| //===--- ConstraintSystem.cpp - Constraint-based Type Checking ------------===// |
| // |
| // This source file is part of the Swift.org open source project |
| // |
| // Copyright (c) 2014 - 2015 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 the constraint-based type checker, anchored by the |
| // \c ConstraintSystem class, which provides type checking and type |
| // inference for expressions. |
| // |
| //===----------------------------------------------------------------------===// |
| #include "ConstraintSystem.h" |
| #include "ConstraintGraph.h" |
| #include "swift/AST/ArchetypeBuilder.h" |
| #include "llvm/ADT/SmallString.h" |
| |
| using namespace swift; |
| using namespace constraints; |
| |
| ConstraintSystem::ConstraintSystem(TypeChecker &tc, DeclContext *dc, |
| ConstraintSystemOptions options) |
| : TC(tc), DC(dc), Options(options), |
| Arena(tc.Context, Allocator, |
| [&](TypeVariableType *baseTypeVar, AssociatedTypeDecl *assocType) { |
| return getMemberType(baseTypeVar, assocType, |
| ConstraintLocatorBuilder(nullptr), |
| /*options=*/0); |
| }), |
| CG(*new ConstraintGraph(*this)) |
| { |
| assert(DC && "context required"); |
| } |
| |
| ConstraintSystem::~ConstraintSystem() { |
| delete &CG; |
| } |
| |
| bool ConstraintSystem::hasFreeTypeVariables() { |
| // Look for any free type variables. |
| for (auto tv : TypeVariables) { |
| if (!tv->getImpl().hasRepresentativeOrFixed()) { |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| void ConstraintSystem::addTypeVariable(TypeVariableType *typeVar) { |
| TypeVariables.push_back(typeVar); |
| |
| // Notify the constraint graph. |
| (void)CG[typeVar]; |
| } |
| |
| void ConstraintSystem::mergeEquivalenceClasses(TypeVariableType *typeVar1, |
| TypeVariableType *typeVar2) { |
| assert(typeVar1 == getRepresentative(typeVar1) && |
| "typeVar1 is not the representative"); |
| assert(typeVar2 == getRepresentative(typeVar2) && |
| "typeVar2 is not the representative"); |
| assert(typeVar1 != typeVar2 && "cannot merge type with itself"); |
| typeVar1->getImpl().mergeEquivalenceClasses(typeVar2, getSavedBindings()); |
| |
| // Merge nodes in the constraint graph. |
| CG.mergeNodes(typeVar1, typeVar2); |
| addTypeVariableConstraintsToWorkList(typeVar1); |
| } |
| |
| void ConstraintSystem::assignFixedType(TypeVariableType *typeVar, Type type, |
| bool updateState) { |
| |
| // If the type to be fixed is an optional type that wraps the type parameter |
| // itself, we do not want to go through with the assignment. To do so would |
| // force the type variable to be adjacent to itself. |
| if (auto optValueType = type->getOptionalObjectType()) { |
| if (optValueType->isEqual(typeVar)) |
| return; |
| } |
| |
| typeVar->getImpl().assignFixedType(type, getSavedBindings()); |
| |
| if (!updateState) |
| return; |
| |
| if (!type->is<TypeVariableType>()) { |
| // If this type variable represents a literal, check whether we picked the |
| // default literal type. First, find the corresponding protocol. |
| ProtocolDecl *literalProtocol = nullptr; |
| // If we have the constraint graph, we can check all type variables in |
| // the equivalence class. This is the More Correct path. |
| // FIXME: Eliminate the less-correct path. |
| auto typeVarRep = getRepresentative(typeVar); |
| for (auto tv : CG[typeVarRep].getEquivalenceClass()) { |
| auto locator = tv->getImpl().getLocator(); |
| if (!locator || !locator->getPath().empty()) |
| continue; |
| |
| auto anchor = locator->getAnchor(); |
| if (!anchor) |
| continue; |
| |
| literalProtocol = TC.getLiteralProtocol(anchor); |
| if (literalProtocol) |
| break; |
| } |
| |
| // If the protocol has a default type, check it. |
| if (literalProtocol) { |
| if (auto defaultType = TC.getDefaultType(literalProtocol, DC)) { |
| // Check whether the nominal types match. This makes sure that we |
| // properly handle Array vs. Array<T>. |
| if (defaultType->getAnyNominal() != type->getAnyNominal()) |
| increaseScore(SK_NonDefaultLiteral); |
| } |
| } |
| } |
| |
| // Notify the constraint graph. |
| CG.bindTypeVariable(typeVar, type); |
| addTypeVariableConstraintsToWorkList(typeVar); |
| } |
| |
| void ConstraintSystem::setMustBeMaterializableRecursive(Type type) |
| { |
| assert(type->isMaterializable() && |
| "argument to setMustBeMaterializableRecursive may not be inherently " |
| "non-materializable"); |
| TypeVariableType *typeVar = nullptr; |
| type = getFixedTypeRecursive(type, typeVar, /*wantRValue=*/false); |
| if (typeVar) { |
| typeVar->getImpl().setMustBeMaterializable(getSavedBindings()); |
| } else if (auto *tupleTy = type->getAs<TupleType>()) { |
| for (auto elt : tupleTy->getElementTypes()) { |
| setMustBeMaterializableRecursive(elt); |
| } |
| } |
| } |
| |
| void ConstraintSystem::addTypeVariableConstraintsToWorkList( |
| TypeVariableType *typeVar) { |
| // Gather the constraints affected by a change to this type variable. |
| SmallVector<Constraint *, 8> constraints; |
| CG.gatherConstraints(typeVar, constraints); |
| |
| // Add any constraints that aren't already active to the worklist. |
| for (auto constraint : constraints) { |
| if (!constraint->isActive()) { |
| ActiveConstraints.splice(ActiveConstraints.end(), |
| InactiveConstraints, constraint); |
| constraint->setActive(true); |
| } |
| } |
| } |
| |
| /// Retrieve a dynamic result signature for the given declaration. |
| static std::tuple<char, ObjCSelector, CanType> |
| getDynamicResultSignature(ValueDecl *decl) { |
| if (auto func = dyn_cast<AbstractFunctionDecl>(decl)) { |
| // Handle functions. |
| auto type = |
| decl->getInterfaceType()->castTo<AnyFunctionType>()->getResult(); |
| return std::make_tuple(func->isStatic(), func->getObjCSelector(), |
| type->getCanonicalType()); |
| } |
| |
| if (auto asd = dyn_cast<AbstractStorageDecl>(decl)) { |
| // Handle properties and subscripts, anchored by the getter's selector. |
| return std::make_tuple(asd->isStatic(), asd->getObjCGetterSelector(), |
| asd->getInterfaceType()->getCanonicalType()); |
| } |
| |
| llvm_unreachable("Not a valid @objc member"); |
| } |
| |
| LookupResult &ConstraintSystem::lookupMember(Type base, DeclName name) { |
| base = base->getCanonicalType(); |
| |
| // Check whether we've already performed this lookup. |
| auto knownMember = MemberLookups.find({base, name}); |
| if (knownMember != MemberLookups.end()) |
| return *knownMember->second; |
| |
| // Lookup the member. |
| NameLookupOptions lookupOptions = defaultMemberLookupOptions; |
| if (isa<AbstractFunctionDecl>(DC)) |
| lookupOptions |= NameLookupFlags::KnownPrivate; |
| |
| MemberLookups[{base, name}] = None; |
| auto lookup = TC.lookupMember(DC, base, name, lookupOptions); |
| auto &result = MemberLookups[{base, name}]; |
| result = std::move(lookup); |
| |
| // If we aren't performing dynamic lookup, we're done. |
| auto instanceTy = base->getRValueType(); |
| if (auto metaTy = instanceTy->getAs<AnyMetatypeType>()) |
| instanceTy = metaTy->getInstanceType(); |
| auto protoTy = instanceTy->getAs<ProtocolType>(); |
| if (!*result || |
| !protoTy || |
| !protoTy->getDecl()->isSpecificProtocol( |
| KnownProtocolKind::AnyObject)) |
| return *result; |
| |
| // We are performing dynamic lookup. Filter out redundant results early. |
| llvm::DenseSet<std::tuple<char, ObjCSelector, CanType>> known; |
| result->filter([&](ValueDecl *decl) -> bool { |
| if (decl->isInvalid()) |
| return false; |
| |
| return known.insert(getDynamicResultSignature(decl)).second; |
| }); |
| |
| return *result; |
| } |
| |
| ArrayRef<Type> ConstraintSystem:: |
| getAlternativeLiteralTypes(KnownProtocolKind kind) { |
| unsigned index; |
| |
| switch (kind) { |
| #define PROTOCOL_WITH_NAME(Id, Name) \ |
| case KnownProtocolKind::Id: llvm_unreachable("Not a literal protocol"); |
| #define LITERAL_CONVERTIBLE_PROTOCOL_WITH_NAME(Id, Name) |
| #include "swift/AST/KnownProtocols.def" |
| |
| case KnownProtocolKind::ArrayLiteralConvertible: index = 0; break; |
| case KnownProtocolKind::DictionaryLiteralConvertible:index = 1; break; |
| case KnownProtocolKind::ExtendedGraphemeClusterLiteralConvertible: index = 2; |
| break; |
| case KnownProtocolKind::FloatLiteralConvertible: index = 3; break; |
| case KnownProtocolKind::IntegerLiteralConvertible: index = 4; break; |
| case KnownProtocolKind::StringInterpolationConvertible: index = 5; break; |
| case KnownProtocolKind::StringLiteralConvertible: index = 6; break; |
| case KnownProtocolKind::NilLiteralConvertible: index = 7; break; |
| case KnownProtocolKind::BooleanLiteralConvertible: index = 8; break; |
| case KnownProtocolKind::UnicodeScalarLiteralConvertible: index = 9; break; |
| case KnownProtocolKind::ColorLiteralConvertible: index = 10; break; |
| case KnownProtocolKind::ImageLiteralConvertible: index = 11; break; |
| case KnownProtocolKind::FileReferenceLiteralConvertible: index = 12; break; |
| } |
| |
| // If we already looked for alternative literal types, return those results. |
| if (AlternativeLiteralTypes[index]) |
| return *AlternativeLiteralTypes[index]; |
| |
| SmallVector<Type, 4> types; |
| |
| // If the default literal type is bridged to a class type, add the class type. |
| if (auto proto = TC.Context.getProtocol(kind)) { |
| if (auto defaultType = TC.getDefaultType(proto, DC)) { |
| if (auto bridgedClassType = TC.getBridgedToObjC(DC, defaultType)) { |
| types.push_back(bridgedClassType); |
| } |
| } |
| } |
| |
| // Some literal kinds are related. |
| switch (kind) { |
| #define PROTOCOL_WITH_NAME(Id, Name) \ |
| case KnownProtocolKind::Id: llvm_unreachable("Not a literal protocol"); |
| #define LITERAL_CONVERTIBLE_PROTOCOL_WITH_NAME(Id, Name) |
| #include "swift/AST/KnownProtocols.def" |
| |
| case KnownProtocolKind::ArrayLiteralConvertible: |
| case KnownProtocolKind::DictionaryLiteralConvertible: |
| break; |
| |
| case KnownProtocolKind::ExtendedGraphemeClusterLiteralConvertible: |
| case KnownProtocolKind::StringInterpolationConvertible: |
| case KnownProtocolKind::StringLiteralConvertible: |
| case KnownProtocolKind::UnicodeScalarLiteralConvertible: |
| break; |
| |
| case KnownProtocolKind::IntegerLiteralConvertible: |
| // Integer literals can be treated as floating point literals. |
| if (auto floatProto = TC.Context.getProtocol( |
| KnownProtocolKind::FloatLiteralConvertible)) { |
| if (auto defaultType = TC.getDefaultType(floatProto, DC)) { |
| types.push_back(defaultType); |
| } |
| } |
| break; |
| |
| case KnownProtocolKind::FloatLiteralConvertible: |
| break; |
| |
| case KnownProtocolKind::NilLiteralConvertible: |
| case KnownProtocolKind::BooleanLiteralConvertible: |
| break; |
| case KnownProtocolKind::ColorLiteralConvertible: |
| case KnownProtocolKind::ImageLiteralConvertible: |
| case KnownProtocolKind::FileReferenceLiteralConvertible: |
| break; |
| } |
| |
| AlternativeLiteralTypes[index] = allocateCopy(types); |
| return *AlternativeLiteralTypes[index]; |
| } |
| |
| ConstraintLocator *ConstraintSystem::getConstraintLocator( |
| Expr *anchor, |
| ArrayRef<ConstraintLocator::PathElement> path, |
| unsigned summaryFlags) { |
| assert(summaryFlags == ConstraintLocator::getSummaryFlagsForPath(path)); |
| |
| // Check whether a locator with this anchor + path already exists. |
| llvm::FoldingSetNodeID id; |
| ConstraintLocator::Profile(id, anchor, path); |
| void *insertPos = nullptr; |
| auto locator = ConstraintLocators.FindNodeOrInsertPos(id, insertPos); |
| if (locator) |
| return locator; |
| |
| // Allocate a new locator and add it to the set. |
| locator = ConstraintLocator::create(getAllocator(), anchor, path, |
| summaryFlags); |
| ConstraintLocators.InsertNode(locator, insertPos); |
| return locator; |
| } |
| |
| ConstraintLocator *ConstraintSystem::getConstraintLocator( |
| const ConstraintLocatorBuilder &builder) { |
| // If the builder has an empty path, just extract its base locator. |
| if (builder.hasEmptyPath()) { |
| return builder.getBaseLocator(); |
| } |
| |
| // We have to build a new locator. Extract the paths from the builder. |
| SmallVector<LocatorPathElt, 4> path; |
| Expr *anchor = builder.getLocatorParts(path); |
| return getConstraintLocator(anchor, path, builder.getSummaryFlags()); |
| } |
| |
| bool ConstraintSystem::addConstraint(Constraint *constraint, |
| bool isExternallySolved, |
| bool simplifyExisting) { |
| switch (simplifyConstraint(*constraint)) { |
| case SolutionKind::Error: |
| if (!failedConstraint) { |
| failedConstraint = constraint; |
| } |
| |
| if (solverState) { |
| solverState->retiredConstraints.push_front(constraint); |
| if (!simplifyExisting) { |
| solverState->generatedConstraints.push_back(constraint); |
| } |
| } |
| |
| return false; |
| |
| case SolutionKind::Solved: |
| // This constraint has already been solved; there is nothing more |
| // to do. |
| // Record solved constraint. |
| if (solverState) { |
| solverState->retiredConstraints.push_front(constraint); |
| if (!simplifyExisting) |
| solverState->generatedConstraints.push_back(constraint); |
| } |
| |
| // Remove the constraint from the constraint graph. |
| if (simplifyExisting) |
| CG.removeConstraint(constraint); |
| |
| return true; |
| |
| case SolutionKind::Unsolved: |
| // We couldn't solve this constraint; add it to the pile. |
| if (!isExternallySolved) { |
| InactiveConstraints.push_back(constraint); |
| } |
| |
| // Add this constraint to the constraint graph. |
| if (!simplifyExisting) |
| CG.addConstraint(constraint); |
| |
| if (!simplifyExisting && solverState) { |
| solverState->generatedConstraints.push_back(constraint); |
| } |
| |
| return false; |
| } |
| } |
| |
| TypeVariableType * |
| ConstraintSystem::getMemberType(TypeVariableType *baseTypeVar, |
| AssociatedTypeDecl *assocType, |
| ConstraintLocatorBuilder locator, |
| unsigned options) { |
| return CG.getMemberType(baseTypeVar, assocType->getName(), [&]() { |
| // FIXME: Premature associated type -> identifier mapping. We should |
| // retain the associated type throughout. |
| auto loc = getConstraintLocator(locator); |
| auto memberTypeVar = createTypeVariable(loc, options); |
| addConstraint(Constraint::create(*this, ConstraintKind::TypeMember, |
| baseTypeVar, memberTypeVar, |
| assocType->getName(), loc)); |
| return memberTypeVar; |
| }); |
| } |
| |
| /// Check whether this is the depth 0, index 0 generic parameter, which is |
| /// used for the 'Self' type of a protocol. |
| static bool isProtocolSelfType(Type type) { |
| auto gp = type->getAs<GenericTypeParamType>(); |
| if (!gp) |
| return false; |
| |
| return gp->getDepth() == 0 && gp->getIndex() == 0; |
| } |
| |
| namespace { |
| /// Function object that retrieves a type variable corresponding to the |
| /// given dependent type. |
| class GetTypeVariable { |
| ConstraintSystem &CS; |
| ConstraintGraph &CG; |
| ConstraintLocatorBuilder &Locator; |
| DependentTypeOpener *Opener; |
| |
| public: |
| GetTypeVariable(ConstraintSystem &cs, |
| ConstraintLocatorBuilder &locator, |
| DependentTypeOpener *opener) |
| : CS(cs), CG(CS.getConstraintGraph()), Locator(locator), Opener(opener) {} |
| |
| TypeVariableType *operator()(Type base, AssociatedTypeDecl *member) { |
| // FIXME: Premature associated type -> identifier mapping. We should |
| // retain the associated type throughout. |
| auto baseTypeVar = base->castTo<TypeVariableType>(); |
| return CG.getMemberType(baseTypeVar, member->getName(), |
| [&]() -> TypeVariableType* { |
| auto implArchetype = baseTypeVar->getImpl().getArchetype(); |
| if (!implArchetype) { |
| // If the base type variable doesn't have an associated archetype, |
| // just form the member constraint. |
| // FIXME: Additional requirements? |
| auto locator = CS.getConstraintLocator( |
| Locator.withPathElement(member)); |
| auto memberTypeVar = CS.createTypeVariable(locator, |
| TVO_PrefersSubtypeBinding); |
| CS.addConstraint(Constraint::create(CS, ConstraintKind::TypeMember, |
| baseTypeVar, memberTypeVar, |
| member->getName(), locator)); |
| return memberTypeVar; |
| } |
| |
| |
| ArchetypeType::NestedType nestedType; |
| ArchetypeType* archetype = nullptr; |
| |
| if (implArchetype->hasNestedType(member->getName())) { |
| nestedType = implArchetype->getNestedType(member->getName()); |
| archetype = nestedType.getValue()->getAs<ArchetypeType>(); |
| } else if (implArchetype->isSelfDerived()) { |
| archetype = implArchetype; |
| } |
| |
| ConstraintLocator *locator; |
| if (archetype) { |
| locator = CS.getConstraintLocator( |
| Locator.withPathElement(LocatorPathElt(archetype))); |
| } else { |
| // FIXME: Occurs when the nested type is a concrete type, |
| // in which case it's quite silly to create a type variable at all. |
| locator = CS.getConstraintLocator(Locator.withPathElement(member)); |
| } |
| |
| auto memberTypeVar = CS.createTypeVariable(locator, |
| TVO_PrefersSubtypeBinding); |
| // Determine whether we should bind the new type variable as a |
| // member of the base type variable, or let it float. |
| Type replacementType; |
| bool shouldBindMember = true; |
| if (Opener) { |
| shouldBindMember = Opener->shouldBindAssociatedType(base, baseTypeVar, |
| member, |
| memberTypeVar, |
| replacementType); |
| } |
| |
| // Bind the member's type variable as a type member of the base, |
| // if needed. |
| if (shouldBindMember) { |
| CS.addConstraint(Constraint::create(CS, ConstraintKind::TypeMember, |
| baseTypeVar, memberTypeVar, |
| member->getName(), locator)); |
| } |
| |
| // If we have a replacement type, bind the member's type |
| // variable to it. |
| if (replacementType) |
| CS.addConstraint(ConstraintKind::Bind, memberTypeVar, |
| replacementType, locator); |
| |
| if (!archetype) { |
| // If the nested type is not an archetype (because it was constrained |
| // to a concrete type by a requirement), return the fresh type |
| // variable now, and let binding occur during overload resolution. |
| return memberTypeVar; |
| } |
| |
| // FIXME: Would be better to walk the requirements of the protocol |
| // of which the associated type is a member. |
| if (auto superclass = member->getSuperclass()) { |
| CS.addConstraint(ConstraintKind::Subtype, memberTypeVar, |
| superclass, locator); |
| } |
| |
| for (auto proto : member->getArchetype()->getConformsTo()) { |
| CS.addConstraint(ConstraintKind::ConformsTo, memberTypeVar, |
| proto->getDeclaredType(), locator); |
| } |
| |
| return memberTypeVar; |
| }); |
| } |
| }; |
| |
| /// Function object that replaces all occurrences of archetypes and |
| /// dependent types with type variables. |
| class ReplaceDependentTypes { |
| ConstraintSystem &cs; |
| DeclContext *dc; |
| bool skipProtocolSelfConstraint; |
| unsigned minOpeningDepth; |
| DependentTypeOpener *opener; |
| ConstraintLocatorBuilder &locator; |
| llvm::DenseMap<CanType, TypeVariableType *> &replacements; |
| GetTypeVariable &getTypeVariable; |
| |
| public: |
| ReplaceDependentTypes( |
| ConstraintSystem &cs, |
| DeclContext *dc, |
| bool skipProtocolSelfConstraint, |
| unsigned minOpeningDepth, |
| DependentTypeOpener *opener, |
| ConstraintLocatorBuilder &locator, |
| llvm::DenseMap<CanType, TypeVariableType *> &replacements, |
| GetTypeVariable &getTypeVariable) |
| : cs(cs), dc(dc), skipProtocolSelfConstraint(skipProtocolSelfConstraint), |
| minOpeningDepth(minOpeningDepth), opener(opener), locator(locator), |
| replacements(replacements), getTypeVariable(getTypeVariable) { } |
| |
| Type operator()(Type type) { |
| assert(!type->is<PolymorphicFunctionType>() && "Shouldn't get here"); |
| |
| // Preserve parens when opening types. |
| if (isa<ParenType>(type.getPointer())) { |
| return type; |
| } |
| |
| // Replace archetypes with fresh type variables. |
| if (auto archetype = type->getAs<ArchetypeType>()) { |
| auto known = replacements.find(archetype->getCanonicalType()); |
| if (known != replacements.end()) |
| return known->second; |
| |
| return archetype; |
| } |
| |
| // Replace a generic type parameter with its corresponding type variable. |
| if (auto genericParam = type->getAs<GenericTypeParamType>()) { |
| if (opener) { |
| // If we have a mapping for this type parameter, there's nothing else to do. |
| if (Type replacement = opener->mapGenericTypeParamType(genericParam)){ |
| return replacement; |
| } |
| } |
| |
| auto known = replacements.find(genericParam->getCanonicalType()); |
| |
| if (known == replacements.end()) |
| return cs.createTypeVariable(nullptr, TVO_PrefersSubtypeBinding); |
| |
| return known->second; |
| } |
| |
| // Replace a dependent member with a fresh type variable and make it a |
| // member of its base type. |
| if (auto dependentMember = type->getAs<DependentMemberType>()) { |
| if (opener) { |
| // If we have a mapping for this type parameter, there's nothing else to do. |
| if (Type replacement |
| = opener->mapDependentMemberType(dependentMember)) { |
| return replacement; |
| } |
| } |
| |
| // Check whether we've already dealt with this dependent member. |
| auto known = replacements.find(dependentMember->getCanonicalType()); |
| if (known != replacements.end()) |
| return known->second; |
| |
| // Replace archetypes in the base type. |
| if (auto base = |
| ((*this)(dependentMember->getBase()))->getAs<TypeVariableType>()) { |
| auto result = getTypeVariable(base, dependentMember->getAssocType()); |
| replacements[dependentMember->getCanonicalType()] = result; |
| return result; |
| } |
| } |
| |
| // Create type variables for all of the parameters in a generic function |
| // type. |
| if (auto genericFn = type->getAs<GenericFunctionType>()) { |
| // Open up the generic parameters and requirements. |
| cs.openGeneric(dc, |
| genericFn->getGenericParams(), |
| genericFn->getRequirements(), |
| skipProtocolSelfConstraint, |
| minOpeningDepth, |
| opener, |
| locator, |
| replacements); |
| |
| // Transform the input and output types. |
| Type inputTy = genericFn->getInput().transform(*this); |
| if (!inputTy) |
| return Type(); |
| |
| Type resultTy = genericFn->getResult().transform(*this); |
| if (!resultTy) |
| return Type(); |
| |
| // Build the resulting (non-generic) function type. |
| return FunctionType::get(inputTy, resultTy, |
| FunctionType::ExtInfo(). |
| withThrows(genericFn->throws())); |
| } |
| |
| // Open up unbound generic types, turning them into bound generic |
| // types with type variables for each parameter. |
| if (auto unbound = type->getAs<UnboundGenericType>()) { |
| auto parentTy = unbound->getParent(); |
| if (parentTy) |
| parentTy = parentTy.transform(*this); |
| |
| auto unboundDecl = unbound->getDecl(); |
| if (unboundDecl->isInvalid()) |
| return ErrorType::get(cs.getASTContext()); |
| |
| // Open up the generic type. |
| cs.openGeneric(unboundDecl, |
| unboundDecl->getGenericParamTypes(), |
| unboundDecl->getGenericRequirements(), |
| /*skipProtocolSelfConstraint=*/false, |
| minOpeningDepth, |
| opener, |
| locator, |
| replacements); |
| |
| // Map the generic parameters to their corresponding type variables. |
| llvm::SmallVector<Type, 4> arguments; |
| for (auto gp : unboundDecl->getGenericParamTypes()) { |
| assert(replacements.count(gp->getCanonicalType()) && |
| "Missing generic parameter?"); |
| arguments.push_back(replacements[gp->getCanonicalType()]); |
| } |
| return BoundGenericType::get(unboundDecl, parentTy, arguments); |
| } |
| |
| return type; |
| } |
| }; |
| } |
| |
| Type ConstraintSystem::openType( |
| Type startingType, |
| ConstraintLocatorBuilder locator, |
| llvm::DenseMap<CanType, TypeVariableType *> &replacements, |
| DeclContext *dc, |
| bool skipProtocolSelfConstraint, |
| unsigned minOpeningDepth, |
| DependentTypeOpener *opener) { |
| GetTypeVariable getTypeVariable{*this, locator, opener}; |
| |
| ReplaceDependentTypes replaceDependentTypes(*this, dc, |
| skipProtocolSelfConstraint, |
| minOpeningDepth, |
| opener, |
| locator, |
| replacements, getTypeVariable); |
| return startingType.transform(replaceDependentTypes); |
| } |
| |
| bool ConstraintSystem::isArrayType(Type t) { |
| t = t->getDesugaredType(); |
| |
| // ArraySliceType<T> desugars to Array<T>. |
| if (isa<ArraySliceType>(t.getPointer())) |
| return true; |
| if (auto boundStruct = dyn_cast<BoundGenericStructType>(t.getPointer())) { |
| return boundStruct->getDecl() == TC.Context.getArrayDecl(); |
| } |
| |
| return false; |
| } |
| |
| Optional<std::pair<Type, Type>> ConstraintSystem::isDictionaryType(Type type) { |
| if (auto boundStruct = type->getAs<BoundGenericStructType>()) { |
| if (boundStruct->getDecl() != TC.Context.getDictionaryDecl()) |
| return None; |
| |
| auto genericArgs = boundStruct->getGenericArgs(); |
| return std::make_pair(genericArgs[0], genericArgs[1]); |
| } |
| |
| return None; |
| } |
| |
| bool ConstraintSystem::isSetType(Type type) { |
| if (auto boundStruct = type->getAs<BoundGenericStructType>()) { |
| return boundStruct->getDecl() == TC.Context.getSetDecl(); |
| } |
| |
| return false; |
| } |
| |
| Type ConstraintSystem::openBindingType(Type type, |
| ConstraintLocatorBuilder locator) { |
| Type result = openType(type, locator); |
| |
| if (isArrayType(type)) { |
| auto boundStruct = cast<BoundGenericStructType>(type.getPointer()); |
| if (auto replacement = getTypeChecker().getArraySliceType( |
| SourceLoc(), boundStruct->getGenericArgs()[0])) { |
| return replacement; |
| } |
| } |
| |
| if (auto dict = isDictionaryType(type)) { |
| if (auto replacement = getTypeChecker().getDictionaryType( |
| SourceLoc(), dict->first, dict->second)) |
| return replacement; |
| } |
| |
| return result; |
| } |
| |
| static Type getFixedTypeRecursiveHelper(ConstraintSystem &cs, |
| TypeVariableType *typeVar, |
| bool wantRValue) { |
| while (auto fixed = cs.getFixedType(typeVar)) { |
| if (wantRValue) |
| fixed = fixed->getRValueType(); |
| |
| typeVar = fixed->getAs<TypeVariableType>(); |
| if (!typeVar) |
| return fixed; |
| } |
| return nullptr; |
| } |
| |
| Type ConstraintSystem::getFixedTypeRecursive(Type type, |
| TypeVariableType *&typeVar, |
| bool wantRValue, |
| bool retainParens) { |
| if (wantRValue) |
| type = type->getRValueType(); |
| |
| if (retainParens) { |
| if (auto parenTy = dyn_cast<ParenType>(type.getPointer())) { |
| type = getFixedTypeRecursive(parenTy->getUnderlyingType(), typeVar, |
| wantRValue, retainParens); |
| return ParenType::get(getASTContext(), type); |
| } |
| } |
| |
| auto desugar = type->getDesugaredType(); |
| typeVar = desugar->getAs<TypeVariableType>(); |
| if (typeVar) { |
| if (auto fixed = getFixedTypeRecursiveHelper(*this, typeVar, wantRValue)) { |
| type = fixed; |
| typeVar = nullptr; |
| } |
| } |
| return type; |
| } |
| |
| void ConstraintSystem::recordOpenedTypes( |
| ConstraintLocatorBuilder locator, |
| const llvm::DenseMap<CanType, TypeVariableType *> &replacements) { |
| if (replacements.empty()) |
| return; |
| |
| // If the last path element is an archetype or associated type, ignore it. |
| SmallVector<LocatorPathElt, 2> pathElts; |
| Expr *anchor = locator.getLocatorParts(pathElts); |
| if (!pathElts.empty() && |
| (pathElts.back().getKind() == ConstraintLocator::Archetype || |
| pathElts.back().getKind() == ConstraintLocator::AssociatedType)) |
| return; |
| |
| // If the locator is empty, ignore it. |
| if (!anchor && pathElts.empty()) |
| return; |
| |
| ConstraintLocator *locatorPtr = getConstraintLocator(locator); |
| assert(locatorPtr && "No locator for opened types?"); |
| assert(std::find_if(OpenedTypes.begin(), OpenedTypes.end(), |
| [&](const std::pair<ConstraintLocator *, |
| ArrayRef<OpenedType>> &entry) { |
| return entry.first == locatorPtr; |
| }) == OpenedTypes.end() && |
| "already registered opened types for this locator"); |
| |
| OpenedType* openedTypes |
| = Allocator.Allocate<OpenedType>(replacements.size()); |
| std::copy(replacements.begin(), replacements.end(), openedTypes); |
| OpenedTypes.push_back({ locatorPtr, |
| llvm::makeArrayRef(openedTypes, |
| replacements.size()) }); |
| } |
| |
| std::pair<Type, Type> |
| ConstraintSystem::getTypeOfReference(ValueDecl *value, |
| bool isTypeReference, |
| bool isSpecialized, |
| ConstraintLocatorBuilder locator, |
| const DeclRefExpr *base, |
| DependentTypeOpener *opener) { |
| llvm::DenseMap<CanType, TypeVariableType *> replacements; |
| |
| if (value->getDeclContext()->isTypeContext() && isa<FuncDecl>(value)) { |
| // Unqualified lookup can find operator names within nominal types. |
| auto func = cast<FuncDecl>(value); |
| assert(func->isOperator() && "Lookup should only find operators"); |
| |
| auto openedType = openType(func->getInterfaceType(), locator, |
| replacements, func, |
| false, |
| value->getDeclContext()->getGenericTypeContextDepth(), |
| opener); |
| auto openedFnType = openedType->castTo<FunctionType>(); |
| |
| // If this is a method whose result type is dynamic Self, replace |
| // DynamicSelf with the actual object type. |
| if (func->hasDynamicSelf()) { |
| Type selfTy = openedFnType->getInput()->getRValueInstanceType(); |
| openedType = openedType->replaceCovariantResultType( |
| selfTy, |
| func->getNumParamPatterns()); |
| openedFnType = openedType->castTo<FunctionType>(); |
| } |
| |
| // The 'Self' type must be bound to an archetype. |
| // FIXME: We eventually want to loosen this constraint, to allow us |
| // to find operator functions both in classes and in protocols to which |
| // a class conforms (if there's a default implementation). |
| addArchetypeConstraint(openedFnType->getInput()->getRValueInstanceType(), |
| getConstraintLocator(locator)); |
| |
| // If we opened up any type variables, record the replacements. |
| recordOpenedTypes(locator, replacements); |
| |
| // The reference implicitly binds 'self'. |
| return { openedType, openedFnType->getResult() }; |
| } |
| |
| // If we have a type declaration, resolve it within the current context. |
| if (auto typeDecl = dyn_cast<TypeDecl>(value)) { |
| // Resolve the reference to this type declaration in our current context. |
| auto type = getTypeChecker().resolveTypeInContext(typeDecl, DC, |
| TR_InExpression, |
| isSpecialized); |
| if (!type) |
| return { nullptr, nullptr }; |
| |
| // Open the type. |
| type = openType(type, locator, replacements, |
| value->getInnermostDeclContext(), |
| false, |
| value->getDeclContext()->getGenericTypeContextDepth(), |
| opener); |
| |
| // If we opened up any type variables, record the replacements. |
| recordOpenedTypes(locator, replacements); |
| |
| // If it's a type reference or it's a module type, we're done. |
| if (isTypeReference || type->is<ModuleType>()) |
| return { type, type }; |
| |
| // If it's a value reference, refer to the metatype. |
| type = MetatypeType::get(type); |
| return { type, type }; |
| } |
| |
| // Determine the type of the value, opening up that type if necessary. |
| Type valueType = TC.getUnopenedTypeOfReference(value, Type(), DC, base, |
| /*wantInterfaceType=*/true); |
| |
| // If this is a let-param whose type is a type variable, this is an untyped |
| // closure param that may be bound to an inout type later. References to the |
| // param should have lvalue type instead. Express the relationship with a new |
| // constraint. |
| if (auto *param = dyn_cast<ParamDecl>(value)) { |
| if (param->isLet() && valueType->is<TypeVariableType>()) { |
| Type paramType = valueType; |
| valueType = createTypeVariable(getConstraintLocator(locator), |
| TVO_CanBindToLValue); |
| addConstraint(ConstraintKind::BindParam, paramType, valueType, |
| getConstraintLocator(locator)); |
| } |
| } |
| |
| // Adjust the type of the reference. |
| valueType = openType(valueType, locator, |
| replacements, |
| value->getInnermostDeclContext(), |
| /*skipProtocolSelfConstraint=*/false, |
| value->getDeclContext()->getGenericTypeContextDepth(), |
| opener); |
| |
| // If we opened up any type variables, record the replacements. |
| recordOpenedTypes(locator, replacements); |
| |
| return { valueType, valueType }; |
| } |
| |
| void ConstraintSystem::openGeneric( |
| DeclContext *dc, |
| ArrayRef<GenericTypeParamType *> params, |
| ArrayRef<Requirement> requirements, |
| bool skipProtocolSelfConstraint, |
| unsigned minOpeningDepth, |
| DependentTypeOpener *opener, |
| ConstraintLocatorBuilder locator, |
| llvm::DenseMap<CanType, TypeVariableType *> &replacements) { |
| auto locatorPtr = getConstraintLocator(locator); |
| |
| // Create the type variables for the generic parameters. |
| for (auto gp : params) { |
| // If we have a mapping for this type parameter, there's nothing else to do. |
| if (opener && opener->mapGenericTypeParamType(gp)) |
| continue; |
| |
| ArchetypeType *archetype = ArchetypeBuilder::mapTypeIntoContext(dc, gp) |
| ->castTo<ArchetypeType>(); |
| auto typeVar = createTypeVariable(getConstraintLocator( |
| locator.withPathElement( |
| LocatorPathElt(archetype))), |
| TVO_PrefersSubtypeBinding | |
| TVO_MustBeMaterializable); |
| replacements[gp->getCanonicalType()] = typeVar; |
| |
| if (gp->getDepth() < minOpeningDepth) |
| addConstraint(ConstraintKind::Bind, typeVar, archetype, locatorPtr); |
| |
| // Note that we opened a generic parameter to a type variable. |
| if (opener) { |
| Type replacementType; |
| opener->openedGenericParameter(gp, typeVar, replacementType); |
| |
| if (replacementType) |
| addConstraint(ConstraintKind::Bind, typeVar, replacementType, |
| locatorPtr); |
| } |
| } |
| |
| |
| GetTypeVariable getTypeVariable{*this, locator, opener}; |
| ReplaceDependentTypes replaceDependentTypes(*this, dc, |
| skipProtocolSelfConstraint, |
| minOpeningDepth, |
| opener, locator, replacements, |
| getTypeVariable); |
| |
| // Remember that any new constraints generated by opening this generic are |
| // due to the opening. |
| locatorPtr = getConstraintLocator( |
| locator.withPathElement(ConstraintLocator::OpenedGeneric)); |
| |
| |
| // Add the requirements as constraints. |
| for (auto req : requirements) { |
| switch (req.getKind()) { |
| case RequirementKind::Conformance: { |
| auto subjectTy = req.getFirstType().transform(replaceDependentTypes); |
| if (auto proto = req.getSecondType()->getAs<ProtocolType>()) { |
| // Determine whether this is the protocol 'Self' constraint we should |
| // skip. |
| if (skipProtocolSelfConstraint && |
| (proto->getDecl() == dc->isProtocolOrProtocolExtensionContext() || |
| proto->getDecl() |
| == dc->getParent()->isProtocolOrProtocolExtensionContext())&& |
| isProtocolSelfType(req.getFirstType())) { |
| break; |
| } |
| |
| addConstraint(ConstraintKind::ConformsTo, subjectTy, proto, |
| locatorPtr); |
| } else { |
| auto boundTy = req.getSecondType().transform(replaceDependentTypes); |
| addConstraint(ConstraintKind::Subtype, subjectTy, boundTy, locatorPtr); |
| } |
| break; |
| } |
| |
| case RequirementKind::SameType: { |
| auto firstTy = req.getFirstType().transform(replaceDependentTypes); |
| auto secondTy = req.getSecondType().transform(replaceDependentTypes); |
| addConstraint(ConstraintKind::Bind, firstTy, secondTy, locatorPtr); |
| break; |
| } |
| |
| case RequirementKind::WitnessMarker: |
| break; |
| } |
| } |
| } |
| |
| /// Add the constraint on the type used for the 'Self' type for a member |
| /// reference. |
| /// |
| /// \param cs The constraint system. |
| /// |
| /// \param objectTy The type of the object that we're using to access the |
| /// member. |
| /// |
| /// \param selfTy The instance type of the context in which the member is |
| /// declared. |
| static void addSelfConstraint(ConstraintSystem &cs, Type objectTy, Type selfTy, |
| ConstraintLocatorBuilder locator){ |
| assert(!selfTy->is<ProtocolType>()); |
| |
| // Otherwise, use a subtype constraint for classes to cope with inheritance. |
| if (selfTy->getClassOrBoundGenericClass()) { |
| cs.addConstraint(ConstraintKind::Subtype, objectTy, selfTy, |
| cs.getConstraintLocator(locator)); |
| return; |
| } |
| |
| // Otherwise, the types must be equivalent. |
| cs.addConstraint(ConstraintKind::Equal, objectTy, selfTy, |
| cs.getConstraintLocator(locator)); |
| } |
| |
| Type ConstraintSystem::replaceSelfTypeInArchetype(ArchetypeType *archetype) { |
| assert(SelfTypeVar && "Meaningless unless there is a type variable for Self"); |
| if (auto parent = archetype->getParent()) { |
| // Replace Self in the parent archetype. If nothing changes, we're done. |
| Type newParent = replaceSelfTypeInArchetype(parent); |
| if (newParent->getAs<ArchetypeType>() == parent) |
| return archetype; |
| |
| // We expect to get a type variable back. |
| return getMemberType(newParent->castTo<TypeVariableType>(), |
| archetype->getAssocType(), |
| ConstraintLocatorBuilder(nullptr), |
| /*options=*/0); |
| } |
| |
| // If the archetype is the same as for the 'Self' type variable, |
| // return the 'Self' type variable. |
| if (SelfTypeVar->getImpl().getArchetype() == archetype) |
| return SelfTypeVar; |
| |
| return archetype; |
| } |
| |
| std::pair<Type, Type> |
| ConstraintSystem::getTypeOfMemberReference(Type baseTy, ValueDecl *value, |
| bool isTypeReference, |
| bool isDynamicResult, |
| ConstraintLocatorBuilder locator, |
| const DeclRefExpr *base, |
| DependentTypeOpener *opener) { |
| // Figure out the instance type used for the base. |
| TypeVariableType *baseTypeVar = nullptr; |
| Type baseObjTy = getFixedTypeRecursive(baseTy, baseTypeVar, |
| /*wantRValue=*/true); |
| bool isInstance = true; |
| if (auto baseMeta = baseObjTy->getAs<AnyMetatypeType>()) { |
| baseObjTy = baseMeta->getInstanceType(); |
| isInstance = false; |
| } |
| |
| // If the base is a module type, just use the type of the decl. |
| if (baseObjTy->is<ModuleType>()) { |
| return getTypeOfReference(value, isTypeReference, /*isSpecialized=*/false, |
| locator, base, opener); |
| } |
| |
| // Handle associated type lookup as a special case, horribly. |
| // FIXME: This is an awful hack. |
| if (auto assocType = dyn_cast<AssociatedTypeDecl>(value)) { |
| // Error recovery path. |
| if (baseObjTy->isOpenedExistential()) { |
| Type memberTy = ErrorType::get(TC.Context); |
| auto openedType = FunctionType::get(baseObjTy, memberTy); |
| return { openedType, memberTy }; |
| } |
| |
| // Refer to a member of the archetype directly. |
| if (auto archetype = baseObjTy->getAs<ArchetypeType>()) { |
| Type memberTy = archetype->getNestedTypeValue(value->getName()); |
| if (!isTypeReference) |
| memberTy = MetatypeType::get(memberTy); |
| |
| auto openedType = FunctionType::get(baseObjTy, memberTy); |
| return { openedType, memberTy }; |
| } |
| |
| // If we have a nominal type that conforms to the protocol in which the |
| // associated type resides, use the witness. |
| if (!baseObjTy->isExistentialType() && |
| baseObjTy->getAnyNominal()) { |
| auto proto = cast<ProtocolDecl>(assocType->getDeclContext()); |
| ProtocolConformance *conformance = nullptr; |
| if (TC.conformsToProtocol(baseObjTy, proto, DC, |
| ConformanceCheckFlags::InExpression, |
| &conformance)) { |
| auto memberTy = conformance->getTypeWitness(assocType, &TC) |
| .getReplacement(); |
| if (!isTypeReference) |
| memberTy = MetatypeType::get(memberTy); |
| |
| auto openedType = FunctionType::get(baseObjTy, memberTy); |
| return { openedType, memberTy }; |
| } |
| } |
| |
| // FIXME: Totally bogus fallthrough. |
| Type memberTy = isTypeReference? assocType->getDeclaredType() |
| : assocType->getType(); |
| auto openedType = FunctionType::get(baseObjTy, memberTy); |
| return { openedType, memberTy }; |
| } |
| |
| // Figure out the declaration context to use when opening this type. |
| DeclContext *dc = value->getInnermostDeclContext(); |
| unsigned minOpeningDepth = |
| value->getDeclContext()->getGenericTypeContextDepth(); |
| |
| // Open the type of the generic function or member of a generic type. |
| Type openedType; |
| auto isClassBoundExistential = false; |
| llvm::DenseMap<CanType, TypeVariableType *> replacements; |
| if (auto genericFn = value->getInterfaceType()->getAs<GenericFunctionType>()){ |
| openedType = openType(genericFn, locator, replacements, dc, |
| /*skipProtocolSelfConstraint=*/true, |
| minOpeningDepth, opener); |
| } else { |
| openedType = TC.getUnopenedTypeOfReference(value, baseTy, DC, base, |
| /*wantInterfaceType=*/true); |
| |
| Type selfTy; |
| if (auto sig = dc->getGenericSignatureOfContext()) { |
| |
| // Open up the generic parameter list for the container. |
| openGeneric(dc, sig->getGenericParams(), sig->getRequirements(), |
| /*skipProtocolSelfConstraint=*/true, minOpeningDepth, |
| opener, locator, replacements); |
| |
| // Open up the type of the member. |
| openedType = openType(openedType, locator, replacements, nullptr, |
| /*skipProtocolSelfConstraint=*/false, |
| minOpeningDepth, opener); |
| |
| // Determine the object type of 'self'. |
| auto nominal = value->getDeclContext()->getDeclaredTypeOfContext() |
| ->getAnyNominal(); |
| |
| // We want to track if the generic context is represented by a |
| // class-bound existential so we won't inappropriately wrap the |
| // self type in an inout later on. |
| if (auto metatype = nominal->getType()->getAs<AnyMetatypeType>()) { |
| isClassBoundExistential = metatype->getInstanceType()-> |
| isClassExistentialType(); |
| } |
| |
| if (dc->isProtocolOrProtocolExtensionContext()) { |
| // Retrieve the type variable for 'Self'. |
| selfTy = replacements[dc->getProtocolSelf()->getDeclaredType() |
| ->getCanonicalType()]; |
| } else { |
| // Open the nominal type. |
| selfTy = openType(nominal->getDeclaredInterfaceType(), locator, |
| replacements); |
| } |
| } else { |
| selfTy = value->getDeclContext()->getDeclaredTypeOfContext(); |
| } |
| |
| // If we have a type reference, look through the metatype. |
| if (isTypeReference) |
| openedType = openedType->castTo<AnyMetatypeType>()->getInstanceType(); |
| |
| // If we're not coming from something function-like, prepend the type |
| // for 'self' to the type. |
| if (!isa<AbstractFunctionDecl>(value) && !isa<EnumElementDecl>(value)) { |
| // If self is a struct, properly qualify it based on our base |
| // qualification. If we have an lvalue coming in, we expect an inout. |
| if (!isClassBoundExistential && |
| !selfTy->hasReferenceSemantics() && |
| baseTy->is<LValueType>()) |
| selfTy = InOutType::get(selfTy); |
| |
| openedType = FunctionType::get(selfTy, openedType); |
| } |
| } |
| |
| // If this is a method whose result type has a dynamic Self return, replace |
| // DynamicSelf with the actual object type. |
| if (auto func = dyn_cast<FuncDecl>(value)) { |
| if (func->hasDynamicSelf() || |
| (baseObjTy->isExistentialType() && |
| func->hasArchetypeSelf())) { |
| openedType = openedType->replaceCovariantResultType( |
| baseObjTy, |
| func->getNumParamPatterns()); |
| } |
| } |
| // If this is an initializer, replace the result type with the base |
| // object type. |
| else if (auto ctor = dyn_cast<ConstructorDecl>(value)) { |
| auto resultTy = baseObjTy; |
| if (ctor->getFailability() != OTK_None) |
| resultTy = OptionalType::get(ctor->getFailability(), resultTy); |
| |
| openedType = openedType->replaceCovariantResultType( |
| resultTy, |
| /*uncurryLevel=*/ 2, |
| /*preserveOptionality=*/ false); |
| } |
| |
| // If we are looking at a member of an existential, open the existential. |
| Type baseOpenedTy = baseObjTy; |
| |
| if (baseObjTy->isExistentialType()) { |
| ArchetypeType *openedArchetype = ArchetypeType::getOpened(baseObjTy); |
| OpenedExistentialTypes.push_back({ getConstraintLocator(locator), |
| openedArchetype }); |
| baseOpenedTy = openedArchetype; |
| } |
| |
| // Constrain the 'self' object type. |
| auto openedFnType = openedType->castTo<FunctionType>(); |
| Type selfObjTy = openedFnType->getInput()->getRValueInstanceType(); |
| if (value->getDeclContext()->isProtocolOrProtocolExtensionContext()) { |
| // For a protocol, substitute the base object directly. We don't need a |
| // conformance constraint because we wouldn't have found the declaration |
| // if it didn't conform. |
| addConstraint(ConstraintKind::Equal, baseOpenedTy, selfObjTy, |
| getConstraintLocator(locator)); |
| } else if (!isDynamicResult) { |
| addSelfConstraint(*this, baseOpenedTy, selfObjTy, locator); |
| } |
| |
| // Compute the type of the reference. |
| Type type; |
| if (auto subscript = dyn_cast<SubscriptDecl>(value)) { |
| // For a subscript, turn the element type into an (@unchecked) |
| // optional or lvalue, depending on whether the result type is |
| // optional/dynamic, is settable, or is not. |
| auto fnType = openedFnType->getResult()->castTo<FunctionType>(); |
| auto elementTy = fnType->getResult(); |
| if (subscript->getAttrs().hasAttribute<OptionalAttr>()) |
| elementTy = OptionalType::get(elementTy->getRValueType()); |
| else if (isDynamicResult) |
| elementTy = ImplicitlyUnwrappedOptionalType::get(elementTy->getRValueType()); |
| |
| type = FunctionType::get(fnType->getInput(), elementTy); |
| } else if (isa<ProtocolDecl>(value->getDeclContext()) && |
| isa<AssociatedTypeDecl>(value)) { |
| // When we have an associated type, the base type conforms to the |
| // given protocol, so use the type witness directly. |
| // FIXME: Diagnose existentials properly. |
| auto proto = cast<ProtocolDecl>(value->getDeclContext()); |
| auto assocType = cast<AssociatedTypeDecl>(value); |
| |
| type = openedFnType->getResult(); |
| if (baseOpenedTy->is<ArchetypeType>()) { |
| // For an archetype, we substitute the base object for the base. |
| // FIXME: Feels like a total hack. |
| } else if (!baseOpenedTy->isExistentialType() && |
| !baseOpenedTy->is<ArchetypeType>()) { |
| ProtocolConformance *conformance = nullptr; |
| if (TC.conformsToProtocol(baseOpenedTy, proto, DC, |
| ConformanceCheckFlags::InExpression, |
| &conformance)) { |
| type = conformance->getTypeWitness(assocType, &TC).getReplacement(); |
| } |
| } |
| } else if (!value->isInstanceMember() || isInstance) { |
| // For a constructor, enum element, static method, static property, |
| // or an instance method referenced through an instance, we've consumed the |
| // curried 'self' already. For a type, strip off the 'self' we artificially |
| // added. |
| type = openedFnType->getResult(); |
| } else if (isDynamicResult && isa<AbstractFunctionDecl>(value)) { |
| // For a dynamic result referring to an instance function through |
| // an object of metatype type, replace the 'Self' parameter with |
| // a AnyObject member. |
| Type anyObjectTy = TC.getProtocol(SourceLoc(), |
| KnownProtocolKind::AnyObject) |
| ->getDeclaredTypeOfContext(); |
| |
| type = openedFnType->replaceSelfParameterType(anyObjectTy); |
| } else { |
| // For an unbound instance method reference, replace the 'Self' |
| // parameter with the base type. |
| type = openedFnType->replaceSelfParameterType(baseObjTy); |
| } |
| |
| // If we opened up any type variables, record the replacements. |
| recordOpenedTypes(locator, replacements); |
| |
| return { openedType, type }; |
| } |
| |
| void ConstraintSystem::addOverloadSet(Type boundType, |
| ArrayRef<OverloadChoice> choices, |
| ConstraintLocator *locator, |
| OverloadChoice *favoredChoice) { |
| assert(!choices.empty() && "Empty overload set"); |
| |
| SmallVector<Constraint *, 4> overloads; |
| |
| // As we do for other favored constraints, if a favored overload has been |
| // specified, let it be the first term in the disjunction. |
| if (favoredChoice) { |
| auto bindOverloadConstraint = |
| Constraint::createBindOverload(*this, |
| boundType, |
| *favoredChoice, |
| locator); |
| |
| bindOverloadConstraint->setFavored(); |
| |
| overloads.push_back(bindOverloadConstraint); |
| } |
| |
| for (auto choice : choices) { |
| if (favoredChoice && (favoredChoice == &choice)) |
| continue; |
| |
| overloads.push_back(Constraint::createBindOverload(*this, boundType, choice, |
| locator)); |
| } |
| |
| auto disjunction = Constraint::createDisjunction(*this, overloads, locator); |
| |
| if (favoredChoice) |
| disjunction->setFavored(); |
| |
| addConstraint(disjunction); |
| } |
| |
| void ConstraintSystem::resolveOverload(ConstraintLocator *locator, |
| Type boundType, |
| OverloadChoice choice) { |
| // Determine the type to which we'll bind the overload set's type. |
| Type refType; |
| Type openedFullType; |
| switch (choice.getKind()) { |
| case OverloadChoiceKind::DeclViaBridge: |
| case OverloadChoiceKind::Decl: |
| case OverloadChoiceKind::DeclViaDynamic: |
| case OverloadChoiceKind::DeclViaUnwrappedOptional: |
| case OverloadChoiceKind::TypeDecl: { |
| bool isTypeReference = choice.getKind() == OverloadChoiceKind::TypeDecl; |
| bool isDynamicResult |
| = choice.getKind() == OverloadChoiceKind::DeclViaDynamic; |
| // Retrieve the type of a reference to the specific declaration choice. |
| if (choice.getBaseType()) { |
| auto getDotBase = [](const Expr *E) -> const DeclRefExpr * { |
| if (E == nullptr) return nullptr; |
| switch (E->getKind()) { |
| case ExprKind::MemberRef: { |
| auto Base = cast<MemberRefExpr>(E)->getBase(); |
| return dyn_cast<const DeclRefExpr>(Base); |
| } |
| case ExprKind::UnresolvedDot: { |
| auto Base = cast<UnresolvedDotExpr>(E)->getBase(); |
| return dyn_cast<const DeclRefExpr>(Base); |
| } |
| default: |
| return nullptr; |
| } |
| }; |
| auto anchor = locator ? locator->getAnchor() : nullptr; |
| auto base = getDotBase(anchor); |
| std::tie(openedFullType, refType) |
| = getTypeOfMemberReference(choice.getBaseType(), choice.getDecl(), |
| isTypeReference, isDynamicResult, |
| locator, base, nullptr); |
| } else { |
| std::tie(openedFullType, refType) |
| = getTypeOfReference(choice.getDecl(), isTypeReference, |
| choice.isSpecialized(), locator); |
| } |
| |
| if (choice.getDecl()->getAttrs().hasAttribute<OptionalAttr>() && |
| !isa<SubscriptDecl>(choice.getDecl())) { |
| // For a non-subscript declaration that is an optional |
| // requirement in a protocol, strip off the lvalue-ness (FIXME: |
| // one cannot assign to such declarations for now) and make a |
| // reference to that declaration be optional. |
| // |
| // Subscript declarations are handled within |
| // getTypeOfMemberReference(); their result types are optional. |
| refType = OptionalType::get(refType->getRValueType()); |
| } |
| // For a non-subscript declaration found via dynamic lookup, strip |
| // off the lvalue-ness (FIXME: as a temporary hack. We eventually |
| // want this to work) and make a reference to that declaration be |
| // an implicitly unwrapped optional. |
| // |
| // Subscript declarations are handled within |
| // getTypeOfMemberReference(); their result types are unchecked |
| // optional. |
| else if (isDynamicResult && !isa<SubscriptDecl>(choice.getDecl())) { |
| refType = ImplicitlyUnwrappedOptionalType::get(refType->getRValueType()); |
| } |
| |
| // If the declaration is unavailable, note that in the score. |
| if (choice.getDecl()->getAttrs().isUnavailable(getASTContext())) { |
| increaseScore(SK_Unavailable); |
| } |
| |
| break; |
| } |
| |
| case OverloadChoiceKind::BaseType: |
| refType = choice.getBaseType(); |
| break; |
| |
| case OverloadChoiceKind::TupleIndex: |
| if (auto lvalueTy = choice.getBaseType()->getAs<LValueType>()) { |
| // When the base of a tuple lvalue, the member is always an lvalue. |
| auto tuple = lvalueTy->getObjectType()->castTo<TupleType>(); |
| refType = tuple->getElementType(choice.getTupleIndex())->getRValueType(); |
| refType = LValueType::get(refType); |
| } else { |
| // When the base is a tuple rvalue, the member is always an rvalue. |
| auto tuple = choice.getBaseType()->castTo<TupleType>(); |
| refType = tuple->getElementType(choice.getTupleIndex()); |
| } |
| break; |
| } |
| |
| // If we have a type variable for the 'Self' of a protocol |
| // requirement that's being opened, and the resulting type has an |
| // archetype in it, replace the 'Self' archetype with the |
| // corresponding type variable. |
| // FIXME: See the comment for SelfTypeVar for information about this hack. |
| if (SelfTypeVar && refType->hasArchetype()) { |
| refType = refType.transform([&](Type type) -> Type { |
| if (auto archetype = type->getAs<ArchetypeType>()) { |
| return replaceSelfTypeInArchetype(archetype); |
| } |
| return type; |
| }); |
| } |
| assert(!refType->hasTypeParameter() && "Cannot have a dependent type here"); |
| |
| // If we're binding to an init member, the 'throws' need to line up between |
| // the bound and reference types. |
| if (choice.isDecl()) { |
| auto decl = choice.getDecl(); |
| if (auto CD = dyn_cast<ConstructorDecl>(decl)) { |
| auto boundFunctionType = boundType->getAs<AnyFunctionType>(); |
| |
| if (boundFunctionType && |
| CD->isBodyThrowing() != boundFunctionType->throws()) { |
| boundType = FunctionType::get(boundFunctionType->getInput(), |
| boundFunctionType->getResult(), |
| boundFunctionType->getExtInfo(). |
| withThrows()); |
| } |
| } |
| } |
| |
| // Add the type binding constraint. |
| addConstraint(ConstraintKind::Bind, boundType, refType, locator); |
| |
| // Note that we have resolved this overload. |
| resolvedOverloadSets |
| = new (*this) ResolvedOverloadSetListItem{resolvedOverloadSets, |
| boundType, |
| choice, |
| locator, |
| openedFullType, |
| refType}; |
| if (TC.getLangOpts().DebugConstraintSolver) { |
| auto &log = getASTContext().TypeCheckerDebug->getStream(); |
| log.indent(solverState? solverState->depth * 2 : 2) |
| << "(overload set choice binding " |
| << boundType->getString() << " := " |
| << refType->getString() << ")\n"; |
| } |
| } |
| |
| /// Given that we're accessing a member of an ImplicitlyUnwrappedOptional<T>, is |
| /// the DC one of the special cases where we should not instead look at T? |
| static bool isPrivilegedAccessToImplicitlyUnwrappedOptional(DeclContext *DC, |
| NominalTypeDecl *D) { |
| assert(D == DC->getASTContext().getImplicitlyUnwrappedOptionalDecl()); |
| |
| // Walk up through the chain of current contexts. |
| for (; ; DC = DC->getParent()) { |
| assert(DC && "ran out of contexts before finding a module scope?"); |
| |
| // Look through local contexts. |
| if (DC->isLocalContext()) { |
| continue; |
| |
| // If we're in a type context that's defining or extending |
| // ImplicitlyUnwrappedOptional<T>, we're privileged. |
| } else if (DC->isTypeContext()) { |
| if (DC->getDeclaredTypeInContext()->getAnyNominal() == D) |
| return true; |
| |
| // Otherwise, we're privileged if we're within the same file that |
| // defines ImplicitlyUnwrappedOptional<T>. |
| } else { |
| assert(DC->isModuleScopeContext()); |
| return (DC == D->getModuleScopeContext()); |
| } |
| } |
| } |
| |
| Type ConstraintSystem::lookThroughImplicitlyUnwrappedOptionalType(Type type) { |
| if (auto boundTy = type->getAs<BoundGenericEnumType>()) { |
| auto boundDecl = boundTy->getDecl(); |
| if (boundDecl == TC.Context.getImplicitlyUnwrappedOptionalDecl() && |
| !isPrivilegedAccessToImplicitlyUnwrappedOptional(DC, boundDecl)) |
| return boundTy->getGenericArgs()[0]; |
| } |
| return Type(); |
| } |
| |
| Type ConstraintSystem::simplifyType(Type type, |
| llvm::SmallPtrSet<TypeVariableType *, 16> &substituting) { |
| return type.transform([&](Type type) -> Type { |
| if (auto tvt = dyn_cast<TypeVariableType>(type.getPointer())) { |
| tvt = getRepresentative(tvt); |
| if (auto fixed = getFixedType(tvt)) { |
| if (substituting.insert(tvt).second) { |
| auto result = simplifyType(fixed, substituting); |
| substituting.erase(tvt); |
| return result; |
| } |
| } |
| |
| return tvt; |
| } |
| |
| // If this is a FunctionType and we inferred new function attributes, apply |
| // them. |
| if (auto ft = dyn_cast<FunctionType>(type.getPointer())) { |
| auto it = extraFunctionAttrs.find(ft); |
| if (it != extraFunctionAttrs.end()) { |
| auto extInfo = ft->getExtInfo(); |
| if (it->second.isNoEscape()) |
| extInfo = extInfo.withNoEscape(); |
| if (it->second.isNoReturn()) |
| extInfo = extInfo.withIsNoReturn(); |
| if (it->second.throws()) |
| extInfo = extInfo.withThrows(); |
| return FunctionType::get(ft->getInput(), ft->getResult(), extInfo); |
| } |
| } |
| |
| |
| return type; |
| }); |
| } |
| |
| Type Solution::simplifyType(TypeChecker &tc, Type type) const { |
| return type.transform([&](Type type) -> Type { |
| if (auto tvt = dyn_cast<TypeVariableType>(type.getPointer())) { |
| auto known = typeBindings.find(tvt); |
| assert(known != typeBindings.end()); |
| return known->second; |
| } |
| |
| // If this is a FunctionType and we inferred new function attributes, apply |
| // them. |
| if (auto ft = dyn_cast<FunctionType>(type.getPointer())) { |
| auto &CS = getConstraintSystem(); |
| auto it = CS.extraFunctionAttrs.find(ft); |
| if (it != CS.extraFunctionAttrs.end()) { |
| auto extInfo = ft->getExtInfo(); |
| if (it->second.isNoEscape()) |
| extInfo = extInfo.withNoEscape(); |
| if (it->second.isNoReturn()) |
| extInfo = extInfo.withIsNoReturn(); |
| if (it->second.throws()) |
| extInfo = extInfo.withThrows(); |
| return FunctionType::get(simplifyType(tc, ft->getInput()), |
| simplifyType(tc, ft->getResult()), |
| extInfo); |
| } |
| } |
| |
| return type; |
| }); |
| } |
