedFunctionConversion(tc, expr, toFunc);
return new (tc.Context) FunctionConversionExpr(expr, toType);
}
}
// Coercions from a type to an existential type.
if (toType->isAnyExistentialType()) {
return coerceExistential(expr, toType, locator);
}
if (toType->getAnyOptionalObjectType() &&
expr->getType()->getAnyOptionalObjectType()) {
return coerceOptionalToOptional(expr, toType, locator, typeFromPattern);
}
// Coercion to Optional<T>.
if (auto toGenericType = toType->getAs<BoundGenericType>()) {
if (toGenericType->getDecl()->classifyAsOptionalType()) {
tc.requireOptionalIntrinsics(expr->getLoc());
Type valueType = toGenericType->getGenericArgs()[0];
expr = coerceToType(expr, valueType, locator);
if (!expr) return nullptr;
auto *result = new (tc.Context) InjectIntoOptionalExpr(expr, toType);
diagnoseOptionalInjection(result);
return result;
}
}
// Coercion from one metatype to another.
if (fromType->is<MetatypeType>()) {
auto toMeta = toType->castTo<MetatypeType>();
return new (tc.Context) MetatypeConversionExpr(expr, toMeta);
}
// Conversion to/from UnresolvedType.
if (fromType->is<UnresolvedType>() || toType->is<UnresolvedType>())
return 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->getLValueOrInOutObjectType();
if (auto func = dyn_cast<AbstractFunctionDecl>(member)) {
// If 'self' is an inout type, turn the base type into an lvalue
// type with the same qualifiers.
auto selfTy = func->getType()->getAs<AnyFunctionType>()->getInput();
if (selfTy->is<InOutType>()) {
// Unless we're looking at a nonmutating existential member. In which
// case, the member will be modeled as an inout but ExistentialMemberRef
// and ArchetypeMemberRef want to take the base as an rvalue.
if (auto *fd = dyn_cast<FuncDecl>(func))
if (!fd->isMutating() &&
baseObjectTy->hasDependentProtocolConformances())
return baseObjectTy;
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.
if (auto *SD = dyn_cast<AbstractStorageDecl>(member)) {
bool isSettableFromHere = SD->isSettable(UseDC)
&& (!UseDC->getASTContext().LangOpts.EnableAccessControl
|| 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->isSetterNonMutating()))
return baseObjectTy;
// If we're calling an accessor, keep the base as an inout type, because the
// getter may be mutating.
if (SD->hasAccessorFunctions() && baseTy->is<InOutType>() &&
semantics != AccessSemantics::DirectToStorage)
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 = expr->getType();
if (fromType->isEqual(toType))
return expr;
// If we're coercing to an rvalue type, just do it.
if (!toType->is<InOutType>())
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.
expr->propagateLValueAccessKind(AccessKind::ReadWrite);
return new (ctx) InOutExpr(expr->getStartLoc(), expr,
toType, /*isImplicit*/true);
}
Expr *ExprRewriter::convertLiteral(Expr *literal,
Type type,
Type openedType,
ProtocolDecl *protocol,
TypeOrName literalType,
DeclName literalFuncName,
ProtocolDecl *builtinProtocol,
TypeOrName builtinLiteralType,
DeclName builtinLiteralFuncName,
bool (*isBuiltinArgType)(Type),
Diag<> brokenProtocolDiag,
Diag<> brokenBuiltinProtocolDiag) {
auto &tc = cs.getTypeChecker();
// 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);
// The literal expression has this type.
literal->setType(type);
return literal;
}
// Check whether this literal type conforms to the builtin protocol.
Optional<ProtocolConformanceRef> builtinConformance;
if (builtinProtocol &&
(builtinConformance =
tc.conformsToProtocol(type, builtinProtocol, cs.DC,
ConformanceCheckFlags::InExpression))) {
// Find the builtin argument type we'll use.
Type argType;
if (builtinLiteralType.is<Type>())
argType = builtinLiteralType.get<Type>();
else
argType = tc.getWitnessType(type, builtinProtocol,
*builtinConformance,
builtinLiteralType.get<Identifier>(),
brokenBuiltinProtocolDiag);
if (!argType)
return nullptr;
// Make sure it's of an appropriate builtin type.
if (isBuiltinArgType && !isBuiltinArgType(argType)) {
tc.diagnose(builtinProtocol->getLoc(), brokenBuiltinProtocolDiag);
return nullptr;
}
// 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);
// The literal expression has this type.
literal->setType(argType);
// Call the builtin conversion operation.
// FIXME: Bogus location info.
Expr *base = TypeExpr::createImplicitHack(literal->getLoc(), type,
tc.Context);
Expr *result = tc.callWitness(base, dc,
builtinProtocol, *builtinConformance,
builtinLiteralFuncName,
literal,
brokenBuiltinProtocolDiag);
if (result)
result->setType(type);
return result;
}
// 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");
// Figure out the (non-builtin) argument type if there is one.
Type argType;
if (literalType.is<Identifier>() &&
literalType.get<Identifier>().empty()) {
// If there is no argument to the constructor function, then just pass in
// the empty tuple.
literal = TupleExpr::createEmpty(tc.Context, literal->getLoc(),
literal->getLoc(),
/*implicit*/!literal->getLoc().isValid());
} else {
// Otherwise, figure out the type of the constructor function and coerce to
// it.
if (literalType.is<Type>())
argType = literalType.get<Type>();
else
argType = tc.getWitnessType(type, protocol, *conformance,
literalType.get<Identifier>(),
brokenProtocolDiag);
if (!argType)
return nullptr;
// If the argument type is in error, we're done.
if (argType->hasError() || argType->getCanonicalType()->hasError())
return nullptr;
// Convert the literal to the non-builtin argument type via the
// builtin protocol, first.
// FIXME: Do we need an opened type here?
literal = convertLiteral(literal, argType, argType, nullptr, Identifier(),
Identifier(), builtinProtocol,
builtinLiteralType, builtinLiteralFuncName,
isBuiltinArgType, brokenProtocolDiag,
brokenBuiltinProtocolDiag);
if (!literal)
return nullptr;
}
// Convert the resulting expression to the final literal type.
// FIXME: Bogus location info.
Expr *base = TypeExpr::createImplicitHack(literal->getLoc(), type,
tc.Context);
literal = tc.callWitness(base, dc,
protocol, *conformance, literalFuncName,
literal, brokenProtocolDiag);
if (literal)
literal->setType(type);
return literal;
}
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();
// 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);
// The literal expression has this type.
literal->setType(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<AbstractFunctionDecl>(
tc, dc, type->getRValueType(), builtinProtocol,
builtinLiteralFuncName, brokenBuiltinProtocolDiag,
*builtinConformance);
if (!witness)
return nullptr;
// Form a reference to the builtin conversion function.
// FIXME: Bogus location info.
Expr *base = TypeExpr::createImplicitHack(literal->getLoc(), type,
tc.Context);
Expr *unresolvedDot = new (tc.Context) UnresolvedDotExpr(
base, SourceLoc(),
witness->getFullName(),
DeclNameLoc(base->getEndLoc()),
/*Implicit=*/true);
(void)tc.typeCheckExpression(unresolvedDot, dc);
ConcreteDeclRef builtinRef = unresolvedDot->getReferencedDecl();
if (!builtinRef) {
tc.diagnose(base->getLoc(), brokenBuiltinProtocolDiag);
return nullptr;
}
// Set the builtin initializer.
if (auto stringLiteral = dyn_cast<StringLiteralExpr>(literal))
stringLiteral->setBuiltinInitializer(builtinRef);
else {
cast<MagicIdentifierLiteralExpr>(literal)
->setBuiltinInitializer(builtinRef);
}
// The literal expression has this type.
literal->setType(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<AbstractFunctionDecl>(
tc, dc, type->getRValueType(), protocol,
literalFuncName, brokenProtocolDiag,
conformance);
if (!witness)
return nullptr;
// Form a reference to the conversion function.
// FIXME: Bogus location info.
Expr *base = TypeExpr::createImplicitHack(literal->getLoc(), type,
tc.Context);
Expr *unresolvedDot = new (tc.Context) UnresolvedDotExpr(
base, SourceLoc(),
witness->getFullName(),
DeclNameLoc(base->getEndLoc()),
/*Implicit=*/true);
(void)tc.typeCheckExpression(unresolvedDot, dc);
ConcreteDeclRef ref = unresolvedDot->getReferencedDecl();
if (!ref) {
tc.diagnose(base->getLoc(), brokenProtocolDiag);
return nullptr;
}
// Set the initializer.
if (auto stringLiteral = dyn_cast<StringLiteralExpr>(literal))
stringLiteral->setInitializer(ref);
else
cast<MagicIdentifierLiteralExpr>(literal)->setInitializer(ref);
// The literal expression has this type.
literal->setType(type);
return literal;
}
/// Determine whether the given type refers to a non-final class (or
/// dynamic self of one).
static bool isNonFinalClass(Type type) {
if (auto dynamicSelf = type->getAs<DynamicSelfType>())
type = dynamicSelf->getSelfType();
if (auto classDecl = type->getClassOrBoundGenericClass())
return !classDecl->isFinal();
if (auto archetype = type->getAs<ArchetypeType>())
if (auto super = archetype->getSuperclass())
return isNonFinalClass(super);
return false;
}
// Non-required constructors may not be not inherited. Therefore when
// constructing a class object, either the metatype must be statically
// derived (rather than an arbitrary value of metatype type) or the referenced
// constructor must be required.
bool
TypeChecker::diagnoseInvalidDynamicConstructorReferences(Expr *base,
DeclNameLoc memberRefLoc,
AnyMetatypeType *metaTy,
ConstructorDecl *ctorDecl,
bool SuppressDiagnostics) {
auto ty = metaTy->getInstanceType();
// FIXME: The "hasClangNode" check here is a complete hack.
if (isNonFinalClass(ty) &&
!base->isStaticallyDerivedMetatype() &&
!ctorDecl->hasClangNode() &&
!(ctorDecl->isRequired() ||
ctorDecl->getDeclContext()->getAsProtocolOrProtocolExtensionContext())) {
if (SuppressDiagnostics)
return false;
diagnose(memberRefLoc, diag::dynamic_construct_class, ty)
.highlight(base->getSourceRange());
auto ctor = cast<ConstructorDecl>(ctorDecl);
diagnose(ctorDecl, diag::note_nonrequired_initializer,
ctor->isImplicit(), ctor->getFullName());
// Constructors cannot be called on a protocol metatype, because there is no
// metatype to witness it.
} else if (isa<ConstructorDecl>(ctorDecl) &&
isa<MetatypeType>(metaTy) &&
ty->isExistentialType()) {
if (SuppressDiagnostics)
return false;
if (base->isStaticallyDerivedMetatype()) {
diagnose(memberRefLoc, diag::construct_protocol_by_name, ty)
.highlight(base->getSourceRange());
} else {
diagnose(memberRefLoc, diag::construct_protocol_value, metaTy)
.highlight(base->getSourceRange());
}
}
return true;
}
Expr *ExprRewriter::finishApply(ApplyExpr *apply, Type openedType,
ConstraintLocatorBuilder locator) {
TypeChecker &tc = cs.getTypeChecker();
auto fn = apply->getFn();
// The function is always an rvalue.
fn = tc.coerceToRValue(fn);
assert(fn && "Rvalue conversion failed?");
if (!fn)
return nullptr;
// Handle applications that look through ImplicitlyUnwrappedOptional<T>.
if (auto fnTy = cs.lookThroughImplicitlyUnwrappedOptionalType(fn->getType()))
fn = coerceImplicitlyUnwrappedOptionalToValue(fn, fnTy, locator);
// 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
= covariant->getType()->castTo<AnyFunctionType>()->getResult();
// Use the subexpression as the function.
fn = covariant->getSubExpr();
}
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 = fn->getType()->getAs<FunctionType>()) {
auto origArg = apply->getArg();
bool hasTrailingClosure =
isa<CallExpr>(apply) && cast<CallExpr>(apply)->hasTrailingClosure();
Expr *arg = coerceCallArguments(origArg, fnType->getInput(),
apply,
apply->getArgumentLabels(argLabelsScratch),
hasTrailingClosure,
locator.withPathElement(
ConstraintLocator::ApplyArgument));
if (!arg) {
return nullptr;
}
apply->setArg(arg);
apply->setType(fnType->getResult());
apply->setIsSuper(isSuper);
assert(!apply->getType()->is<PolymorphicFunctionType>() &&
"Polymorphic function type slipped through");
Expr *result = tc.substituteInputSugarTypeForResult(apply);
// Try closing the existential, if there is one.
closeExistential(result);
// If we have a covariant result type, perform the conversion now.
if (covariantResultType) {
if (covariantResultType->is<FunctionType>())
result = new (tc.Context) CovariantFunctionConversionExpr(
result,
covariantResultType);
else
result = new (tc.Context) CovariantReturnConversionExpr(
result,
covariantResultType);
}
// Extract all arguments.
auto *CEA = arg;
if (auto *TSE = dyn_cast<TupleShuffleExpr>(CEA))
CEA = TSE->getSubExpr();
// The argument is either a ParenExpr or TupleExpr.
ArrayRef<Expr *> arguments;
ArrayRef<TypeBase *> types;
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 = arg->getType()->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);
}
}
}
return result;
}
// If this is an UnresolvedType in the system, preserve it.
if (fn->getType()->is<UnresolvedType>()) {
apply->setType(fn->getType());
return apply;
}
// We have a type constructor.
auto metaTy = fn->getType()->castTo<AnyMetatypeType>();
auto ty = metaTy->getInstanceType();
// If this is an UnresolvedType in the system, preserve it.
if (ty->is<UnresolvedType>()) {
apply->setType(ty);
return apply;
}
// If the metatype value isn't a type expression, the user should reference
// '.init' explicitly, for clarity.
if (!fn->isTypeReference()) {
cs.TC.diagnose(apply->getArg()->getStartLoc(),
diag::missing_init_on_metatype_initialization)
.fixItInsert(apply->getArg()->getStartLoc(), ".init");
}
// 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.
assert(ty->getNominalOrBoundGenericNominal() || ty->is<DynamicSelfType>() ||
ty->hasDependentProtocolConformances());
auto ctorLocator = cs.getConstraintLocator(
locator.withPathElement(ConstraintLocator::ApplyFunction)
.withPathElement(ConstraintLocator::ConstructorMember));
auto selected = getOverloadChoiceIfAvailable(ctorLocator);
// We have the constructor.
auto choice = selected->choice;
auto decl = choice.getDecl();
// 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(),
decl, 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);
}
// 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.
static bool 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.
static bool 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) || isa<ParenExpr>(parent)) {
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;
}
// Return true if, when replacing "<expr>" with "<expr> as T", parentheses need
// to be added around <expr> first in order to maintain the correct precedence.
static bool exprNeedsParensBeforeAddingAs(TypeChecker &TC, DeclContext *DC,
Expr *expr) {
auto asPG =
TC.lookupPrecedenceGroup(DC, DC->getASTContext().Id_CastingPrecedence,
SourceLoc());
if (!asPG) return true;
return exprNeedsParensInsideFollowingOperator(TC, DC, expr, asPG);
}
// Return true if, when replacing "<expr>" with "<expr> as T", parentheses need
// to be added around the new expression in order to maintain the correct
// precedence.
static bool exprNeedsParensAfterAddingAs(TypeChecker &TC, DeclContext *DC,
Expr *expr, Expr *rootExpr) {
auto asPG =
TC.lookupPrecedenceGroup(DC, DC->getASTContext().Id_CastingPrecedence,
SourceLoc());
if (!asPG) return true;
return exprNeedsParensOutsideFollowingOperator(TC, DC, expr, rootExpr, asPG);
}
static bool exprNeedsParensInsidePostfixOperator(TypeChecker &TC,
DeclContext *DC,
Expr *expr) {
// Prefix and infix operators will bind outside of a postfix operator.
// Postfix operators will get token-merged with a new postfix operator.
return (isa<PrefixUnaryExpr>(expr) ||
isa<PostfixUnaryExpr>(expr) ||
isa<OptionalEvaluationExpr>(expr) ||
expr->isInfixOperator());
}
namespace {
class ExprWalker : public ASTWalker {
ExprRewriter &Rewriter;
SmallVector<ClosureExpr *, 4> closuresToTypeCheck;
public:
ExprWalker(ExprRewriter &Rewriter) : Rewriter(Rewriter) { }
~ExprWalker() {
// If we're re-typechecking an expression for diagnostics, don't
// visit closures that have non-single expression bodies.
if (Rewriter.SkipClosures)
return;
auto &cs = Rewriter.getConstraintSystem();
auto &tc = cs.getTypeChecker();
for (auto *closure : closuresToTypeCheck)
tc.typeCheckClosureBody(closure);
}
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 = closure->getType()->castTo<FunctionType>();
auto *params = closure->getParameters();
if (tc.coerceParameterListToType(params, closure, fnType))
return { false, nullptr };
// 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() && !body->getType()->isVoid()) {
closure = Rewriter.coerceClosureExprToVoid(closure);
// A single-expression closure with a Never expression type
// coerces to any other function type.
} else if (!fnType->getResult()->isUninhabited() &&
body->getType()->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.
closuresToTypeCheck.push_back(closure);
}
tc.ClosuresWithUncomputedCaptures.push_back(closure);
return { false, closure };
}
Rewriter.walkToExprPre(expr);
return { true, expr };
}
Expr *walkToExprPost(Expr *expr) override {
Expr *result = Rewriter.walkToExprPost(expr);
if (result && result->getType())
Rewriter.checkForImportedUsedConformances(result->getType());
return result;
}
/// \brief Ignore statements.
std::pair<bool, Stmt *> walkToStmtPre(Stmt *stmt) override {
return { false, stmt };
}
/// \brief Ignore declarations.
bool walkToDeclPre(Decl *decl) override { return false; }
};
}
/// 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) {
bool diagnosed = false;
for (unsigned i = 0, e = solution.Fixes.size(); i != e; ++i)
diagnosed |= applySolutionFix(E, solution, i);
return diagnosed;
}
/// \brief Apply the specified Fix # to this solution, producing a fixit hint
/// diagnostic for it and returning true. If the fixit hint turned out to be
/// bogus, this returns false and doesn't emit anything.
bool ConstraintSystem::applySolutionFix(Expr *expr,
const Solution &solution,
unsigned fixNo) {
auto &fix = solution.Fixes[fixNo];
// Some fixes need more information from the locator.
ConstraintLocator *locator = fix.second;
// In the case of us having applied a type member constraint against a
// synthesized type variable during diagnostic generation, we may not have
// a valid locator.
if (!locator)
return false;
// Resolve the locator to a specific expression.
SourceRange range;
bool isSubscriptMember =
(!locator->getPath().empty() &&
locator->getPath().back().getKind() == ConstraintLocator::SubscriptMember);
ConstraintLocator *resolved = simplifyLocator(*this, locator, range);
// If we didn't manage to resolve directly to an expression, we don't
// have a great diagnostic to give, so bail.
if (!resolved || !resolved->getAnchor() ||
!resolved->getPath().empty())
return false;
Expr *affected = resolved->getAnchor();
// FIXME: Work around an odd locator representation that doesn't separate the
// base of a subscript member from the member access.
if (isSubscriptMember) {
if (auto subscript = dyn_cast<SubscriptExpr>(affected))
affected = subscript->getBase();
}
switch (fix.first.getKind()) {
case FixKind::None:
llvm_unreachable("no-fix marker should never make it into solution");
case FixKind::ForceOptional: {
const Expr *unwrapped = affected->getValueProvidingExpr();
auto type = solution.simplifyType(TC, affected->getType())
->getRValueObjectType();
if (auto tryExpr = dyn_cast<OptionalTryExpr>(unwrapped)) {
TC.diagnose(tryExpr->getTryLoc(), diag::missing_unwrap_optional_try,
type)
.fixItReplace({tryExpr->getTryLoc(), tryExpr->getQuestionLoc()},
"try!");
} else {
auto diag = TC.diagnose(affected->getLoc(),
diag::missing_unwrap_optional, type);
bool parensNeeded =
exprNeedsParensInsidePostfixOperator(TC, DC, affected);
if (parensNeeded) {
diag.fixItInsert(affected->getStartLoc(), "(")
.fixItInsertAfter(affected->getEndLoc(), ")!");
} else {
diag.fixItInsertAfter(affected->getEndLoc(), "!");
}
}
return true;
}
case FixKind::OptionalChaining: {
auto type = solution.simplifyType(TC, affected->getType())
->getRValueObjectType();
auto diag = TC.diagnose(affected->getLoc(),
diag::missing_unwrap_optional, type);
diag.fixItInsertAfter(affected->getEndLoc(), "?");
return true;
}
case FixKind::ForceDowncast: {
auto fromType = solution.simplifyType(TC, affected->getType())
->getRValueObjectType();
Type toType = solution.simplifyType(TC,
fix.first.getTypeArgument(*this));
bool useAs = TC.isExplicitlyConvertibleTo(fromType, toType, DC);
bool useAsBang = !useAs && TC.checkedCastMaySucceed(fromType, toType,
DC);
if (!useAs && !useAsBang)
return false;
bool needsParensInside = exprNeedsParensBeforeAddingAs(TC, DC, affected);
bool needsParensOutside = exprNeedsParensAfterAddingAs(TC, DC, affected,
expr);
llvm::SmallString<2> insertBefore;
llvm::SmallString<32> insertAfter;
if (needsParensOutside) {
insertBefore += "(";
}
if (needsParensInside) {
insertBefore += "(";
insertAfter += ")";
}
insertAfter += useAs ? " as " : " as! ";
insertAfter += toType.getString();
if (needsParensOutside)
insertAfter += ")";
auto diagID = useAs ? diag::missing_explicit_conversion
: diag::missing_forced_downcast;
auto diag = TC.diagnose(affected->getLoc(), diagID, fromType, toType);
if (!insertBefore.empty()) {
diag.fixItInsert(affected->getStartLoc(), insertBefore);
}
diag.fixItInsertAfter(affected->getEndLoc(), insertAfter);
return true;
}
case FixKind::AddressOf: {
auto type = solution.simplifyType(TC, affected->getType())
->getRValueObjectType();
TC.diagnose(affected->getLoc(), diag::missing_address_of, type)
.fixItInsert(affected->getStartLoc(), "&");
return true;
}
case FixKind::CoerceToCheckedCast: {
if (auto *coerceExpr = dyn_cast<CoerceExpr>(locator->getAnchor())) {
Expr *subExpr = coerceExpr->getSubExpr();
auto fromType =
solution.simplifyType(TC, subExpr->getType())->getRValueType();
auto toType =
solution.simplifyType(TC, coerceExpr->getCastTypeLoc().getType());
auto castKind = TC.typeCheckCheckedCast(
fromType, toType, DC,
coerceExpr->getLoc(),
subExpr->getSourceRange(),
coerceExpr->getCastTypeLoc().getSourceRange(),
[&](Type commonTy) -> bool {
return TC.convertToType(subExpr, commonTy, DC);
},
/*suppressDiagnostics=*/ true);
switch (castKind) {
// Invalid cast.
case CheckedCastKind::Unresolved:
// Fix didn't work, let diagnoseFailureForExpr handle this.
return false;
case CheckedCastKind::Coercion:
llvm_unreachable("Coercions handled in other disjunction branch");
// Valid casts.
case CheckedCastKind::ArrayDowncast:
case CheckedCastKind::DictionaryDowncast:
case CheckedCastKind::SetDowncast:
case CheckedCastKind::ValueCast:
case CheckedCastKind::BridgeFromObjectiveC:
TC.diagnose(coerceExpr->getLoc(), diag::missing_forced_downcast,
fromType, toType)
.highlight(coerceExpr->getSourceRange())
.fixItReplace(coerceExpr->getLoc(), "as!");
return true;
}
}
return false;
}
}
// FIXME: It would be really nice to emit a follow-up note showing where
// we got the other type information from, e.g., the parameter we're
// initializing.
return false;
}
/// \brief 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 suppressDiagnostics,
bool skipClosures) {
// If any fixes needed to be applied to arrive at this solution, resolve
// them to specific expressions.
if (!solution.Fixes.empty()) {
// If we can diagnose the problem with the fixits that we've pre-assumed,
// do so now.
if (applySolutionFixes(expr, solution))
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;
}
ExprRewriter rewriter(*this, solution, suppressDiagnostics, skipClosures);
ExprWalker walker(rewriter);
// Apply the solution to the expression.
auto result = expr->walk(walker);
if (!result)
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 (result->getType()->isLValueType() && !discardedExpr) {
// We referenced an lvalue. Load it.
result = rewriter.coerceToType(result, result->getType()->getRValueType(),
getConstraintLocator(expr));
}
if (result)
rewriter.finalize(result);
return result;
}
Expr *ConstraintSystem::applySolutionShallow(const Solution &solution,
Expr *expr,
bool suppressDiagnostics) {
ExprRewriter rewriter(*this, solution, suppressDiagnostics,
/*skipClosures=*/false);
rewriter.walkToExprPre(expr);
Expr *result = rewriter.walkToExprPost(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,
/*skipClosures=*/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) {
unsigned index = 0;
if (afd->getExtensionType())
++index;
for (auto param : *afd->getParameterList(index))
if (param->isVariadic())
return true;
return false;
}
static bool argumentNamesMatch(Expr *arg, ArrayRef<Identifier> names) {
auto tupleType = arg->getType()->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,
MutableArrayRef<Expr *> arguments,
Diag<> brokenProtocolDiag) {
// Construct an empty constraint system and solution.
ConstraintSystem cs(*this, dc, ConstraintSystemOptions());
// 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<AbstractFunctionDecl>(
*this, dc, type->getRValueType(), protocol,
name, brokenProtocolDiag);
if (!witness)
return nullptr;
// Form a syntactic expression that describes the reference to the
// witness.
// FIXME: Egregious hack.
auto unresolvedDot = new (Context) UnresolvedDotExpr(
base, SourceLoc(),
witness->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,
/*isTypeReference=*/false,
/*isDynamicResult=*/false,
FunctionRefKind::DoubleApply,
dotLocator);
// Form the call argument.
// FIXME: Standardize all callers to always provide all argument names,
// rather than hack around this.
CallExpr *call;
auto argLabels = witness->getFullName().getArgumentNames();
if (arguments.size() == 1 &&
(isVariadicWitness(witness) ||
argumentNamesMatch(arguments[0], argLabels))) {
call = CallExpr::create(Context, unresolvedDot, arguments[0], { },
{ }, /*hasTrailingClosure=*/false,
/*implicit=*/true);
} 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.size() > 0) {
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);
}
// Add the conversion from the argument to the function parameter type.
cs.addConstraint(ConstraintKind::ArgumentTupleConversion,
call->getArg()->getType(),
openedType->castTo<FunctionType>()->getInput(),
cs.getConstraintLocator(call,
ConstraintLocator::ApplyArgument));
// Solve the system.
SmallVector<Solution, 1> solutions;
// If the system failed to produce a solution, post any available diagnostics.
if (cs.solve(solutions) || solutions.size() != 1) {
cs.salvage(solutions, base);
return nullptr;
}
Solution &solution = solutions.front();
ExprRewriter rewriter(cs, solution,
/*suppressDiagnostics=*/false,
/*skipClosures=*/false);
auto memberRef = rewriter.buildMemberRef(base, openedFullType,
base->getStartLoc(),
witness,
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;
}
/// \brief Convert an expression via a builtin protocol.
///
/// \param solution The solution to the expression's constraint system,
/// which must have included a constraint that the expression's type
/// conforms to the give \c protocol.
/// \param expr The expression to convert.
/// \param locator The locator describing where the conversion occurs.
/// \param builtinName The name of the builtin method to use for the
/// last step of the conversion.
/// \param brokenBuiltinDiag Diagnostic to emit if the builtin definition
/// is broken.
///
/// \returns the converted expression.
static Expr *convertViaMember(const Solution &solution, Expr *expr,
ConstraintLocator *locator,
Identifier builtinName,
Diag<> brokenBuiltinDiag) {
auto &cs = solution.getConstraintSystem();
// FIXME: Cache name.
auto &tc = cs.getTypeChecker();
auto &ctx = tc.Context;
auto type = expr->getType();
// Look for the builtin name. If we don't have it, we need to call the
// general name via the witness table.
NameLookupOptions lookupOptions = defaultMemberLookupOptions;
if (isa<AbstractFunctionDecl>(cs.DC))
lookupOptions |= NameLookupFlags::KnownPrivate;
auto members = tc.lookupMember(cs.DC, type->getRValueType(), builtinName,
lookupOptions);
// Find the builtin method.
if (members.size() != 1) {
tc.diagnose(expr->getLoc(), brokenBuiltinDiag);
return nullptr;
}
FuncDecl *builtinMethod = dyn_cast<FuncDecl>(members[0].Decl);
if (!builtinMethod) {
tc.diagnose(expr->getLoc(), brokenBuiltinDiag);
return nullptr;
}
// Form a reference to the builtin method.
Expr *memberRef = new (ctx) MemberRefExpr(expr, SourceLoc(),
builtinMethod,
DeclNameLoc(expr->getLoc()),
/*Implicit=*/true);
bool failed = tc.typeCheckExpressionShallow(memberRef, cs.DC);
assert(!failed && "Could not reference witness?");
(void)failed;
// Call the builtin method.
expr = CallExpr::createImplicit(ctx, memberRef, { }, { });
failed = tc.typeCheckExpressionShallow(expr, cs.DC);
assert(!failed && "Could not call witness?");
(void)failed;
return expr;
}
Expr *
Solution::convertBooleanTypeToBuiltinI1(Expr *expr, ConstraintLocator *locator) const {
auto &tc = getConstraintSystem().getTypeChecker();
auto result = convertViaMember(*this, expr, locator,
tc.Context.Id_getBuiltinLogicValue,
diag::broken_bool);
if (result && !result->getType()->isBuiltinIntegerType(1)) {
tc.diagnose(expr->getLoc(), diag::broken_bool);
return nullptr;
}
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());
isSomeExpr->setType(tc.lookupBoolType(cs.DC));
return isSomeExpr;
}
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