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swift-mirror/lib/Sema/CSApply.cpp
John McCall 607b326ab5 When type-checking downcasts, just optimistically 
assume that we know about all the optional types in play.

This isn't correct for types that can dynamically be
more optional than they appear statically, e.g. archetypes
and existentials, but it's the easiest thing to do,
and there are workarounds.  I filed rdar://16374053
to handle doing the right thing.

Swift SVN r15254
2014-03-20 00:25:00 +00:00

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154 KiB
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//===--- CSApply.cpp - Constraint Application -----------------------------===//
//
// 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 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/AST/Attr.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 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;
}
Type Solution::computeSubstitutions(Type origType, DeclContext *dc,
Type openedType,
SmallVectorImpl<Substitution> &substitutions) const {
auto &tc = getConstraintSystem().getTypeChecker();
auto &ctx = tc.Context;
// Gather the substitutions from archetypes to concrete types, found
// by identifying all of the type variables in the original type
// FIXME: It's unfortunate that we're using archetypes here, but we don't
// have another way to map from type variables back to dependent types (yet);
TypeSubstitutionMap typeSubstitutions;
auto type = openedType.transform([&](Type type) -> Type {
if (auto tv = dyn_cast<TypeVariableType>(type.getPointer())) {
auto archetype = tv->getImpl().getArchetype();
auto simplified = getFixedType(tv);
typeSubstitutions[archetype] = simplified;
return SubstitutedType::get(archetype, simplified,
tc.Context);
}
return type;
});
auto currentModule = getConstraintSystem().DC->getParentModule();
SmallVector<ProtocolConformance *, 4> currentConformances;
ArrayRef<Requirement> requirements;
if (auto genericFn = origType->getAs<GenericFunctionType>()) {
requirements = genericFn->getRequirements();
} else {
requirements = dc->getDeclaredTypeOfContext()->getAnyNominal()
->getGenericRequirements();
}
for (const auto &req : requirements) {
// Drop requirements for parameters that have been constrained away to
// concrete types.
auto firstArchetype
= ArchetypeBuilder::mapTypeIntoContext(dc, req.getFirstType())
->getAs<ArchetypeType>();
if (!firstArchetype)
continue;
switch (req.getKind()) {
case RequirementKind::Conformance:
// If this is a protocol conformance requirement, get the conformance
// and record it.
if (auto protoType = req.getSecondType()->getAs<ProtocolType>()) {
assert(firstArchetype
== substitutions.back().Archetype && "Archetype out-of-sync");
ProtocolConformance *conformance = nullptr;
Type replacement = substitutions.back().Replacement;
bool conforms = tc.conformsToProtocol(replacement,
protoType->getDecl(),
getConstraintSystem().DC,
&conformance);
assert((conforms ||
replacement->isExistentialType() ||
replacement->is<GenericTypeParamType>()) &&
"Constraint system missed a conformance?");
(void)conforms;
assert(conformance ||
replacement->isExistentialType() ||
replacement->is<ArchetypeType>() ||
replacement->is<GenericTypeParamType>());
currentConformances.push_back(conformance);
break;
}
break;
case RequirementKind::SameType:
// Same-type requirements aren't recorded in substitutions.
break;
case RequirementKind::WitnessMarker:
// Flush the current conformances.
if (!substitutions.empty()) {
substitutions.back().Conformance
= ctx.AllocateCopy(currentConformances);
currentConformances.clear();
}
// Each value witness marker starts a new substitution.
substitutions.push_back(Substitution());
substitutions.back().Archetype = firstArchetype;
substitutions.back().Replacement =
tc.substType(currentModule, substitutions.back().Archetype,
typeSubstitutions);
break;
}
}
// Flush the final conformances.
if (!substitutions.empty()) {
substitutions.back().Conformance = ctx.AllocateCopy(currentConformances);
currentConformances.clear();
}
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.
static FuncDecl *findNamedWitness(TypeChecker &tc, DeclContext *dc,
Type type, ProtocolDecl *proto,
Identifier name,
Diag<> diag) {
// Find the named requirement.
FuncDecl *requirement = nullptr;
for (auto member : proto->getMembers()) {
auto fd = dyn_cast<FuncDecl>(member);
if (!fd || !fd->hasName())
continue;
if (fd->getName() == name) {
requirement = fd;
break;
}
}
if (!requirement || requirement->isInvalid()) {
tc.diagnose(proto->getLoc(), diag);
return nullptr;
}
// Find the member used to satisfy the named requirement.
ProtocolConformance *conformance = 0;
bool conforms = tc.conformsToProtocol(type, proto, dc, &conformance);
if (!conforms)
return nullptr;
// For an archetype, just return the requirement from the protocol. There
// are no protocol conformance tables.
if (type->is<ArchetypeType>()) {
return requirement;
}
assert(conformance && "Missing conformance information");
// FIXME: Dropping substitutions here.
return cast<FuncDecl>(conformance->getWitness(requirement, &tc).getDecl());
}
/// Adjust the given type to become the self type when referring to
/// the given member.
static Type adjustSelfTypeForMember(Type baseTy, ValueDecl *member,
bool IsDirectPropertyAccess,
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 non-@mutating 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->isExistentialType() ||
baseObjectTy->is<ArchetypeType>()))
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 and the base needs to be mutable.
if (auto *VD = dyn_cast<VarDecl>(member)) {
if (VD->hasAccessorFunctions() && baseTy->is<InOutType>() &&
!IsDirectPropertyAccess)
return InOutType::get(baseObjectTy);
// If the member is immutable in this context, the base is always an
// unqualified baseObjectTy.
if (!VD->isSettable(UseDC))
return baseObjectTy;
}
// If the base of the subscript is mutable, then we may be invoking a mutable
// getter or setter.
if (isa<SubscriptDecl>(member) && !baseTy->hasReferenceSemantics() &&
baseTy->is<InOutType>())
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;
}
/// Return true if a MemberReferenceExpr with the specified base and member in
/// the specified DeclContext should be implicitly marked as
/// "isDirectPropertyAccess".
static bool isImplicitDirectMemberReference(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 (auto *AFD_DC = dyn_cast<AbstractFunctionDecl>(DC))
if (member->hasStorage() && member->hasAccessorFunctions() &&
// In a ctor or dtor.
(isa<ConstructorDecl>(AFD_DC) || isa<DestructorDecl>(AFD_DC)) &&
// Ctor or dtor are for immediate class, not a derived class.
AFD_DC->getParent() == member->getDeclContext() &&
// Is a "self.property" reference.
isa<DeclRefExpr>(base) &&
AFD_DC->getImplicitSelfDecl() == cast<DeclRefExpr>(base)->getDecl()) {
// Access this directly instead of going through (e.g.) observing accessors.
return true;
}
// If the value is always directly accessed from this context, do it.
return member->isUseFromContextDirect(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;
private:
/// \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.
Expr *coerceTupleToTuple(Expr *expr, TupleType *fromTuple,
TupleType *toTuple,
ConstraintLocatorBuilder locator,
SmallVectorImpl<int> &sources,
SmallVectorImpl<unsigned> &variadicArgs);
/// \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.
///
/// \param expr The expression to be coerced.
/// \param toType The tupe 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 the expression to another type via a user-defined
/// conversion.
///
/// \param expr The expression to be coerced.
/// \param toType The tupe 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 *coerceViaUserConversion(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);
/// \brief Coerce an expression of unchecked optional type to its
/// underlying value type, in the correct way for an implicit
/// look-through.
Expr *coerceUncheckedOptionalToValue(Expr *expr, Type objTy,
ConstraintLocatorBuilder locator);
public:
/// \brief Build a reference to the given declaration.
Expr *buildDeclRef(ValueDecl *decl, SourceLoc loc, Type openedType,
ConstraintLocatorBuilder locator,
bool specialized, bool implicit,
bool isDirectPropertyAccess) {
// 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(isa<FuncDecl>(decl) && "Can only refer to functions here");
assert(cast<FuncDecl>(decl)->isOperator() && "Must be an operator");
auto openedFnType = openedType->castTo<FunctionType>();
auto baseTy = simplifyType(openedFnType->getInput())
->getRValueInstanceType();
Expr * base = new (ctx) MetatypeExpr(nullptr, loc,
MetatypeType::get(baseTy, ctx));
return buildMemberRef(base, openedType, SourceLoc(), decl,
loc, openedFnType->getResult(),
locator, implicit, isDirectPropertyAccess);
}
// 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->getPotentialGenericDeclContext();
SmallVector<Substitution, 4> substitutions;
auto type = solution.computeSubstitutions(genericFn, dc, openedType,
substitutions);
return new (ctx) DeclRefExpr(ConcreteDeclRef(ctx, decl, substitutions),
loc, implicit, isDirectPropertyAccess,
type);
}
auto type = simplifyType(openedType);
return new (ctx) DeclRefExpr(decl, loc, implicit, isDirectPropertyAccess,
type);
}
/// Describes an opened existential that has not yet been closed.
struct OpenedExistential {
/// The existential value being opened.
Expr *ExistentialValue;
/// The opaque value (of archetype type) stored within the
/// existential.
OpaqueValueExpr *OpaqueValue;
};
/// A mapping from archetype types that resulted from opening an
/// existential to the opened existential. This mapping captures
/// only those existentials that have been opened, but for which
/// we have not yet created an \c OpenExistentialExpr.
llvm::SmallDenseMap<ArchetypeType *, OpenedExistential> OpenedExistentials;
/// Open an existential value into a new, opaque value of
/// archetype type.
///
/// \param base An expression of existential type whose value will
/// be opened.
///
/// \returns A pair (expr, type) that provides a reference to the value
/// stored within the expression or its metatype (if the base was a
/// metatype) and the new archetype that describes the dynamic type stored
/// within the existential.
std::tuple<Expr *, ArchetypeType *>
openExistentialReference(Expr *base) {
auto &tc = cs.getTypeChecker();
base = tc.coerceToRValue(base);
auto baseTy = base->getType()->getRValueType();
bool isMetatype = false;
if (auto metaTy = baseTy->getAs<MetatypeType>()) {
isMetatype = true;
baseTy = metaTy->getInstanceType();
}
assert(baseTy->isExistentialType() && "Type must be existential");
// Create the archetype.
SmallVector<ProtocolDecl *, 4> protocols;
auto &ctx = tc.Context;
(void)baseTy->isExistentialType(protocols);
auto archetype = ArchetypeType::getOpened(baseTy);
// Create the opaque opened value. If we started with a
// metatype, it's a metatype.
Type opaqueType = archetype;
if (isMetatype)
opaqueType = MetatypeType::get(archetype, ctx);
auto archetypeVal = new (ctx) OpaqueValueExpr(base->getLoc(), opaqueType);
archetypeVal->setUniquelyReferenced(true);
// Record this opened existential.
OpenedExistentials[archetype] = { base, archetypeVal };
return std::make_tuple(archetypeVal, archetype);
}
/// \brief Build a new member reference with the given base and member.
Expr *buildMemberRef(Expr *base, Type openedFullType, SourceLoc dotLoc,
ValueDecl *member, SourceLoc memberLoc,
Type openedType, ConstraintLocatorBuilder locator,
bool Implicit, bool IsDirectPropertyAccess) {
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 UncheckedOptional<T>.
if (!Implicit) {
if (auto objTy = cs.lookThroughUncheckedOptionalType(baseTy)) {
base = coerceUncheckedOptionalToValue(base, objTy, locator);
if (!base) return nullptr;
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<MetatypeType>()) {
baseIsInstance = false;
baseTy = baseMeta->getInstanceType();
}
// 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 (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->getPotentialGenericDeclContext();
// Build a reference to the generic member.
SmallVector<Substitution, 4> substitutions;
refTy = solution.computeSubstitutions(member->getInterfaceType(),
dc,
openedFullType,
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 = tc.getUnopenedTypeOfReference(member, Type(), dc,
/*wantInterfaceType=*/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()) ||
isa<ConstructorDecl>(func)) {
// For a DynamicSelf method on an existential, open up the
// existential.
if (func->getExtensionType()->is<ProtocolType>() &&
baseTy->isExistentialType()) {
std::tie(base, baseTy) = openExistentialReference(base);
containerTy = baseTy;
openedType = openedType->replaceResultType(
baseTy,
func->getNumParamPatterns()-1);
// The member reference is a specialized declaration
// reference that replaces the Self of the protocol with
// the existential type; change it to refer to the opened
// archetype type.
// FIXME: We should do this before we create the
// specialized declaration reference, but that requires
// redundant hasDynamicSelf checking.
auto oldSubstitutions = memberRef.getSubstitutions();
SmallVector<Substitution, 4> newSubstitutions(
oldSubstitutions.begin(),
oldSubstitutions.end());
auto &selfSubst = newSubstitutions.front();
assert(selfSubst.Archetype->getSelfProtocol() &&
"Not the Self archetype for a protocol?");
selfSubst.Replacement = baseTy;
unsigned numConformances = selfSubst.Conformance.size();
auto newConformances
= context.Allocate<ProtocolConformance *>(numConformances);
std::fill(newConformances.begin(), newConformances.end(), nullptr);
selfSubst.Conformance = newConformances;
memberRef = ConcreteDeclRef(context, memberRef.getDecl(),
newSubstitutions);
}
refTy = refTy->replaceResultType(containerTy,
func->getNumParamPatterns());
dynamicSelfFnType = refTy->replaceResultType(
baseTy,
func->getNumParamPatterns());
// 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(!IsDirectPropertyAccess &&
"Direct property access doesn't make sense for this");
assert(!dynamicSelfFnType && "No reference type to convert to");
Expr *ref = new (context) DeclRefExpr(memberRef, memberLoc, Implicit);
ref->setType(refTy);
return new (context) DotSyntaxBaseIgnoredExpr(base, dotLoc, ref);
}
// Otherwise, we're referring to a member of a type.
// Is it an archetype or existential member?
bool isArchetypeOrExistentialRef
= isa<ProtocolDecl>(member->getDeclContext()) &&
(baseTy->is<ArchetypeType>() || baseTy->isExistentialType());
// If we are referring to an optional member of a protocol.
if (isArchetypeOrExistentialRef && member->getAttrs().isOptional()) {
auto proto =tc.getProtocol(memberLoc, KnownProtocolKind::AnyObject);
if (!proto)
return nullptr;
baseTy = proto->getDeclaredType();
}
// References to properties with accessors and storage usually go
// through the accessors, but sometimes are direct.
if (auto *VD = dyn_cast<VarDecl>(member))
IsDirectPropertyAccess |= isImplicitDirectMemberReference(base, VD, dc);
if (baseIsInstance) {
// Convert the base to the appropriate container type, turning it
// into an lvalue if required.
Type selfTy;
if (isArchetypeOrExistentialRef)
selfTy = baseTy;
else {
// If the base is already an lvalue with the right base type, we can
// pass it as an inout qualified type.
selfTy = containerTy;
if (selfTy->isEqual(baseTy) && !selfTy->hasReferenceSemantics())
if (base->getType()->is<LValueType>())
selfTy = InOutType::get(selfTy);
}
base = coerceObjectArgumentToType(
base, selfTy, member, IsDirectPropertyAccess,
locator.withPathElement(ConstraintLocator::MemberRefBase));
} else {
// Convert the base to an rvalue of the appropriate metatype.
base = coerceToType(base,
MetatypeType::get(isArchetypeOrExistentialRef
? baseTy
: containerTy,
context),
locator.withPathElement(
ConstraintLocator::MemberRefBase));
if (!base)
return nullptr;
base = tc.coerceToRValue(base);
}
assert(base && "Unable to convert base?");
// Handle archetype and existential references.
if (isArchetypeOrExistentialRef) {
assert(!IsDirectPropertyAccess &&
"Direct property access doesn't make sense for this");
assert(!dynamicSelfFnType &&
"Archetype/existential DynamicSelf with extra conversion");
Expr *ref;
if (member->getAttrs().isOptional()) {
base = tc.coerceToRValue(base);
if (!base) return nullptr;
ref = new (context) DynamicMemberRefExpr(base, dotLoc, memberRef,
memberLoc);
} else {
assert(!dynamicSelfFnType && "Converted type doesn't make sense here");
ref = new (context) MemberRefExpr(base, dotLoc, memberRef,
memberLoc, Implicit,
IsDirectPropertyAccess);
cast<MemberRefExpr>(ref)->setIsSuper(isSuper);
}
ref->setImplicit(Implicit);
ref->setType(simplifyType(openedType));
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");
auto result
= new (context) MemberRefExpr(base, dotLoc, memberRef,
memberLoc, Implicit,
IsDirectPropertyAccess);
result->setIsSuper(isSuper);
// Skip the synthesized 'self' input type of the opened type.
result->setType(simplifyType(openedType));
return result;
}
assert(!IsDirectPropertyAccess &&
"Direct property access doesn't make sense for this");
// Handle all other references.
Expr *ref = new (context) DeclRefExpr(memberRef, memberLoc, Implicit);
ref->setType(refTy);
// 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.
return new (context) DotSyntaxBaseIgnoredExpr(base, dotLoc, ref);
} else {
assert((!baseIsInstance || member->isInstanceMember()) &&
"can't call a static method on an instance");
apply = new (context) DotSyntaxCallExpr(ref, dotLoc, base);
}
return finishApply(apply, openedType, nullptr);
}
/// \brief Build a new dynamic member reference with the given base and
/// member.
Expr *buildDynamicMemberRef(Expr *base, SourceLoc dotLoc, ValueDecl *member,
SourceLoc memberLoc, Type openedType,
ConstraintLocatorBuilder locator) {
auto &context = cs.getASTContext();
// If we're specializing a polymorphic function, compute the set of
// substitutions and form the member reference.
Optional<ConcreteDeclRef> memberRef(member);
if (auto func = dyn_cast<FuncDecl>(member)) {
auto resultTy = func->getType()->castTo<AnyFunctionType>()->getResult();
(void)resultTy;
assert(!resultTy->is<PolymorphicFunctionType>() &&
"Polymorphic function type slipped through");
}
// The base must always be an rvalue.
base = cs.getTypeChecker().coerceToRValue(base);
if (!base) return nullptr;
auto result = new (context) DynamicMemberRefExpr(base, dotLoc, *memberRef,
memberLoc);
result->setType(simplifyType(openedType));
return result;
}
/// \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, and string literals. The first step
/// uses \c protocol while the second step uses \c builtinProtocol.
///
/// \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,
Identifier literalFuncName,
ProtocolDecl *builtinProtocol,
TypeOrName builtinLiteralType,
Identifier builtinLiteralFuncName,
bool (*isBuiltinArgType)(Type),
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 Nothing;
}
/// \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 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.
///
/// \returns the coerced expression, which will have type \c ToType.
Expr *coerceToType(Expr *expr, Type toType,
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 IsDirectPropertyAccess True if this is a direct access to
/// computed properties that have storage.
///
/// \param locator Locator used to describe where in this expression we are.
Expr *coerceObjectArgumentToType(Expr *expr,
Type baseTy, ValueDecl *member,
bool IsDirectPropertyAccess,
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.
Expr *buildSubscript(Expr *base, Expr *index,
ConstraintLocatorBuilder locator) {
// 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 UncheckedOptional<T>.
if (auto objTy = cs.lookThroughUncheckedOptionalType(baseTy)) {
base = coerceUncheckedOptionalToValue(base, objTy, locator);
if (!base) return nullptr;
}
// 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();
// Coerce the index argument.
index = coerceToType(index, indexTy,
locator.withPathElement(
ConstraintLocator::SubscriptIndex));
if (!index)
return nullptr;
// Form the subscript expression.
// Handle dynamic lookup.
if (selected.choice.getKind() == OverloadChoiceKind::DeclViaDynamic ||
subscript->getAttrs().isOptional()) {
// If we've found an optional method in a protocol, the base type is
// AnyObject.
if (selected.choice.getKind() != OverloadChoiceKind::DeclViaDynamic) {
auto proto = tc.getProtocol(index->getStartLoc(),
KnownProtocolKind::AnyObject);
if (!proto)
return nullptr;
baseTy = proto->getDeclaredType();
}
base = coerceObjectArgumentToType(base, baseTy, subscript, false,
locator);
if (!base)
return nullptr;
auto subscriptExpr = new (tc.Context) DynamicSubscriptExpr(base,
index,
subscript);
subscriptExpr->setType(resultTy);
return subscriptExpr;
}
// 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,
substitutions);
// Convert the base.
auto openedFullFnType = selected.openedFullType->castTo<FunctionType>();
auto openedBaseType = openedFullFnType->getInput();
containerTy = solution.simplifyType(tc, openedBaseType);
base = coerceObjectArgumentToType(base, containerTy, subscript, false,
locator);
locator.withPathElement(ConstraintLocator::MemberRefBase);
if (!base)
return nullptr;
// Form the generic subscript expression.
auto subscriptExpr
= new (tc.Context) SubscriptExpr(base, index,
ConcreteDeclRef(tc.Context,
subscript,
substitutions));
subscriptExpr->setType(resultTy);
subscriptExpr->setIsSuper(isSuper);
return subscriptExpr;
}
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, false,
locator);
if (!base)
return nullptr;
// Form a normal subscript.
auto *subscriptExpr
= new (tc.Context) SubscriptExpr(base, index, subscript);
subscriptExpr->setType(resultTy);
subscriptExpr->setIsSuper(isSuper);
return subscriptExpr;
}
/// \brief Build a new reference to another constructor.
Expr *buildOtherConstructorRef(Type openedFullType,
ConstructorDecl *ctor, SourceLoc loc,
bool implicit) {
auto &tc = cs.getTypeChecker();
auto &ctx = tc.Context;
// Compute the concrete reference.
ConcreteDeclRef ref;
Type resultTy;
if (ctor->getInterfaceType()->is<GenericFunctionType>()) {
// Compute the reference to the generic constructor.
SmallVector<Substitution, 4> substitutions;
resultTy = solution.computeSubstitutions(
ctor->getInterfaceType(),
ctor,
openedFullType,
substitutions);
ref = ConcreteDeclRef(ctx, ctor, substitutions);
// 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());
} else {
ref = ConcreteDeclRef(ctor);
resultTy = ctor->getInitializerType();
}
// Build the constructor reference.
Expr *refExpr = new (ctx) OtherConstructorDeclRefExpr(ref, loc, implicit,
resultTy);
return refExpr;
}
public:
ExprRewriter(ConstraintSystem &cs, const Solution &solution)
: cs(cs), dc(cs.DC), solution(solution) { }
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 *handleIntegerLiteralExpr(LiteralExpr *expr) {
auto &tc = cs.getTypeChecker();
ProtocolDecl *protocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::IntegerLiteralConvertible);
ProtocolDecl *builtinProtocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::BuiltinIntegerLiteralConvertible);
// 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::FloatLiteralConvertible)) {
if (auto defaultFloatType = tc.getDefaultType(floatProtocol, dc)) {
if (defaultFloatType->isEqual(type))
type = defaultFloatType;
}
}
// Find the maximum-sized builtin integer type.
// FIXME: Cache name lookup.
auto maxTypeName = tc.Context.getIdentifier("MaxBuiltinIntegerType");
UnqualifiedLookup lookup(maxTypeName, tc.getStdlibModule(dc), &tc);
auto maxTypeDecl
= dyn_cast_or_null<TypeAliasDecl>(lookup.getSingleTypeResult());
if (!maxTypeDecl ||
!maxTypeDecl->getUnderlyingType()->is<BuiltinIntegerType>()) {
tc.diagnose(expr->getLoc(), diag::no_MaxBuiltinIntegerType_found);
return nullptr;
}
auto maxType = maxTypeDecl->getUnderlyingType();
return convertLiteral(
expr,
type,
expr->getType(),
protocol,
tc.Context.getIdentifier("IntegerLiteralType"),
tc.Context.getIdentifier("convertFromIntegerLiteral"),
builtinProtocol,
maxType,
tc.Context.getIdentifier("_convertFromBuiltinIntegerLiteral"),
nullptr,
diag::integer_literal_broken_proto,
diag::builtin_integer_literal_broken_proto);
}
Expr *visitIntegerLiteralExpr(IntegerLiteralExpr *expr) {
return handleIntegerLiteralExpr(expr);
}
Expr *visitFloatLiteralExpr(FloatLiteralExpr *expr) {
auto &tc = cs.getTypeChecker();
ProtocolDecl *protocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::FloatLiteralConvertible);
ProtocolDecl *builtinProtocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::BuiltinFloatLiteralConvertible);
// 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.
auto maxTypeName = tc.Context.getIdentifier("MaxBuiltinFloatType");
UnqualifiedLookup lookup(maxTypeName, tc.getStdlibModule(dc), &tc);
auto maxTypeDecl
= dyn_cast_or_null<TypeAliasDecl>(lookup.getSingleTypeResult());
if (!maxTypeDecl ||
!maxTypeDecl->getUnderlyingType()->is<BuiltinFloatType>()) {
tc.diagnose(expr->getLoc(), diag::no_MaxBuiltinFloatType_found);
return nullptr;
}
auto maxType = maxTypeDecl->getUnderlyingType();
return convertLiteral(
expr,
type,
expr->getType(),
protocol,
tc.Context.getIdentifier("FloatLiteralType"),
tc.Context.getIdentifier("convertFromFloatLiteral"),
builtinProtocol,
maxType,
tc.Context.getIdentifier("_convertFromBuiltinFloatLiteral"),
nullptr,
diag::float_literal_broken_proto,
diag::builtin_float_literal_broken_proto);
}
Expr *visitCharacterLiteralExpr(CharacterLiteralExpr *expr) {
auto &tc = cs.getTypeChecker();
ProtocolDecl *protocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::CharacterLiteralConvertible);
ProtocolDecl *builtinProtocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::BuiltinCharacterLiteralConvertible);
// 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;
}
return convertLiteral(
expr,
type,
expr->getType(),
protocol,
tc.Context.getIdentifier("CharacterLiteralType"),
tc.Context.getIdentifier("convertFromCharacterLiteral"),
builtinProtocol,
Type(BuiltinIntegerType::get(32, tc.Context)),
tc.Context.getIdentifier("_convertFromBuiltinCharacterLiteral"),
[] (Type type) -> bool {
if (auto builtinInt = type->getAs<BuiltinIntegerType>()) {
return builtinInt->isFixedWidth(32);
}
return false;
},
diag::character_literal_broken_proto,
diag::builtin_character_literal_broken_proto);
}
Expr *handleStringLiteralExpr(LiteralExpr *expr) {
auto stringLiteral = dyn_cast<StringLiteralExpr>(expr);
auto magicLiteral = dyn_cast<MagicIdentifierLiteralExpr>(expr);
assert(bool(stringLiteral) != bool(magicLiteral) &&
"literal must be either a string literal or a magic literal");
auto &tc = cs.getTypeChecker();
ProtocolDecl *protocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::StringLiteralConvertible);
// 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;
}
TupleTypeElt elementsArray[3] = {
TupleTypeElt(tc.Context.TheRawPointerType),
TupleTypeElt(BuiltinIntegerType::getWordType(tc.Context)),
TupleTypeElt(BuiltinIntegerType::get(1, tc.Context))
};
Identifier CFSLID = tc.Context.getIdentifier("convertFromStringLiteral");
// If the type can handle UTF-16 string literals, prefer them.
Identifier CFBSLID;
ProtocolDecl *builtinProtocol
= tc.getProtocol(
expr->getLoc(),
KnownProtocolKind::BuiltinUTF16StringLiteralConvertible);
ArrayRef<TupleTypeElt> elements;
if (tc.conformsToProtocol(type, builtinProtocol, cs.DC)) {
CFBSLID = tc.Context.getIdentifier(
"_convertFromBuiltinUTF16StringLiteral");
elements = llvm::makeArrayRef(elementsArray).slice(0, 2);
if (stringLiteral)
stringLiteral->setEncoding(StringLiteralExpr::UTF16);
else
magicLiteral->setStringEncoding(StringLiteralExpr::UTF16);
} else {
// Otherwise, fall back to UTF-8.
builtinProtocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::BuiltinStringLiteralConvertible);
CFBSLID = tc.Context.getIdentifier("_convertFromBuiltinStringLiteral");
elements = elementsArray;
if (stringLiteral)
stringLiteral->setEncoding(StringLiteralExpr::UTF8);
else
magicLiteral->setStringEncoding(StringLiteralExpr::UTF8);
}
return convertLiteral(expr,
type,
expr->getType(),
protocol,
tc.Context.getIdentifier("StringLiteralType"),
CFSLID,
builtinProtocol,
TupleType::get(elements, tc.Context),
CFBSLID,
nullptr,
diag::string_literal_broken_proto,
diag::builtin_string_literal_broken_proto);
}
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::StringInterpolationConvertible);
assert(interpolationProto && "Missing string interpolation protocol?");
// FIXME: Cache name,
auto name = tc.Context.getIdentifier("convertFromStringInterpolation");
auto member = findNamedWitness(tc, dc, type, interpolationProto, name,
diag::interpolation_broken_proto);
if (!member)
return nullptr;
// Build a reference to the convertFromStringInterpolation member.
auto typeRef = new (tc.Context) MetatypeExpr(
nullptr, expr->getStartLoc(),
MetatypeType::get(type, tc.Context));
Expr *memberRef = new (tc.Context) MemberRefExpr(typeRef,
expr->getStartLoc(),
member,
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 coerced segments.
SmallVector<Expr *, 4> segments;
unsigned index = 0;
ConstraintLocatorBuilder locatorBuilder(cs.getConstraintLocator(expr));
for (auto segment : expr->getSegments()) {
segment = coerceToType(segment, type,
locatorBuilder.withPathElement(
LocatorPathElt::getInterpolationArgument(
index++)));
if (!segment)
return nullptr;
segments.push_back(segment);
}
Expr *argument = nullptr;
if (segments.size() == 1)
argument = segments.front();
else {
SmallVector<TupleTypeElt, 4> tupleElements(segments.size(),
TupleTypeElt(type));
argument = new (tc.Context) TupleExpr(expr->getStartLoc(),
tc.Context.AllocateCopy(segments),
nullptr,
expr->getStartLoc(),
/*hasTrailingClosure=*/false,
/*Implicit=*/true,
TupleType::get(tupleElements,
tc.Context));
}
// Call the convertFromStringInterpolation member with the arguments.
ApplyExpr *apply = new (tc.Context) CallExpr(memberRef, argument,
/*Implicit=*/true);
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);
}
}
/// \brief Retrieve the type of a reference to the given declaration.
Type getTypeOfDeclReference(ValueDecl *decl, bool isSpecialized) {
if (auto typeDecl = dyn_cast<TypeDecl>(decl)) {
// Resolve the reference to this type declaration in our
// current context.
auto type = cs.getTypeChecker().resolveTypeInContext(typeDecl, dc,
isSpecialized);
if (!type)
return nullptr;
// Refer to the metatype of this type.
return MetatypeType::get(type, cs.getASTContext());
}
return cs.TC.getUnopenedTypeOfReference(decl, Type(), dc,
/*wantInterfaceType=*/true);
}
Expr *visitDeclRefExpr(DeclRefExpr *expr) {
auto locator = cs.getConstraintLocator(expr);
// Find the overload choice used for this declaration reference.
auto selected = getOverloadChoice(locator);
auto choice = selected.choice;
auto decl = choice.getDecl();
// FIXME: Cannibalize the existing DeclRefExpr rather than allocating a
// new one?
return buildDeclRef(decl, expr->getLoc(), selected.openedFullType,
locator, expr->isSpecialized(), expr->isImplicit(),
expr->isDirectPropertyAccess());
}
Expr *visitSuperRefExpr(SuperRefExpr *expr) {
simplifyExprType(expr);
return expr;
}
Expr *visitOtherConstructorDeclRefExpr(OtherConstructorDeclRefExpr *expr) {
expr->setType(expr->getDecl()->getInitializerType());
return expr;
}
Expr *visitUnresolvedConstructorExpr(UnresolvedConstructorExpr *expr) {
// Resolve the callee to the constructor declaration selected.
auto selected = getOverloadChoice(
cs.getConstraintLocator(
expr,
ConstraintLocator::ConstructorMember));
auto choice = selected.choice;
auto *ctor = cast<ConstructorDecl>(choice.getDecl());
auto arg = expr->getSubExpr()->getSemanticsProvidingExpr();
auto &tc = cs.getTypeChecker();
// If the subexpression is a metatype, build a direct reference to the
// constructor.
if (arg->getType()->is<MetatypeType>()) {
return buildMemberRef(expr->getSubExpr(),
selected.openedFullType,
expr->getDotLoc(),
ctor,
expr->getConstructorLoc(),
expr->getType(),
ConstraintLocatorBuilder(
cs.getConstraintLocator(expr)),
expr->isImplicit(),
/*IsDirectPropertyAccess=*/false);
}
// The subexpression must be either 'self' or 'super'.
if (!arg->isSuperExpr()) {
// 'super' references have already been fully checked; handle the
// 'self' case below.
bool diagnoseBadInitRef = true;
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())) {
tc.diagnose(expr->getDotLoc(),
diag::init_delegation_outside_initializer);
}
}
}
// 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();
}
}
}
tc.diagnose(expr->getDotLoc(), diag::bad_init_ref_base, hasSuper);
}
}
// Build a partial application of the initializer.
Expr *ctorRef = buildOtherConstructorRef(selected.openedFullType,
ctor, expr->getConstructorLoc(),
expr->isImplicit());
auto *call
= new (cs.getASTContext()) DotSyntaxCallExpr(ctorRef,
expr->getDotLoc(),
expr->getSubExpr());
return finishApply(call, expr->getType(),
ConstraintLocatorBuilder(
cs.getConstraintLocator(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->getLoc(), selected.openedFullType,
locator, expr->isSpecialized(), expr->isImplicit(),
/*isDirectPropertyAccess*/false);
}
Expr *visitOverloadedMemberRefExpr(OverloadedMemberRefExpr *expr) {
auto selected = getOverloadChoice(
cs.getConstraintLocator(expr,
ConstraintLocator::Member));
return buildMemberRef(expr->getBase(),
selected.openedFullType,
expr->getDotLoc(),
selected.choice.getDecl(), expr->getMemberLoc(),
selected.openedType,
cs.getConstraintLocator(expr),
expr->isImplicit(), /*direct ivar*/false);
}
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 selected = getOverloadChoice(
cs.getConstraintLocator(expr,
ConstraintLocator::Member));
return buildMemberRef(expr->getBase(),
selected.openedFullType,
expr->getDotLoc(),
selected.choice.getDecl(), expr->getNameLoc(),
selected.openedType,
cs.getConstraintLocator(expr),
expr->isImplicit(),
expr->isDirectPropertyAccess());
}
Expr *visitDynamicMemberRefExpr(DynamicMemberRefExpr *expr) {
auto selected = getOverloadChoice(
cs.getConstraintLocator(expr,
ConstraintLocator::Member));
return buildDynamicMemberRef(expr->getBase(), expr->getDotLoc(),
selected.choice.getDecl(),
expr->getNameLoc(),
selected.openedType,
cs.getConstraintLocator(expr));
}
Expr *visitUnresolvedMemberExpr(UnresolvedMemberExpr *expr) {
// Dig out the type of the base, which will be the result
// type of this expression.
Type baseTy = simplifyType(expr->getType())->getRValueType();
auto &tc = cs.getTypeChecker();
auto baseMetaTy = MetatypeType::get(baseTy, tc.Context);
// Find the selected member.
auto selected = getOverloadChoice(
cs.getConstraintLocator(
expr, ConstraintLocator::UnresolvedMember));
auto member = selected.choice.getDecl();
// The base expression is simply the metatype of the base type.
auto base = new (tc.Context) MetatypeExpr(nullptr,
expr->getDotLoc(),
baseMetaTy);
// Build the member reference.
auto result = buildMemberRef(base,
selected.openedFullType,
expr->getDotLoc(), member,
expr->getNameLoc(),
selected.openedType,
cs.getConstraintLocator(expr),
expr->isImplicit(), /*direct ivar*/false);
if (!result)
return nullptr;
// If there was an argument, apply it.
if (auto arg = expr->getArgument()) {
ApplyExpr *apply = new (tc.Context) CallExpr(result, arg,
/*Implicit=*/false);
result = finishApply(apply, Type(), cs.getConstraintLocator(expr));
}
return result;
}
private:
struct MemberPartialApplication {
unsigned level : 31;
// Selector for the partial_application_of_method_invalid diagnostic
// message.
enum : unsigned {
Struct,
Enum,
Archetype,
Protocol,
ObjC
};
unsigned kind : 3;
};
// A map used to track partial applications of methods to require that they
// be fully applied. Partial applications of value types would capture
// 'self' as an inout and hide any mutation of 'self', which is surprising.
llvm::SmallDenseMap<Expr*, MemberPartialApplication, 2>
InvalidPartialApplications;
Expr *applyMemberRefExpr(Expr *expr,
Expr *base,
SourceLoc dotLoc,
SourceLoc nameLoc,
bool implicit) {
// Determine the declaration selected for this overloaded reference.
auto selected = getOverloadChoice(
cs.getConstraintLocator(
expr,
ConstraintLocator::MemberRefBase));
switch (selected.choice.getKind()) {
case OverloadChoiceKind::Decl: {
auto member = buildMemberRef(base,
selected.openedFullType,
dotLoc,
selected.choice.getDecl(),
nameLoc,
selected.openedType,
cs.getConstraintLocator(expr),
implicit, /*direct ivar*/false);
// If this is an application of a value type method, arrange for us to
// check that it gets fully applied.
FuncDecl *fn = nullptr;
unsigned kind;
if (auto apply = dyn_cast<ApplyExpr>(member)) {
auto selfTy = apply->getArg()->getType()->getRValueType();
auto fnDeclRef = dyn_cast<DeclRefExpr>(apply->getFn());
if (!fnDeclRef)
goto not_value_type_member;
fn = dyn_cast<FuncDecl>(fnDeclRef->getDecl());
if (selfTy->getStructOrBoundGenericStruct())
kind = MemberPartialApplication::Struct;
else if (selfTy->getEnumOrBoundGenericEnum())
kind = MemberPartialApplication::Enum;
else if (fnDeclRef->getDecl()->isObjC())
kind = MemberPartialApplication::ObjC;
else
goto not_value_type_member;
} else if (auto pmRef = dyn_cast<MemberRefExpr>(member)) {
auto baseTy = pmRef->getBase()->getType();
if (baseTy->hasReferenceSemantics())
goto not_value_type_member;
if (baseTy->isExistentialType()) {
kind = MemberPartialApplication::Protocol;
} else if (isa<FuncDecl>(pmRef->getMember().getDecl()))
kind = MemberPartialApplication::Archetype;
else
goto not_value_type_member;
fn = dyn_cast<FuncDecl>(pmRef->getMember().getDecl());
}
if (!fn)
goto not_value_type_member;
if (fn->isInstanceMember())
InvalidPartialApplications.insert({
member,
// We need to apply all of the non-self argument clauses.
{fn->getNaturalArgumentCount() - 1, kind},
});
not_value_type_member:
return member;
}
case OverloadChoiceKind::DeclViaDynamic:
return buildDynamicMemberRef(base, dotLoc,
selected.choice.getDecl(),
nameLoc,
selected.openedType,
cs.getConstraintLocator(expr));
case OverloadChoiceKind::TupleIndex: {
auto baseTy = base->getType()->getRValueType();
if (auto objTy = cs.lookThroughUncheckedOptionalType(baseTy)) {
base = coerceUncheckedOptionalToValue(base, objTy,
cs.getConstraintLocator(base));
if (!base) return nullptr;
}
return new (cs.getASTContext()) TupleElementExpr(
base,
dotLoc,
selected.choice.getTupleIndex(),
nameLoc,
simplifyType(expr->getType()));
}
case OverloadChoiceKind::BaseType: {
// FIXME: Losing ".0" sugar here.
return base;
}
case OverloadChoiceKind::TypeDecl:
llvm_unreachable("Nonsensical overload choice");
}
}
public:
Expr *visitUnresolvedSelectorExpr(UnresolvedSelectorExpr *expr) {
return applyMemberRefExpr(expr, expr->getBase(), expr->getDotLoc(),
expr->getNameRange().Start,
expr->isImplicit());
llvm_unreachable("not implemented");
}
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 *visitIdentityExpr(IdentityExpr *expr) {
expr->setType(expr->getSubExpr()->getType());
return expr;
}
Expr *visitTupleExpr(TupleExpr *expr) {
return simplifyExprType(expr);
}
Expr *visitSubscriptExpr(SubscriptExpr *expr) {
return buildSubscript(expr->getBase(), expr->getIndex(),
cs.getConstraintLocator(expr));
}
Expr *visitArrayExpr(ArrayExpr *expr) {
Type openedType = expr->getType();
Type arrayTy = simplifyType(openedType);
auto &tc = cs.getTypeChecker();
ProtocolDecl *arrayProto
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ArrayLiteralConvertible);
assert(arrayProto && "type-checked array literal w/o protocol?!");
ProtocolConformance *conformance = nullptr;
bool conforms = tc.conformsToProtocol(arrayTy, arrayProto,
cs.DC, &conformance);
(void)conforms;
assert(conforms && "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: Cache the name.
Expr *typeRef = new (tc.Context) MetatypeExpr(nullptr,
expr->getLoc(),
MetatypeType::get(arrayTy,
tc.Context));
auto name = tc.Context.getIdentifier("convertFromArrayLiteral");
auto arg = expr->getSubExpr();
Expr *result = tc.callWitness(typeRef, dc, arrayProto, conformance,
name, arg, diag::array_protocol_broken);
if (!result)
return nullptr;
expr->setSemanticExpr(result);
expr->setType(arrayTy);
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::DictionaryLiteralConvertible);
ProtocolConformance *conformance = nullptr;
bool conforms = tc.conformsToProtocol(dictionaryTy, dictionaryProto,
cs.DC, &conformance);
if (!conforms)
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.
Expr *typeRef = new (tc.Context) MetatypeExpr(
nullptr,
expr->getLoc(),
MetatypeType::get(dictionaryTy,
tc.Context));
auto name = tc.Context.getIdentifier("convertFromDictionaryLiteral");
auto arg = expr->getSubExpr();
Expr *result = tc.callWitness(typeRef, dc, dictionaryProto,
conformance, name, arg,
diag::dictionary_protocol_broken);
if (!result)
return nullptr;
expr->setSemanticExpr(result);
expr->setType(dictionaryTy);
return expr;
}
Expr *visitDynamicSubscriptExpr(DynamicSubscriptExpr *expr) {
return buildSubscript(expr->getBase(), expr->getIndex(),
cs.getConstraintLocator(expr));
}
Expr *visitTupleElementExpr(TupleElementExpr *expr) {
// Handle accesses that implicitly look through UncheckedOptional<T>.
auto base = expr->getBase();
auto baseTy = base->getType()->getRValueType();
if (auto objTy = cs.lookThroughUncheckedOptionalType(baseTy)) {
base = coerceUncheckedOptionalToValue(base, objTy,
cs.getConstraintLocator(base));
if (!base) return nullptr;
expr->setBase(base);
}
simplifyExprType(expr);
return expr;
}
Expr *visitClosureExpr(ClosureExpr *expr) {
llvm_unreachable("Handled by the walker directly");
}
Expr *visitAutoClosureExpr(AutoClosureExpr *expr) {
llvm_unreachable("Already type-checked");
}
Expr *visitModuleExpr(ModuleExpr *expr) { return expr; }
Expr *visitAddressOfExpr(AddressOfExpr *expr) {
// Compute the type of the address-of expression.
auto lv = expr->getSubExpr()->getType()->castTo<LValueType>();
expr->setType(InOutType::get(lv->getObjectType()));
return expr;
}
Expr *visitNewArrayExpr(NewArrayExpr *expr) {
auto &tc = cs.getTypeChecker();
// Convert the subexpression to an array bound.
auto outerBoundLocator
= cs.getConstraintLocator(expr->getBounds()[0].Value);
auto outerBound = solution.convertToArrayBound(expr->getBounds()[0].Value,
outerBoundLocator);
if (!outerBound)
return nullptr;
expr->getBounds()[0].Value = outerBound;
// Dig out the element type of the new array expression.
auto resultType = simplifyType(expr->getType());
auto elementType = resultType->castTo<BoundGenericType>()
->getGenericArgs()[0];
expr->setElementType(elementType);
// Make sure that the result type is a slice type, even if
// canonicalization mapped it down to Array<T>.
auto sliceType = dyn_cast<ArraySliceType>(resultType.getPointer());
if (!sliceType) {
resultType = tc.getArraySliceType(expr->getLoc(), elementType);
if (!resultType)
return nullptr;
sliceType = cast<ArraySliceType>(resultType.getPointer());
}
expr->setType(resultType);
// Find the appropriate injection function.
Expr* injectionFn = tc.buildArrayInjectionFnRef(dc, sliceType,
expr->getBounds()[0].Value->getType(),
expr->getNewLoc());
if (!injectionFn)
return nullptr;
expr->setInjectionFunction(injectionFn);
// If we gave an explicit construction closure, it should have
// IndexType -> ElementType type.
if (expr->hasConstructionFunction()) {
// FIXME: Assume the index type is DefaultIntegerLiteralType for now.
auto intProto =
tc.getProtocol(expr->getConstructionFunction()->getLoc(),
KnownProtocolKind::IntegerLiteralConvertible);
Type intTy = tc.getDefaultType(intProto, dc);
Type constructionTy = FunctionType::get(intTy, elementType);
auto constructionFn = expr->getConstructionFunction();
auto locator = cs.getConstraintLocator(
expr,
ConstraintLocator::NewArrayConstructor);
constructionFn = solution.coerceToType(constructionFn, constructionTy,
locator);
if (!constructionFn)
return nullptr;
expr->setConstructionFunction(constructionFn);
} else {
// If the element type is default constructible, form a partial
// application of it.
auto selected = getOverloadChoice(cs.getConstraintLocator(expr,
ConstraintLocator::NewArrayElement));
auto baseElementType = elementType;
while (true) {
if (auto arrayTy = baseElementType->getAs<ArrayType>())
baseElementType = arrayTy->getBaseType();
else if (auto sliceTy =
dyn_cast<ArraySliceType>(baseElementType.getPointer()))
baseElementType = sliceTy->getBaseType();
else
break;
}
Expr *ctor = tc.buildRefExpr(selected.choice.getDecl(), dc,
SourceLoc(), /*implicit*/ true);
Expr *metaty = new (tc.Context) MetatypeExpr(nullptr, SourceLoc(),
MetatypeType::get(baseElementType, tc.Context));
Expr *applyExpr = new(tc.Context) ConstructorRefCallExpr(ctor, metaty);
if (tc.typeCheckExpression(applyExpr, dc, Type(), /*discarded*/ false))
llvm_unreachable("should not fail");
expr->setConstructionFunction(applyExpr);
}
return expr;
}
Expr *visitMetatypeExpr(MetatypeExpr *expr) {
auto &tc = cs.getTypeChecker();
if (Expr *base = expr->getBase()) {
base = tc.coerceToRValue(base);
if (!base) return nullptr;
expr->setBase(base);
expr->setType(MetatypeType::get(base->getType(), tc.Context));
}
return expr;
}
Expr *visitOpaqueValueExpr(OpaqueValueExpr *expr) {
return expr;
}
Expr *visitDefaultValueExpr(DefaultValueExpr *expr) {
llvm_unreachable("Already type-checked");
}
Expr *visitApplyExpr(ApplyExpr *expr) {
auto result = finishApply(expr, expr->getType(),
ConstraintLocatorBuilder(
cs.getConstraintLocator(expr)));
// See if this application advanced a partial value type application.
auto foundApplication = InvalidPartialApplications.find(
expr->getFn()->getSemanticsProvidingExpr());
if (foundApplication != InvalidPartialApplications.end()) {
unsigned level = foundApplication->second.level;
assert(level > 0);
InvalidPartialApplications.erase(foundApplication);
if (level > 1)
InvalidPartialApplications.insert({
result, {
level - 1,
foundApplication->second.kind
}
});
}
return result;
}
Expr *visitRebindSelfInConstructorExpr(RebindSelfInConstructorExpr *expr) {
return expr;
}
Expr *visitIfExpr(IfExpr *expr) {
auto resultTy = simplifyType(expr->getType());
expr->setType(resultTy);
// Convert the condition to a logic value.
auto cond
= solution.convertToLogicValue(expr->getCondExpr(),
cs.getConstraintLocator(expr));
if (!cond) {
cond->setType(ErrorType::get(cs.getASTContext()));
} else {
expr->setCondExpr(cond);
}
// Coerce the then/else branches to the common type.
expr->setThenExpr(coerceToType(expr->getThenExpr(), resultTy,
ConstraintLocatorBuilder(
cs.getConstraintLocator(expr))
.withPathElement(
ConstraintLocator::IfThen)));
expr->setElseExpr(coerceToType(expr->getElseExpr(), resultTy,
ConstraintLocatorBuilder(
cs.getConstraintLocator(expr))
.withPathElement(
ConstraintLocator::IfElse)));
return expr;
}
Expr *visitImplicitConversionExpr(ImplicitConversionExpr *expr) {
llvm_unreachable("Already type-checked");
}
Expr *visitIsaExpr(IsaExpr *expr) {
// Turn the subexpression into an rvalue.
auto &tc = cs.getTypeChecker();
auto sub = tc.coerceToRValue(expr->getSubExpr());
if (!sub)
return nullptr;
expr->setSubExpr(sub);
// Set the type we checked against.
auto toType = simplifyType(expr->getCastTypeLoc().getType());
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);
});
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,
expr->getSubExpr()->getType(),
expr->getCastTypeLoc().getType());
expr->setCastKind(castKind);
break;
case CheckedCastKind::Downcast:
case CheckedCastKind::SuperToArchetype:
case CheckedCastKind::ArchetypeToArchetype:
case CheckedCastKind::ArchetypeToConcrete:
case CheckedCastKind::ExistentialToArchetype:
case CheckedCastKind::ExistentialToConcrete:
case CheckedCastKind::ConcreteToArchetype:
case CheckedCastKind::ConcreteToUnrelatedExistential:
// 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.
}
return expr;
}
Expr *visitConditionalCheckedCastExpr(ConditionalCheckedCastExpr *expr) {
// Simplify the type we're casting to.
auto toType = simplifyType(expr->getCastTypeLoc().getType());
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);
});
switch (castKind) {
/// Invalid cast.
case CheckedCastKind::Unresolved:
return nullptr;
case CheckedCastKind::Coercion: {
// This is a coercion. 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::Downcast:
case CheckedCastKind::SuperToArchetype:
case CheckedCastKind::ArchetypeToArchetype:
case CheckedCastKind::ArchetypeToConcrete:
case CheckedCastKind::ExistentialToArchetype:
case CheckedCastKind::ExistentialToConcrete:
case CheckedCastKind::ConcreteToArchetype:
case CheckedCastKind::ConcreteToUnrelatedExistential:
expr->setCastKind(castKind);
break;
}
Type finalResultType = simplifyType(expr->getType());
// Handle optional operands or optional results.
// 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.
/// A helper function to plumb a stack of optional types.
auto plumbOptionals = [](Type type, SmallVectorImpl<Type> &optionals) {
while (auto valueType = type->getAnyOptionalObjectType()) {
optionals.push_back(type);
type = valueType;
}
return type;
};
Expr *subExpr = expr->getSubExpr();
Type srcType = subExpr->getType();
// There's nothing special to do if the operand isn't optional.
SmallVector<Type, 4> srcOptionals;
srcType = plumbOptionals(srcType, srcOptionals);
if (srcOptionals.empty()) {
expr->setType(finalResultType);
return expr;
}
SmallVector<Type, 4> destOptionals;
auto destValueType = plumbOptionals(finalResultType, destOptionals);
// This is a checked cast, so the result type will always have
// at least one level of optional, which should become the type
// of the checked-cast expression.
assert(!destOptionals.empty() &&
"result of checked cast is not an optional type");
expr->setType(destOptionals.back());
// 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() - 1 <= 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() - 1);
// 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() - 1;
// Drill down on the operand until it's non-optional.
SourceLoc fakeQuestionLoc = subExpr->getEndLoc();
for (unsigned i : indices(srcOptionals)) {
// As we move into the range of mapped optionals, start
// lowering the depth.
unsigned depth = failureDepth;
if (i >= numRequiredOptionals) {
depth -= (i - numRequiredOptionals) + 1;
}
Type valueType =
(i + 1 == srcOptionals.size() ? srcType : srcOptionals[i+1]);
subExpr = new (tc.Context) BindOptionalExpr(subExpr, fakeQuestionLoc,
depth, valueType);
subExpr->setImplicit(true);
}
expr->setSubExpr(subExpr);
// If we're casting to an optional type, we need to capture the
// final M bindings.
Expr *result = expr;
if (destOptionals.size() > 1) {
// 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, expr->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 {
result = new (tc.Context) OptionalEvaluationExpr(result,
finalResultType);
}
return result;
}
Expr *visitCoerceExpr(CoerceExpr *expr) {
return expr;
}
Expr *visitAssignExpr(AssignExpr *expr) {
llvm_unreachable("Handled by ExprWalker");
}
Expr *visitAssignExpr(AssignExpr *expr, ConstraintLocator *srcLocator) {
// 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;
// Convert the source to the simplified destination type.
Expr *src = solution.coerceToType(expr->getSrc(),
destTy,
srcLocator);
if (!src)
return nullptr;
expr->setSrc(src);
return expr;
}
Expr *visitDiscardAssignmentExpr(DiscardAssignmentExpr *expr) {
return simplifyExprType(expr);
}
Expr *visitUnresolvedPatternExpr(UnresolvedPatternExpr *expr) {
llvm_unreachable("should have been eliminated during name binding");
}
Expr *visitBindOptionalExpr(BindOptionalExpr *expr) {
Type valueType = simplifyType(expr->getType());
Type optType =
cs.getTypeChecker().getOptionalType(expr->getQuestionLoc(), valueType);
if (!optType) return nullptr;
Expr *subExpr = coerceToType(expr->getSubExpr(), optType,
cs.getConstraintLocator(expr));
if (!subExpr) return nullptr;
// Complain if the sub-expression was converted to T? via the
// inject-into-optional implicit conversion.
//
// It should be the case that that's always the last conversion applied.
if (isa<InjectIntoOptionalExpr>(subExpr)) {
cs.getTypeChecker().diagnose(subExpr->getLoc(),
diag::binding_injected_optional,
expr->getSubExpr()->getType()->getRValueType())
.highlight(subExpr->getSourceRange())
.fixItRemove(expr->getQuestionLoc());
}
expr->setSubExpr(subExpr);
expr->setType(valueType);
return expr;
}
Expr *visitOptionalEvaluationExpr(OptionalEvaluationExpr *expr) {
Type optType = simplifyType(expr->getType());
Expr *subExpr = coerceToType(expr->getSubExpr(), optType,
cs.getConstraintLocator(expr));
if (!subExpr) return nullptr;
expr->setSubExpr(subExpr);
expr->setType(optType);
return expr;
}
/// Whether this type is AnyObject or an implicit lvalue thereof.
bool isDynamicLookupType(Type type) {
// Look through lvalues.
type = type->getRValueType();
// Check whether we have a protocol type.
auto protoTy = type->getAs<ProtocolType>();
if (!protoTy)
return false;
// Check whether this is AnyObject.
return protoTy->getDecl()->isSpecificProtocol(
KnownProtocolKind::AnyObject);
}
Expr *visitForceValueExpr(ForceValueExpr *expr) {
Type valueType = simplifyType(expr->getType());
auto &tc = cs.getTypeChecker();
// If the subexpression is of AnyObject type, introduce a conditional
// cast to the value type. This cast produces a value of optional type.
Expr *subExpr = expr->getSubExpr();
if (isDynamicLookupType(expr->getSubExpr()->getType()) &&
!isDynamicLookupType(valueType)) {
// Coerce the subexpression to an rvalue.
subExpr = tc.coerceToRValue(subExpr);
if (!subExpr) return nullptr;
// Create a conditional checked cast to the value type, e.g., x as T.
bool isArchetype = valueType->is<ArchetypeType>();
auto cast = new (tc.Context) ConditionalCheckedCastExpr(
subExpr,
SourceLoc(),
TypeLoc::withoutLoc(valueType));
cast->setImplicit(true);
cast->setType(OptionalType::get(valueType));
cast->setCastKind(isArchetype? CheckedCastKind::ExistentialToArchetype
: CheckedCastKind::ExistentialToConcrete);
subExpr = cast;
} else {
bool isDynamicLookup = isa<DynamicLookupExpr>(subExpr);
Type optType;
if (isDynamicLookup)
optType = UncheckedOptionalType::get(valueType);
else
optType = OptionalType::get(valueType);
// Coerce the subexpression to the appropriate optional type.
subExpr = coerceToType(subExpr, optType,
cs.getConstraintLocator(expr));
if (!subExpr) return nullptr;
// Complain if the sub-expression was converted to T? via the
// inject-into-optional implicit conversion.
//
// It should be the case that that's always the last conversion applied.
if (isa<InjectIntoOptionalExpr>(subExpr)) {
tc.diagnose(subExpr->getLoc(), diag::forcing_injected_optional,
expr->getSubExpr()->getType()->getRValueType())
.highlight(subExpr->getSourceRange())
.fixItRemove(expr->getExclaimLoc());
}
}
expr->setSubExpr(subExpr);
expr->setType(valueType);
return expr;
}
Expr *visitOpenExistentialExpr(OpenExistentialExpr *expr) {
llvm_unreachable("Already type-checked");
}
void finalize() {
// Check that all value type methods were fully applied.
auto &tc = cs.getTypeChecker();
for (auto &unapplied : InvalidPartialApplications) {
tc.diagnose(unapplied.first->getLoc(),
diag::partial_application_of_method_invalid,
unapplied.second.kind);
}
// We should have complained above if there were any
// existentials that haven't been closed yet.
assert((OpenedExistentials.empty() ||
!InvalidPartialApplications.empty()) &&
"Opened existentials have not been closed");
}
};
}
/// \brief Given a constraint locator, find the owner of default arguments for
/// that tuple, i.e., a FuncDecl.
static AbstractFunctionDecl *
findDefaultArgsOwner(ConstraintSystem &cs, const Solution &solution,
ConstraintLocator *locator) {
if (locator->getPath().empty() || !locator->getAnchor())
return nullptr;
// If the locator points to a function application, find the function itself.
if (locator->getPath().back().getKind() == ConstraintLocator::ApplyArgument) {
assert(locator->getPath().back().getNewSummaryFlags() == 0 &&
"ApplyArgument adds no flags");
SmallVector<LocatorPathElt, 4> newPath;
newPath.append(locator->getPath().begin(), locator->getPath().end()-1);
unsigned newFlags = locator->getSummaryFlags();
// 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 {
newPath.push_back(ConstraintLocator::ApplyFunction);
}
assert(newPath.back().getNewSummaryFlags() == 0 &&
"added element that changes the flags?");
locator = cs.getConstraintLocator(locator->getAnchor(), newPath, newFlags);
}
// Simplify the locator.
SourceRange range1, range2;
locator = simplifyLocator(cs, locator, range1, range2);
// 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<OverloadChoice> {
auto known = solution.overloadChoices.find(locator);
if (known == solution.overloadChoices.end()) {
return Nothing;
}
return known->second.choice;
})) {
return cast<AbstractFunctionDecl>(resolved.getDecl());
}
return nullptr;
}
/// Produce the caller-side default argument for this default argument, or
/// null if the default argument will be provided by the callee.
static Expr *getCallerDefaultArg(TypeChecker &tc, DeclContext *dc,
SourceLoc loc, AbstractFunctionDecl *&owner,
unsigned index) {
auto defArg = owner->getDefaultArg(index);
MagicIdentifierLiteralExpr::Kind magicKind;
switch (defArg.first) {
case DefaultArgumentKind::None:
llvm_unreachable("No default argument here?");
case DefaultArgumentKind::Normal:
return nullptr;
case DefaultArgumentKind::Inherited:
// Update the owner to reflect inheritance here.
owner = owner->getOverriddenDecl();
return getCallerDefaultArg(tc, dc, loc, owner, index);
case DefaultArgumentKind::Column:
magicKind = MagicIdentifierLiteralExpr::Column;
break;
case DefaultArgumentKind::File:
magicKind = MagicIdentifierLiteralExpr::File;
break;
case DefaultArgumentKind::Line:
magicKind = MagicIdentifierLiteralExpr::Line;
break;
case DefaultArgumentKind::Function:
magicKind = MagicIdentifierLiteralExpr::Function;
break;
}
// Create the default argument, which is a converted magic identifier
// literal expression.
Expr *init = new (tc.Context) MagicIdentifierLiteralExpr(magicKind, loc,
/*Implicit=*/true);
bool invalid = tc.typeCheckExpression(init, dc, defArg.second,
/*discardedExpr=*/false);
assert(!invalid && "conversion cannot fail");
(void)invalid;
return init;
}
Expr *ExprRewriter::coerceTupleToTuple(Expr *expr, TupleType *fromTuple,
TupleType *toTuple,
ConstraintLocatorBuilder locator,
SmallVectorImpl<int> &sources,
SmallVectorImpl<unsigned> &variadicArgs){
auto &tc = cs.getTypeChecker();
// Capture the tuple expression, if there is one.
Expr *innerExpr = expr;
while (auto paren = dyn_cast<IdentityExpr>(innerExpr))
innerExpr = paren->getSubExpr();
TupleExpr *fromTupleExpr = dyn_cast<TupleExpr>(innerExpr);
/// Check each of the tuple elements in the destination.
bool hasVarArg = false;
bool anythingShuffled = false;
bool hasInits = false;
SmallVector<TupleTypeElt, 4> toSugarFields;
SmallVector<TupleTypeElt, 4> fromTupleExprFields(
fromTuple->getFields().size());
SmallVector<Expr *, 2> callerDefaultArgs;
AbstractFunctionDecl *defaultArgsOwner = nullptr;
for (unsigned i = 0, n = toTuple->getFields().size(); i != n; ++i) {
const auto &toElt = toTuple->getFields()[i];
auto toEltType = toElt.getType();
// If we're default-initializing this member, there's nothing to do.
if (sources[i] == TupleShuffleExpr::DefaultInitialize) {
// Dig out the owner of the default arguments.
if (!defaultArgsOwner) {
defaultArgsOwner
= findDefaultArgsOwner(cs, solution,
cs.getConstraintLocator(locator));
assert(defaultArgsOwner && "Missing default arguments owner?");
} else {
assert(findDefaultArgsOwner(cs, solution,
cs.getConstraintLocator(locator))
== defaultArgsOwner);
}
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(),
defaultArgsOwner, i)) {
callerDefaultArgs.push_back(defArg);
sources[i] = TupleShuffleExpr::CallerDefaultInitialize;
}
continue;
}
// If this is the variadic argument, note it.
if (sources[i] == TupleShuffleExpr::FirstVariadic) {
assert(i == n-1 && "Vararg not at the end?");
toSugarFields.push_back(toElt);
hasVarArg = true;
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->getFields()[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(TupleTypeElt(fromEltType,
toElt.getName(),
toElt.getDefaultArgKind(),
toElt.isVararg()));
fromTupleExprFields[sources[i]] = fromElt;
hasInits |= toElt.hasInit();
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(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(TupleTypeElt(convertedElt->getType(),
toElt.getName(),
toElt.getDefaultArgKind(),
toElt.isVararg()));
fromTupleExprFields[sources[i]] = TupleTypeElt(convertedElt->getType(),
fromElt.getName(),
fromElt.getDefaultArgKind(),
fromElt.isVararg());
hasInits |= toElt.hasInit();
}
// Convert all of the variadic arguments to the destination type.
Expr *injectionFn = nullptr;
if (hasVarArg) {
Type toEltType = toTuple->getFields().back().getVarargBaseTy();
for (int fromFieldIdx : variadicArgs) {
const auto &fromElt = fromTuple->getFields()[fromFieldIdx];
Type fromEltType = fromElt.getType();
// If the source and destination types match, there's nothing to do.
if (toEltType->isEqual(fromEltType)) {
sources.push_back(fromFieldIdx);
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);
sources.push_back(fromFieldIdx);
fromTupleExprFields[fromFieldIdx] = TupleTypeElt(
convertedElt->getType(),
fromElt.getName(),
fromElt.getDefaultArgKind(),
fromElt.isVararg());
}
// Find the appropriate injection function.
ArraySliceType *sliceType
= cast<ArraySliceType>(
toTuple->getFields().back().getType().getPointer());
Type boundType = BuiltinIntegerType::getWordType(tc.Context);
injectionFn = tc.buildArrayInjectionFnRef(dc,
sliceType, boundType,
expr->getStartLoc());
if (!injectionFn)
return nullptr;
}
// 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.
for (auto paren = dyn_cast<IdentityExpr>(expr); paren;
paren = dyn_cast<IdentityExpr>(paren->getSubExpr()))
paren->setType(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.
for (auto paren = dyn_cast<IdentityExpr>(expr); paren;
paren = dyn_cast<IdentityExpr>(paren->getSubExpr()))
paren->setType(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,
defaultArgsOwner,
callerDefaultArgsCopy,
toSugarType);
shuffle->setVarargsInjectionFunction(injectionFn);
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.
Expr *injectionFn = nullptr;
const auto &lastField = toTuple->getFields().back();
if (lastField.isVararg()) {
// Find the appropriate injection function.
ArraySliceType *sliceType
= cast<ArraySliceType>(lastField.getType().getPointer());
Type boundType = BuiltinIntegerType::getWordType(tc.Context);
injectionFn = tc.buildArrayInjectionFnRef(dc,
sliceType, boundType,
expr->getStartLoc());
if (!injectionFn)
return nullptr;
}
// If we're initializing the varargs list, use its base type.
const auto &field = toTuple->getFields()[toScalarIdx];
Type toScalarType;
if (field.isVararg())
toScalarType = field.getVarargBaseTy();
else
toScalarType = field.getType();
// Coerce the expression to the type 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->getFields()) {
if (field.hasInit()) {
hasInit = true;
break;
}
if (i == toScalarIdx) {
if (field.isVararg()) {
assert(expr->getType()->isEqual(field.getVarargBaseTy()) &&
"scalar field is not equivalent to dest vararg field?!");
sugarFields.push_back(TupleTypeElt(field.getType(),
field.getName(),
field.getDefaultArgKind(),
true));
}
else {
assert(expr->getType()->isEqual(field.getType()) &&
"scalar field is not equivalent to dest tuple field?!");
sugarFields.push_back(TupleTypeElt(expr->getType(),
field.getName()));
}
// Record the
} else {
sugarFields.push_back(field);
}
++i;
}
// Compute the elements of the resulting tuple.
SmallVector<ScalarToTupleExpr::Element, 4> elements;
AbstractFunctionDecl *defaultArgsOwner = nullptr;
i = 0;
for (auto &field : toTuple->getFields()) {
// Use a null entry to indicate that this is the scalar field.
if (i == toScalarIdx) {
elements.push_back(ScalarToTupleExpr::Element());
++i;
continue;
}
if (field.isVararg()) {
++i;
continue;
}
assert(field.hasInit() && "Expected a default argument");
// Dig out the owner of the default arguments.
if (!defaultArgsOwner) {
defaultArgsOwner
= findDefaultArgsOwner(cs, solution,
cs.getConstraintLocator(locator));
assert(defaultArgsOwner && "Missing default arguments owner?");
} else {
assert(findDefaultArgsOwner(cs, solution,
cs.getConstraintLocator(locator))
== defaultArgsOwner);
}
// Create a caller-side default argument, if we need one.
if (auto defArg = getCallerDefaultArg(tc, dc, expr->getLoc(),
defaultArgsOwner, i)) {
// Record the caller-side default argument expression.
// FIXME: Do we need to record what this was synthesized from?
elements.push_back(defArg);
} else {
// Record the owner of the default argument.
elements.push_back(defaultArgsOwner);
}
++i;
}
Type destSugarTy = hasInit? toTuple
: TupleType::get(sugarFields, tc.Context);
return new (tc.Context) ScalarToTupleExpr(expr, destSugarTy,
tc.Context.AllocateCopy(elements),
injectionFn);
}
Expr *ExprRewriter::coerceExistential(Expr *expr, Type toType,
ConstraintLocatorBuilder locator) {
auto &tc = solution.getConstraintSystem().getTypeChecker();
Type fromType = expr->getType();
// Compute the conformances for each of the protocols in the existential
// type.
SmallVector<ProtocolDecl *, 4> protocols;
bool isExistential = toType->isExistentialType(protocols);
assert(isExistential && "Not converting to existential?");
(void)isExistential;
SmallVector<ProtocolConformance *, 4> conformances;
for (auto proto : protocols) {
ProtocolConformance *conformance = nullptr;
bool conforms = tc.conformsToProtocol(fromType, proto, cs.DC, &conformance);
assert(conforms && "Type does not conform to protocol?");
(void)conforms;
conformances.push_back(conformance);
}
// If we have all of the conformances we need, create an erasure expression.
return new (tc.Context) ErasureExpr(expr, toType,
tc.Context.AllocateCopy(conformances));
}
Expr *ExprRewriter::coerceViaUserConversion(Expr *expr, Type toType,
ConstraintLocatorBuilder locator) {
auto &tc = solution.getConstraintSystem().getTypeChecker();
// Determine the locator that corresponds to the conversion member.
auto storedLocator
= cs.getConstraintLocator(
locator.withPathElement(ConstraintLocator::ConversionMember));
auto knownOverload = solution.overloadChoices.find(storedLocator);
if (knownOverload != solution.overloadChoices.end()) {
auto selected = knownOverload->second;
// FIXME: Location information is suspect throughout.
// Form a reference to the conversion member.
auto memberRef = buildMemberRef(expr,
selected.openedFullType,
expr->getStartLoc(),
selected.choice.getDecl(),
expr->getEndLoc(),
selected.openedType,
locator,
/*Implicit=*/true, /*direct ivar*/false);
// Form an empty tuple.
Expr *args = new (tc.Context) TupleExpr(expr->getStartLoc(),
expr->getEndLoc(),
/*Implicit=*/true,
TupleType::getEmpty(tc.Context));
// Call the conversion function with an empty tuple.
ApplyExpr *apply = new (tc.Context) CallExpr(memberRef, args,
/*Implicit=*/true);
auto openedType = selected.openedType->castTo<FunctionType>()->getResult();
expr = finishApply(apply, openedType,
ConstraintLocatorBuilder(
cs.getConstraintLocator(apply)));
if (!expr)
return nullptr;
return coerceToType(expr, toType, locator);
}
// If there was no conversion member, look for a constructor member.
// This is only used for handling interpolated string literals, where
// we allow construction or conversion.
storedLocator
= cs.getConstraintLocator(
locator.withPathElement(ConstraintLocator::ConstructorMember));
knownOverload = solution.overloadChoices.find(storedLocator);
assert(knownOverload != solution.overloadChoices.end());
auto selected = knownOverload->second;
// FIXME: Location information is suspect throughout.
// Form a reference to the constructor.
// Form a reference to the constructor or enum declaration.
Expr *typeBase = new (tc.Context) MetatypeExpr(
nullptr,
expr->getStartLoc(),
MetatypeType::get(toType,tc.Context));
Expr *declRef = buildMemberRef(typeBase,
selected.openedFullType,
expr->getStartLoc(),
selected.choice.getDecl(),
expr->getStartLoc(),
selected.openedType,
storedLocator,
/*Implicit=*/true, /*direct ivar*/false);
// FIXME: Lack of openedType here is an issue.
ApplyExpr *apply = new (tc.Context) CallExpr(declRef, expr,
/*Implicit=*/true);
expr = finishApply(apply, toType, locator);
if (!expr)
return nullptr;
return coerceToType(expr, toType, locator);
}
Expr *ExprRewriter::coerceOptionalToOptional(Expr *expr, Type toType,
ConstraintLocatorBuilder locator) {
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];
expr = new (tc.Context) BindOptionalExpr(expr, expr->getSourceRange().End,
/*depth*/ 0, fromValueType);
expr->setImplicit(true);
expr = coerceToType(expr, toValueType, locator);
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::coerceUncheckedOptionalToValue(Expr *expr, Type objTy,
ConstraintLocatorBuilder locator) {
// Coerce to an r-value.
auto rvalueTy = expr->getType()->getRValueType();
assert(rvalueTy->getUncheckedOptionalObjectType()->isEqual(objTy));
if (cs.getTypeChecker().requireOptionalIntrinsics(expr->getLoc()))
return nullptr;
expr = coerceToType(expr, rvalueTy, /*bogus?*/ locator);
if (!expr) return nullptr;
expr = new (cs.getTypeChecker().Context) ForceValueExpr(expr, expr->getEndLoc());
expr->setType(objTy);
expr->setImplicit();
return expr;
}
Expr *ExprRewriter::coerceToType(Expr *expr, Type toType,
ConstraintLocatorBuilder locator) {
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 = expr->getType()->castTo<TupleType>();
auto toTuple = toType->castTo<TupleType>();
SmallVector<int, 4> sources;
SmallVector<unsigned, 4> variadicArgs;
bool failed = computeTupleShuffle(fromTuple, toTuple, sources,
variadicArgs,
hasMandatoryTupleLabels(expr));
assert(!failed && "Couldn't convert tuple to tuple?");
(void)failed;
return coerceTupleToTuple(expr, fromTuple, toTuple, locator, sources,
variadicArgs);
}
case ConversionRestrictionKind::ScalarToTuple: {
auto toTuple = toType->castTo<TupleType>();
return coerceScalarToTuple(expr, toTuple,
toTuple->getFieldForScalarInit(), locator);
}
case ConversionRestrictionKind::TupleToScalar: {
// 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: {
// Load from the lvalue.
expr = new (tc.Context) LoadExpr(expr, fromType->getRValueType());
// Coerce the result.
return coerceToType(expr, toType, locator);
}
case ConversionRestrictionKind::Existential:
return coerceExistential(expr, toType, locator);
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;
return new (tc.Context) InjectIntoOptionalExpr(expr, toType);
}
case ConversionRestrictionKind::OptionalToUncheckedOptional:
case ConversionRestrictionKind::UncheckedOptionalToOptional:
case ConversionRestrictionKind::OptionalToOptional:
return coerceOptionalToOptional(expr, toType, locator);
case ConversionRestrictionKind::ForceUnchecked: {
auto valueTy = fromType->getUncheckedOptionalObjectType();
assert(valueTy);
expr = coerceUncheckedOptionalToValue(expr, valueTy, locator);
if (!expr) return nullptr;
return coerceToType(expr, toType, locator);
}
case ConversionRestrictionKind::User:
return coerceViaUserConversion(expr, toType, locator);
}
}
// Tuple-to-scalar conversion.
// FIXME: Will go away when tuple labels go away.
if (auto fromTuple = fromType->getAs<TupleType>()) {
if (fromTuple->getNumElements() == 1 &&
!fromTuple->getFields()[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 @assignment operator like "++i", the operand is converted from
// an implicit lvalue to an inout argument.
assert(toIO->getObjectType()->isEqual(fromLValue->getObjectType()));
return new (tc.Context) AddressOfExpr(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->getFieldForScalarInit();
if (scalarIdx >= 0 &&
toTuple->getElementType(scalarIdx)->is<InOutType>())
performLoad = false;
}
if (performLoad) {
// Load from the lvalue.
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,
hasMandatoryTupleLabels(expr))) {
return coerceTupleToTuple(expr, fromTuple, toTuple,
locator, sources, variadicArgs);
}
}
// Coerce scalar to tuple.
int toScalarIdx = toTuple->getFieldForScalarInit();
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.
expr = new (tc.Context) DerivedToBaseExpr(expr, toType);
return expr;
}
}
}
// 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 @auto_closures to
// be subtypes of non-@auto_closures, 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);
Pattern *pattern = TuplePattern::create(tc.Context, expr->getLoc(),
ArrayRef<TuplePatternElt>(),
expr->getLoc());
pattern->setType(TupleType::getEmpty(tc.Context));
Closure->setParams(pattern);
// Compute the capture list, now that we have analyzed the expression.
tc.computeCaptures(Closure);
return Closure;
}
// Coercion to a block function type from non-block function type.
auto fromFunc = fromType->getAs<FunctionType>();
if (toFunc->isBlock() && (!fromFunc || !fromFunc->isBlock())) {
// Coerce the expression to the non-block form of the function type.
auto toNonBlockTy = FunctionType::get(toFunc->getInput(),
toFunc->getResult());
expr = coerceToType(expr, toNonBlockTy, locator);
// Bridge to the block form of this function type.
return new (tc.Context) BridgeToBlockExpr(expr, toType);
}
// Coercion from one function type to another.
if (fromFunc) {
return new (tc.Context) FunctionConversionExpr(expr, toType);
}
}
// Coercions from a type to an existential type.
if (toType->isExistentialType()) {
return coerceExistential(expr, toType, locator);
}
// 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;
return new (tc.Context) InjectIntoOptionalExpr(expr, toType);
}
}
// Coerce via conversion function or constructor.
if (fromType->getNominalOrBoundGenericNominal()||
fromType->is<ArchetypeType>() ||
toType->getNominalOrBoundGenericNominal() ||
toType->is<ArchetypeType>()) {
return coerceViaUserConversion(expr, toType, locator);
}
// Coercion from one metatype to another.
if (fromType->is<MetatypeType>()) {
if (auto toMeta = toType->getAs<MetatypeType>()) {
return new (tc.Context) MetatypeConversionExpr(expr, toMeta);
}
}
llvm_unreachable("Unhandled coercion");
}
Expr *
ExprRewriter::coerceObjectArgumentToType(Expr *expr,
Type baseTy, ValueDecl *member,
bool IsDirectPropertyAccess,
ConstraintLocatorBuilder locator) {
Type toType = adjustSelfTypeForMember(baseTy, member, IsDirectPropertyAccess,
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 AddressOfExpr to convert it to an explicit inout argument for the
// receiver.
return new (ctx) AddressOfExpr(expr->getStartLoc(), expr,
toType, /*isImplicit*/true);
}
Expr *ExprRewriter::convertLiteral(Expr *literal,
Type type,
Type openedType,
ProtocolDecl *protocol,
TypeOrName literalType,
Identifier literalFuncName,
ProtocolDecl *builtinProtocol,
TypeOrName builtinLiteralType,
Identifier builtinLiteralFuncName,
bool (*isBuiltinArgType)(Type),
Diag<> brokenProtocolDiag,
Diag<> brokenBuiltinProtocolDiag) {
auto &tc = cs.getTypeChecker();
// Check whether this literal type conforms to the builtin protocol.
ProtocolConformance *builtinConformance = nullptr;
if (tc.conformsToProtocol(type, builtinProtocol, cs.DC, &builtinConformance)){
// 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;
}
// The literal expression has this type.
literal->setType(argType);
// Call the builtin conversion operation.
Expr *base = new (tc.Context) MetatypeExpr(nullptr, literal->getLoc(),
MetatypeType::get(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");
ProtocolConformance *conformance = nullptr;
bool conforms = tc.conformsToProtocol(type, protocol, cs.DC, &conformance);
assert(conforms && "must conform to literal protocol");
(void)conforms;
// Figure out the (non-builtin) argument type.
Type argType;
if (literalType.is<Type>())
argType = literalType.get<Type>();
else
argType = tc.getWitnessType(type, protocol, conformance,
literalType.get<Identifier>(),
brokenProtocolDiag);
if (!argType)
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.
Expr *base = new (tc.Context) MetatypeExpr(nullptr, literal->getLoc(),
MetatypeType::get(type,
tc.Context));
literal = tc.callWitness(base, dc,
protocol, conformance, literalFuncName,
literal, brokenProtocolDiag);
if (literal)
literal->setType(type);
return literal;
}
Expr *ExprRewriter::finishApply(ApplyExpr *apply, Type openedType,
ConstraintLocatorBuilder locator) {
TypeChecker &tc = cs.getTypeChecker();
// Handle applications that implicitly look through UncheckedOptional<T>.
auto fn = apply->getFn();
if (auto fnTy = cs.lookThroughUncheckedOptionalType(fn->getType())) {
fn = coerceUncheckedOptionalToValue(fn, fnTy, locator);
if (!fn) return nullptr;
}
// The function is always an rvalue.
fn = tc.coerceToRValue(fn);
assert(fn && "Rvalue conversion failed?");
if (!fn)
return nullptr;
// 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.
if (auto fnType = fn->getType()->getAs<FunctionType>()) {
auto origArg = apply->getArg();
Expr *arg = coerceToType(origArg, fnType->getInput(),
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);
// If the result is an archetype from an opened existential, erase
// the existential and create the OpenExistentialExpr.
// FIXME: This is a localized form of a much more general rule for
// placement of open existential expressions. It only works for
// DynamicSelf.
if (auto archetypeTy = result->getType()->getAs<ArchetypeType>()) {
auto opened = OpenedExistentials.find(archetypeTy);
if (opened != OpenedExistentials.end()) {
// Erase the archetype to its corresponding existential.
result = coerceToType(result, archetypeTy->getOpenedExistentialType(),
locator);
if (!result)
return result;
// Create the expression that opens the existential.
result = new (tc.Context) OpenExistentialExpr(
opened->second.ExistentialValue,
opened->second.OpaqueValue,
result);
// Remove this from the set of opened existentials.
OpenedExistentials.erase(opened);
}
}
// 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);
}
return result;
}
// We have a type constructor.
auto metaTy = fn->getType()->castTo<MetatypeType>();
auto ty = metaTy->getInstanceType();
// If we're "constructing" a tuple type, it's simply a conversion.
if (auto tupleTy = ty->getAs<TupleType>()) {
// FIXME: Need an AST to represent this properly.
return coerceToType(apply->getArg(), tupleTy, locator);
}
// We're constructing a value of nominal type. Look for the constructor or
// enum element to use.
assert(ty->getNominalOrBoundGenericNominal() || ty->is<DynamicSelfType>() ||
ty->is<ArchetypeType>() || ty->isExistentialType());
auto selected = getOverloadChoiceIfAvailable(
cs.getConstraintLocator(
locator.withPathElement(
ConstraintLocator::ConstructorMember)));
// 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'.
Expr *declRef = buildMemberRef(fn,
selected->openedFullType,
/*DotLoc=*/SourceLoc(),
decl, fn->getEndLoc(),
selected->openedType, locator,
/*Implicit=*/true, /*direct ivar*/false);
declRef->setImplicit(apply->isImplicit());
apply->setFn(declRef);
// If we're 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 abstract.
if ((ty->getClassOrBoundGenericClass() || ty->is<DynamicSelfType>()) &&
!fn->isStaticallyDerivedMetatype() &&
!cast<ConstructorDecl>(decl)->isRequired()) {
tc.diagnose(apply->getLoc(), diag::dynamic_construct_class, ty)
.highlight(fn->getSourceRange());
auto ctor = cast<ConstructorDecl>(decl);
// FIXME: Better description of the initializer than just it's type.
if (ctor->isImplicit())
tc.diagnose(decl, diag::note_nonabstract_implicit_initializer,
ctor->getArgumentType());
else
tc.diagnose(decl, diag::note_nonabstract_initializer);
} else if (isa<ConstructorDecl>(decl) && ty->isExistentialType() &&
fn->isStaticallyDerivedMetatype()) {
tc.diagnose(apply->getLoc(), diag::static_construct_existential, ty)
.highlight(fn->getSourceRange());
}
// Tail-recur to actually call the constructor.
return finishApply(apply, openedType, locator);
}
/// \brief Apply a given solution to the expression, producing a fully
/// type-checked expression.
Expr *ConstraintSystem::applySolution(const Solution &solution,
Expr *expr) {
class ExprWalker : public ASTWalker {
ExprRewriter &Rewriter;
unsigned LeftSideOfAssignment = 0;
public:
ExprWalker(ExprRewriter &Rewriter) : Rewriter(Rewriter) { }
std::pair<bool, Expr *> walkToExprPre(Expr *expr) override {
// For a default-value expression, do nothing.
if (isa<DefaultValueExpr>(expr)) {
return { false, expr };
}
// 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>();
Pattern *params = closure->getParams();
TypeResolutionOptions TROptions;
TROptions |= TR_OverrideType;
TROptions |= TR_FromNonInferredPattern;
if (tc.coercePatternToType(params, closure, fnType->getInput(),
TROptions))
return { false, nullptr };
closure->setParams(params);
// If this is a single-expression closure, convert the expression
// in the body to the result type of the closure.
if (closure->hasSingleExpressionBody()) {
// Enter the context of the closure when type-checking the body.
llvm::SaveAndRestore<DeclContext *> savedDC(Rewriter.dc, closure);
Expr *body = closure->getSingleExpressionBody()->walk(*this);
if (body)
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.
tc.typeCheckClosureBody(closure);
}
// Compute the capture list, now that we have type-checked the body.
tc.computeCaptures(closure);
return { false, closure };
}
// Don't recurse into metatype expressions that have a specified type.
if (auto metatypeExpr = dyn_cast<MetatypeExpr>(expr)) {
if (metatypeExpr->getBaseTypeRepr())
return { false, expr };
}
// Track whether we're in the left-hand side of an assignment...
if (auto assign = dyn_cast<AssignExpr>(expr)) {
++LeftSideOfAssignment;
if (auto dest = assign->getDest()->walk(*this))
assign->setDest(dest);
else
return { false, nullptr };
--LeftSideOfAssignment;
auto &cs = Rewriter.getConstraintSystem();
auto srcLocator = cs.getConstraintLocator(
assign->getSrc(),
ConstraintLocator::AssignSource);
if (auto src = assign->getSrc()->walk(*this))
assign->setSrc(src);
else
return { false, nullptr };
expr = Rewriter.visitAssignExpr(assign, srcLocator);
return { false, expr };
}
// ...so we can verify that '_' only appears there.
if (isa<DiscardAssignmentExpr>(expr) && LeftSideOfAssignment == 0)
Rewriter.getConstraintSystem().getTypeChecker()
.diagnose(expr->getLoc(), diag::discard_expr_outside_of_assignment);
return { true, expr };
}
Expr *walkToExprPost(Expr *expr) override {
return Rewriter.visit(expr);
}
/// \brief Ignore statements.
std::pair<bool, Stmt *> walkToStmtPre(Stmt *stmt) override {
return { false, stmt };
}
/// \brief Ignore declarations.
bool walkToDeclPre(Decl *decl) override { return false; }
};
ExprRewriter rewriter(*this, solution);
ExprWalker walker(rewriter);
auto result = expr->walk(walker);
rewriter.finalize();
return result;
}
Expr *ConstraintSystem::applySolutionShallow(const Solution &solution,
Expr *expr) {
ExprRewriter rewriter(*this, solution);
return rewriter.visit(expr);
}
Expr *Solution::coerceToType(Expr *expr, Type toType,
ConstraintLocator *locator) const {
auto &cs = getConstraintSystem();
ExprRewriter rewriter(cs, *this);
return rewriter.coerceToType(expr, toType, locator);
}
Expr *TypeChecker::callWitness(Expr *base, DeclContext *dc,
ProtocolDecl *protocol,
ProtocolConformance *conformance,
Identifier name,
MutableArrayRef<Expr *> arguments,
Diag<> brokenProtocolDiag) {
// Construct an empty constraint system and solution.
ConstraintSystem cs(*this, dc);
// Find the witness we need to use.
auto type = base->getType();
if (auto metaType = type->getAs<MetatypeType>())
type = metaType->getInstanceType();
auto witness = findNamedWitness(*this, dc, type->getRValueType(), protocol,
name, brokenProtocolDiag);
if (!witness)
return nullptr;
// Form a reference to the witness itself.
Type openedFullType, openedType;
std::tie(openedFullType, openedType)
= cs.getTypeOfMemberReference(base->getType(), witness,
/*isTypeReference=*/false,
/*isDynamicResult=*/false);
auto locator = cs.getConstraintLocator(base);
// Form the call argument.
Expr *arg;
if (arguments.size() == 1)
arg = arguments[0];
else {
SmallVector<TupleTypeElt, 4> elementTypes;
for (auto elt : arguments)
elementTypes.push_back(TupleTypeElt(elt->getType()));
arg = new (Context) TupleExpr(base->getStartLoc(),
Context.AllocateCopy(arguments),
nullptr,
base->getEndLoc(),
/*hasTrailingClosure=*/false,
/*Implicit=*/true,
TupleType::get(elementTypes, Context));
}
// Add the conversion from the argument to the function parameter type.
cs.addConstraint(ConstraintKind::Conversion, arg->getType(),
openedType->castTo<FunctionType>()->getInput(),
cs.getConstraintLocator(arg,
ConstraintLocator::ApplyArgument));
// Solve the system.
SmallVector<Solution, 1> solutions;
bool failed = cs.solve(solutions);
(void)failed;
assert(!failed && "Unable to solve for call to witness?");
Solution &solution = solutions.front();
ExprRewriter rewriter(cs, solution);
auto memberRef = rewriter.buildMemberRef(base, openedFullType,
base->getStartLoc(),
witness, base->getEndLoc(),
openedType, locator,
/*Implicit=*/true,
/*direct ivar*/false);
// Call the witness.
ApplyExpr *apply = new (Context) CallExpr(memberRef, arg, /*Implicit=*/true);
return rewriter.finishApply(apply, openedType,
cs.getConstraintLocator(arg));
}
/// \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 protocol The protocol to use for conversion.
/// \param generalName The name of the protocol method to use for the
/// conversion.
/// \param builtinName The name of the builtin method to use for the
/// last step of the conversion.
/// \param brokenProtocolDiag Diagnostic to emit if the protocol
/// definition is missing.
/// \param brokenBuiltinDiag Diagnostic to emit if the builtin definition
/// is broken.
///
/// \returns the converted expression.
static Expr *convertViaBuiltinProtocol(const Solution &solution,
Expr *expr,
ConstraintLocator *locator,
ProtocolDecl *protocol,
Identifier generalName,
Identifier builtinName,
Diag<> brokenProtocolDiag,
Diag<> brokenBuiltinDiag) {
auto &cs = solution.getConstraintSystem();
ExprRewriter rewriter(cs, solution);
// 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.
auto witnesses = tc.lookupMember(type->getRValueType(), builtinName, cs.DC);
if (!witnesses) {
// Find the witness we need to use.
auto witness = findNamedWitness(tc, cs.DC, type->getRValueType(), protocol,
generalName, brokenProtocolDiag);
// Form a reference to this member.
Expr *memberRef = new (ctx) MemberRefExpr(expr, expr->getStartLoc(),
witness, expr->getEndLoc(),
/*Implicit=*/true);
bool failed = tc.typeCheckExpressionShallow(memberRef, cs.DC);
if (failed) {
// If the member reference expression failed to type check, the Expr's
// type does not conform to the given protocol.
tc.diagnose(expr->getLoc(),
diag::type_does_not_conform,
type,
protocol->getType());
return nullptr;
}
// Call the witness.
Expr *arg = new (ctx) TupleExpr(expr->getStartLoc(), expr->getEndLoc(),
/*Implicit=*/true,
TupleType::getEmpty(ctx));
expr = new (ctx) CallExpr(memberRef, arg, /*Implicit=*/true);
failed = tc.typeCheckExpressionShallow(expr, cs.DC);
assert(!failed && "Could not call witness?");
(void)failed;
// At this point, we must have a type with the builtin member.
type = expr->getType();
witnesses = tc.lookupMember(type->getRValueType(), builtinName, cs.DC);
if (!witnesses) {
tc.diagnose(protocol->getLoc(), brokenProtocolDiag);
return nullptr;
}
}
// Find the builtin method.
if (witnesses.size() != 1) {
tc.diagnose(protocol->getLoc(), brokenBuiltinDiag);
return nullptr;
}
FuncDecl *builtinMethod = dyn_cast<FuncDecl>(witnesses[0]);
if (!builtinMethod) {
tc.diagnose(protocol->getLoc(), brokenBuiltinDiag);
return nullptr;
}
// Form a reference to the builtin method.
Expr *memberRef = new (ctx) MemberRefExpr(expr, SourceLoc(),
builtinMethod, expr->getLoc(),
/*Implicit=*/true);
bool failed = tc.typeCheckExpressionShallow(memberRef, cs.DC);
assert(!failed && "Could not reference witness?");
(void)failed;
// Call the builtin method.
Expr *arg = new (ctx) TupleExpr(expr->getStartLoc(), expr->getEndLoc(),
/*Implicit=*/true, TupleType::getEmpty(ctx));
expr = new (ctx) CallExpr(memberRef, arg, /*Implicit=*/true);
failed = tc.typeCheckExpressionShallow(expr, cs.DC);
assert(!failed && "Could not call witness?");
(void)failed;
return expr;
}
Expr *
Solution::convertToLogicValue(Expr *expr, ConstraintLocator *locator) const {
auto &tc = getConstraintSystem().getTypeChecker();
// Special case: already a builtin logic value.
if (expr->getType()->getRValueType()->isBuiltinIntegerType(1)) {
return tc.coerceToRValue(expr);
}
// FIXME: Cache names.
auto result = convertViaBuiltinProtocol(
*this, expr, locator,
tc.getProtocol(expr->getLoc(),
KnownProtocolKind::LogicValue),
tc.Context.getIdentifier("getLogicValue"),
tc.Context.getIdentifier("_getBuiltinLogicValue"),
diag::condition_broken_proto,
diag::broken_bool);
if (result && !result->getType()->isBuiltinIntegerType(1)) {
tc.diagnose(expr->getLoc(), diag::broken_bool);
return nullptr;
}
return result;
}
Expr *
Solution::convertToArrayBound(Expr *expr, ConstraintLocator *locator) const {
// FIXME: Cache names.
auto &tc = getConstraintSystem().getTypeChecker();
auto result = convertViaBuiltinProtocol(
*this, expr, locator,
tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ArrayBound),
tc.Context.getIdentifier("getArrayBoundValue"),
tc.Context.getIdentifier("_getBuiltinArrayBoundValue"),
diag::broken_array_bound_proto,
diag::broken_builtin_array_bound);
if (result && !result->getType()->is<BuiltinIntegerType>()) {
tc.diagnose(expr->getLoc(), diag::broken_builtin_array_bound);
return nullptr;
}
return result;
}
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