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fuchsia / third_party / swift / 41d581e4eff7db8d6697a177c8b68eb9c856c115 / . / lib / Sema / CSApply.cpp
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//===--- CSApply.cpp - Constraint Application -----------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file implements application of a solution to a constraint
// system to a particular expression, resulting in a
// fully-type-checked expression.
//
//===----------------------------------------------------------------------===//
#include "ConstraintSystem.h"
#include "swift/AST/ArchetypeBuilder.h"
#include "swift/AST/ASTVisitor.h"
#include "swift/AST/ASTWalker.h"
#include "swift/Basic/StringExtras.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/SaveAndRestore.h"
using namespace swift;
using namespace constraints;
/// \brief Get a substitution corresponding to the type witness.
/// Inspired by ProtocolConformance::getTypeWitnessByName.
const Substitution *
getTypeWitnessByName(ProtocolConformance *conformance,
Identifier name,
LazyResolver *resolver) {
// Find the named requirement.
AssociatedTypeDecl *assocType = nullptr;
auto members = conformance->getProtocol()->lookupDirect(name);
for (auto member : members) {
assocType = dyn_cast<AssociatedTypeDecl>(member);
if (assocType)
break;
}
if (!assocType)
return nullptr;
assert(conformance && "Missing conformance information");
return &conformance->getTypeWitness(assocType, resolver);
}
/// \brief Retrieve the fixed type for the given type variable.
Type Solution::getFixedType(TypeVariableType *typeVar) const {
auto knownBinding = typeBindings.find(typeVar);
assert(knownBinding != typeBindings.end());
return knownBinding->second;
}
/// Determine whether the given type is an opened AnyObject.
///
/// This comes up in computeSubstitutions() when accessing
/// members via dynamic lookup.
static bool isOpenedAnyObject(Type type) {
auto archetype = type->getAs<ArchetypeType>();
if (!archetype)
return false;
auto existential = archetype->getOpenedExistentialType();
if (!existential)
return false;
SmallVector<ProtocolDecl *, 2> protocols;
existential->isExistentialType(protocols);
return protocols.size() == 1 &&
protocols[0]->isSpecificProtocol(KnownProtocolKind::AnyObject);
}
Type Solution::computeSubstitutions(
Type origType, DeclContext *dc,
Type openedType,
ConstraintLocator *locator,
SmallVectorImpl<Substitution> &result) const {
auto &tc = getConstraintSystem().getTypeChecker();
// Produce the concrete form of the opened type.
Type type = simplifyType(tc, openedType);
// Gather the substitutions from dependent types to concrete types.
auto openedTypes = OpenedTypes.find(locator);
if (openedTypes == OpenedTypes.end())
return type;
TypeSubstitutionMap subs;
for (const auto &opened : openedTypes->second) {
subs[opened.first->castTo<GenericTypeParamType>()] =
getFixedType(opened.second);
}
auto mod = getConstraintSystem().DC->getParentModule();
GenericSignature *sig;
if (auto genericFn = origType->getAs<GenericFunctionType>()) {
sig = genericFn->getGenericSignature();
} else {
sig = dc->getGenericSignatureOfContext();
}
auto lookupConformanceFn =
[&](CanType original, Type replacement, ProtocolType *protoType)
-> ProtocolConformanceRef {
if (replacement->hasError() ||
isOpenedAnyObject(replacement) ||
replacement->is<GenericTypeParamType>()) {
return ProtocolConformanceRef(protoType->getDecl());
}
auto conformance = tc.conformsToProtocol(
replacement,
protoType->getDecl(),
getConstraintSystem().DC,
(ConformanceCheckFlags::InExpression|
ConformanceCheckFlags::Used));
return *conformance;
};
sig->getSubstitutions(*mod, subs, lookupConformanceFn, result);
return type;
}
/// \brief Find a particular named function witness for a type that conforms to
/// the given protocol.
///
/// \param tc The type check we're using.
///
/// \param dc The context in which we need a witness.
///
/// \param type The type whose witness to find.
///
/// \param proto The protocol to which the type conforms.
///
/// \param name The name of the requirement.
///
/// \param diag The diagnostic to emit if the protocol definition doesn't
/// have a requirement with the given name.
///
/// \returns The named witness, or nullptr if no witness could be found.
template <typename DeclTy>
static DeclTy *findNamedWitnessImpl(
TypeChecker &tc, DeclContext *dc, Type type,
ProtocolDecl *proto, DeclName name,
Diag<> diag,
Optional<ProtocolConformanceRef> conformance = None) {
// Find the named requirement.
DeclTy *requirement = nullptr;
for (auto member : proto->getMembers()) {
auto d = dyn_cast<DeclTy>(member);
if (!d || !d->hasName())
continue;
if (d->getFullName().matchesRef(name)) {
requirement = d;
break;
}
}
if (!requirement || requirement->isInvalid()) {
tc.diagnose(proto->getLoc(), diag);
return nullptr;
}
// Find the member used to satisfy the named requirement.
if (!conformance) {
conformance = tc.conformsToProtocol(type, proto, dc,
ConformanceCheckFlags::InExpression);
if (!conformance)
return nullptr;
}
// For a type with dependent conformance, just return the requirement from
// the protocol. There are no protocol conformance tables.
if (!conformance->isConcrete())
return requirement;
auto concrete = conformance->getConcrete();
// FIXME: Dropping substitutions here.
return cast_or_null<DeclTy>(concrete->getWitness(requirement, &tc).getDecl());
}
static bool shouldAccessStorageDirectly(Expr *base, VarDecl *member,
DeclContext *DC) {
// This only matters for stored properties.
if (!member->hasStorage())
return false;
// ... referenced from constructors and destructors.
auto *AFD = dyn_cast<AbstractFunctionDecl>(DC);
if (AFD == nullptr)
return false;
if (!isa<ConstructorDecl>(AFD) && !isa<DestructorDecl>(AFD))
return false;
// ... via a "self.property" reference.
auto *DRE = dyn_cast<DeclRefExpr>(base);
if (DRE == nullptr)
return false;
if (AFD->getImplicitSelfDecl() != cast<DeclRefExpr>(base)->getDecl())
return false;
// Convenience initializers do not require special handling.
// FIXME: This is a language change -- for now, keep the old behavior
#if 0
if (auto *CD = dyn_cast<ConstructorDecl>(AFD))
if (!CD->isDesignatedInit())
return false;
#endif
// Ctor or dtor are for immediate class, not a derived class.
if (AFD->getParent()->getDeclaredTypeOfContext()->getCanonicalType() !=
member->getDeclContext()->getDeclaredTypeOfContext()->getCanonicalType())
return false;
return true;
}
/// Return the implicit access kind for a MemberRefExpr with the
/// specified base and member in the specified DeclContext.
static AccessSemantics
getImplicitMemberReferenceAccessSemantics(Expr *base, VarDecl *member,
DeclContext *DC) {
// Properties that have storage and accessors are frequently accessed through
// accessors. However, in the init and destructor methods for the type
// immediately containing the property, accesses are done direct.
if (shouldAccessStorageDirectly(base, member, DC)) {
// The storage better not be resilient.
assert(member->hasFixedLayout(DC->getParentModule(),
DC->getResilienceExpansion()) &&
"Designated initializers and destructors of resilient types "
"cannot be @_transparent or defined in extensions");
// Access this directly instead of going through (e.g.) observing or
// trivial accessors.
return AccessSemantics::DirectToStorage;
}
// Check for property behavior initializations.
if (auto *AFD_DC = dyn_cast<AbstractFunctionDecl>(DC)) {
if (member->hasBehaviorNeedingInitialization() &&
// In a ctor.
isa<ConstructorDecl>(AFD_DC) &&
// Ctor is for immediate class, not a derived class.
AFD_DC->getParent()->getDeclaredTypeOfContext()->getCanonicalType() ==
member->getDeclContext()->getDeclaredTypeOfContext()->getCanonicalType() &&
// Is a "self.property" reference.
isa<DeclRefExpr>(base) &&
AFD_DC->getImplicitSelfDecl() == cast<DeclRefExpr>(base)->getDecl()) {
// Do definite initialization analysis to handle this property.
return AccessSemantics::BehaviorInitialization;
}
}
// If the value is always directly accessed from this context, do it.
return member->getAccessSemanticsFromContext(DC);
}
void ConstraintSystem::propagateLValueAccessKind(Expr *E,
AccessKind accessKind,
bool allowOverwrite) {
E->propagateLValueAccessKind(accessKind,
[&](Expr *E) -> Type {
return getType(E);
},
allowOverwrite);
}
namespace {
/// \brief Rewrites an expression by applying the solution of a constraint
/// system to that expression.
class ExprRewriter : public ExprVisitor<ExprRewriter, Expr *> {
public:
ConstraintSystem &cs;
DeclContext *dc;
const Solution &solution;
bool SuppressDiagnostics;
bool SkipClosures;
/// Recognize used conformances from an imported type when we must emit
/// the witness table.
///
/// This arises in _BridgedStoredNSError, where we wouldn't
/// otherwise pull in the witness table, causing dynamic casts to
/// perform incorrectly, and _ErrorCodeProtocol, where we need to
/// check for _BridgedStoredNSError conformances on the
/// corresponding ErrorType.
void checkForImportedUsedConformances(Type toType) {
cs.getTypeChecker().useBridgedNSErrorConformances(dc, toType);
}
/// \brief Coerce the given tuple to another tuple type.
///
/// \param expr The expression we're converting.
///
/// \param fromTuple The tuple type we're converting from, which is the same
/// as \c expr->getType().
///
/// \param toTuple The tuple type we're converting to.
///
/// \param locator Locator describing where this tuple conversion occurs.
///
/// \param sources The sources of each of the elements to be used in the
/// resulting tuple, as provided by \c computeTupleShuffle.
///
/// \param variadicArgs The source indices that are mapped to the variadic
/// parameter of the resulting tuple, as provided by \c computeTupleShuffle.
///
/// \param typeFromPattern Optionally, the caller can specify the pattern
/// from where the toType is derived, so that we can deliver better fixit.
Expr *coerceTupleToTuple(Expr *expr, TupleType *fromTuple,
TupleType *toTuple,
ConstraintLocatorBuilder locator,
SmallVectorImpl<int> &sources,
SmallVectorImpl<unsigned> &variadicArgs,
Optional<Pattern*> typeFromPattern = None);
/// \brief Coerce the given scalar value to the given tuple type.
///
/// \param expr The expression to be coerced.
/// \param toTuple The tuple type to which the expression will be coerced.
/// \param toScalarIdx The index of the scalar field within the tuple type
/// \c toType.
/// \param locator Locator describing where this conversion occurs.
///
/// \returns The coerced expression, whose type will be equivalent to
/// \c toTuple.
Expr *coerceScalarToTuple(Expr *expr, TupleType *toTuple,
int toScalarIdx,
ConstraintLocatorBuilder locator);
/// \brief Coerce the given value to existential type.
///
/// The following conversions are supported:
/// - concrete to existential
/// - existential to existential
/// - concrete metatype to existential metatype
/// - existential metatype to existential metatype
///
/// \param expr The expression to be coerced.
/// \param toType The type to which the expression will be coerced.
/// \param locator Locator describing where this conversion occurs.
///
/// \return The coerced expression, whose type will be equivalent to
/// \c toType.
Expr *coerceExistential(Expr *expr, Type toType,
ConstraintLocatorBuilder locator);
/// \brief Coerce an expression of (possibly unchecked) optional
/// type to have a different (possibly unchecked) optional type.
Expr *coerceOptionalToOptional(Expr *expr, Type toType,
ConstraintLocatorBuilder locator,
Optional<Pattern*> typeFromPattern = None);
/// \brief Coerce an expression of implicitly unwrapped optional type to its
/// underlying value type, in the correct way for an implicit
/// look-through.
Expr *coerceImplicitlyUnwrappedOptionalToValue(Expr *expr, Type objTy,
ConstraintLocatorBuilder locator);
public:
/// \brief Build a reference to the given declaration.
Expr *buildDeclRef(ValueDecl *decl, DeclNameLoc loc, Type openedType,
ConstraintLocatorBuilder locator,
bool specialized, bool implicit,
FunctionRefKind functionRefKind,
AccessSemantics semantics) {
// Determine the declaration selected for this overloaded reference.
auto &ctx = cs.getASTContext();
// If this is a member of a nominal type, build a reference to the
// member with an implied base type.
if (decl->getDeclContext()->isTypeContext() && isa<FuncDecl>(decl)) {
assert(cast<FuncDecl>(decl)->isOperator() && "Must be an operator");
auto openedFnType = openedType->castTo<FunctionType>();
auto simplifiedFnType
= simplifyType(openedFnType)->castTo<FunctionType>();
auto baseTy = simplifiedFnType->getInput()->getRValueInstanceType();
// Handle operator requirements found in protocols.
if (auto proto = dyn_cast<ProtocolDecl>(decl->getDeclContext())) {
// If we don't have an archetype or existential, we have to call the
// witness.
// FIXME: This is awful. We should be able to handle this as a call to
// the protocol requirement with Self == the concrete type, and SILGen
// (or later) can devirtualize as appropriate.
if (!baseTy->is<ArchetypeType>() && !baseTy->isAnyExistentialType()) {
auto &tc = cs.getTypeChecker();
auto conformance =
tc.conformsToProtocol(baseTy, proto, cs.DC,
(ConformanceCheckFlags::InExpression|
ConformanceCheckFlags::Used));
if (conformance && conformance->isConcrete()) {
if (auto witnessRef =
conformance->getConcrete()->getWitness(decl, &tc)) {
// Hack up an AST that we can type-check (independently) to get
// it into the right form.
// FIXME: the hop through 'getDecl()' is because
// SpecializedProtocolConformance doesn't substitute into
// witnesses' ConcreteDeclRefs.
Type expectedFnType = simplifiedFnType->getResult();
Expr *refExpr;
ValueDecl *witness = witnessRef.getDecl();
if (witness->getDeclContext()->isTypeContext()) {
Expr *base =
TypeExpr::createImplicitHack(loc.getBaseNameLoc(), baseTy,
ctx);
refExpr = new (ctx) MemberRefExpr(base, SourceLoc(), witness,
loc, /*Implicit=*/true);
} else {
auto declRefExpr = new (ctx) DeclRefExpr(witness, loc,
/*Implicit=*/false);
declRefExpr->setFunctionRefKind(functionRefKind);
refExpr = declRefExpr;
}
if (tc.typeCheckExpression(refExpr, cs.DC,
TypeLoc::withoutLoc(expectedFnType),
CTP_CannotFail))
return nullptr;
cs.cacheExprTypes(refExpr);
// Remove an outer function-conversion expression. This
// happens when we end up referring to a witness for a
// superclass conformance, and 'Self' differs.
if (auto fnConv = dyn_cast<FunctionConversionExpr>(refExpr))
refExpr = fnConv->getSubExpr();
return refExpr;
}
}
}
}
// Build a reference to the protocol requirement.
Expr *base =
cs.cacheType(TypeExpr::createImplicitHack(loc.getBaseNameLoc(),
baseTy,
ctx));
return buildMemberRef(base, openedType, SourceLoc(), decl,
loc, openedFnType->getResult(),
locator, locator, implicit, functionRefKind,
semantics, /*isDynamic=*/false);
}
// If this is a declaration with generic function type, build a
// specialized reference to it.
if (auto genericFn
= decl->getInterfaceType()->getAs<GenericFunctionType>()) {
auto dc = decl->getInnermostDeclContext();
SmallVector<Substitution, 4> substitutions;
auto type = solution.computeSubstitutions(
genericFn, dc, openedType,
getConstraintSystem().getConstraintLocator(locator),
substitutions);
auto declRefExpr =
new (ctx) DeclRefExpr(ConcreteDeclRef(ctx, decl, substitutions),
loc, implicit, semantics, type);
cs.cacheType(declRefExpr);
declRefExpr->setFunctionRefKind(functionRefKind);
return declRefExpr;
}
auto type = simplifyType(openedType);
// If we've ended up trying to assign an inout type here, it means we're
// missing an ampersand in front of the ref.
if (auto inoutType = type->getAs<InOutType>()) {
auto &tc = cs.getTypeChecker();
tc.diagnose(loc.getBaseNameLoc(), diag::missing_address_of,
inoutType->getInOutObjectType())
.fixItInsert(loc.getBaseNameLoc(), "&");
return nullptr;
}
auto declRefExpr = new (ctx) DeclRefExpr(decl, loc, implicit, semantics,
type);
cs.cacheType(declRefExpr);
declRefExpr->setFunctionRefKind(functionRefKind);
return declRefExpr;
}
/// Describes an opened existential that has not yet been closed.
struct OpenedExistential {
/// The archetype describing this opened existential.
ArchetypeType *Archetype;
/// The existential value being opened.
Expr *ExistentialValue;
/// The opaque value (of archetype type) stored within the
/// existential.
OpaqueValueExpr *OpaqueValue;
/// The depth of this currently-opened existential. Once the
/// depth of the expression stack is equal to this value, the
/// existential can be closed.
unsigned Depth;
};
/// A stack of opened existentials that have not yet been closed.
/// Ordered by decreasing depth.
llvm::SmallVector<OpenedExistential, 2> OpenedExistentials;
/// A stack of expressions being walked, used to compute existential depth.
llvm::SmallVector<Expr *, 8> ExprStack;
/// Members which are AbstractFunctionDecls but not FuncDecls cannot
/// mutate self.
bool isNonMutatingMember(ValueDecl *member) {
if (!isa<AbstractFunctionDecl>(member))
return false;
return !isa<FuncDecl>(member) || !cast<FuncDecl>(member)->isMutating();
}
unsigned getNaturalArgumentCount(ValueDecl *member) {
if (auto func = dyn_cast<AbstractFunctionDecl>(member)) {
// For functions, close the existential once the function
// has been fully applied.
return func->getNumParameterLists();
} else {
// For storage, close the existential either when it's
// accessed (if it's an rvalue only) or when it is loaded or
// stored (if it's an lvalue).
assert(isa<AbstractStorageDecl>(member) &&
"unknown member when opening existential");
return 1;
}
}
/// If the expression might be a dynamic method call, return the base
/// value for the call.
Expr *getBaseExpr(Expr *expr) {
// Keep going up as long as this expression is the parent's base.
if (auto unresolvedDot = dyn_cast<UnresolvedDotExpr>(expr)) {
return unresolvedDot->getBase();
// Remaining cases should only come up when we're re-typechecking.
// FIXME: really it would be much better if Sema had stricter phase
// separation.
} else if (auto dotSyntax = dyn_cast<DotSyntaxCallExpr>(expr)) {
return dotSyntax->getArg();
} else if (auto ctorRef = dyn_cast<ConstructorRefCallExpr>(expr)) {
return ctorRef->getArg();
} else if (auto apply = dyn_cast<ApplyExpr>(expr)) {
return apply->getFn();
} else if (auto memberRef = dyn_cast<MemberRefExpr>(expr)) {
return memberRef->getBase();
} else if (auto dynMemberRef = dyn_cast<DynamicMemberRefExpr>(expr)) {
return dynMemberRef->getBase();
} else if (auto subscriptRef = dyn_cast<SubscriptExpr>(expr)) {
return subscriptRef->getBase();
} else if (auto dynSubscriptRef = dyn_cast<DynamicSubscriptExpr>(expr)) {
return dynSubscriptRef->getBase();
} else if (auto load = dyn_cast<LoadExpr>(expr)) {
return load->getSubExpr();
} else if (auto inout = dyn_cast<InOutExpr>(expr)) {
return inout->getSubExpr();
} else if (auto force = dyn_cast<ForceValueExpr>(expr)) {
return force->getSubExpr();
} else {
return nullptr;
}
}
/// Calculates the nesting depth of the current application.
unsigned getArgCount(unsigned maxArgCount) {
unsigned e = ExprStack.size();
unsigned argCount;
// Starting from the current expression, count up if the expression is
// equal to its parent expression's base.
Expr *prev = ExprStack.back();
for (argCount = 1; argCount < maxArgCount && argCount < e; argCount++) {
Expr *result = ExprStack[e - argCount - 1];
Expr *base = getBaseExpr(result);
if (base != prev)
break;
prev = result;
}
return argCount;
}
/// Open an existential value into a new, opaque value of
/// archetype type.
///
/// \param base An expression of existential type whose value will
/// be opened.
///
/// \param archetype The archetype that describes the opened existential
/// type.
///
/// \param member The member that is being referenced on the existential
/// type.
///
/// \returns An OpaqueValueExpr that provides a reference to the value
/// stored within the expression or its metatype (if the base was a
/// metatype).
Expr *openExistentialReference(Expr *base, ArchetypeType *archetype,
ValueDecl *member) {
assert(archetype && "archetype not already opened?");
auto &tc = cs.getTypeChecker();
// Dig out the base type.
Type baseTy = cs.getType(base);
// Look through lvalues.
bool isLValue = false;
if (auto lvalueTy = baseTy->getAs<LValueType>()) {
isLValue = true;
baseTy = lvalueTy->getObjectType();
}
// Look through metatypes.
bool isMetatype = false;
if (auto metaTy = baseTy->getAs<AnyMetatypeType>()) {
isMetatype = true;
baseTy = metaTy->getInstanceType();
}
assert(baseTy->isAnyExistentialType() && "Type must be existential");
// If the base was an lvalue but it will only be treated as an
// rvalue, turn the base into an rvalue now. This results in
// better SILGen.
if (isLValue &&
(isNonMutatingMember(member) ||
isMetatype || baseTy->isClassExistentialType())) {
base = cs.coerceToRValue(base);
isLValue = false;
}
// Determine the number of applications that need to occur before
// we can close this existential, and record it.
unsigned maxArgCount = getNaturalArgumentCount(member);
unsigned depth = ExprStack.size() - getArgCount(maxArgCount);
// Create the opaque opened value. If we started with a
// metatype, it's a metatype.
Type opaqueType = archetype;
if (isMetatype)
opaqueType = MetatypeType::get(opaqueType);
if (isLValue)
opaqueType = LValueType::get(opaqueType);
ASTContext &ctx = tc.Context;
auto archetypeVal = new (ctx) OpaqueValueExpr(base->getLoc(), opaqueType);
cs.cacheType(archetypeVal);
// Record the opened existential.
OpenedExistentials.push_back({archetype, base, archetypeVal, depth});
return archetypeVal;
}
/// Trying to close the active existential, if there is one.
bool closeExistential(Expr *&result, bool force=false) {
if (OpenedExistentials.empty())
return false;
auto &record = OpenedExistentials.back();
assert(record.Depth <= ExprStack.size() - 1);
if (!force && record.Depth < ExprStack.size() - 1)
return false;
// If we had a return type of 'Self', erase it.
ConstraintSystem &innerCS = solution.getConstraintSystem();
auto &tc = innerCS.getTypeChecker();
Type resultTy;
resultTy = cs.getType(result);
if (resultTy->hasOpenedExistential(record.Archetype)) {
Type erasedTy = resultTy->eraseOpenedExistential(
innerCS.DC->getParentModule(),
record.Archetype);
result = coerceToType(result, erasedTy, nullptr);
}
// If the opaque value has an l-value access kind, then
// the OpenExistentialExpr isn't making a derived l-value, which
// means this is our only chance to propagate the l-value access kind
// down to the original existential value. Otherwise, propagateLVAK
// will handle this.
if (record.OpaqueValue->hasLValueAccessKind())
cs.propagateLValueAccessKind(record.ExistentialValue,
record.OpaqueValue->getLValueAccessKind());
// Form the open-existential expression.
result = new (tc.Context) OpenExistentialExpr(
record.ExistentialValue,
record.OpaqueValue,
result);
cs.cacheType(result);
OpenedExistentials.pop_back();
return true;
}
/// Is the given function a constructor of a class or protocol?
/// Such functions are subject to DynamicSelf manipulations.
///
/// We want to avoid taking the DynamicSelf paths for other
/// constructors for two reasons:
/// - it's an unnecessary cost
/// - optionality preservation has a problem with constructors on
/// optional types
static bool isPolymorphicConstructor(AbstractFunctionDecl *fn) {
if (!isa<ConstructorDecl>(fn))
return false;
auto *parent =
fn->getParent()->getAsNominalTypeOrNominalTypeExtensionContext();
return parent && (isa<ClassDecl>(parent) || isa<ProtocolDecl>(parent));
}
/// \brief Build a new member reference with the given base and member.
Expr *buildMemberRef(Expr *base, Type openedFullType, SourceLoc dotLoc,
ValueDecl *member, DeclNameLoc memberLoc,
Type openedType, ConstraintLocatorBuilder locator,
ConstraintLocatorBuilder memberLocator,
bool Implicit, FunctionRefKind functionRefKind,
AccessSemantics semantics, bool isDynamic) {
auto &tc = cs.getTypeChecker();
auto &context = tc.Context;
bool isSuper = base->isSuperExpr();
Type baseTy = cs.getType(base)->getRValueType();
// Explicit member accesses are permitted to implicitly look
// through ImplicitlyUnwrappedOptional<T>.
if (!Implicit) {
if (auto objTy = cs.lookThroughImplicitlyUnwrappedOptionalType(baseTy)) {
base = coerceImplicitlyUnwrappedOptionalToValue(base, objTy, locator);
baseTy = objTy;
}
}
// Figure out the actual base type, and whether we have an instance of
// that type or its metatype.
bool baseIsInstance = true;
if (auto baseMeta = baseTy->getAs<AnyMetatypeType>()) {
baseIsInstance = false;
baseTy = baseMeta->getInstanceType();
// If the member is a constructor, verify that it can be legally
// referenced from this base.
if (auto ctor = dyn_cast<ConstructorDecl>(member)) {
if (!tc.diagnoseInvalidDynamicConstructorReferences(base, memberLoc,
baseMeta, ctor, SuppressDiagnostics))
return nullptr;
}
}
// Produce a reference to the member, the type of the container it
// resides in, and the type produced by the reference itself.
Type containerTy;
ConcreteDeclRef memberRef;
Type refTy;
Type dynamicSelfFnType;
if (member->getInterfaceType()->is<GenericFunctionType>() ||
openedFullType->hasTypeVariable()) {
// We require substitutions. Figure out what they are.
// Figure out the declaration context where we'll get the generic
// parameters.
auto dc = member->getInnermostDeclContext();
// Build a reference to the generic member.
SmallVector<Substitution, 4> substitutions;
refTy = solution.computeSubstitutions(
member->getInterfaceType(),
dc,
openedFullType,
getConstraintSystem().getConstraintLocator(memberLocator),
substitutions);
memberRef = ConcreteDeclRef(context, member, substitutions);
if (auto openedFullFnType = openedFullType->getAs<FunctionType>()) {
auto openedBaseType = openedFullFnType->getInput()
->getRValueInstanceType();
containerTy = solution.simplifyType(tc, openedBaseType);
}
} else {
// No substitutions required; the declaration reference is simple.
containerTy = member->getDeclContext()->getDeclaredTypeOfContext();
memberRef = member;
refTy = openedFullType;
}
// If we opened up an existential when referencing this member, update
// the base accordingly.
auto knownOpened = solution.OpenedExistentialTypes.find(
getConstraintSystem().getConstraintLocator(
memberLocator));
bool openedExistential = false;
if (knownOpened != solution.OpenedExistentialTypes.end()) {
base = openExistentialReference(base, knownOpened->second, member);
baseTy = knownOpened->second;
containerTy = baseTy;
openedExistential = true;
}
// If this is a method whose result type is dynamic Self, or a
// construction, replace the result type with the actual object type.
if (auto func = dyn_cast<AbstractFunctionDecl>(member)) {
if ((isa<FuncDecl>(func) &&
(cast<FuncDecl>(func)->hasDynamicSelf() ||
(openedExistential &&
cast<FuncDecl>(func)->hasArchetypeSelf()))) ||
isPolymorphicConstructor(func)) {
refTy = refTy->replaceCovariantResultType(containerTy,
func->getNumParameterLists());
dynamicSelfFnType = refTy->replaceCovariantResultType(
baseTy,
func->getNumParameterLists());
if (openedExistential) {
// Replace the covariant result type in the opened type. We need to
// handle dynamic member references, which wrap the function type
// in an optional.
OptionalTypeKind optKind;
if (auto optObject = openedType->getAnyOptionalObjectType(optKind))
openedType = optObject;
openedType = openedType->replaceCovariantResultType(
baseTy,
func->getNumParameterLists()-1);
if (optKind != OptionalTypeKind::OTK_None)
openedType = OptionalType::get(optKind, openedType);
}
// If the type after replacing DynamicSelf with the provided base
// type is no different, we don't need to perform a conversion here.
if (refTy->isEqual(dynamicSelfFnType))
dynamicSelfFnType = nullptr;
}
}
// If we're referring to the member of a module, it's just a simple
// reference.
if (baseTy->is<ModuleType>()) {
assert(semantics == AccessSemantics::Ordinary &&
"Direct property access doesn't make sense for this");
assert(!dynamicSelfFnType && "No reference type to convert to");
auto ref = new (context) DeclRefExpr(memberRef, memberLoc, Implicit);
cs.setType(ref, refTy);
ref->setFunctionRefKind(functionRefKind);
return cs.cacheType(new (context)
DotSyntaxBaseIgnoredExpr(base, dotLoc, ref));
}
// Otherwise, we're referring to a member of a type.
Type selfTy;
if (isa<ProtocolDecl>(member->getDeclContext()) &&
(baseTy->is<ArchetypeType>() || baseTy->isExistentialType()))
selfTy = baseTy;
else
selfTy = containerTy;
// References to properties with accessors and storage usually go
// through the accessors, but sometimes are direct.
if (auto *VD = dyn_cast<VarDecl>(member)) {
if (semantics == AccessSemantics::Ordinary)
semantics = getImplicitMemberReferenceAccessSemantics(base, VD, dc);
}
if (baseIsInstance) {
// Convert the base to the appropriate container type, turning it
// into an lvalue if required.
// If the base is already an lvalue with the right base type, we can
// pass it as an inout qualified type.
if (selfTy->isEqual(baseTy))
if (cs.getType(base)->is<LValueType>())
selfTy = InOutType::get(selfTy);
base = coerceObjectArgumentToType(
base, selfTy, member, semantics,
locator.withPathElement(ConstraintLocator::MemberRefBase));
} else {
// Convert the base to an rvalue of the appropriate metatype.
base = coerceToType(base,
MetatypeType::get(selfTy),
locator.withPathElement(
ConstraintLocator::MemberRefBase));
if (!base)
return nullptr;
base = cs.coerceToRValue(base);
}
assert(base && "Unable to convert base?");
// Handle dynamic references.
if (isDynamic || member->getAttrs().hasAttribute<OptionalAttr>()) {
base = cs.coerceToRValue(base);
if (!base) return nullptr;
Expr *ref = new (context) DynamicMemberRefExpr(base, dotLoc, memberRef,
memberLoc);
ref->setImplicit(Implicit);
// FIXME: FunctionRefKind
// Compute the type of the reference.
Type refType = simplifyType(openedType);
// If the base was an opened existential, erase the opened
// existential.
if (openedExistential &&
refType->hasOpenedExistential(knownOpened->second)) {
refType = refType->eraseOpenedExistential(
cs.DC->getParentModule(),
knownOpened->second);
}
cs.setType(ref, refType);
closeExistential(ref, /*force=*/openedExistential);
return ref;
}
// For types and properties, build member references.
if (isa<TypeDecl>(member) || isa<VarDecl>(member)) {
assert(!dynamicSelfFnType && "Converted type doesn't make sense here");
if (!baseIsInstance && member->isInstanceMember()) {
assert(memberLocator.getBaseLocator() &&
cs.UnevaluatedRootExprs.count(
memberLocator.getBaseLocator()->getAnchor()) &&
"Attempt to reference an instance member of a metatype");
auto baseInstanceTy = cs.getType(base)->getRValueInstanceType();
base = new (context) UnevaluatedInstanceExpr(base, baseInstanceTy);
cs.cacheType(base);
base->setImplicit();
}
auto memberRefExpr
= new (context) MemberRefExpr(base, dotLoc, memberRef,
memberLoc, Implicit, semantics);
memberRefExpr->setIsSuper(isSuper);
// Skip the synthesized 'self' input type of the opened type.
cs.setType(memberRefExpr, simplifyType(openedType));
Expr *result = memberRefExpr;
closeExistential(result);
return result;
}
// Handle all other references.
auto declRefExpr = new (context) DeclRefExpr(memberRef, memberLoc,
Implicit, semantics);
declRefExpr->setFunctionRefKind(functionRefKind);
cs.setType(declRefExpr, refTy);
Expr *ref = declRefExpr;
// If the reference needs to be converted, do so now.
if (dynamicSelfFnType) {
ref = new (context) CovariantFunctionConversionExpr(ref,
dynamicSelfFnType);
cs.cacheType(ref);
}
ApplyExpr *apply;
if (isa<ConstructorDecl>(member)) {
// FIXME: Provide type annotation.
apply = new (context) ConstructorRefCallExpr(ref, base);
} else if (!baseIsInstance && member->isInstanceMember()) {
// Reference to an unbound instance method.
Expr *result = new (context) DotSyntaxBaseIgnoredExpr(base, dotLoc,
ref);
cs.cacheType(result);
closeExistential(result, /*force=*/openedExistential);
return result;
} else {
assert((!baseIsInstance || member->isInstanceMember()) &&
"can't call a static method on an instance");
apply = new (context) DotSyntaxCallExpr(ref, dotLoc, base);
if (Implicit) {
apply->setImplicit();
}
}
return finishApply(apply, openedType, locator);
}
/// \brief Describes either a type or the name of a type to be resolved.
typedef llvm::PointerUnion<Identifier, Type> TypeOrName;
/// \brief Convert the given literal expression via a protocol pair.
///
/// This routine handles the two-step literal conversion process used
/// by integer, float, character, extended grapheme cluster, and string
/// literals. The first step uses \c builtinProtocol while the second
/// step uses \c protocol.
///
/// \param literal The literal expression.
///
/// \param type The literal type. This type conforms to \c protocol,
/// and may also conform to \c builtinProtocol.
///
/// \param openedType The literal type as it was opened in the type system.
///
/// \param protocol The protocol that describes the literal requirement.
///
/// \param literalType Either the name of the associated type in
/// \c protocol that describes the argument type of the conversion function
/// (\c literalFuncName) or the argument type itself.
///
/// \param literalFuncName The name of the conversion function requirement
/// in \c protocol.
///
/// \param builtinProtocol The "builtin" form of the protocol, which
/// always takes builtin types and can only be properly implemented
/// by standard library types. If \c type does not conform to this
/// protocol, it's literal type will.
///
/// \param builtinLiteralType Either the name of the associated type in
/// \c builtinProtocol that describes the argument type of the builtin
/// conversion function (\c builtinLiteralFuncName) or the argument type
/// itself.
///
/// \param builtinLiteralFuncName The name of the conversion function
/// requirement in \c builtinProtocol.
///
/// \param isBuiltinArgType Function that determines whether the given
/// type is acceptable as the argument type for the builtin conversion.
///
/// \param brokenProtocolDiag The diagnostic to emit if the protocol
/// is broken.
///
/// \param brokenBuiltinProtocolDiag The diagnostic to emit if the builtin
/// protocol is broken.
///
/// \returns the converted literal expression.
Expr *convertLiteral(Expr *literal,
Type type,
Type openedType,
ProtocolDecl *protocol,
TypeOrName literalType,
DeclName literalFuncName,
ProtocolDecl *builtinProtocol,
TypeOrName builtinLiteralType,
DeclName builtinLiteralFuncName,
bool (*isBuiltinArgType)(Type),
Diag<> brokenProtocolDiag,
Diag<> brokenBuiltinProtocolDiag);
/// \brief Convert the given literal expression via a protocol pair.
///
/// This routine handles the two-step literal conversion process used
/// by integer, float, character, extended grapheme cluster, and string
/// literals. The first step uses \c builtinProtocol while the second
/// step uses \c protocol.
///
/// \param literal The literal expression.
///
/// \param type The literal type. This type conforms to \c protocol,
/// and may also conform to \c builtinProtocol.
///
/// \param protocol The protocol that describes the literal requirement.
///
/// \param literalType The name of the associated type in \c protocol that
/// describes the argument type of the conversion function (\c
/// literalFuncName).
///
/// \param literalFuncName The name of the conversion function requirement
/// in \c protocol.
///
/// \param builtinProtocol The "builtin" form of the protocol, which
/// always takes builtin types and can only be properly implemented
/// by standard library types. If \c type does not conform to this
/// protocol, it's literal type will.
///
/// \param builtinLiteralFuncName The name of the conversion function
/// requirement in \c builtinProtocol.
///
/// \param brokenProtocolDiag The diagnostic to emit if the protocol
/// is broken.
///
/// \param brokenBuiltinProtocolDiag The diagnostic to emit if the builtin
/// protocol is broken.
///
/// \returns the converted literal expression.
Expr *convertLiteralInPlace(Expr *literal,
Type type,
ProtocolDecl *protocol,
Identifier literalType,
DeclName literalFuncName,
ProtocolDecl *builtinProtocol,
DeclName builtinLiteralFuncName,
Diag<> brokenProtocolDiag,
Diag<> brokenBuiltinProtocolDiag);
/// \brief Finish a function application by performing the appropriate
/// conversions on the function and argument expressions and setting
/// the resulting type.
///
/// \param apply The function application to finish type-checking, which
/// may be a newly-built expression.
///
/// \param openedType The "opened" type this expression had during
/// type checking, which will be used to specialize the resulting,
/// type-checked expression appropriately.
///
/// \param locator The locator for the original expression.
Expr *finishApply(ApplyExpr *apply, Type openedType,
ConstraintLocatorBuilder locator);
private:
/// \brief Retrieve the overload choice associated with the given
/// locator.
SelectedOverload getOverloadChoice(ConstraintLocator *locator) {
return *getOverloadChoiceIfAvailable(locator);
}
/// \brief Retrieve the overload choice associated with the given
/// locator.
Optional<SelectedOverload>
getOverloadChoiceIfAvailable(ConstraintLocator *locator) {
auto known = solution.overloadChoices.find(locator);
if (known != solution.overloadChoices.end())
return known->second;
return None;
}
/// \brief Simplify the given type by substituting all occurrences of
/// type variables for their fixed types.
Type simplifyType(Type type) {
return solution.simplifyType(cs.getTypeChecker(), type);
}
public:
/// \brief Coerce a closure expression with a non-Void return type to a
/// contextual function type with a Void return type.
///
/// This operation cannot fail.
///
/// \param expr The closure expression to coerce.
///
/// \returns The coerced closure expression.
///
ClosureExpr *coerceClosureExprToVoid(ClosureExpr *expr);
/// \brief Coerce a closure expression with a Never return type to a
/// contextual function type with some other return type.
///
/// This operation cannot fail.
///
/// \param expr The closure expression to coerce.
///
/// \returns The coerced closure expression.
///
ClosureExpr *coerceClosureExprFromNever(ClosureExpr *expr);
/// \brief Coerce the given expression to the given type.
///
/// This operation cannot fail.
///
/// \param expr The expression to coerce.
/// \param toType The type to coerce the expression to.
/// \param locator Locator used to describe where in this expression we are.
/// \param typeFromPattern Optionally, the caller can specify the pattern
/// from where the toType is derived, so that we can deliver better fixit.
///
/// \returns the coerced expression, which will have type \c ToType.
Expr *coerceToType(Expr *expr, Type toType,
ConstraintLocatorBuilder locator,
Optional<Pattern*> typeFromPattern = None);
using LevelTy = llvm::PointerEmbeddedInt<unsigned, 2>;
/// \brief Coerce the given expression (which is the argument to a call) to
/// the given parameter type.
///
/// This operation cannot fail.
///
/// \param arg The argument expression.
/// \param paramType The parameter type.
/// \param applyOrLevel For function applications, the ApplyExpr that forms
/// the call. Otherwise, a specific level describing which parameter level
/// we're applying.
/// \param argLabels The argument labels provided for the call.
/// \param hasTrailingClosure Whether the last argument is a trailing
/// closure.
/// \param locator Locator used to describe where in this expression we are.
///
/// \returns the coerced expression, which will have type \c ToType.
Expr *
coerceCallArguments(Expr *arg, Type paramType,
llvm::PointerUnion<ApplyExpr *, LevelTy> applyOrLevel,
ArrayRef<Identifier> argLabels,
bool hasTrailingClosure,
ConstraintLocatorBuilder locator);
/// \brief Coerce the given object argument (e.g., for the base of a
/// member expression) to the given type.
///
/// \param expr The expression to coerce.
///
/// \param baseTy The base type
///
/// \param member The member being accessed.
///
/// \param semantics The kind of access we've been asked to perform.
///
/// \param locator Locator used to describe where in this expression we are.
Expr *coerceObjectArgumentToType(Expr *expr,
Type baseTy, ValueDecl *member,
AccessSemantics semantics,
ConstraintLocatorBuilder locator);
private:
/// \brief Build a new subscript.
///
/// \param base The base of the subscript.
/// \param index The index of the subscript.
/// \param locator The locator used to refer to the subscript.
/// \param isImplicit Whether this is an implicit subscript.
Expr *buildSubscript(Expr *base, Expr *index,
ArrayRef<Identifier> argLabels,
bool hasTrailingClosure,
ConstraintLocatorBuilder locator,
bool isImplicit, AccessSemantics semantics) {
// Determine the declaration selected for this subscript operation.
auto selected = getOverloadChoiceIfAvailable(
cs.getConstraintLocator(
locator.withPathElement(
ConstraintLocator::SubscriptMember)));
// Handles situation where there was a solution available but it didn't
// have a proper overload selected from subscript call, might be because
// solver was allowed to return free or unresolved types, which can
// happen while running diagnostics on one of the expressions.
if (!selected.hasValue()) {
auto &tc = cs.TC;
auto baseType = cs.getType(base);
if (auto errorType = baseType->getAs<ErrorType>()) {
tc.diagnose(base->getLoc(), diag::cannot_subscript_base,
errorType->getOriginalType())
.highlight(base->getSourceRange());
} else {
tc.diagnose(base->getLoc(), diag::cannot_subscript_ambiguous_base)
.highlight(base->getSourceRange());
}
return nullptr;
}
auto choice = selected->choice;
auto subscript = cast<SubscriptDecl>(choice.getDecl());
auto &tc = cs.getTypeChecker();
auto baseTy = cs.getType(base)->getRValueType();
// Check whether the base is 'super'.
bool isSuper = base->isSuperExpr();
// Handle accesses that implicitly look through ImplicitlyUnwrappedOptional<T>.
if (auto objTy = cs.lookThroughImplicitlyUnwrappedOptionalType(baseTy)) {
base = coerceImplicitlyUnwrappedOptionalToValue(base, objTy, locator);
baseTy = cs.getType(base);
}
// Figure out the index and result types.
auto containerTy
= subscript->getDeclContext()->getDeclaredTypeOfContext();
auto subscriptTy = simplifyType(selected->openedType);
auto indexTy = subscriptTy->castTo<AnyFunctionType>()->getInput();
auto resultTy = subscriptTy->castTo<AnyFunctionType>()->getResult();
// If we opened up an existential when performing the subscript, open
// the base accordingly.
auto knownOpened = solution.OpenedExistentialTypes.find(
getConstraintSystem().getConstraintLocator(
locator.withPathElement(
ConstraintLocator::SubscriptMember)));
if (knownOpened != solution.OpenedExistentialTypes.end()) {
base = openExistentialReference(base, knownOpened->second, subscript);
baseTy = knownOpened->second;
containerTy = baseTy;
}
// Coerce the index argument.
index = coerceCallArguments(
index, indexTy, LevelTy(1), argLabels,
hasTrailingClosure,
locator.withPathElement(ConstraintLocator::SubscriptIndex));
if (!index)
return nullptr;
// Form the subscript expression.
// Handle dynamic lookup.
if (choice.getKind() == OverloadChoiceKind::DeclViaDynamic ||
subscript->getAttrs().hasAttribute<OptionalAttr>()) {
base = coerceObjectArgumentToType(base, baseTy, subscript,
AccessSemantics::Ordinary, locator);
if (!base)
return nullptr;
// TODO: diagnose if semantics != AccessSemantics::Ordinary?
auto subscriptExpr = DynamicSubscriptExpr::create(tc.Context, base,
index, subscript,
isImplicit);
cs.setType(subscriptExpr, resultTy);
Expr *result = subscriptExpr;
closeExistential(result);
return result;
}
// Handle subscripting of generics.
if (subscript->getDeclContext()->isGenericContext()) {
auto dc = subscript->getDeclContext();
// Compute the substitutions used to reference the subscript.
SmallVector<Substitution, 4> substitutions;
solution.computeSubstitutions(
subscript->getInterfaceType(),
dc,
selected->openedFullType,
getConstraintSystem().getConstraintLocator(
locator.withPathElement(ConstraintLocator::SubscriptMember)),
substitutions);
// Convert the base.
auto openedFullFnType = selected->openedFullType->castTo<FunctionType>();
auto openedBaseType = openedFullFnType->getInput();
containerTy = solution.simplifyType(tc, openedBaseType);
base = coerceObjectArgumentToType(
base, containerTy, subscript, AccessSemantics::Ordinary,
locator.withPathElement(ConstraintLocator::MemberRefBase));
if (!base)
return nullptr;
// Form the generic subscript expression.
auto subscriptExpr
= SubscriptExpr::create(tc.Context, base, index,
ConcreteDeclRef(tc.Context, subscript,
substitutions),
isImplicit,
semantics);
cs.setType(subscriptExpr, resultTy);
subscriptExpr->setIsSuper(isSuper);
Expr *result = subscriptExpr;
closeExistential(result);
return result;
}
Type selfTy = containerTy;
if (selfTy->isEqual(baseTy) && !selfTy->hasReferenceSemantics())
if (cs.getType(base)->is<LValueType>())
selfTy = InOutType::get(selfTy);
// Coerce the base to the container type.
base = coerceObjectArgumentToType(base, selfTy, subscript,
AccessSemantics::Ordinary, locator);
if (!base)
return nullptr;
// Form a normal subscript.
auto *subscriptExpr
= SubscriptExpr::create(tc.Context, base, index, subscript,
isImplicit, semantics);
cs.setType(subscriptExpr, resultTy);
subscriptExpr->setIsSuper(isSuper);
Expr *result = subscriptExpr;
closeExistential(result);
return result;
}
/// \brief Build a new reference to another constructor.
Expr *buildOtherConstructorRef(Type openedFullType,
ConstructorDecl *ctor, DeclNameLoc loc,
ConstraintLocatorBuilder locator,
bool implicit) {
auto &tc = cs.getTypeChecker();
auto &ctx = tc.Context;
// Compute the concrete reference.
ConcreteDeclRef ref;
Type resultTy;
if (ctor->getInitializerInterfaceType()->is<GenericFunctionType>()) {
// Compute the reference to the generic constructor.
SmallVector<Substitution, 4> substitutions;
resultTy = solution.computeSubstitutions(
ctor->getInterfaceType(),
ctor,
openedFullType,
getConstraintSystem().getConstraintLocator(locator),
substitutions);
ref = ConcreteDeclRef(ctx, ctor, substitutions);
} else {
Type containerTy = ctor->getDeclContext()->getDeclaredTypeOfContext();
resultTy = openedFullType->replaceCovariantResultType(
containerTy, ctor->getNumParameterLists());
ref = ConcreteDeclRef(ctor);
}
// The constructor was opened with the allocating type, not the
// initializer type. Map the former into the latter.
auto resultFnTy = resultTy->castTo<FunctionType>();
auto selfTy = resultFnTy->getInput()->getRValueInstanceType();
if (!selfTy->hasReferenceSemantics())
selfTy = InOutType::get(selfTy);
resultTy = FunctionType::get(selfTy, resultFnTy->getResult(),
resultFnTy->getExtInfo());
// Build the constructor reference.
return cs.cacheType(
new (ctx) OtherConstructorDeclRefExpr(ref, loc, implicit, resultTy));
}
/// Bridge the given value (which is an error type) to NSError.
Expr *bridgeErrorToObjectiveC(Expr *value) {
auto &tc = cs.getTypeChecker();
// Use _bridgeErrorToNSError to convert to an NSError.
auto fn = tc.Context.getBridgeErrorToNSError(&tc);
SourceLoc loc = value->getLoc();
if (!fn) {
tc.diagnose(loc, diag::missing_nserror_bridging_function);
return nullptr;
}
tc.validateDecl(fn);
ConcreteDeclRef fnDeclRef(fn);
auto fnRef = new (tc.Context) DeclRefExpr(fnDeclRef, DeclNameLoc(loc),
/*Implicit=*/true);
cs.setType(fnRef, fn->getInterfaceType());
fnRef->setFunctionRefKind(FunctionRefKind::SingleApply);
Expr *call = CallExpr::createImplicit(tc.Context, fnRef, { value }, { });
if (tc.typeCheckExpressionShallow(call, dc))
return nullptr;
cs.cacheType(call);
// The return type of _bridgeErrorToNSError is formally
// 'AnyObject' to avoid stdlib-to-Foundation dependencies, but it's
// really NSError. Abuse CovariantReturnConversionExpr to fix this.
auto nsErrorDecl = tc.Context.getNSErrorDecl();
assert(nsErrorDecl && "Missing NSError?");
Type nsErrorType = nsErrorDecl->getDeclaredInterfaceType();
return cs.cacheType(new (tc.Context)
CovariantReturnConversionExpr(call, nsErrorType));
}
/// Bridge the given value to its corresponding Objective-C object
/// type.
///
/// This routine should only be used for bridging value types.
///
/// \param value The value to be bridged.
Expr *bridgeToObjectiveC(Expr *value) {
// TODO: It would be nicer to represent this as a special AST node
// instead of inlining the bridging calls in the AST. Doing so would
// simplify the AST and make it easier for SILGen to peephole bridging
// conversions.
auto &tc = cs.getTypeChecker();
// Find the _ObjectiveCBridgeable protocol.
auto bridgedProto
= tc.Context.getProtocol(KnownProtocolKind::ObjectiveCBridgeable);
// Find the conformance of the value type to _ObjectiveCBridgeable.
Type valueType = cs.getType(value)->getRValueType();
if (auto conformance =
tc.conformsToProtocol(valueType, bridgedProto, cs.DC,
(ConformanceCheckFlags::InExpression|
ConformanceCheckFlags::Used))) {
// Form the call.
return cs.cacheType(
tc.callWitness(value, cs.DC, bridgedProto, *conformance,
tc.Context.Id_bridgeToObjectiveC,
{ }, diag::broken_bridged_to_objc_protocol));
}
// If there is an Error conformance, try bridging as an error.
if (tc.isConvertibleTo(valueType,
tc.Context.getProtocol(KnownProtocolKind::Error)
->getDeclaredType(),
cs.DC))
return bridgeErrorToObjectiveC(value);
// Fall back to universal bridging.
auto bridgeAnything = tc.Context.getBridgeAnythingToObjectiveC(&tc);
value = cs.coerceToRValue(value);
auto valueSub = Substitution(valueType, {});
auto bridgeAnythingRef = ConcreteDeclRef(tc.Context, bridgeAnything,
valueSub);
auto valueParenTy = ParenType::get(tc.Context, cs.getType(value));
auto bridgeTy = tc.Context.getProtocol(KnownProtocolKind::AnyObject)
->getDeclaredType();
auto bridgeFnTy = FunctionType::get(valueParenTy, bridgeTy);
// FIXME: Wrap in ParenExpr to prevent bogus "tuple passed as argument"
// errors.
auto valueParen = new (tc.Context) ParenExpr(SourceLoc(),
value,
SourceLoc(),
/*trailing closure*/ false,
valueParenTy);
valueParen->setImplicit();
auto fnRef = new (tc.Context) DeclRefExpr(bridgeAnythingRef,
DeclNameLoc(),
/*implicit*/ true,
AccessSemantics::Ordinary,
bridgeFnTy);
fnRef->setFunctionRefKind(FunctionRefKind::SingleApply);
Expr *call = CallExpr::createImplicit(tc.Context, fnRef, valueParen,
{ Identifier() });
cs.setType(call, bridgeTy);
cs.cacheSubExprTypes(call);
return call;
}
/// Bridge the given object from Objective-C to its value type.
///
/// This routine should only be used for bridging value types.
///
/// \param object The object, whose type should already be of the type
/// that the value type bridges through.
///
/// \param valueType The value type to which we are bridging.
///
/// \param conditional Whether the bridging should be conditional. If false,
/// uses forced bridging.
///
/// \returns a value of type \c valueType (optional if \c conditional) that
/// stores the bridged result or (when \c conditional) an empty optional if
/// conditional bridging fails.
Expr *bridgeFromObjectiveC(Expr *object, Type valueType, bool conditional) {
auto &tc = cs.getTypeChecker();
// Find the _BridgedToObjectiveC protocol.
auto bridgedProto
= tc.Context.getProtocol(KnownProtocolKind::ObjectiveCBridgeable);
// Try to find the conformance of the value type to _BridgedToObjectiveC.
auto bridgedToObjectiveCConformance
= tc.conformsToProtocol(valueType,
bridgedProto,
cs.DC,
(ConformanceCheckFlags::InExpression|
ConformanceCheckFlags::Used));
FuncDecl *fn = nullptr;
if (bridgedToObjectiveCConformance) {
// The conformance to _BridgedToObjectiveC is statically known.
// Retrieve the bridging operation to be used if a static conformance
// to _BridgedToObjectiveC can be proven.
fn = conditional
? tc.Context.getConditionallyBridgeFromObjectiveCBridgeable(&tc)
: tc.Context.getForceBridgeFromObjectiveCBridgeable(&tc);
} else {
// Retrieve the bridging operation to be used if a static conformance
// to _BridgedToObjectiveC cannot be proven.
fn = conditional ? tc.Context.getConditionallyBridgeFromObjectiveC(&tc)
: tc.Context.getForceBridgeFromObjectiveC(&tc);
}
if (!fn) {
tc.diagnose(object->getLoc(), diag::missing_bridging_function,
conditional);
return nullptr;
}
tc.validateDecl(fn);
// Form a reference to the function. The bridging operations are generic,
// so we need to form substitutions and compute the resulting type.
auto Conformances =
tc.Context.AllocateUninitialized<ProtocolConformanceRef>(
bridgedToObjectiveCConformance ? 1 : 0);
if (bridgedToObjectiveCConformance) {
Conformances[0] = *bridgedToObjectiveCConformance;
}
auto fnGenericParams
= fn->getGenericSignatureOfContext()->getGenericParams();
Substitution Subs[1] = {
Substitution(valueType, Conformances)
};
ConcreteDeclRef fnSpecRef(tc.Context, fn, Subs);
auto fnRef = new (tc.Context) DeclRefExpr(fnSpecRef,
DeclNameLoc(
object->getStartLoc()),
/*Implicit=*/true);
fnRef->setFunctionRefKind(FunctionRefKind::SingleApply);
TypeSubstitutionMap subMap;
auto genericParam = fnGenericParams[0];
subMap[genericParam->getCanonicalType()->castTo<SubstitutableType>()]
= valueType;
cs.setType(fnRef, fn->getInterfaceType().subst(dc->getParentModule(),
subMap,
None));
// Form the arguments.
Expr *args[2] = {
object,
cs.cacheType(new (tc.Context) DotSelfExpr(
cs.cacheType(
TypeExpr::createImplicitHack(object->getLoc(),
valueType,
tc.Context)),
object->getLoc(), object->getLoc(),
MetatypeType::get(valueType)))
};
args[1]->setImplicit();
// Form the call and type-check it.
Expr *call = CallExpr::createImplicit(tc.Context, fnRef, args,
{ Identifier(), Identifier() });
if (tc.typeCheckExpressionShallow(call, dc))
return nullptr;
cs.cacheExprTypes(call);
return call;
}
/// Bridge the given object from Objective-C to its value type.
///
/// This routine should only be used for bridging value types.
///
/// \param object The object, whose type should already be of the type
/// that the value type bridges through.
///
/// \param valueType The value type to which we are bridging.
///
/// \returns a value of type \c valueType that stores the bridged result.
Expr *forceBridgeFromObjectiveC(Expr *object, Type valueType) {
return bridgeFromObjectiveC(object, valueType, false);
}
TypeAliasDecl *MaxIntegerTypeDecl = nullptr;
TypeAliasDecl *MaxFloatTypeDecl = nullptr;
public:
ExprRewriter(ConstraintSystem &cs, const Solution &solution,
bool suppressDiagnostics, bool skipClosures)
: cs(cs), dc(cs.DC), solution(solution),
SuppressDiagnostics(suppressDiagnostics),
SkipClosures(skipClosures) { }
ConstraintSystem &getConstraintSystem() const { return cs; }
/// \brief Simplify the expression type and return the expression.
///
/// This routine is used for 'simple' expressions that only need their
/// types simplified, with no further computation.
Expr *simplifyExprType(Expr *expr) {
auto toType = simplifyType(cs.getType(expr));
cs.setType(expr, toType);
return expr;
}
Expr *visitErrorExpr(ErrorExpr *expr) {
// Do nothing with error expressions.
return expr;
}
Expr *visitCodeCompletionExpr(CodeCompletionExpr *expr) {
// Do nothing with code completion expressions.
return expr;
}
Expr *handleIntegerLiteralExpr(LiteralExpr *expr) {
// If the literal has been assigned a builtin integer type,
// don't mess with it.
if (cs.getType(expr)->is<BuiltinIntegerType>())
return expr;
auto &tc = cs.getTypeChecker();
ProtocolDecl *protocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByIntegerLiteral);
ProtocolDecl *builtinProtocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByBuiltinIntegerLiteral);
// For type-sugar reasons, prefer the spelling of the default literal
// type.
auto type = simplifyType(cs.getType(expr));
if (auto defaultType = tc.getDefaultType(protocol, dc)) {
if (defaultType->isEqual(type))
type = defaultType;
}
if (auto floatProtocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByFloatLiteral)) {
if (auto defaultFloatType = tc.getDefaultType(floatProtocol, dc)) {
if (defaultFloatType->isEqual(type))
type = defaultFloatType;
}
}
// Find the maximum-sized builtin integer type.
if (!MaxIntegerTypeDecl) {
SmallVector<ValueDecl *, 1> lookupResults;
tc.getStdlibModule(dc)->lookupValue(/*filter=*/{},
tc.Context.Id_MaxBuiltinIntegerType,
NLKind::QualifiedLookup,
lookupResults);
if (lookupResults.size() == 1) {
MaxIntegerTypeDecl = dyn_cast<TypeAliasDecl>(lookupResults.front());
tc.validateDecl(MaxIntegerTypeDecl);
}
}
if (!MaxIntegerTypeDecl ||
!MaxIntegerTypeDecl->hasUnderlyingType() ||
!MaxIntegerTypeDecl->getUnderlyingType()->is<BuiltinIntegerType>()) {
tc.diagnose(expr->getLoc(), diag::no_MaxBuiltinIntegerType_found);
return nullptr;
}
tc.validateDecl(MaxIntegerTypeDecl);
auto maxType = MaxIntegerTypeDecl->getUnderlyingType();
DeclName initName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_integerLiteral });
DeclName builtinInitName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_builtinIntegerLiteral });
return convertLiteral(
expr,
type,
cs.getType(expr),
protocol,
tc.Context.Id_IntegerLiteralType,
initName,
builtinProtocol,
maxType,
builtinInitName,
nullptr,
diag::integer_literal_broken_proto,
diag::builtin_integer_literal_broken_proto);
}
Expr *visitNilLiteralExpr(NilLiteralExpr *expr) {
auto &tc = cs.getTypeChecker();
auto *protocol = tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByNilLiteral);
// For type-sugar reasons, prefer the spelling of the default literal
// type.
auto type = simplifyType(cs.getType(expr));
if (auto defaultType = tc.getDefaultType(protocol, dc)) {
if (defaultType->isEqual(type))
type = defaultType;
}
DeclName initName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_nilLiteral });
return convertLiteral(expr, type, cs.getType(expr), protocol,
Identifier(), initName,
nullptr, Identifier(),
Identifier(),
[] (Type type) -> bool {
return false;
},
diag::nil_literal_broken_proto,
diag::nil_literal_broken_proto);
}
Expr *visitIntegerLiteralExpr(IntegerLiteralExpr *expr) {
return handleIntegerLiteralExpr(expr);
}
Expr *visitFloatLiteralExpr(FloatLiteralExpr *expr) {
// If the literal has been assigned a builtin float type,
// don't mess with it.
if (cs.getType(expr)->is<BuiltinFloatType>())
return expr;
auto &tc = cs.getTypeChecker();
ProtocolDecl *protocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByFloatLiteral);
ProtocolDecl *builtinProtocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByBuiltinFloatLiteral);
// For type-sugar reasons, prefer the spelling of the default literal
// type.
auto type = simplifyType(cs.getType(expr));
if (auto defaultType = tc.getDefaultType(protocol, dc)) {
if (defaultType->isEqual(type))
type = defaultType;
}
// Find the maximum-sized builtin float type.
// FIXME: Cache name lookup.
if (!MaxFloatTypeDecl) {
SmallVector<ValueDecl *, 1> lookupResults;
tc.getStdlibModule(dc)->lookupValue(/*filter=*/{},
tc.Context.Id_MaxBuiltinFloatType,
NLKind::QualifiedLookup,
lookupResults);
if (lookupResults.size() == 1)
MaxFloatTypeDecl = dyn_cast<TypeAliasDecl>(lookupResults.front());
}
if (!MaxFloatTypeDecl ||
!MaxFloatTypeDecl->hasUnderlyingType() ||
!MaxFloatTypeDecl->getUnderlyingType()->is<BuiltinFloatType>()) {
tc.diagnose(expr->getLoc(), diag::no_MaxBuiltinFloatType_found);
return nullptr;
}
tc.validateDecl(MaxFloatTypeDecl);
auto maxType = MaxFloatTypeDecl->getUnderlyingType();
DeclName initName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_floatLiteral });
DeclName builtinInitName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_builtinFloatLiteral });
return convertLiteral(
expr,
type,
cs.getType(expr),
protocol,
tc.Context.Id_FloatLiteralType,
initName,
builtinProtocol,
maxType,
builtinInitName,
nullptr,
diag::float_literal_broken_proto,
diag::builtin_float_literal_broken_proto);
}
Expr *visitBooleanLiteralExpr(BooleanLiteralExpr *expr) {
if (cs.getType(expr) && cs.getType(expr)->is<BuiltinIntegerType>())
return expr;
auto &tc = cs.getTypeChecker();
ProtocolDecl *protocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByBooleanLiteral);
ProtocolDecl *builtinProtocol
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByBuiltinBooleanLiteral);
if (!protocol || !builtinProtocol)
return nullptr;
auto type = simplifyType(cs.getType(expr));
DeclName initName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_booleanLiteral });
DeclName builtinInitName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_builtinBooleanLiteral });
return convertLiteral(
expr,
type,
cs.getType(expr),
protocol,
tc.Context.Id_BooleanLiteralType,
initName,
builtinProtocol,
Type(BuiltinIntegerType::get(BuiltinIntegerWidth::fixed(1),
tc.Context)),
builtinInitName,
nullptr,
diag::boolean_literal_broken_proto,
diag::builtin_boolean_literal_broken_proto);
}
Expr *handleStringLiteralExpr(LiteralExpr *expr) {
if (cs.getType(expr) && !cs.getType(expr)->hasTypeVariable())
return expr;
auto stringLiteral = dyn_cast<StringLiteralExpr>(expr);
auto magicLiteral = dyn_cast<MagicIdentifierLiteralExpr>(expr);
assert(bool(stringLiteral) != bool(magicLiteral) &&
"literal must be either a string literal or a magic literal");
auto type = simplifyType(cs.getType(expr));
auto &tc = cs.getTypeChecker();
bool isStringLiteral = true;
bool isGraphemeClusterLiteral = false;
ProtocolDecl *protocol = tc.getProtocol(
expr->getLoc(), KnownProtocolKind::ExpressibleByStringLiteral);
if (!tc.conformsToProtocol(type, protocol, cs.DC,
ConformanceCheckFlags::InExpression)) {
// If the type does not conform to ExpressibleByStringLiteral, it should
// be ExpressibleByExtendedGraphemeClusterLiteral.
protocol = tc.getProtocol(
expr->getLoc(),
KnownProtocolKind::ExpressibleByExtendedGraphemeClusterLiteral);
isStringLiteral = false;
isGraphemeClusterLiteral = true;
}
if (!tc.conformsToProtocol(type, protocol, cs.DC,
ConformanceCheckFlags::InExpression)) {
// ... or it should be ExpressibleByUnicodeScalarLiteral.
protocol = tc.getProtocol(
expr->getLoc(),
KnownProtocolKind::ExpressibleByUnicodeScalarLiteral);
isStringLiteral = false;
isGraphemeClusterLiteral = false;
}
// For type-sugar reasons, prefer the spelling of the default literal
// type.
if (auto defaultType = tc.getDefaultType(protocol, dc)) {
if (defaultType->isEqual(type))
type = defaultType;
}
ProtocolDecl *builtinProtocol;
Identifier literalType;
DeclName literalFuncName;
DeclName builtinLiteralFuncName;
Diag<> brokenProtocolDiag;
Diag<> brokenBuiltinProtocolDiag;
if (isStringLiteral) {
// If the string contains only ASCII, force a UTF8 representation
bool forceASCII = stringLiteral != nullptr;
if (forceASCII) {
for (auto c: stringLiteral->getValue()) {
if (c & (1 << 7)) {
forceASCII = false;
break;
}
}
}
literalType = tc.Context.Id_StringLiteralType;
literalFuncName = DeclName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_stringLiteral });
// If the string contains non-ASCII and the type can handle
// UTF-16 string literals, prefer them.
builtinProtocol = tc.getProtocol(
expr->getLoc(),
KnownProtocolKind::ExpressibleByBuiltinUTF16StringLiteral);
if (!forceASCII &&
tc.conformsToProtocol(type, builtinProtocol, cs.DC,
ConformanceCheckFlags::InExpression)) {
builtinLiteralFuncName
= DeclName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_builtinUTF16StringLiteral,
tc.Context.getIdentifier("utf16CodeUnitCount") });
if (stringLiteral)
stringLiteral->setEncoding(StringLiteralExpr::UTF16);
else
magicLiteral->setStringEncoding(StringLiteralExpr::UTF16);
} else {
// Otherwise, fall back to UTF-8.
builtinProtocol = tc.getProtocol(
expr->getLoc(),
KnownProtocolKind::ExpressibleByBuiltinStringLiteral);
builtinLiteralFuncName
= DeclName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_builtinStringLiteral,
tc.Context.getIdentifier("utf8CodeUnitCount"),
tc.Context.getIdentifier("isASCII") });
if (stringLiteral)
stringLiteral->setEncoding(StringLiteralExpr::UTF8);
else
magicLiteral->setStringEncoding(StringLiteralExpr::UTF8);
}
brokenProtocolDiag = diag::string_literal_broken_proto;
brokenBuiltinProtocolDiag = diag::builtin_string_literal_broken_proto;
} else if (isGraphemeClusterLiteral) {
literalType = tc.Context.Id_ExtendedGraphemeClusterLiteralType;
literalFuncName
= DeclName(tc.Context, tc.Context.Id_init,
{tc.Context.Id_extendedGraphemeClusterLiteral});
builtinLiteralFuncName
= DeclName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_builtinExtendedGraphemeClusterLiteral,
tc.Context.getIdentifier("utf8CodeUnitCount"),
tc.Context.getIdentifier("isASCII") });
builtinProtocol = tc.getProtocol(
expr->getLoc(),
KnownProtocolKind::ExpressibleByBuiltinExtendedGraphemeClusterLiteral);
brokenProtocolDiag =
diag::extended_grapheme_cluster_literal_broken_proto;
brokenBuiltinProtocolDiag =
diag::builtin_extended_grapheme_cluster_literal_broken_proto;
} else {
// Otherwise, we should have just one Unicode scalar.
literalType = tc.Context.Id_UnicodeScalarLiteralType;
literalFuncName
= DeclName(tc.Context, tc.Context.Id_init,
{tc.Context.Id_unicodeScalarLiteral});
builtinLiteralFuncName
= DeclName(tc.Context, tc.Context.Id_init,
{tc.Context.Id_builtinUnicodeScalarLiteral});
builtinProtocol = tc.getProtocol(
expr->getLoc(),
KnownProtocolKind::ExpressibleByBuiltinUnicodeScalarLiteral);
brokenProtocolDiag = diag::unicode_scalar_literal_broken_proto;
brokenBuiltinProtocolDiag =
diag::builtin_unicode_scalar_literal_broken_proto;
stringLiteral->setEncoding(StringLiteralExpr::OneUnicodeScalar);
}
return convertLiteralInPlace(expr,
type,
protocol,
literalType,
literalFuncName,
builtinProtocol,
builtinLiteralFuncName,
brokenProtocolDiag,
brokenBuiltinProtocolDiag);
}
Expr *visitStringLiteralExpr(StringLiteralExpr *expr) {
return handleStringLiteralExpr(expr);
}
Expr *
visitInterpolatedStringLiteralExpr(InterpolatedStringLiteralExpr *expr) {
// Figure out the string type we're converting to.
auto openedType = cs.getType(expr);
auto type = simplifyType(openedType);
cs.setType(expr, type);
// Find the string interpolation protocol we need.
auto &tc = cs.getTypeChecker();
auto interpolationProto
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByStringInterpolation);
assert(interpolationProto && "Missing string interpolation protocol?");
DeclName name(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_stringInterpolation });
auto member
= findNamedWitnessImpl<ConstructorDecl>(
tc, dc, type,
interpolationProto, name,
diag::interpolation_broken_proto);
DeclName segmentName(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_stringInterpolationSegment });
auto segmentMember
= findNamedWitnessImpl<ConstructorDecl>(
tc, dc, type, interpolationProto, segmentName,
diag::interpolation_broken_proto);
if (!member || !segmentMember)
return nullptr;
// Build a reference to the init(stringInterpolation:) initializer.
// FIXME: This location info is bogus.
auto *typeRef =
cs.cacheType(TypeExpr::createImplicitHack(expr->getStartLoc(),
type, tc.Context));
Expr *memberRef =
new (tc.Context) MemberRefExpr(typeRef,
expr->getStartLoc(),
member,
DeclNameLoc(expr->getStartLoc()),
/*Implicit=*/true);
bool failed = tc.typeCheckExpressionShallow(memberRef, cs.DC);
cs.cacheExprTypes(memberRef);
assert(!failed && "Could not reference string interpolation witness");
(void)failed;
// Create a tuple containing all of the segments.
SmallVector<Expr *, 4> segments;
SmallVector<Identifier, 4> names;
unsigned index = 0;
ConstraintLocatorBuilder locatorBuilder(cs.getConstraintLocator(expr));
for (auto segment : expr->getSegments()) {
auto locator = cs.getConstraintLocator(
locatorBuilder.withPathElement(
LocatorPathElt::getInterpolationArgument(index++)));
// Find the initializer we chose.
auto choice = getOverloadChoice(locator);
auto memberRef = buildMemberRef(
typeRef, choice.openedFullType,
segment->getStartLoc(), choice.choice.getDecl(),
DeclNameLoc(segment->getStartLoc()),
choice.openedType,
locator, locator, /*Implicit=*/true,
choice.choice.getFunctionRefKind(),
AccessSemantics::Ordinary,
/*isDynamic=*/false);
ApplyExpr *apply =
CallExpr::createImplicit(
tc.Context, memberRef,
{ segment },
{ tc.Context.Id_stringInterpolationSegment });
cs.cacheType(apply->getArg());
auto converted = finishApply(apply, openedType, locatorBuilder);
if (!converted)
return nullptr;
segments.push_back(converted);
if (index == 1) {
names.push_back(tc.Context.Id_stringInterpolation);
} else {
names.push_back(Identifier());
}
}
// Call the init(stringInterpolation:) initializer with the arguments.
ApplyExpr *apply = CallExpr::createImplicit(tc.Context, memberRef,
segments, names);
cs.cacheSubExprTypes(apply);
expr->setSemanticExpr(finishApply(apply, openedType, locatorBuilder));
return expr;
}
Expr *visitMagicIdentifierLiteralExpr(MagicIdentifierLiteralExpr *expr) {
switch (expr->getKind()) {
case MagicIdentifierLiteralExpr::File:
case MagicIdentifierLiteralExpr::Function:
return handleStringLiteralExpr(expr);
case MagicIdentifierLiteralExpr::Line:
case MagicIdentifierLiteralExpr::Column:
return handleIntegerLiteralExpr(expr);
case MagicIdentifierLiteralExpr::DSOHandle:
return expr;
}
llvm_unreachable("Unhandled MagicIdentifierLiteralExpr in switch.");
}
Expr *visitObjectLiteralExpr(ObjectLiteralExpr *expr) {
if (cs.getType(expr) && !cs.getType(expr)->hasTypeVariable())
return expr;
auto &ctx = cs.getASTContext();
auto &tc = cs.getTypeChecker();
// Figure out the type we're converting to.
auto openedType = cs.getType(expr);
auto type = simplifyType(openedType);
cs.setType(expr, type);
if (type->is<UnresolvedType>()) return expr;
Type conformingType = type;
if (auto baseType = conformingType->getAnyOptionalObjectType()) {
// The type may be optional due to a failable initializer in the
// protocol.
conformingType = baseType;
}
// Find the appropriate object literal protocol.
auto proto = tc.getLiteralProtocol(expr);
assert(proto && "Missing object literal protocol?");
auto conformance =
tc.conformsToProtocol(conformingType, proto, cs.DC,
ConformanceCheckFlags::InExpression);
assert(conformance && "object literal type conforms to protocol");
Expr *base =
cs.cacheType(TypeExpr::createImplicitHack(expr->getLoc(),
conformingType,
ctx));
SmallVector<Expr *, 4> args;
if (!isa<TupleExpr>(expr->getArg()))
return nullptr;
auto tupleArg = cast<TupleExpr>(expr->getArg());
for (auto elt : tupleArg->getElements())
args.push_back(elt);
DeclName constrName(tc.getObjectLiteralConstructorName(expr));
Expr *semanticExpr = tc.callWitness(base, dc, proto, *conformance,
constrName, args,
diag::object_literal_broken_proto);
expr->setSemanticExpr(semanticExpr);
return expr;
}
Expr *visitDeclRefExpr(DeclRefExpr *expr) {
auto locator = cs.getConstraintLocator(expr);
// Find the overload choice used for this declaration reference.
auto selected = getOverloadChoiceIfAvailable(locator);
if (!selected.hasValue()) {
auto *varDecl = cast<VarDecl>(expr->getDecl());
assert(varDecl->getType()->is<UnresolvedType>() &&
"should only happen for closure arguments in CSDiags");
cs.setType(expr, varDecl->getType());
return expr;
}
auto choice = selected->choice;
auto decl = choice.getDecl();
// FIXME: Cannibalize the existing DeclRefExpr rather than allocating a
// new one?
return buildDeclRef(decl, expr->getNameLoc(), selected->openedFullType,
locator, expr->isSpecialized(),
expr->isImplicit(),
expr->getFunctionRefKind(),
expr->getAccessSemantics());
}
Expr *visitSuperRefExpr(SuperRefExpr *expr) {
simplifyExprType(expr);
return expr;
}
Expr *visitTypeExpr(TypeExpr *expr) {
auto toType = simplifyType(expr->getTypeLoc().getType());
expr->getTypeLoc().setType(toType, /*validated=*/true);
cs.setType(expr, MetatypeType::get(toType));
return expr;
}
Expr *visitOtherConstructorDeclRefExpr(OtherConstructorDeclRefExpr *expr) {
assert(!expr->getDeclRef().isSpecialized());
cs.setType(expr, expr->getDecl()->getInitializerInterfaceType());
return expr;
}
Expr *visitDotSyntaxBaseIgnoredExpr(DotSyntaxBaseIgnoredExpr *expr) {
return simplifyExprType(expr);
}
Expr *visitOverloadedDeclRefExpr(OverloadedDeclRefExpr *expr) {
// Determine the declaration selected for this overloaded reference.
auto locator = cs.getConstraintLocator(expr);
auto selected = getOverloadChoice(locator);
auto choice = selected.choice;
auto decl = choice.getDecl();
return buildDeclRef(decl, expr->getNameLoc(), selected.openedFullType,
locator, expr->isSpecialized(), expr->isImplicit(),
choice.getFunctionRefKind(),
AccessSemantics::Ordinary);
}
Expr *visitUnresolvedDeclRefExpr(UnresolvedDeclRefExpr *expr) {
// FIXME: We should have generated an overload set from this, in which
// case we can emit a typo-correction error here but recover well.
return nullptr;
}
Expr *visitUnresolvedSpecializeExpr(UnresolvedSpecializeExpr *expr) {
// Our specializations should have resolved the subexpr to the right type.
if (auto DRE = dyn_cast<DeclRefExpr>(expr->getSubExpr())) {
assert(DRE->getGenericArgs().empty() ||
DRE->getGenericArgs().size() == expr->getUnresolvedParams().size());
if (DRE->getGenericArgs().empty()) {
SmallVector<TypeRepr *, 8> GenArgs;
for (auto TL : expr->getUnresolvedParams())
GenArgs.push_back(TL.getTypeRepr());
DRE->setGenericArgs(GenArgs);
}
}
return expr->getSubExpr();
}
Expr *visitMemberRefExpr(MemberRefExpr *expr) {
auto memberLocator = cs.getConstraintLocator(expr,
ConstraintLocator::Member);
auto selected = getOverloadChoice(memberLocator);
bool isDynamic
= selected.choice.getKind() == OverloadChoiceKind::DeclViaDynamic;
return buildMemberRef(expr->getBase(),
selected.openedFullType,
expr->getDotLoc(),
selected.choice.getDecl(), expr->getNameLoc(),
selected.openedType,
cs.getConstraintLocator(expr),
memberLocator,
expr->isImplicit(),
selected.choice.getFunctionRefKind(),
expr->getAccessSemantics(),
isDynamic);
}
Expr *visitDynamicMemberRefExpr(DynamicMemberRefExpr *expr) {
llvm_unreachable("already type-checked?");
}
Expr *visitUnresolvedMemberExpr(UnresolvedMemberExpr *expr) {
// Dig out the type of the base, which will be the result type of this
// expression. If constraint solving resolved this to an UnresolvedType,
// then we're in an ambiguity tolerant mode used for diagnostic
// generation. Just leave this as an unresolved member reference.
Type resultTy = simplifyType(cs.getType(expr));
if (resultTy->getRValueType()->is<UnresolvedType>()) {
cs.setType(expr, resultTy);
return expr;
}
Type baseTy = resultTy->getRValueType();
auto &tc = cs.getTypeChecker();
// Find the selected member.
auto memberLocator = cs.getConstraintLocator(
expr, ConstraintLocator::UnresolvedMember);
auto selected = getOverloadChoice(memberLocator);
auto member = selected.choice.getDecl();
// If the member came by optional unwrapping, then unwrap the base type.
if (selected.choice.getKind()
== OverloadChoiceKind::DeclViaUnwrappedOptional) {
baseTy = baseTy->getAnyOptionalObjectType();
assert(baseTy
&& "got unwrapped optional decl from non-optional base?!");
}
// The base expression is simply the metatype of the base type.
// FIXME: This location info is bogus.
auto base =
cs.cacheType(TypeExpr::createImplicitHack(expr->getDotLoc(),
baseTy, tc.Context));
// Build the member reference.
bool isDynamic
= selected.choice.getKind() == OverloadChoiceKind::DeclViaDynamic;
auto result = buildMemberRef(base,
selected.openedFullType,
expr->getDotLoc(), member,
expr->getNameLoc(),
selected.openedType,
cs.getConstraintLocator(expr),
memberLocator,
expr->isImplicit(),
selected.choice.getFunctionRefKind(),
AccessSemantics::Ordinary,
isDynamic);
if (!result)
return nullptr;
// If there was an argument, apply it.
if (auto arg = expr->getArgument()) {
ApplyExpr *apply = CallExpr::create(tc.Context, result, arg,
expr->getArgumentLabels(),
expr->getArgumentLabelLocs(),
expr->hasTrailingClosure(),
/*implicit=*/false);
result = finishApply(apply, Type(), cs.getConstraintLocator(expr));
}
result = coerceToType(result, resultTy, cs.getConstraintLocator(expr));
return result;
}
private:
/// A list of "suspicious" optional injections that come from
/// forced downcasts.
SmallVector<InjectIntoOptionalExpr *, 4> SuspiciousOptionalInjections;
public:
/// A list of optional injections that have been diagnosed.
llvm::SmallPtrSet<InjectIntoOptionalExpr *, 4> DiagnosedOptionalInjections;
private:
/// Create a member reference to the given constructor.
Expr *applyCtorRefExpr(Expr *expr, Expr *base, SourceLoc dotLoc,
DeclNameLoc nameLoc, bool implicit,
ConstraintLocator *ctorLocator,
ConstructorDecl *ctor,
FunctionRefKind functionRefKind,
Type openedType) {
// If the subexpression is a metatype, build a direct reference to the
// constructor.
if (cs.getType(base)->is<AnyMetatypeType>()) {
return buildMemberRef(base, openedType, dotLoc, ctor, nameLoc,
cs.getType(expr),
ConstraintLocatorBuilder(
cs.getConstraintLocator(expr)),
ctorLocator,
implicit,
functionRefKind,
AccessSemantics::Ordinary,
/*isDynamic=*/false);
}
// The subexpression must be either 'self' or 'super'.
if (!base->isSuperExpr()) {
// 'super' references have already been fully checked; handle the
// 'self' case below.
auto &tc = cs.getTypeChecker();
bool diagnoseBadInitRef = true;
auto arg = base->getSemanticsProvidingExpr();
if (auto dre = dyn_cast<DeclRefExpr>(arg)) {
if (dre->getDecl()->getName() == cs.getASTContext().Id_self) {
// We have a reference to 'self'.
diagnoseBadInitRef = false;
// Make sure the reference to 'self' occurs within an initializer.
if (!dyn_cast_or_null<ConstructorDecl>(
cs.DC->getInnermostMethodContext())) {
if (!SuppressDiagnostics)
tc.diagnose(dotLoc, diag::init_delegation_outside_initializer);
return nullptr;
}
}
}
// If we need to diagnose this as a bad reference to an initializer,
// do so now.
if (diagnoseBadInitRef) {
// Determine whether 'super' would have made sense as a base.
bool hasSuper = false;
if (auto func = cs.DC->getInnermostMethodContext()) {
if (auto nominalType
= func->getDeclContext()->getDeclaredTypeOfContext()) {
if (auto classDecl = nominalType->getClassOrBoundGenericClass()) {
hasSuper = classDecl->hasSuperclass();
}
}
}
if (SuppressDiagnostics)
return nullptr;
tc.diagnose(dotLoc, diag::bad_init_ref_base, hasSuper);
}
}
// Build a partial application of the delegated initializer.
Expr *ctorRef = buildOtherConstructorRef(openedType, ctor, nameLoc,
ctorLocator, implicit);
auto *call = new (cs.getASTContext()) DotSyntaxCallExpr(ctorRef, dotLoc,
base);
return finishApply(call, cs.getType(expr),
ConstraintLocatorBuilder(
cs.getConstraintLocator(expr)));
}
Expr *applyMemberRefExpr(Expr *expr, Expr *base, SourceLoc dotLoc,
DeclNameLoc nameLoc, bool implicit) {
// If we have a constructor member, handle it as a constructor.
auto ctorLocator = cs.getConstraintLocator(
expr,
ConstraintLocator::ConstructorMember);
if (auto selected = getOverloadChoiceIfAvailable(ctorLocator)) {
auto choice = selected->choice;
auto *ctor = cast<ConstructorDecl>(choice.getDecl());
return applyCtorRefExpr(expr, base, dotLoc, nameLoc, implicit,
ctorLocator, ctor, choice.getFunctionRefKind(),
selected->openedFullType);
}
// Determine the declaration selected for this overloaded reference.
auto memberLocator = cs.getConstraintLocator(expr,
ConstraintLocator::Member);
auto selectedElt = getOverloadChoiceIfAvailable(memberLocator);
if (!selectedElt) {
// If constraint solving resolved this to an UnresolvedType, then we're
// in an ambiguity tolerant mode used for diagnostic generation. Just
// leave this as whatever type of member reference it already is.
Type resultTy = simplifyType(cs.getType(expr));
cs.setType(expr, resultTy);
return expr;
}
auto selected = *selectedElt;
switch (selected.choice.getKind()) {
case OverloadChoiceKind::DeclViaBridge: {
// Look through an implicitly unwrapped optional.
auto baseTy = cs.getType(base)->getRValueType();
if (auto objTy = cs.lookThroughImplicitlyUnwrappedOptionalType(baseTy)){
base = coerceImplicitlyUnwrappedOptionalToValue(base, objTy,
cs.getConstraintLocator(base));
baseTy = cs.getType(base)->getRValueType();
}
if (auto baseMetaTy = baseTy->getAs<MetatypeType>()) {
auto &tc = cs.getTypeChecker();
auto &ctx = tc.Context;
auto classTy = ctx.getBridgedToObjC(cs.DC,
baseMetaTy->getInstanceType());
// FIXME: We're dropping side effects in the base here!
base =
cs.cacheType(TypeExpr::createImplicitHack(base->getLoc(), classTy,
tc.Context));
} else {
// Bridge the base to its corresponding Objective-C object.
base = bridgeToObjectiveC(base);
}
// Fall through to build the member reference.
SWIFT_FALLTHROUGH;
}
case OverloadChoiceKind::Decl:
case OverloadChoiceKind::DeclViaUnwrappedOptional:
case OverloadChoiceKind::DeclViaDynamic: {
bool isDynamic
= selected.choice.getKind() == OverloadChoiceKind::DeclViaDynamic;
auto member = buildMemberRef(base,
selected.openedFullType,
dotLoc,
selected.choice.getDecl(),
nameLoc,
selected.openedType,
cs.getConstraintLocator(expr),
memberLocator,
implicit,
selected.choice.getFunctionRefKind(),
AccessSemantics::Ordinary,
isDynamic);
return member;
}
case OverloadChoiceKind::TupleIndex: {
auto baseTy = cs.getType(base)->getRValueType();
if (auto objTy = cs.lookThroughImplicitlyUnwrappedOptionalType(baseTy)){
base = coerceImplicitlyUnwrappedOptionalToValue(base, objTy,
cs.getConstraintLocator(base));
}
Type toType = simplifyType(cs.getType(expr));
// If the result type is an rvalue and the base contains lvalues, need a full
// tuple coercion to properly load & set access kind on all underlying elements
// before taking a single element.
baseTy = cs.getType(base);
if (!toType->isLValueType() && baseTy->isLValueType())
base = coerceToType(base, baseTy->getRValueType(), cs.getConstraintLocator(base));
return cs.cacheType(new (cs.getASTContext())
TupleElementExpr(base, dotLoc,
selected.choice.getTupleIndex(),
nameLoc.getBaseNameLoc(), toType));
}
case OverloadChoiceKind::BaseType: {
// FIXME: Losing ".0" sugar here.
return base;
}
case OverloadChoiceKind::TypeDecl:
llvm_unreachable("Nonsensical overload choice");
}
llvm_unreachable("Unhandled OverloadChoiceKind in switch.");
}
public:
Expr *visitUnresolvedDotExpr(UnresolvedDotExpr *expr) {
return applyMemberRefExpr(expr, expr->getBase(), expr->getDotLoc(),
expr->getNameLoc(), expr->isImplicit());
}
Expr *visitSequenceExpr(SequenceExpr *expr) {
llvm_unreachable("Expression wasn't parsed?");
}
Expr *visitArrowExpr(ArrowExpr *expr) {
llvm_unreachable("Arrow expr wasn't converted to type?");
}
Expr *visitIdentityExpr(IdentityExpr *expr) {
cs.setType(expr, cs.getType(expr->getSubExpr()));
return expr;
}
Expr *visitAnyTryExpr(AnyTryExpr *expr) {
cs.setType(expr, cs.getType(expr->getSubExpr()));
return expr;
}
Expr *visitOptionalTryExpr(OptionalTryExpr *expr) {
return simplifyExprType(expr);
}
Expr *visitParenExpr(ParenExpr *expr) {
auto &ctx = cs.getASTContext();
cs.setType(expr, ParenType::get(ctx, cs.getType(expr->getSubExpr())));
return expr;
}
Expr *visitTupleExpr(TupleExpr *expr) {
return simplifyExprType(expr);
}
Expr *visitSubscriptExpr(SubscriptExpr *expr) {
return buildSubscript(expr->getBase(), expr->getIndex(),
expr->getArgumentLabels(),
expr->hasTrailingClosure(),
cs.getConstraintLocator(expr),
expr->isImplicit(),
expr->getAccessSemantics());
}
Expr *visitArrayExpr(ArrayExpr *expr) {
Type openedType = cs.getType(expr);
Type arrayTy = simplifyType(openedType);
auto &tc = cs.getTypeChecker();
ProtocolDecl *arrayProto
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByArrayLiteral);
assert(arrayProto && "type-checked array literal w/o protocol?!");
auto conformance =
tc.conformsToProtocol(arrayTy, arrayProto, cs.DC,
ConformanceCheckFlags::InExpression);
assert(conformance && "Type does not conform to protocol?");
// Call the witness that builds the array literal.
// FIXME: callWitness() may end up re-doing some work we already did
// to convert the array literal elements to the element type. It would
// be nicer to re-use them.
// FIXME: This location info is bogus.
Expr *typeRef =
cs.cacheType(TypeExpr::createImplicitHack(expr->getLoc(),
arrayTy, tc.Context));
DeclName name(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_arrayLiteral });
// Restructure the argument to provide the appropriate labels in the
// tuple.
SmallVector<TupleTypeElt, 4> typeElements;
SmallVector<Identifier, 4> names;
bool first = true;
for (auto elt : expr->getElements()) {
if (first) {
typeElements.push_back(TupleTypeElt(cs.getType(elt),
tc.Context.Id_arrayLiteral));
names.push_back(tc.Context.Id_arrayLiteral);
first = false;
continue;
}
typeElements.push_back(cs.getType(elt));
names.push_back(Identifier());
}
Type argType = TupleType::get(typeElements, tc.Context);
Expr *arg = cs.cacheType(
TupleExpr::create(tc.Context, SourceLoc(),
expr->getElements(),
names,
{ },
SourceLoc(), /*HasTrailingClosure=*/false,
/*Implicit=*/true,
argType));
Expr *result = tc.callWitness(typeRef, dc, arrayProto, *conformance,
name, arg, diag::array_protocol_broken);
if (!result)
return nullptr;
expr->setSemanticExpr(result);
cs.setType(expr, arrayTy);
cs.cacheSubExprTypes(expr);
// If the array element type was defaulted, note that in the expression.
if (solution.DefaultedConstraints.count(cs.getConstraintLocator(expr)))
expr->setIsTypeDefaulted();
return expr;
}
Expr *visitDictionaryExpr(DictionaryExpr *expr) {
Type openedType = cs.getType(expr);
Type dictionaryTy = simplifyType(openedType);
auto &tc = cs.getTypeChecker();
ProtocolDecl *dictionaryProto
= tc.getProtocol(expr->getLoc(),
KnownProtocolKind::ExpressibleByDictionaryLiteral);
auto conformance =
tc.conformsToProtocol(dictionaryTy, dictionaryProto, cs.DC,
ConformanceCheckFlags::InExpression);
if (!conformance)
return nullptr;
// Call the witness that builds the dictionary literal.
// FIXME: callWitness() may end up re-doing some work we already did
// to convert the dictionary literal elements to the (key, value) tuple.
// It would be nicer to re-use them.
// FIXME: Cache the name.
// FIXME: This location info is bogus.
Expr *typeRef =
cs.cacheType(TypeExpr::createImplicitHack(expr->getLoc(),
dictionaryTy, tc.Context));
DeclName name(tc.Context, tc.Context.Id_init,
{ tc.Context.Id_dictionaryLiteral });
// Restructure the argument to provide the appropriate labels in the
// tuple.
SmallVector<TupleTypeElt, 4> typeElements;
SmallVector<Identifier, 4> names;
bool first = true;
for (auto elt : expr->getElements()) {
if (first) {
typeElements.push_back(TupleTypeElt(cs.getType(elt),
tc.Context.Id_dictionaryLiteral));
names.push_back(tc.Context.Id_dictionaryLiteral);
first = false;
continue;
}
typeElements.push_back(cs.getType(elt));
names.push_back(Identifier());
}
Type argType = TupleType::get(typeElements, tc.Context);
Expr *arg =
cs.cacheType(
TupleExpr::create(tc.Context, expr->getLBracketLoc(),
expr->getElements(),
names,
{ },
expr->getRBracketLoc(),
/*HasTrailingClosure=*/false,
/*Implicit=*/false,
argType));
Expr *result = tc.callWitness(typeRef, dc, dictionaryProto,
*conformance, name, arg,
diag::dictionary_protocol_broken);
if (!result)
return nullptr;
expr->setSemanticExpr(result);
cs.setType(expr, dictionaryTy);
cs.cacheSubExprTypes(expr);
// If the dictionary key or value type was defaulted, note that in the
// expression.
if (solution.DefaultedConstraints.count(cs.getConstraintLocator(expr)))
expr->setIsTypeDefaulted();
return expr;
}
Expr *visitDynamicSubscriptExpr(DynamicSubscriptExpr *expr) {
return buildSubscript(expr->getBase(), expr->getIndex(),
expr->getArgumentLabels(),
expr->hasTrailingClosure(),
cs.getConstraintLocator(expr),
expr->isImplicit(), AccessSemantics::Ordinary);
}
Expr *visitTupleElementExpr(TupleElementExpr *expr) {
// Handle accesses that implicitly look through ImplicitlyUnwrappedOptional<T>.
auto base = expr->getBase();
auto baseTy = cs.getType(base)->getRValueType();
if (auto objTy = cs.lookThroughImplicitlyUnwrappedOptionalType(baseTy)) {
base = coerceImplicitlyUnwrappedOptionalToValue(base, objTy,
cs.getConstraintLocator(base));
expr->setBase(base);
}
simplifyExprType(expr);
return expr;
}
Expr *visitCaptureListExpr(CaptureListExpr *expr) {
// The type of the capture list is the type of the closure contained
// inside it.
cs.setType(expr, cs.getType(expr->getClosureBody()));
return expr;
}
Expr *visitClosureExpr(ClosureExpr *expr) {
llvm_unreachable("Handled by the walker directly");
}
Expr *visitAutoClosureExpr(AutoClosureExpr *expr) {
llvm_unreachable("Already type-checked");
}
Expr *visitInOutExpr(InOutExpr *expr) {
// The default assumption is that inouts are read-write. It's easier
// to do this unconditionally here and then overwrite in the exception
// case (when we turn the inout into an UnsafePointer) than to try to
// discover that we're in that case right now.
if (!cs.getType(expr->getSubExpr())->is<UnresolvedType>())
cs.propagateLValueAccessKind(expr->getSubExpr(), AccessKind::ReadWrite);
auto objectTy = cs.getType(expr->getSubExpr())->getRValueType();
// The type is simply inout of whatever the lvalue's object type was.
cs.setType(expr, InOutType::get(objectTy));
return expr;
}
Expr *visitDynamicTypeExpr(DynamicTypeExpr *expr) {
Expr *base = expr->getBase();
base = cs.coerceToRValue(base);
if (!base) return nullptr;
expr->setBase(base);
return simplifyExprType(expr);
}
Expr *visitOpaqueValueExpr(OpaqueValueExpr *expr) {
llvm_unreachable("Already type-checked");
}
Expr *visitApplyExpr(ApplyExpr *expr) {
return finishApply(expr, cs.getType(expr),
ConstraintLocatorBuilder(
cs.getConstraintLocator(expr)));
}
Expr *visitRebindSelfInConstructorExpr(RebindSelfInConstructorExpr *expr) {
// A non-failable initializer cannot delegate to a failable
// initializer.
OptionalTypeKind calledOTK;
Expr *unwrappedSubExpr = expr->getSubExpr()->getSemanticsProvidingExpr();
Type valueTy
= cs.getType(unwrappedSubExpr)->getAnyOptionalObjectType(calledOTK);
auto inCtor = cast<ConstructorDecl>(cs.DC->getInnermostMethodContext());
if (calledOTK != OTK_None && inCtor->getFailability() == OTK_None) {
bool isError = (calledOTK == OTK_Optional);
// If we're suppressing diagnostics, just fail.
if (isError && SuppressDiagnostics)
return nullptr;
bool isChaining;
auto *otherCtorRef = expr->getCalledConstructor(isChaining);
auto &tc = cs.getTypeChecker();
auto &ctx = tc.Context;
if (isError) {
if (auto *optTry = dyn_cast<OptionalTryExpr>(unwrappedSubExpr)) {
tc.diagnose(optTry->getTryLoc(),
diag::delegate_chain_nonoptional_to_optional_try,
isChaining);
tc.diagnose(optTry->getTryLoc(), diag::init_delegate_force_try)
.fixItReplace({optTry->getTryLoc(), optTry->getQuestionLoc()},
"try!");
tc.diagnose(inCtor->getLoc(), diag::init_propagate_failure)
.fixItInsertAfter(inCtor->getLoc(), "?");
} else {
// Give the user the option of adding '!' or making the enclosing
// initializer failable.
ConstructorDecl *ctor = otherCtorRef->getDecl();
tc.diagnose(otherCtorRef->getLoc(),
diag::delegate_chain_nonoptional_to_optional,
isChaining, ctor->getFullName());
tc.diagnose(otherCtorRef->getLoc(), diag::init_force_unwrap)
.fixItInsertAfter(expr->getEndLoc(), "!");
tc.diagnose(inCtor->getLoc(), diag::init_propagate_failure)
.fixItInsertAfter(inCtor->getLoc(), "?");
}
}
// Recover by injecting the force operation (the first option).
Expr *newSub = new (ctx) ForceValueExpr(expr->getSubExpr(),
expr->getEndLoc());
cs.setType(newSub, valueTy);
newSub->setImplicit();
expr->setSubExpr(newSub);
}
return expr;
}
Expr *visitIfExpr(IfExpr *expr) {
auto resultTy = simplifyType(cs.getType(expr));
cs.setType(expr, resultTy);
// Convert the condition to a logic value.
auto cond
= solution.convertBooleanTypeToBuiltinI1(expr->getCondExpr(),
cs.getConstraintLocator(expr));
if (!cond) {
cs.setType(expr->getCondExpr(), ErrorType::get(resultTy));
} else {
expr->setCondExpr(cond);
}
// Coerce the then/else branches to the common type.
expr->setThenExpr(coerceToType(expr->getThenExpr(), resultTy,
cs.getConstraintLocator(expr->getThenExpr())));
expr->setElseExpr(coerceToType(expr->getElseExpr(), resultTy,
cs.getConstraintLocator(expr->getElseExpr())));
return expr;
}
Expr *visitImplicitConversionExpr(ImplicitConversionExpr *expr) {
llvm_unreachable("Already type-checked");
}
Expr *visitIsExpr(IsExpr *expr) {
// Turn the subexpression into an rvalue.
auto &tc = cs.getTypeChecker();
auto toType = simplifyType(expr->getCastTypeLoc().getType());
auto sub = cs.coerceToRValue(expr->getSubExpr());
if (!sub)
return nullptr;
checkForImportedUsedConformances(toType);
expr->setSubExpr(sub);
// Set the type we checked against.
expr->getCastTypeLoc().setType(toType, /*validated=*/true);
auto fromType = cs.getType(sub);
auto castKind = tc.typeCheckCheckedCast(
fromType, toType, cs.DC,
expr->getLoc(),
sub->getSourceRange(),
expr->getCastTypeLoc().getSourceRange(),
[&](Type commonTy) -> bool {
return tc.convertToType(sub, commonTy, cs.DC);
},
SuppressDiagnostics);
switch (castKind) {
case CheckedCastKind::Unresolved:
// Invalid type check.
return nullptr;
case CheckedCastKind::Coercion:
// Check is trivially true.
tc.diagnose(expr->getLoc(), diag::isa_is_always_true, "is");
expr->setCastKind(castKind);
break;
case CheckedCastKind::ValueCast:
// Check the cast target is a non-foreign type
if (auto cls = toType->getAs<ClassType>()) {
if (cls->getDecl()->getForeignClassKind() ==
ClassDecl::ForeignKind::CFType) {
tc.diagnose(expr->getLoc(), diag::isa_is_foreign_check, toType);
}
}
expr->setCastKind(castKind);
break;
case CheckedCastKind::ArrayDowncast:
case CheckedCastKind::DictionaryDowncast:
case CheckedCastKind::SetDowncast:
case CheckedCastKind::BridgeFromObjectiveC:
// Valid checks.
expr->setCastKind(castKind);
break;
}
// SIL-generation magically turns this into a Bool; make sure it can.
if (!cs.getASTContext().getGetBoolDecl(&cs.getTypeChecker())) {
tc.diagnose(expr->getLoc(), diag::bool_intrinsics_not_found);
// Continue anyway.
}
// Dig through the optionals in the from/to types.
SmallVector<Type, 2> fromOptionals;
fromType->lookThroughAllAnyOptionalTypes(fromOptionals);
SmallVector<Type, 2> toOptionals;
toType->lookThroughAllAnyOptionalTypes(toOptionals);
// If we have an imbalance of optionals or a collection
// downcast, handle this as a checked cast followed by a
// a 'hasValue' check.
if (fromOptionals.size() != toOptionals.size() ||
castKind == CheckedCastKind::ArrayDowncast ||
castKind == CheckedCastKind::DictionaryDowncast ||
castKind == CheckedCastKind::SetDowncast) {
auto toOptType = OptionalType::get(toType);
ConditionalCheckedCastExpr *cast
= new (tc.Context) ConditionalCheckedCastExpr(
sub, expr->getLoc(), SourceLoc(),
TypeLoc::withoutLoc(toType));
cs.setType(cast, toOptType);
if (expr->isImplicit())
cast->setImplicit();
// Type-check this conditional case.
Expr *result = visitConditionalCheckedCastExpr(cast);
if (!result)
return nullptr;
// Extract a Bool from the resulting expression.
return solution.convertOptionalToBool(result,
cs.getConstraintLocator(expr));
}
return expr;
}
/// Handle optional operands and results in an explicit cast.
Expr *handleOptionalBindings(ExplicitCastExpr *cast,
Type finalResultType,
bool conditionalCast) {
auto &tc = cs.getTypeChecker();
unsigned destExtraOptionals = conditionalCast ? 1 : 0;
// FIXME: some of this work needs to be delayed until runtime to
// properly account for archetypes dynamically being optional
// types. For example, if we're casting T to NSView?, that
// should succeed if T=NSObject? and its value is actually nil.
Expr *subExpr = cast->getSubExpr();
Type srcType = cs.getType(subExpr);
SmallVector<Type, 4> srcOptionals;
srcType = srcType->lookThroughAllAnyOptionalTypes(srcOptionals);
SmallVector<Type, 4> destOptionals;
auto destValueType
= finalResultType->lookThroughAllAnyOptionalTypes(destOptionals);
// Complain about conditional casts to foreign class types; they can't
// actually be conditionally checked.
if (conditionalCast) {
auto destObjectType = destValueType;
if (auto metaTy = destObjectType->getAs<MetatypeType>())
destObjectType = metaTy->getInstanceType();
if (auto destClass = destObjectType->getClassOrBoundGenericClass()) {
if (destClass->getForeignClassKind() ==
ClassDecl::ForeignKind::CFType) {
if (SuppressDiagnostics)
return nullptr;
tc.diagnose(cast->getLoc(), diag::conditional_downcast_foreign,
destValueType);
}
}
}
// There's nothing special to do if the operand isn't optional
// and we don't need any bridging.
if (srcOptionals.empty()) {
cs.setType(cast, finalResultType);
return cast;
}
// If this is a conditional cast, the result type will always
// have at least one level of optional, which should become the
// type of the checked-cast expression.
if (conditionalCast) {
assert(!destOptionals.empty() &&
"result of checked cast is not an optional type");
cs.setType(cast, destOptionals.back());
} else {
cs.setType(cast, destValueType);
}
// The result type (without the final optional) is a subtype of
// the operand type, so it will never have a higher depth.
assert(destOptionals.size() - destExtraOptionals <= srcOptionals.size());
// The outermost N levels of optionals on the operand must all
// be present or the cast fails. The innermost M levels of
// optionals on the operand are reflected in the requested
// destination type, so we should map these nils into the result.
unsigned numRequiredOptionals =
srcOptionals.size() - (destOptionals.size() - destExtraOptionals);
// The number of OptionalEvaluationExprs between the point of the
// inner cast and the enclosing OptionalEvaluationExpr (exclusive)
// which represents failure for the entire operation.
unsigned failureDepth = destOptionals.size() - destExtraOptionals;
// Drill down on the operand until it's non-optional.
SourceLoc fakeQuestionLoc = subExpr->getEndLoc();
for (unsigned i : indices(srcOptionals)) {
Type valueType =
(i + 1 == srcOptionals.size() ? srcType : srcOptionals[i+1]);
// As we move into the range of mapped optionals, start
// lowering the depth.
unsigned depth = failureDepth;
if (i >= numRequiredOptionals) {
depth -= (i - numRequiredOptionals) + 1;
} else if (!conditionalCast) {
// For a forced cast, force the required optionals.
subExpr = new (tc.Context) ForceValueExpr(subExpr, fakeQuestionLoc);
cs.setType(subExpr, valueType);
subExpr->setImplicit(true);
continue;
}
subExpr =
cs.cacheType(new (tc.Context) BindOptionalExpr(subExpr,
fakeQuestionLoc,
depth, valueType));
subExpr->setImplicit(true);
}
cast->setSubExpr(subExpr);
// If we're casting to an optional type, we need to capture the
// final M bindings.
Expr *result = cast;
if (destOptionals.size() > destExtraOptionals) {
if (conditionalCast) {
// If the innermost cast fails, the entire expression fails. To
// get this behavior, we have to bind and then re-inject the result.
// (SILGen should know how to peephole this.)
result =
cs.cacheType(new (tc.Context) BindOptionalExpr(result,
cast->getEndLoc(),
failureDepth,
destValueType));
result->setImplicit(true);
}
for (unsigned i = destOptionals.size(); i != 0; --i) {
Type destType = destOptionals[i-1];
result =
cs.cacheType(new (tc.Context) InjectIntoOptionalExpr(result,
destType));
result =
cs.cacheType(new (tc.Context) OptionalEvaluationExpr(result,
destType));
}
// Otherwise, we just need to capture the failure-depth binding.
} else if (conditionalCast) {
result =
cs.cacheType(new (tc.Context) OptionalEvaluationExpr(result,
finalResultType));
}
return result;
}
Expr *visitCoerceExpr(CoerceExpr *expr) {
// Simplify the type we're casting to.
auto toType = simplifyType(expr->getCastTypeLoc().getType());
expr->getCastTypeLoc().setType(toType, /*validated=*/true);
checkForImportedUsedConformances(toType);
// Determine whether we performed a coercion or downcast.
if (cs.shouldAttemptFixes()) {
auto locator = cs.getConstraintLocator(expr);
unsigned choice = solution.getDisjunctionChoice(locator);
(void) choice;
assert(choice == 0 &&
"checked cast branch of disjunction should have resulted in Fix");
}
auto &tc = cs.getTypeChecker();
auto sub = cs.coerceToRValue(expr->getSubExpr());
// The subexpression is always an rvalue.
if (!sub)
return nullptr;
// Convert the subexpression.
if (tc.convertToType(sub, toType, cs.DC))
return nullptr;
expr->setSubExpr(sub);
cs.setType(expr, toType);
return expr;
}
Expr *visitForcedCheckedCastExpr(ForcedCheckedCastExpr *expr) {
// Simplify the type we're casting to.
auto toType = simplifyType(expr->getCastTypeLoc().getType());
expr->getCastTypeLoc().setType(toType, /*validated=*/true);
checkForImportedUsedConformances(toType);
// The subexpression is always an rvalue.
auto &tc = cs.getTypeChecker();
auto sub = cs.coerceToRValue(expr->getSubExpr());
if (!sub)
return nullptr;
expr->setSubExpr(sub);
auto fromType = cs.getType(sub);
auto castKind = tc.typeCheckCheckedCast(
fromType, toType, cs.DC,
expr->getLoc(),
sub->getSourceRange(),
expr->getCastTypeLoc().getSourceRange(),
[&](Type commonTy) -> bool {
return tc.convertToType(sub, commonTy,
cs.DC);
},
SuppressDiagnostics);
switch (castKind) {
/// Invalid cast.
case CheckedCastKind::Unresolved:
return nullptr;
case CheckedCastKind::Coercion: {
if (SuppressDiagnostics)
return nullptr;
if (cs.getType(sub)->isEqual(toType)) {
tc.diagnose(expr->getLoc(), diag::forced_downcast_noop, toType)
.fixItRemove(SourceRange(expr->getLoc(),
expr->getCastTypeLoc().getSourceRange().End));
} else {
tc.diagnose(expr->getLoc(), diag::forced_downcast_coercion,
cs.getType(sub), toType)
.fixItReplace(SourceRange(expr->getLoc(), expr->getExclaimLoc()),
"as");
}
// 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.
cs.setType(result, toType);
return result;
}
// Valid casts.
case CheckedCastKind::ArrayDowncast:
case CheckedCastKind::DictionaryDowncast:
case CheckedCastKind::SetDowncast:
case CheckedCastKind::ValueCast:
case CheckedCastKind::BridgeFromObjectiveC:
expr->setCastKind(castKind);
break;
}
return handleOptionalBindings(expr, simplifyType(cs.getType(expr)),
/*conditionalCast=*/false);
}
Expr *visitConditionalCheckedCastExpr(ConditionalCheckedCastExpr *expr) {
// Simplify the type we're casting to.
auto toType = simplifyType(expr->getCastTypeLoc().getType());
checkForImportedUsedConformances(toType);
expr->getCastTypeLoc().setType(toType, /*validated=*/true);
// The subexpression is always an rvalue.
auto &tc = cs.getTypeChecker();
auto sub = cs.coerceToRValue(expr->getSubExpr());
if (!sub)
return nullptr;
expr->setSubExpr(sub);
auto fromType = cs.getType(sub);
auto castKind = tc.typeCheckCheckedCast(
fromType, toType, cs.DC,
expr->getLoc(),
sub->getSourceRange(),
expr->getCastTypeLoc().getSourceRange(),
[&](Type commonTy) -> bool {
return tc.convertToType(sub, commonTy,
cs.DC);
},
SuppressDiagnostics);
switch (castKind) {
/// Invalid cast.
case CheckedCastKind::Unresolved:
return nullptr;
case CheckedCastKind::Coercion: {
if (SuppressDiagnostics)
return nullptr;
tc.diagnose(expr->getLoc(), diag::conditional_downcast_coercion,
cs.getType(sub), toType);
// Convert the subexpression.
bool failed = tc.convertToType(sub, toType, cs.DC);
(void)failed;
assert(!failed && "Not convertible?");
// Transmute the checked cast into a coercion expression.
Expr *result = new (tc.Context) CoerceExpr(sub, expr->getLoc(),
expr->getCastTypeLoc());
// The result type is the type we're converting to.
cs.setType(result, toType);
// Wrap the result in an optional.
return cs.cacheType(new (tc.Context) InjectIntoOptionalExpr(
result,
OptionalType::get(toType)));
}
// Valid casts.
case CheckedCastKind::ArrayDowncast:
case CheckedCastKind::DictionaryDowncast:
case CheckedCastKind::SetDowncast:
case CheckedCastKind::ValueCast:
case CheckedCastKind::BridgeFromObjectiveC:
expr->setCastKind(castKind);
break;
}
return handleOptionalBindings(expr, simplifyType(cs.getType(expr)),
/*conditionalCast=*/true);
}
Expr *visitAssignExpr(AssignExpr *expr) {
// Compute the type to which the source must be converted to allow
// assignment to the destination.
//
// FIXME: This is also computed when the constraint system is set up.
auto destTy = cs.computeAssignDestType(expr->getDest(), expr->getLoc());
if (!destTy)
return nullptr;
cs.propagateLValueAccessKind(expr->getDest(), AccessKind::Write);
// Convert the source to the simplified destination type.
auto locator =
ConstraintLocatorBuilder(cs.getConstraintLocator(expr->getSrc()));
Expr *src = coerceToType(expr->getSrc(), destTy, locator);
if (!src)
return nullptr;
expr->setSrc(src);
return expr;
}
Expr *visitDiscardAssignmentExpr(DiscardAssignmentExpr *expr) {
return simplifyExprType(expr);
}
Expr *visitUnresolvedPatternExpr(UnresolvedPatternExpr *expr) {
// If we end up here, we should have diagnosed somewhere else
// already.
if (!SuppressDiagnostics) {
cs.TC.diagnose(expr->getLoc(), diag::pattern_in_expr,
expr->getSubPattern()->getKind());
}
return expr;
}
Expr *visitBindOptionalExpr(BindOptionalExpr *expr) {
return simplifyExprType(expr);
}
Expr *visitOptionalEvaluationExpr(OptionalEvaluationExpr *expr) {
Type optType = simplifyType(cs.getType(expr));
// If this is an optional chain that isn't chaining anything, and if the
// subexpression is already optional (not IUO), then this is a noop:
// reject it. This avoids confusion of the model (where the programmer
// thought it was doing something) and keeps pointless ?'s out of the
// code.
if (!SuppressDiagnostics)
if (auto *Bind = dyn_cast<BindOptionalExpr>(
expr->getSubExpr()->getSemanticsProvidingExpr())) {
if (cs.getType(Bind->getSubExpr())->isEqual(optType))
cs.TC.diagnose(expr->getLoc(), diag::optional_chain_noop,
optType).fixItRemove(Bind->getQuestionLoc());
else
cs.TC.diagnose(expr->getLoc(), diag::optional_chain_isnt_chaining);
}
Expr *subExpr = coerceToType(expr->getSubExpr(), optType,
cs.getConstraintLocator(expr));
if (!subExpr) return nullptr;
expr->setSubExpr(subExpr);
cs.setType(expr, optType);
return expr;
}
Expr *visitForceValueExpr(ForceValueExpr *expr) {
Type valueType = simplifyType(cs.getType(expr));
cs.setType(expr, valueType);
// Coerce the object type, if necessary.
auto subExpr = expr->getSubExpr();
if (auto objectTy = cs.getType(subExpr)->getAnyOptionalObjectType()) {
if (objectTy && !objectTy->isEqual(valueType)) {
auto coercedSubExpr = coerceToType(subExpr,
OptionalType::get(valueType),
cs.getConstraintLocator(subExpr));
expr->setSubExpr(coercedSubExpr);
}
}
return expr;
}
Expr *visitOpenExistentialExpr(OpenExistentialExpr *expr) {
llvm_unreachable("Already type-checked");
}
Expr *visitEnumIsCaseExpr(EnumIsCaseExpr *expr) {
// Should already be type-checked.
return simplifyExprType(expr);
}
Expr *visitEditorPlaceholderExpr(EditorPlaceholderExpr *E) {
simplifyExprType(E);
auto valueType = cs.getType(E);
auto &tc = cs.getTypeChecker();
auto &ctx = tc.Context;
// Synthesize a call to _undefined() of appropriate type.
FuncDecl *undefinedDecl = ctx.getUndefinedDecl(&tc);
if (!undefinedDecl) {
tc.diagnose(E->getLoc(), diag::missing_undefined_runtime);
return nullptr;
}
DeclRefExpr *fnRef = new (ctx) DeclRefExpr(undefinedDecl, DeclNameLoc(),
/*Implicit=*/true);
fnRef->setFunctionRefKind(FunctionRefKind::SingleApply);
StringRef msg = "attempt to evaluate editor placeholder";
Expr *argExpr = new (ctx) StringLiteralExpr(msg, E->getLoc(),
/*implicit*/true);
Expr *callExpr = CallExpr::createImplicit(ctx, fnRef, { argExpr },
{ Identifier() });
bool invalid = tc.typeCheckExpression(callExpr, cs.DC,
TypeLoc::withoutLoc(valueType),
CTP_CannotFail);
(void) invalid;
assert(!invalid && "conversion cannot fail");
cs.cacheExprTypes(callExpr);
E->setSemanticExpr(callExpr);
return E;
}
Expr *visitObjCSelectorExpr(ObjCSelectorExpr *E) {
// Dig out the reference to a declaration.
Expr *subExpr = E->getSubExpr();
ValueDecl *foundDecl = nullptr;
while (subExpr) {
// Declaration reference.
if (auto declRef = dyn_cast<DeclRefExpr>(subExpr)) {
foundDecl = declRef->getDecl();
break;
}
// Constructor reference.
if (auto ctorRef = dyn_cast<OtherConstructorDeclRefExpr>(subExpr)) {
foundDecl = ctorRef->getDecl();
break;
}
// Member reference.
if (auto memberRef = dyn_cast<MemberRefExpr>(subExpr)) {
foundDecl = memberRef->getMember().getDecl();
break;
}
// Dynamic member reference.
if (auto dynMemberRef = dyn_cast<DynamicMemberRefExpr>(subExpr)) {
foundDecl = dynMemberRef->getMember().getDecl();
break;
}
// Look through parentheses.
if (auto paren = dyn_cast<ParenExpr>(subExpr)) {
subExpr = paren->getSubExpr();
continue;
}
// Look through "a.b" to "b".
if (auto dotSyntax = dyn_cast<DotSyntaxBaseIgnoredExpr>(subExpr)) {
subExpr = dotSyntax->getRHS();
continue;
}
// Look through self-rebind expression.
if (auto rebindSelf = dyn_cast<RebindSelfInConstructorExpr>(subExpr)) {
subExpr = rebindSelf->getSubExpr();
continue;
}
// Look through optional binding within the monadic "?".
if (auto bind = dyn_cast<BindOptionalExpr>(subExpr)) {
subExpr = bind->getSubExpr();
continue;
}
// Look through optional evaluation of the monadic "?".
if (auto optEval = dyn_cast<OptionalEvaluationExpr>(subExpr)) {
subExpr = optEval->getSubExpr();
continue;
}
// Look through an implicit force-value.
if (auto force = dyn_cast<ForceValueExpr>(subExpr)) {
subExpr = force->getSubExpr();
continue;
}
// Look through implicit open-existential operations.
if (auto open = dyn_cast<OpenExistentialExpr>(subExpr)) {
if (open->isImplicit()) {
subExpr = open->getSubExpr();
continue;
}
break;
}
// Look to the referenced member in a self-application.
if (auto selfApply = dyn_cast<SelfApplyExpr>(subExpr)) {
subExpr = selfApply->getFn();
continue;
}
// Look through implicit conversions.
if (auto conversion = dyn_cast<ImplicitConversionExpr>(subExpr)) {
subExpr = conversion->getSubExpr();
continue;
}
// Look through explicit coercions.
if (auto coercion = dyn_cast<CoerceExpr>(subExpr)) {
subExpr = coercion->getSubExpr();
continue;
}
break;
}
if (!subExpr) return nullptr;
// If we didn't find any declaration at all, we're stuck.
auto &tc = cs.getTypeChecker();
if (!foundDecl) {
tc.diagnose(E->getLoc(), diag::expr_selector_no_declaration)
.highlight(subExpr->getSourceRange());
return E;
}
// Check whether we found an entity that #selector could refer to.
// If we found a method or initializer, check it.
AbstractFunctionDecl *method = nullptr;
if (auto func = dyn_cast<AbstractFunctionDecl>(foundDecl)) {
// Methods and initializers.
// If this isn't a method, complain.
if (!func->getDeclContext()->isTypeContext()) {
tc.diagnose(E->getLoc(), diag::expr_selector_not_method,
func->getDeclContext()->isModuleScopeContext(),
func->getFullName())
.highlight(subExpr->getSourceRange());
tc.diagnose(func, diag::decl_declared_here, func->getFullName());
return E;
}
// Check that we requested a method.
switch (E->getSelectorKind()) {
case ObjCSelectorExpr::Method:
break;
case ObjCSelectorExpr::Getter:
case ObjCSelectorExpr::Setter:
// Complain that we cannot ask for the getter or setter of a
// method.
tc.diagnose(E->getModifierLoc(),
diag::expr_selector_expected_property,
E->getSelectorKind() == ObjCSelectorExpr::Setter,
foundDecl->getDescriptiveKind(),
foundDecl->getFullName())
.fixItRemoveChars(E->getModifierLoc(),
E->getSubExpr()->getStartLoc());
// Update the AST to reflect the fix.
E->overrideObjCSelectorKind(ObjCSelectorExpr::Method, SourceLoc());
break;
}
// Note the method we're referring to.
method = func;
} else if (auto var = dyn_cast<VarDecl>(foundDecl)) {
// Properties.
// If this isn't a property on a type, complain.
if (!var->getDeclContext()->isTypeContext()) {
tc.diagnose(E->getLoc(), diag::expr_selector_not_property,
isa<ParamDecl>(var), var->getFullName())
.highlight(subExpr->getSourceRange());
tc.diagnose(var, diag::decl_declared_here, var->getFullName());
return E;
}
// Check that we requested a property getter or setter.
switch (E->getSelectorKind()) {
case ObjCSelectorExpr::Method: {
bool isSettable = var->isSettable(cs.DC) &&
var->isSetterAccessibleFrom(cs.DC);
auto primaryDiag =
tc.diagnose(E->getLoc(), diag::expr_selector_expected_method,
isSettable, var->getFullName());
primaryDiag.highlight(subExpr->getSourceRange());
// The point at which we will insert the modifier.
SourceLoc modifierLoc = E->getSubExpr()->getStartLoc();
// If the property is settable, we don't know whether the
// user wanted the getter or setter. Provide notes for each.
if (isSettable) {
// Flush the primary diagnostic. We have notes to add.
primaryDiag.flush();
// Add notes for the getter and setter, respectively.
tc.diagnose(modifierLoc, diag::expr_selector_add_modifier,
false, var->getFullName())
.fixItInsert(modifierLoc, "getter: ");
tc.diagnose(modifierLoc, diag::expr_selector_add_modifier,
true, var->getFullName())
.fixItInsert(modifierLoc, "setter: ");
// Bail out now. We don't know what the user wanted, so
// don't fill in the details.
return E;
}
// The property is non-settable, so add "getter:".
primaryDiag.fixItInsert(modifierLoc, "getter: ");
E->overrideObjCSelectorKind(ObjCSelectorExpr::Getter, modifierLoc);
method = var->getGetter();
break;
}
case ObjCSelectorExpr::Getter:
method = var->getGetter();
break;
case ObjCSelectorExpr::Setter:
// Make sure we actually have a setter.
if (!var->isSettable(cs.DC)) {
tc.diagnose(E->getLoc(), diag::expr_selector_property_not_settable,
var->getDescriptiveKind(), var->getFullName());
tc.diagnose(var, diag::decl_declared_here, var->getFullName());
return E;
}
// Make sure the setter is accessible.
if (!var->isSetterAccessibleFrom(cs.DC)) {
tc.diagnose(E->getLoc(),
diag::expr_selector_property_setter_inaccessible,
var->getDescriptiveKind(), var->getFullName());
tc.diagnose(var, diag::decl_declared_here, var->getFullName());
return E;
}
method = var->getSetter();
break;
}
} else {
// Cannot reference with #selector.
tc.diagnose(E->getLoc(), diag::expr_selector_no_declaration)
.highlight(subExpr->getSourceRange());
tc.diagnose(foundDecl, diag::decl_declared_here,
foundDecl->getFullName());
return E;
}
assert(method && "Didn't find a method?");
// The declaration we found must be exposed to Objective-C.
if (!method->isObjC()) {
tc.diagnose(E->getLoc(), diag::expr_selector_not_objc,
foundDecl->getDescriptiveKind(), foundDecl->getFullName())
.highlight(subExpr->getSourceRange());
tc.diagnose(foundDecl, diag::make_decl_objc,
foundDecl->getDescriptiveKind())
.fixItInsert(foundDecl->getAttributeInsertionLoc(false),
"@objc ");
return E;
}
// Note which method we're referencing.
E->setMethod(method);
return E;
}
Expr *visitObjCKeyPathExpr(ObjCKeyPathExpr *E) {
if (auto semanticE = E->getSemanticExpr())
cs.setType(E, cs.getType(semanticE));
return E;
}
/// Interface for ExprWalker
void walkToExprPre(Expr *expr) {
ExprStack.push_back(expr);
}
Expr *walkToExprPost(Expr *expr) {
Expr *result = visit(expr);
// Mark any _ObjectiveCBridgeable conformances as 'used'.
if (result) {
auto &tc = cs.getTypeChecker();
tc.useObjectiveCBridgeableConformances(cs.DC, cs.getType(result));
}
assert(expr == ExprStack.back());
ExprStack.pop_back();
return result;
}
void finalize(Expr *&result) {
assert(ExprStack.empty());
assert(OpenedExistentials.empty());
auto &tc = cs.getTypeChecker();
// Look at all of the suspicious optional injections
for (auto injection : SuspiciousOptionalInjections) {
// If we already diagnosed this injection, we're done.
if (DiagnosedOptionalInjections.count(injection)) {
continue;
}
auto *cast = findForcedDowncast(tc.Context, injection->getSubExpr());
if (!cast)
continue;
if (isa<ParenExpr>(injection->getSubExpr()))
continue;
tc.diagnose(injection->getLoc(), diag::inject_forced_downcast,
cs.getType(injection->getSubExpr())->getRValueType());
auto exclaimLoc = cast->getExclaimLoc();
tc.diagnose(exclaimLoc, diag::forced_to_conditional_downcast,
cs.getType(injection)->getAnyOptionalObjectType())
.fixItReplace(exclaimLoc, "?");
tc.diagnose(cast->getStartLoc(), diag::silence_inject_forced_downcast)
.fixItInsert(cast->getStartLoc(), "(")
.fixItInsertAfter(cast->getEndLoc(), ")");
}
}
/// Diagnose an optional injection that is probably not what the
/// user wanted, because it comes from a forced downcast.
void diagnoseOptionalInjection(InjectIntoOptionalExpr *injection) {
// Don't diagnose when we're injecting into
auto toOptionalType = cs.getType(injection);
if (toOptionalType->getImplicitlyUnwrappedOptionalObjectType())
return;
// Check whether we have a forced downcast.
auto &tc = cs.getTypeChecker();
auto *cast = findForcedDowncast(tc.Context, injection->getSubExpr());
if (!cast)
return;
SuspiciousOptionalInjections.push_back(injection);
}
};
}
/// Resolve a locator to the specific declaration it references, if possible.
///
/// \param cs The constraint system in which the locator will be resolved.
///
/// \param locator The locator to resolve.
///
/// \param findOvlChoice A function that searches for the overload choice
/// associated with the given locator, or an empty optional if there is no such
/// overload.
///
/// \returns the decl to which the locator resolved.
///
static ConcreteDeclRef
resolveLocatorToDecl(ConstraintSystem &cs, ConstraintLocator *locator,
std::function<Optional<SelectedOverload>(ConstraintLocator *)> findOvlChoice,
std::function<ConcreteDeclRef (ValueDecl *decl,
Type openedType,
ConstraintLocator *declLocator)>
getConcreteDeclRef)
{
assert(locator && "Null locator");
if (!locator->getAnchor())
return ConcreteDeclRef();
auto anchor = locator->getAnchor();
// Unwrap any specializations, constructor calls, implicit conversions, and
// '.'s.
// FIXME: This is brittle.
do {
if (auto specialize = dyn_cast<UnresolvedSpecializeExpr>(anchor)) {
anchor = specialize->getSubExpr();
continue;
}
if (auto implicit = dyn_cast<ImplicitConversionExpr>(anchor)) {
anchor = implicit->getSubExpr();
continue;
}
if (auto identity = dyn_cast<IdentityExpr>(anchor)) {
anchor = identity->getSubExpr();
continue;
}
if (auto tryExpr = dyn_cast<AnyTryExpr>(anchor)) {
if (isa<OptionalTryExpr>(tryExpr))
break;
anchor = tryExpr->getSubExpr();
continue;
}
if (auto selfApply = dyn_cast<SelfApplyExpr>(anchor)) {
anchor = selfApply->getFn();
continue;
}
if (auto dotSyntax = dyn_cast<DotSyntaxBaseIgnoredExpr>(anchor)) {
anchor = dotSyntax->getRHS();
continue;
}
break;
} while (true);
// Simple case: direct reference to a declaration.
if (auto dre = dyn_cast<DeclRefExpr>(anchor))
return dre->getDeclRef();
// Simple case: direct reference to a declaration.
if (auto mre = dyn_cast<MemberRefExpr>(anchor))
return mre->getMember();
if (auto ctorRef = dyn_cast<OtherConstructorDeclRefExpr>(anchor))
return ctorRef->getDeclRef();
if (isa<OverloadedDeclRefExpr>(anchor) ||
isa<UnresolvedDeclRefExpr>(anchor)) {
// Overloaded and unresolved cases: find the resolved overload.
auto anchorLocator = cs.getConstraintLocator(anchor);
if (auto selected = findOvlChoice(anchorLocator)) {
if (selected->choice.isDecl())
return getConcreteDeclRef(selected->choice.getDecl(),
selected->openedType,
anchorLocator);
}
}
if (isa<UnresolvedMemberExpr>(anchor)) {
// Unresolved member: find the resolved overload.
auto anchorLocator = cs.getConstraintLocator(anchor,
ConstraintLocator::UnresolvedMember);
if (auto selected = findOvlChoice(anchorLocator)) {
if (selected->choice.isDecl())
return getConcreteDeclRef(selected->choice.getDecl(),
selected->openedType,
anchorLocator);
}
}
if (isa<UnresolvedDotExpr>(anchor)) {
// Unresolved member: find the resolved overload.
auto anchorLocator = cs.getConstraintLocator(anchor,
ConstraintLocator::Member);
if (auto selected = findOvlChoice(anchorLocator)) {
if (selected->choice.isDecl())
return getConcreteDeclRef(selected->choice.getDecl(),
selected->openedType,
anchorLocator);
}
}
if (auto subscript = dyn_cast<SubscriptExpr>(anchor)) {
// Subscript expressions may have a declaration. If so, use it.
if (subscript->hasDecl())
return subscript->getDecl();
// Otherwise, find the resolved overload.
auto anchorLocator =
cs.getConstraintLocator(anchor, ConstraintLocator::SubscriptMember);
if (auto selected = findOvlChoice(anchorLocator)) {
if (selected->choice.isDecl())
return getConcreteDeclRef(selected->choice.getDecl(),
selected->openedType,
anchorLocator);
}
}
if (auto subscript = dyn_cast<DynamicSubscriptExpr>(anchor)) {
// Dynamic subscripts are always resolved.
return subscript->getMember();
}
return ConcreteDeclRef();
}
ConcreteDeclRef Solution::resolveLocatorToDecl(
ConstraintLocator *locator) const {
auto &cs = getConstraintSystem();
// Simplify the locator.
SourceRange range;
locator = simplifyLocator(cs, locator, range);
// If we didn't map down to a specific expression, we can't handle a default
// argument.
if (!locator->getAnchor() || !locator->getPath().empty())
return nullptr;
if (auto resolved
= ::resolveLocatorToDecl(cs, locator,
[&](ConstraintLocator *locator) -> Optional<SelectedOverload> {
auto known = overloadChoices.find(locator);
if (known == overloadChoices.end()) {
return None;
}
return known->second;
},
[&](ValueDecl *decl, Type openedType, ConstraintLocator *locator)
-> ConcreteDeclRef {
if (decl->getInnermostDeclContext()->isGenericContext()) {
SmallVector<Substitution, 4> subs;
computeSubstitutions(
decl->getInterfaceType(),
decl->getInnermostDeclContext(),
openedType, locator, subs);
return ConcreteDeclRef(cs.getASTContext(), decl, subs);
}
return decl;
})) {
return resolved;
}
return ConcreteDeclRef();
}
/// \brief Given a constraint locator, find the declaration reference
/// to the callee, it is a call to a declaration.
static ConcreteDeclRef
findCalleeDeclRef(ConstraintSystem &cs, const Solution &solution,
ConstraintLocator *locator) {
if (locator->getPath().empty() || !locator->getAnchor())
return nullptr;
// If the locator points to a function application, find the function itself.
bool isSubscript =
locator->getPath().back().getKind() == ConstraintLocator::SubscriptIndex;
if (locator->getPath().back().getKind() == ConstraintLocator::ApplyArgument ||
isSubscript) {
assert(locator->getPath().back().getNewSummaryFlags() == 0 &&
"ApplyArgument/SubscriptIndex adds no flags");
SmallVector<LocatorPathElt, 4> newPath;
newPath.append(locator->getPath().begin(), locator->getPath().end()-1);
unsigned newFlags = locator->getSummaryFlags();
// If we have an interpolation argument, dig out the constructor if we
// can.
// FIXME: This representation is actually quite awful
if (newPath.size() == 1 &&
newPath[0].getKind() == ConstraintLocator::InterpolationArgument) {
newPath.push_back(ConstraintLocator::ConstructorMember);
locator = cs.getConstraintLocator(locator->getAnchor(), newPath, newFlags);
auto known = solution.overloadChoices.find(locator);
if (known != solution.overloadChoices.end()) {
auto &choice = known->second.choice;
if (choice.getKind() == OverloadChoiceKind::Decl)
return cast<AbstractFunctionDecl>(choice.getDecl());
}
return nullptr;
} else if (isSubscript) {
newPath.push_back(ConstraintLocator::SubscriptMember);
} else {
newPath.push_back(ConstraintLocator::ApplyFunction);
}
assert(newPath.back().getNewSummaryFlags() == 0 &&
"added element that changes the flags?");
locator = cs.getConstraintLocator(locator->getAnchor(), newPath, newFlags);
}
return solution.resolveLocatorToDecl(locator);
}
static bool
shouldApplyAddingLabelFixit(TuplePattern *tuplePattern, TupleType *fromTuple,
TupleType *toTuple,
std::vector<std::pair<SourceLoc, std::string>> &locInsertPairs) {
std::vector<TuplePattern*> patternParts;
std::vector<TupleType*> fromParts;
std::vector<TupleType*> toParts;
patternParts.push_back(tuplePattern);
fromParts.push_back(fromTuple);
toParts.push_back(toTuple);
while (!patternParts.empty()) {
TuplePattern *curPattern = patternParts.back();
TupleType *curFrom = fromParts.back();
TupleType *curTo = toParts.back();
patternParts.pop_back();
fromParts.pop_back();
toParts.pop_back();
unsigned n = curPattern->getElements().size();
if (curFrom->getElements().size() != n ||
curTo->getElements().size() != n)
return false;
for (unsigned i = 0; i < n; i++) {
Pattern* subPat = curPattern->getElement(i).getPattern();
const TupleTypeElt &subFrom = curFrom->getElement(i);
const TupleTypeElt &subTo = curTo->getElement(i);
if ((subFrom.getType()->getKind() == TypeKind::Tuple) ^
(subTo.getType()->getKind() == TypeKind::Tuple))
return false;
auto addLabelFunc = [&]() {
if (subFrom.getName().empty() && !subTo.getName().empty()) {
llvm::SmallString<8> Name;
Name.append(subTo.getName().str());
Name.append(": ");
locInsertPairs.push_back({subPat->getStartLoc(), Name.str()});
}
};
if (auto subFromTuple = subFrom.getType()->getAs<TupleType>()) {
fromParts.push_back(subFromTuple);
toParts.push_back(subTo.getType()->getAs<TupleType>());
patternParts.push_back(static_cast<TuplePattern*>(subPat));
addLabelFunc();
} else if (subFrom.getType()->isEqual(subTo.getType())) {
addLabelFunc();
} else
return false;
}
}
return true;
}
/// Produce the caller-side default argument for this default argument, or
/// null if the default argument will be provided by the callee.
static std::pair<Expr *, DefaultArgumentKind>
getCallerDefaultArg(ConstraintSystem &cs, DeclContext *dc,
SourceLoc loc, ConcreteDeclRef &owner,
unsigned index) {
auto &tc = cs.getTypeChecker();
auto ownerFn = cast<AbstractFunctionDecl>(owner.getDecl());
auto defArg = ownerFn->getDefaultArg(index);
Expr *init = nullptr;
switch (defArg.first) {
case DefaultArgumentKind::None:
llvm_unreachable("No default argument here?");
case DefaultArgumentKind::Normal:
return {nullptr, defArg.first};
case DefaultArgumentKind::Inherited:
// Update the owner to reflect inheritance here.
owner = ownerFn->getOverriddenDecl();
return getCallerDefaultArg(cs, dc, loc, owner, index);
case DefaultArgumentKind::Column:
init = new (tc.Context) MagicIdentifierLiteralExpr(
MagicIdentifierLiteralExpr::Column, loc,
/*Implicit=*/true);
break;
case DefaultArgumentKind::File:
init = new (tc.Context) MagicIdentifierLiteralExpr(
MagicIdentifierLiteralExpr::File, loc,
/*Implicit=*/true);
break;
case DefaultArgumentKind::Line:
init = new (tc.Context) MagicIdentifierLiteralExpr(
MagicIdentifierLiteralExpr::Line, loc,
/*Implicit=*/true);
break;
case DefaultArgumentKind::Function:
init = new (tc.Context) MagicIdentifierLiteralExpr(
MagicIdentifierLiteralExpr::Function, loc,
/*Implicit=*/true);
break;
case DefaultArgumentKind::DSOHandle:
init = new (tc.Context) MagicIdentifierLiteralExpr(
MagicIdentifierLiteralExpr::DSOHandle, loc,
/*Implicit=*/true);
break;
case DefaultArgumentKind::Nil:
init = new (tc.Context) NilLiteralExpr(loc, /*Implicit=*/true);
break;
case DefaultArgumentKind::EmptyArray:
init = ArrayExpr::create(tc.Context, loc, {}, {}, loc);
init->setImplicit();
break;
case DefaultArgumentKind::EmptyDictionary:
init = DictionaryExpr::create(tc.Context, loc, {}, loc);
init->setImplicit();
break;
}
// Convert the literal to the appropriate type.
bool invalid = tc.typeCheckExpression(init, dc,
TypeLoc::withoutLoc(defArg.second),
CTP_CannotFail);
assert(!invalid && "conversion cannot fail");
(void)invalid;
cs.cacheExprTypes(init);
return {init, defArg.first};
}
static Expr *lookThroughIdentityExprs(Expr *expr) {
while (true) {
if (auto ident = dyn_cast<IdentityExpr>(expr)) {
expr = ident->getSubExpr();
} else if (auto anyTry = dyn_cast<AnyTryExpr>(expr)) {
if (isa<OptionalTryExpr>(anyTry))
return expr;
expr = anyTry->getSubExpr();
} else {
return expr;
}
}
}
/// Rebuild the ParenTypes for the given expression, whose underlying expression
/// should be set to the given type. This has to apply to exactly the same
/// levels of sugar that were stripped off by lookThroughIdentityExprs.
static Type rebuildIdentityExprs(ConstraintSystem &cs, Expr *expr, Type type) {
ASTContext &ctx = cs.getASTContext();
if (auto paren = dyn_cast<ParenExpr>(expr)) {
type = rebuildIdentityExprs(cs, paren->getSubExpr(), type);
cs.setType(paren, ParenType::get(ctx, type));
return cs.getType(paren);
}
if (auto ident = dyn_cast<IdentityExpr>(expr)) {
type = rebuildIdentityExprs(cs, ident->getSubExpr(), type);
cs.setType(ident, type);
return cs.getType(ident);
}
if (auto ident = dyn_cast<AnyTryExpr>(expr)) {
if (isa<OptionalTryExpr>(ident))
return type;
type = rebuildIdentityExprs(cs, ident->getSubExpr(), type);
cs.setType(ident, type);
return cs.getType(ident);
}
return type;
}
Expr *ExprRewriter::coerceTupleToTuple(Expr *expr, TupleType *fromTuple,
TupleType *toTuple,
ConstraintLocatorBuilder locator,
SmallVectorImpl<int> &sources,
SmallVectorImpl<unsigned> &variadicArgs,
Optional<Pattern*> typeFromPattern){
auto &tc = cs.getTypeChecker();
// Capture the tuple expression, if there is one.
Expr *innerExpr = lookThroughIdentityExprs(expr);
TupleExpr *fromTupleExpr = dyn_cast<TupleExpr>(innerExpr);
/// Check each of the tuple elements in the destination.
bool hasVariadic = false;
unsigned variadicParamIdx = toTuple->getNumElements();
bool anythingShuffled = false;
bool hasInits = false;
SmallVector<TupleTypeElt, 4> toSugarFields;
SmallVector<TupleTypeElt, 4> fromTupleExprFields(
fromTuple->getElements().size());
SmallVector<Expr *, 2> callerDefaultArgs;
ConcreteDeclRef callee =
findCalleeDeclRef(cs, solution, cs.getConstraintLocator(locator));
for (unsigned i = 0, n = toTuple->getNumElements(); i != n; ++i) {
const auto &toElt = toTuple->getElement(i);
auto toEltType = toElt.getType();
// If we're default-initializing this member, there's nothing to do.
if (sources[i] == TupleShuffleExpr::DefaultInitialize) {
anythingShuffled = true;
hasInits = true;
toSugarFields.push_back(toElt);
// Create a caller-side default argument, if we need one.
if (auto defArg = getCallerDefaultArg(cs, dc, expr->getLoc(),
callee, i).first) {
callerDefaultArgs.push_back(defArg);
sources[i] = TupleShuffleExpr::CallerDefaultInitialize;
}
continue;
}
// If this is the variadic argument, note it.
if (sources[i] == TupleShuffleExpr::Variadic) {
assert(!hasVariadic && "two variadic parameters?");
toSugarFields.push_back(toElt);
hasVariadic = true;
variadicParamIdx = i;
anythingShuffled = true;
continue;
}
// If the source and destination index are different, we'll be shuffling.
if ((unsigned)sources[i] != i) {
anythingShuffled = true;
}
// We're matching one element to another. If the types already
// match, there's nothing to do.
const auto &fromElt = fromTuple->getElement(sources[i]);
auto fromEltType = fromElt.getType();
if (fromEltType->isEqual(toEltType)) {
// Get the sugared type directly from the tuple expression, if there
// is one.
if (fromTupleExpr)
fromEltType = cs.getType(fromTupleExpr->getElement(sources[i]));
toSugarFields.push_back(toElt.getWithType(fromEltType));
fromTupleExprFields[sources[i]] = fromElt;
continue;
}
// We need to convert the source element to the destination type.
if (!fromTupleExpr) {
// FIXME: Lame! We can't express this in the AST.
auto anchorExpr = locator.getBaseLocator()->getAnchor();
InFlightDiagnostic diag = tc.diagnose(anchorExpr->getLoc(),
diag::tuple_conversion_not_expressible,
fromTuple, toTuple);
if (typeFromPattern) {
std::vector<std::pair<SourceLoc, std::string>> locInsertPairs;
TuplePattern *tupleP = dyn_cast<TuplePattern>(typeFromPattern.getValue());
if (tupleP && shouldApplyAddingLabelFixit(tupleP, toTuple, fromTuple,
locInsertPairs)) {
for (auto &Pair : locInsertPairs) {
diag.fixItInsert(Pair.first, Pair.second);
}
}
}
return nullptr;
}
// Actually convert the source element.
auto convertedElt
= coerceToType(fromTupleExpr->getElement(sources[i]), toEltType,
locator.withPathElement(
LocatorPathElt::getTupleElement(sources[i])));
if (!convertedElt)
return nullptr;
fromTupleExpr->setElement(sources[i], convertedElt);
// Record the sugared field name.
toSugarFields.push_back(toElt.getWithType(cs.getType(convertedElt)));
fromTupleExprFields[sources[i]] =
fromElt.getWithType(cs.getType(convertedElt));
}
// Convert all of the variadic arguments to the destination type.
ArraySliceType *arrayType = nullptr;
if (hasVariadic) {
Type toEltType = toTuple->getElements()[variadicParamIdx].getVarargBaseTy();
for (int fromFieldIdx : variadicArgs) {
const auto &fromElt = fromTuple->getElement(fromFieldIdx);
Type fromEltType = fromElt.getType();
// If the source and destination types match, there's nothing to do.
if (toEltType->isEqual(fromEltType)) {
fromTupleExprFields[fromFieldIdx] = fromElt;
continue;
}
// We need to convert the source element to the destination type.
if (!fromTupleExpr) {
// FIXME: Lame! We can't express this in the AST.
tc.diagnose(expr->getLoc(),
diag::tuple_conversion_not_expressible,
fromTuple, toTuple);
return nullptr;
}
// Actually convert the source element.
auto convertedElt = coerceToType(
fromTupleExpr->getElement(fromFieldIdx),
toEltType,
locator.withPathElement(
LocatorPathElt::getTupleElement(fromFieldIdx)));
if (!convertedElt)
return nullptr;
fromTupleExpr->setElement(fromFieldIdx, convertedElt);
fromTupleExprFields[fromFieldIdx] =
fromElt.getWithType(cs.getType(convertedElt));
}
// Find the appropriate injection function.
if (tc.requireArrayLiteralIntrinsics(expr->getStartLoc()))
return nullptr;
arrayType = cast<ArraySliceType>(
toTuple->getElements()[variadicParamIdx].getType().getPointer());
}
// Compute the updated 'from' tuple type, since we may have
// performed some conversions in place.
Type fromTupleType = TupleType::get(fromTupleExprFields, tc.Context);
if (fromTupleExpr) {
cs.setType(fromTupleExpr, fromTupleType);
// Update the types of parentheses around the tuple expression.
rebuildIdentityExprs(cs, expr, fromTupleType);
}
// Compute the re-sugared tuple type.
Type toSugarType = hasInits? toTuple
: TupleType::get(toSugarFields, tc.Context);
// If we don't have to shuffle anything, we're done.
if (!anythingShuffled && fromTupleExpr) {
cs.setType(fromTupleExpr, toSugarType);
// Update the types of parentheses around the tuple expression.
rebuildIdentityExprs(cs, expr, toSugarType);
return expr;
}
// Create the tuple shuffle.
ArrayRef<int> mapping = tc.Context.AllocateCopy(sources);
auto callerDefaultArgsCopy = tc.Context.AllocateCopy(callerDefaultArgs);
auto shuffle =
cs.cacheType(new (tc.Context) TupleShuffleExpr(
expr, mapping,
TupleShuffleExpr::SourceIsTuple,
callee,
tc.Context.AllocateCopy(variadicArgs),
callerDefaultArgsCopy,
toSugarType));
shuffle->setVarargsArrayType(arrayType);
return shuffle;
}
Expr *ExprRewriter::coerceScalarToTuple(Expr *expr, TupleType *toTuple,
int toScalarIdx,
ConstraintLocatorBuilder locator) {
auto &tc = solution.getConstraintSystem().getTypeChecker();
// If the destination type is variadic, compute the injection function to use.
Type arrayType = nullptr;
const auto &lastField = toTuple->getElements().back();
if (lastField.isVararg()) {
// Find the appropriate injection function.
arrayType = cast<ArraySliceType>(lastField.getType().getPointer());
if (tc.requireArrayLiteralIntrinsics(expr->getStartLoc()))
return nullptr;
}
// If we're initializing the varargs list, use its base type.
const auto &field = toTuple->getElement(toScalarIdx);
Type toScalarType;
if (field.isVararg())
toScalarType = field.getVarargBaseTy();
else
toScalarType = field.getType();
// Coerce the expression to the scalar type.
expr = coerceToType(expr, toScalarType,
locator.withPathElement(
ConstraintLocator::ScalarToTuple));
if (!expr)
return nullptr;
// Preserve the sugar of the scalar field.
// FIXME: This doesn't work if the type has default values because they fail
// to canonicalize.
SmallVector<TupleTypeElt, 4> sugarFields;
bool hasInit = false;
int i = 0;
for (auto &field : toTuple->getElements()) {
if (i == toScalarIdx) {
if (field.isVararg()) {
assert(cs.getType(expr)->isEqual(field.getVarargBaseTy()) &&
"scalar field is not equivalent to dest vararg field?!");
sugarFields.push_back(field);
}
else {
assert(cs.getType(expr)->isEqual(field.getType()) &&
"scalar field is not equivalent to dest tuple field?!");
sugarFields.push_back(field.getWithType(cs.getType(expr)));
}
// Record the
} else {
sugarFields.push_back(field);
}
++i;
}
// Compute the elements of the resulting tuple.
SmallVector<int, 4> elements;
SmallVector<unsigned, 1> variadicArgs;
SmallVector<Expr*, 4> callerDefaultArgs;
ConcreteDeclRef callee =
findCalleeDeclRef(cs, solution, cs.getConstraintLocator(locator));
i = 0;
for (auto &field : toTuple->getElements()) {
if (field.isVararg()) {
elements.push_back(TupleShuffleExpr::Variadic);
if (i == toScalarIdx) {
variadicArgs.push_back(i);
++i;
continue;
}
}
// This is the scalar field, so act like we're shuffling the 0th element.
assert(i == toScalarIdx);
elements.push_back(0);
++i;
}
Type destSugarTy = hasInit? toTuple
: TupleType::get(sugarFields, tc.Context);
return cs.cacheType(
new (tc.Context) TupleShuffleExpr(expr,
tc.Context.AllocateCopy(elements),
TupleShuffleExpr::SourceIsScalar,
callee,
tc.Context.AllocateCopy(variadicArgs),
tc.Context.AllocateCopy(callerDefaultArgs),
destSugarTy));
}
/// Collect the conformances for all the protocols of an existential type.
/// If the source type is also existential, we don't want to check conformance
/// because most protocols do not conform to themselves -- however we still
/// allow the conversion here, except the ErasureExpr ends up with trivial
/// conformances.
static ArrayRef<ProtocolConformanceRef>
collectExistentialConformances(TypeChecker &tc, Type fromType, Type toType,
DeclContext *DC) {
SmallVector<ProtocolDecl *, 4> protocols;
toType->getAnyExistentialTypeProtocols(protocols);
SmallVector<ProtocolConformanceRef, 4> conformances;
for (auto proto : protocols) {
conformances.push_back(
*tc.containsProtocol(fromType, proto, DC,
(ConformanceCheckFlags::InExpression|
ConformanceCheckFlags::Used)));
}
return tc.Context.AllocateCopy(conformances);
}
Expr *ExprRewriter::coerceExistential(Expr *expr, Type toType,
ConstraintLocatorBuilder locator) {
auto &tc = solution.getConstraintSystem().getTypeChecker();
Type fromType = cs.getType(expr);
// Handle existential coercions that implicitly look through ImplicitlyUnwrappedOptional<T>.
if (auto ty = cs.lookThroughImplicitlyUnwrappedOptionalType(fromType)) {
expr = coerceImplicitlyUnwrappedOptionalToValue(expr, ty, locator);
fromType = cs.getType(expr);
assert(!fromType->is<AnyMetatypeType>());
// FIXME: Hack. We shouldn't try to coerce existential when there is no
// existential upcast to perform.
if (fromType->isEqual(toType))
return expr;
}
Type fromInstanceType = fromType;
Type toInstanceType = toType;
// Look through metatypes
while (fromInstanceType->is<AnyMetatypeType>() &&
toInstanceType->is<ExistentialMetatypeType>()) {
fromInstanceType = fromInstanceType->castTo<AnyMetatypeType>()->getInstanceType();
toInstanceType = toInstanceType->castTo<ExistentialMetatypeType>()->getInstanceType();
}
ASTContext &ctx = tc.Context;
auto conformances =
collectExistentialConformances(tc, fromInstanceType, toInstanceType, cs.DC);
// For existential-to-existential coercions, open the source existential.
if (fromType->isAnyExistentialType()) {
fromType = ArchetypeType::getAnyOpened(fromType);
auto *archetypeVal =
cs.cacheType(
new (ctx) OpaqueValueExpr(expr->getLoc(),
fromType));
auto *result =
cs.cacheType(new (ctx) ErasureExpr(archetypeVal, toType, conformances));
return cs.cacheType(
new (ctx) OpenExistentialExpr(expr, archetypeVal, result));
}
// If the type we are trying to coerce is a tuple, let's look through
// its elements to see if there are any LValue types present, such requires
// load or address-of operation first before proceeding with erasure.
if (auto tupleType = fromType->getAs<TupleType>()) {
bool coerceToRValue = false;
for (auto element : tupleType->getElements()) {
if (element.getType()->is<LValueType>()) {
coerceToRValue = true;
break;
}
}
// Tuple has one or more LValue types associated with it,
// which requires coercion to RValue, let's perform it here by creating
// new tuple type with LValue(s) stripped off and coercing
// expression to that type, which would do required transformation.
if (coerceToRValue) {
SmallVector<TupleTypeElt, 2> elements;
for (auto &element : tupleType->getElements())
elements.push_back(TupleTypeElt(element.getType()->getRValueType(),
element.getName(),
element.getParameterFlags()));
// New type is guaranteed to be a tuple because source type is one.
auto toTuple = TupleType::get(elements, ctx)->castTo<TupleType>();
SmallVector<int, 4> sources;
SmallVector<unsigned, 4> variadicArgs;
bool failed = computeTupleShuffle(tupleType, toTuple,
sources, variadicArgs);
assert(!failed && "Couldn't convert tuple to tuple?");
(void)failed;
coerceTupleToTuple(expr, tupleType, toTuple, locator, sources,
variadicArgs);
}
}
return cs.cacheType(new (ctx) ErasureExpr(expr, toType, conformances));
}
static unsigned getOptionalBindDepth(const BoundGenericType *bgt) {
if (bgt->getDecl()->classifyAsOptionalType()) {
auto tyarg = bgt->getGenericArgs()[0];
unsigned innerDepth = 0;
if (auto wrappedBGT = dyn_cast<BoundGenericType>(tyarg->
getCanonicalType())) {
innerDepth = getOptionalBindDepth(wrappedBGT);
}
return 1 + innerDepth;
}
return 0;
}
static Type getOptionalBaseType(const Type &type) {
if (auto bgt = dyn_cast<BoundGenericType>(type->
getCanonicalType())) {
if (bgt->getDecl()->classifyAsOptionalType()) {
return getOptionalBaseType(bgt->getGenericArgs()[0]);
}
}
return type;
}
Expr *ExprRewriter::coerceOptionalToOptional(Expr *expr, Type toType,
ConstraintLocatorBuilder locator,
Optional<Pattern*> typeFromPattern) {
auto &tc = cs.getTypeChecker();
Type fromType = cs.getType(expr);
auto fromGenericType = fromType->castTo<BoundGenericType>();
auto toGenericType = toType->castTo<BoundGenericType>();
assert(fromGenericType->getDecl()->classifyAsOptionalType());
assert(toGenericType->getDecl()->classifyAsOptionalType());
tc.requireOptionalIntrinsics(expr->getLoc());
Type fromValueType = fromGenericType->getGenericArgs()[0];
Type toValueType = toGenericType->getGenericArgs()[0];
// If the option kinds are the same, and the wrapped types are the same,
// but the arities are different, we can peephole the optional-to-optional
// conversion into a series of nested injections.
auto toDepth = getOptionalBindDepth(toGenericType);
auto fromDepth = getOptionalBindDepth(fromGenericType);
if (toDepth > fromDepth) {
auto toBaseType = getOptionalBaseType(toGenericType);
auto fromBaseType = getOptionalBaseType(fromGenericType);
if ((toGenericType->getDecl() == fromGenericType->getDecl()) &&
toBaseType->isEqual(fromBaseType)) {
auto diff = toDepth - fromDepth;
auto isIUO = fromGenericType->getDecl()->
classifyAsOptionalType() == OTK_ImplicitlyUnwrappedOptional;
while (diff) {
const Type &t = cs.getType(expr);
const Type &wrapped = isIUO ?
Type(ImplicitlyUnwrappedOptionalType::get(t)) :
Type(OptionalType::get(t));
expr =
cs.cacheType(new (tc.Context) InjectIntoOptionalExpr(expr, wrapped));
diagnoseOptionalInjection(cast<InjectIntoOptionalExpr>(expr));
diff--;
}
return expr;
}
}
expr =
cs.cacheType(new (tc.Context) BindOptionalExpr(expr,
expr->getSourceRange().End,
/*depth*/ 0, fromValueType));
expr->setImplicit(true);
expr = coerceToType(expr, toValueType, locator, typeFromPattern);
if (!expr) return nullptr;
expr = cs.cacheType(new (tc.Context) InjectIntoOptionalExpr(expr, toType));
expr = cs.cacheType(new (tc.Context) OptionalEvaluationExpr(expr, toType));
expr->setImplicit(true);
return expr;
}
Expr *ExprRewriter::coerceImplicitlyUnwrappedOptionalToValue(Expr *expr, Type objTy,
ConstraintLocatorBuilder locator) {
auto optTy = cs.getType(expr);
// Coerce to an r-value.
if (optTy->is<LValueType>())
objTy = LValueType::get(objTy);
expr = new (cs.getTypeChecker().Context) ForceValueExpr(expr,
expr->getEndLoc());
cs.setType(expr, objTy);
expr->setImplicit();
return expr;
}
/// Determine whether the given expression is a reference to an
/// unbound instance member of a type.
static bool isReferenceToMetatypeMember(ConstraintSystem &cs, Expr *expr) {
expr = expr->getSemanticsProvidingExpr();
if (auto dotIgnored = dyn_cast<DotSyntaxBaseIgnoredExpr>(expr))
return cs.getType(dotIgnored->getLHS())->is<AnyMetatypeType>();
if (auto dotSyntax = dyn_cast<DotSyntaxCallExpr>(expr))
return cs.getType(dotSyntax->getBase())->is<AnyMetatypeType>();
return false;
}
Expr *ExprRewriter::coerceCallArguments(
Expr *arg, Type paramType,
llvm::PointerUnion<ApplyExpr *, LevelTy> applyOrLevel,
ArrayRef<Identifier> argLabels,
bool hasTrailingClosure,
ConstraintLocatorBuilder locator) {
bool allParamsMatch = cs.getType(arg)->isEqual(paramType);
// Find the callee declaration.
ConcreteDeclRef callee =
findCalleeDeclRef(cs, solution, cs.getConstraintLocator(locator));
// Determine the level,
unsigned level = 0;
if (applyOrLevel.is<LevelTy>()) {
// Level specified by caller.
level = applyOrLevel.get<LevelTy>();
} else if (callee) {
// Determine the level based on the application itself.
auto apply = applyOrLevel.get<ApplyExpr *>();
// Only calls to members of types can have level > 0.
auto calleeDecl = callee.getDecl();
if (calleeDecl->getDeclContext()->isTypeContext()) {
// Level 1 if we're not applying "self".
if (auto call = dyn_cast<CallExpr>(apply)) {
if (!calleeDecl->isInstanceMember() ||
!isReferenceToMetatypeMember(cs, call->getDirectCallee()))
level = 1;
} else if (isa<PrefixUnaryExpr>(apply) ||
isa<PostfixUnaryExpr>(apply) ||
isa<BinaryExpr>(apply)) {
level = 1;
}
}
}
// Determine the parameter bindings.
auto params = decomposeParamType(paramType, callee.getDecl(), level);
auto args = decomposeArgType(cs.getType(arg), argLabels);
// Quickly test if any further fix-ups for the argument types are necessary.
// FIXME: This hack is only necessary to work around some problems we have
// for inferring the type of an unresolved member reference expression in
// an optional context. We should seek a more holistic fix for this.
if (allParamsMatch &&
(params.size() == args.size())) {
if (auto argTuple = dyn_cast<TupleExpr>(arg)) {
auto argElts = argTuple->getElements();
for (size_t i = 0; i < params.size(); i++) {
if (auto dotExpr = dyn_cast<DotSyntaxCallExpr>(argElts[i])) {
auto paramTy = params[i].Ty->getLValueOrInOutObjectType();
auto argTy = cs.getType(dotExpr)->getLValueOrInOutObjectType();
if (!paramTy->isEqual(argTy)) {
allParamsMatch = false;
break;
}
}
}
}
}
if (allParamsMatch)
return arg;
MatchCallArgumentListener listener;
SmallVector<ParamBinding, 4> parameterBindings;
bool failed = constraints::matchCallArguments(args, params,
hasTrailingClosure,
/*allowFixes=*/false, listener,
parameterBindings);
assert(!failed && "Call arguments did not match up?");
(void)failed;
// We should either have parentheses or a tuple.
TupleExpr *argTuple = dyn_cast<TupleExpr>(arg);
ParenExpr *argParen = dyn_cast<ParenExpr>(arg);
// FIXME: Eventually, we want to enforce that we have either argTuple or
// argParen here.
// Local function to extract the ith argument expression, which papers
// over some of the weirdness with tuples vs. parentheses.
auto getArg = [&](unsigned i) -> Expr * {
if (argTuple)
return argTuple->getElement(i);
assert(i == 0 && "Scalar only has a single argument");
if (argParen)
return argParen->getSubExpr();
return arg;
};
// Local function to extract the ith argument label, which papers over some
// of the weirdness with tuples vs. parentheses.
auto getArgLabel = [&](unsigned i) -> Identifier {
if (argTuple)
return argTuple->getElementName(i);
assert(i == 0 && "Scalar only has a single argument");
return Identifier();
};
// Local function to produce a locator to refer to the ith element of the
// argument tuple.
auto getArgLocator = [&](unsigned argIdx, unsigned paramIdx)
-> ConstraintLocatorBuilder {
return locator.withPathElement(
LocatorPathElt::getApplyArgToParam(argIdx, paramIdx));
};
auto &tc = getConstraintSystem().getTypeChecker();
SmallVector<TupleTypeElt, 4> toSugarFields;
SmallVector<TupleTypeElt, 4> fromTupleExprFields(
argTuple? argTuple->getNumElements() : 1);
SmallVector<Expr*, 4> fromTupleExpr(argTuple? argTuple->getNumElements() : 1);
SmallVector<unsigned, 4> variadicArgs;
SmallVector<Expr *, 2> callerDefaultArgs;
Type sliceType = nullptr;
SmallVector<int, 4> sources;
for (unsigned paramIdx = 0, numParams = parameterBindings.size();
paramIdx != numParams; ++paramIdx) {
// Extract the parameter.
const auto &param = params[paramIdx];
// Handle variadic parameters.
if (param.isVariadic()) {
// Find the appropriate injection function.
if (tc.requireArrayLiteralIntrinsics(arg->getStartLoc()))
return nullptr;
// Record this parameter.
auto paramBaseType = param.Ty;
assert(sliceType.isNull() && "Multiple variadic parameters?");
sliceType = tc.getArraySliceType(arg->getLoc(), paramBaseType);
toSugarFields.push_back(
TupleTypeElt(sliceType, param.Label, param.parameterFlags));
sources.push_back(TupleShuffleExpr::Variadic);
// Convert the arguments.
for (auto argIdx : parameterBindings[paramIdx]) {
auto arg = getArg(argIdx);
auto argType = cs.getType(arg);
variadicArgs.push_back(argIdx);
// If the argument type exactly matches, this just works.
if (argType->isEqual(paramBaseType)) {
fromTupleExprFields[argIdx] = TupleTypeElt(argType,
getArgLabel(argIdx));
fromTupleExpr[argIdx] = arg;
continue;
}
// Convert the argument.
auto convertedArg = coerceToType(arg, paramBaseType,
getArgLocator(argIdx, paramIdx));
if (!convertedArg)
return nullptr;
// Add the converted argument.
fromTupleExpr[argIdx] = convertedArg;
fromTupleExprFields[argIdx] = TupleTypeElt(cs.getType(convertedArg),
getArgLabel(argIdx));
}
continue;
}
// If we are using a default argument, handle it now.
if (parameterBindings[paramIdx].empty()) {
// Create a caller-side default argument, if we need one.
Expr *defArg;
DefaultArgumentKind defArgKind;
std::tie(defArg, defArgKind) = getCallerDefaultArg(cs, dc, arg->getLoc(),
callee, paramIdx);
// Note that we'll be doing a shuffle involving default arguments.
toSugarFields.push_back(TupleTypeElt(
param.isVariadic()
? tc.getArraySliceType(arg->getLoc(),
param.Ty)
: param.Ty,
param.Label,
param.parameterFlags));
if (defArg) {
callerDefaultArgs.push_back(defArg);
sources.push_back(TupleShuffleExpr::CallerDefaultInitialize);
} else {
sources.push_back(TupleShuffleExpr::DefaultInitialize);
}
continue;
}
// Extract the argument used to initialize this parameter.
assert(parameterBindings[paramIdx].size() == 1);
unsigned argIdx = parameterBindings[paramIdx].front();
auto arg = getArg(argIdx);
auto argType = cs.getType(arg);
// If the argument and parameter indices differ, or if the names differ,
// this is a shuffle.
sources.push_back(argIdx);
// If the types exactly match, this is easy.
auto paramType = param.Ty;
if (argType->isEqual(paramType)) {
toSugarFields.push_back(
TupleTypeElt(argType, param.Label, param.parameterFlags));
fromTupleExprFields[argIdx] =
TupleTypeElt(paramType, param.Label, param.parameterFlags);
fromTupleExpr[argIdx] = arg;
continue;
}
// Convert the argument.
auto convertedArg = coerceToType(arg, paramType,
getArgLocator(argIdx, paramIdx));
if (!convertedArg)
return nullptr;
// Add the converted argument.
fromTupleExpr[argIdx] = convertedArg;
fromTupleExprFields[argIdx] = TupleTypeElt(
cs.getType(convertedArg), getArgLabel(argIdx), param.parameterFlags);
toSugarFields.push_back(
TupleTypeElt(argType, param.Label, param.parameterFlags));
}
// Compute a new 'arg', from the bits we have. We have three cases: the
// scalar case, the paren case, and the tuple literal case.
if (!argTuple && !argParen) {
assert(fromTupleExpr.size() == 1 && fromTupleExpr[0]);
arg = fromTupleExpr[0];
} else if (argParen) {
// If the element changed, rebuild a new ParenExpr.
assert(fromTupleExpr.size() == 1 && fromTupleExpr[0]);
if (fromTupleExpr[0] != argParen->getSubExpr()) {
bool argParenImplicit = argParen->isImplicit();
argParen =
cs.cacheType(new (tc.Context)
ParenExpr(argParen->getLParenLoc(),
fromTupleExpr[0],
argParen->getRParenLoc(),
argParen->hasTrailingClosure(),
cs.getType(fromTupleExpr[0])));
if (argParenImplicit) {
argParen->setImplicit();
}
arg = argParen;
} else {
// coerceToType may have updated the element type of the ParenExpr in
// place. If so, propagate the type out to the ParenExpr as well.
cs.setType(argParen, cs.getType(fromTupleExpr[0]));
}
} else {
assert(argTuple);
bool anyChanged = false;
for (unsigned i = 0, e = argTuple->getNumElements(); i != e; ++i)
if (fromTupleExpr[i] != argTuple->getElement(i)) {
anyChanged = true;
break;
}
// If anything about the TupleExpr changed, rebuild a new one.
Type argTupleType = TupleType::get(fromTupleExprFields, tc.Context);
if (anyChanged || !cs.getType(argTuple)->isEqual(argTupleType)) {
auto EltNames = argTuple->getElementNames();
auto EltNameLocs = argTuple->getElementNameLocs();
argTuple =
cs.cacheType(TupleExpr::create(tc.Context, argTuple->getLParenLoc(),
fromTupleExpr, EltNames, EltNameLocs,
argTuple->getRParenLoc(),
argTuple->hasTrailingClosure(),
argTuple->isImplicit(),
argTupleType));
arg = argTuple;
}
}
// If we don't have to shuffle anything, we're done.
if (cs.getType(arg)->isEqual(paramType))
return arg;
// If we came from a scalar, create a scalar-to-tuple conversion.
auto isSourceScalar = TupleShuffleExpr::SourceIsScalar_t(argTuple == nullptr);
// Create the tuple shuffle.
ArrayRef<int> mapping = tc.Context.AllocateCopy(sources);
auto callerDefaultArgsCopy = tc.Context.AllocateCopy(callerDefaultArgs);
auto *shuffle =
cs.cacheType(new (tc.Context) TupleShuffleExpr(
arg, mapping,
isSourceScalar,
callee,
tc.Context.AllocateCopy(variadicArgs),
callerDefaultArgsCopy,
paramType));
shuffle->setVarargsArrayType(sliceType);
return shuffle;
}
/// If the expression is an explicit closure expression (potentially wrapped in
/// IdentityExprs), change the type of the closure and identities to the
/// specified type and return true. Otherwise, return false with no effect.
static bool applyTypeToClosureExpr(ConstraintSystem &cs,
Expr *expr, Type toType) {
// Look through identity expressions, like parens.
if (auto IE = dyn_cast<IdentityExpr>(expr)) {
if (!applyTypeToClosureExpr(cs, IE->getSubExpr(), toType)) return false;
cs.setType(IE, toType);
return true;
}
// If we found an explicit ClosureExpr, update its type.
if (auto CE = dyn_cast<ClosureExpr>(expr)) {
cs.setType(CE, toType);
return true;
}
// Otherwise fail.
return false;
}
ClosureExpr *ExprRewriter::coerceClosureExprToVoid(ClosureExpr *closureExpr) {
auto &tc = cs.getTypeChecker();
// Re-write the single-expression closure to return '()'
assert(closureExpr->hasSingleExpressionBody());
// A single-expression body contains a single return statement
// prior to this transformation.
auto member = closureExpr->getBody()->getElement(0);
if (member.is<Stmt *>()) {
auto returnStmt = cast<ReturnStmt>(member.get<Stmt *>());
auto singleExpr = returnStmt->getResult();
auto voidExpr =
cs.cacheType(
TupleExpr::createEmpty(tc.Context,
singleExpr->getStartLoc(),
singleExpr->getEndLoc(),
/*implicit*/true));
returnStmt->setResult(voidExpr);
// For l-value types, reset to the object type. This might not be strictly
// necessary any more, but it's probably still a good idea.
if (cs.getType(singleExpr)->getAs<LValueType>())
cs.setType(singleExpr,
cs.getType(singleExpr)->getLValueOrInOutObjectType());
tc.checkIgnoredExpr(singleExpr);
SmallVector<ASTNode, 2> elements;
elements.push_back(singleExpr);
elements.push_back(returnStmt);
auto braceStmt = BraceStmt::create(tc.Context,
closureExpr->getStartLoc(),
elements,
closureExpr->getEndLoc(),
/*implicit*/true);
closureExpr->setImplicit();
closureExpr->setBody(braceStmt, /*isSingleExpression*/true);
}
// Finally, compute the proper type for the closure.
auto fnType = cs.getType(closureExpr)->getAs<FunctionType>();
Type inputType = fnType->getInput();
auto newClosureType = FunctionType::get(inputType,
tc.Context.TheEmptyTupleType,
fnType->getExtInfo());
cs.setType(closureExpr, newClosureType);
return closureExpr;
}
ClosureExpr *ExprRewriter::coerceClosureExprFromNever(ClosureExpr *closureExpr) {
auto &tc = cs.getTypeChecker();
// Re-write the single-expression closure to drop the 'return'.
assert(closureExpr->hasSingleExpressionBody());
// A single-expression body contains a single return statement
// prior to this transformation.
auto member = closureExpr->getBody()->getElement(0);
if (member.is<Stmt *>()) {
auto returnStmt = cast<ReturnStmt>(member.get<Stmt *>());
auto singleExpr = returnStmt->getResult();
tc.checkIgnoredExpr(singleExpr);
SmallVector<ASTNode, 1> elements;
elements.push_back(singleExpr);
auto braceStmt = BraceStmt::create(tc.Context,
closureExpr->getStartLoc(),
elements,
closureExpr->getEndLoc(),
/*implicit*/true);
closureExpr->setImplicit();
closureExpr->setBody(braceStmt, /*isSingleExpression*/true);
}
return closureExpr;
}
static void
maybeDiagnoseUnsupportedFunctionConversion(ConstraintSystem &cs, Expr *expr,
AnyFunctionType *toType) {
auto &tc = cs.getTypeChecker();
Type fromType = cs.getType(expr);
auto fromFnType = fromType->getAs<AnyFunctionType>();
// Conversions to C function pointer type are limited. Since a C function
// pointer captures no context, we can only do the necessary thunking or
// codegen if the original function is a direct reference to a global function
// or context-free closure or local function.
if (toType->getRepresentation()
== AnyFunctionType::Representation::CFunctionPointer) {
// Can convert from an ABI-compatible C function pointer.
if (fromFnType
&& fromFnType->getRepresentation()
== AnyFunctionType::Representation::CFunctionPointer)
return;
// Can convert a decl ref to a global or local function that doesn't
// capture context. Look through ignored bases too.
// TODO: Look through static method applications to the type.
auto semanticExpr = expr->getSemanticsProvidingExpr();
while (auto ignoredBase = dyn_cast<DotSyntaxBaseIgnoredExpr>(semanticExpr)){
semanticExpr = ignoredBase->getRHS()->getSemanticsProvidingExpr();
}
auto maybeDiagnoseFunctionRef = [&](FuncDecl *fn) {
// TODO: We could allow static (or class final) functions too by
// "capturing" the metatype in a thunk.
if (fn->getDeclContext()->isTypeContext()) {
tc.diagnose(expr->getLoc(),
diag::c_function_pointer_from_method);
} else if (fn->getGenericParams()) {
tc.diagnose(expr->getLoc(),
diag::c_function_pointer_from_generic_function);
} else {
tc.maybeDiagnoseCaptures(expr, fn);
}
};
if (auto declRef = dyn_cast<DeclRefExpr>(semanticExpr)) {
if (auto fn = dyn_cast<FuncDecl>(declRef->getDecl())) {
return maybeDiagnoseFunctionRef(fn);
}
}
if (auto memberRef = dyn_cast<MemberRefExpr>(semanticExpr)) {
if (auto fn = dyn_cast<FuncDecl>(memberRef->getMember().getDecl())) {
return maybeDiagnoseFunctionRef(fn);
}
}
// Unwrap closures with explicit capture lists.
if (auto capture = dyn_cast<CaptureListExpr>(semanticExpr))
semanticExpr = capture->getClosureBody();
// Can convert a literal closure that doesn't capture context.
if (auto closure = dyn_cast<ClosureExpr>(semanticExpr)) {
tc.maybeDiagnoseCaptures(expr, closure);
return;
}
tc.diagnose(expr->getLoc(),
diag::invalid_c_function_pointer_conversion_expr);
}
}
static CollectionUpcastConversionExpr::ConversionPair
buildElementConversion(ExprRewriter &rewriter,
SourceLoc srcLoc,
Type srcCollectionType,
Type destCollectionType,
ConstraintLocatorBuilder locator,
unsigned typeArgIndex) {
// We don't need this stuff unless we've got generalized casts.
Type srcType = srcCollectionType->castTo<BoundGenericType>()
->getGenericArgs()[typeArgIndex];
Type destType = destCollectionType->castTo<BoundGenericType>()
->getGenericArgs()[typeArgIndex];
// Build the conversion.
ASTContext &ctx = rewriter.getConstraintSystem().getASTContext();
auto opaque =
rewriter.cs.cacheType(new (ctx) OpaqueValueExpr(srcLoc, srcType));
auto conversion =
rewriter.coerceToType(opaque, destType,
locator.withPathElement(
ConstraintLocator::PathElement::getGenericArgument(typeArgIndex)));
return { opaque, conversion };
}
Expr *ExprRewriter::coerceToType(Expr *expr, Type toType,
ConstraintLocatorBuilder locator,
Optional<Pattern*> typeFromPattern) {
auto &tc = cs.getTypeChecker();
// The type we're converting from.
Type fromType = cs.getType(expr);
// If the types are already equivalent, we don't have to do anything.
if (fromType->isEqual(toType))
return expr;
// If the solver recorded what we should do here, just do it immediately.
auto knownRestriction = solution.ConstraintRestrictions.find(
{ fromType->getCanonicalType(),
toType->getCanonicalType() });
if (knownRestriction != solution.ConstraintRestrictions.end()) {
switch (knownRestriction->second) {
case ConversionRestrictionKind::TupleToTuple: {
auto fromTuple = fromType->castTo<TupleType>();
auto toTuple = toType->castTo<TupleType>();
SmallVector<int, 4> sources;
SmallVector<unsigned, 4> variadicArgs;
bool failed = computeTupleShuffle(fromTuple, toTuple,
sources, variadicArgs);
assert(!failed && "Couldn't convert tuple to tuple?");
(void)failed;
return coerceTupleToTuple(expr, fromTuple, toTuple, locator, sources,
variadicArgs, typeFromPattern);
}
case ConversionRestrictionKind::ScalarToTuple: {
auto toTuple = toType->castTo<TupleType>();
return coerceScalarToTuple(expr, toTuple,
toTuple->getElementForScalarInit(), locator);
}
case ConversionRestrictionKind::TupleToScalar: {
// If this was a single-element tuple expression, reach into that
// subexpression.
// FIXME: This is a hack to deal with @lvalue-ness issues. It loses
// source information.
if (auto fromTupleExpr = dyn_cast<TupleExpr>(expr)) {
if (fromTupleExpr->getNumElements() == 1) {
return coerceToType(fromTupleExpr->getElement(0), toType,
locator.withPathElement(
LocatorPathElt::getTupleElement(0)));
}
}
// Extract the element.
auto fromTuple = fromType->castTo<TupleType>();
expr =
cs.cacheType(
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 =
cs.cacheType(
new (tc.Context) ArchetypeToSuperExpr(expr,
fromArchetype->getSuperclass()));
// If we are done succeeded, use the coerced result.
if (cs.getType(expr)->isEqual(toType)) {
return expr;
}
fromType = cs.getType(expr);
}
// Coercion from subclass to superclass.
return cs.cacheType(new (tc.Context) DerivedToBaseExpr(expr, toType));
}
case ConversionRestrictionKind::LValueToRValue: {
if (toType->is<TupleType>() || fromType->is<TupleType>())
break;
// Load from the lvalue.
cs.propagateLValueAccessKind(expr, AccessKind::Read);
expr = cs.cacheType(
new (tc.Context) LoadExpr(expr, fromType->getRValueType()));
// Coerce the result.
return coerceToType(expr, toType, locator);
}
case ConversionRestrictionKind::Existential:
case ConversionRestrictionKind::MetatypeToExistentialMetatype:
return coerceExistential(expr, toType, locator);
case ConversionRestrictionKind::ClassMetatypeToAnyObject: {
assert(tc.getLangOpts().EnableObjCInterop
&& "metatypes can only be cast to objects w/ objc runtime!");
return cs.cacheType(
new (tc.Context) ClassMetatypeToObjectExpr(expr, toType));
}
case ConversionRestrictionKind::ExistentialMetatypeToAnyObject: {
assert(tc.getLangOpts().EnableObjCInterop
&& "metatypes can only be cast to objects w/ objc runtime!");
return cs.cacheType(
new (tc.Context) ExistentialMetatypeToObjectExpr(expr, toType));
}
case ConversionRestrictionKind::ProtocolMetatypeToProtocolClass: {
return cs.cacheType(
new (tc.Context) ProtocolMetatypeToObjectExpr(expr, toType));
}
case ConversionRestrictionKind::ValueToOptional: {
auto toGenericType = toType->castTo<BoundGenericType>();
assert(toGenericType->getDecl()->classifyAsOptionalType());
tc.requireOptionalIntrinsics(expr->getLoc());
Type valueType = toGenericType->getGenericArgs()[0];
expr = coerceToType(expr, valueType, locator);
if (!expr) return nullptr;
auto *result =
cs.cacheType(new (tc.Context) InjectIntoOptionalExpr(expr, toType));
diagnoseOptionalInjection(result);
return result;
}
case ConversionRestrictionKind::OptionalToImplicitlyUnwrappedOptional:
case ConversionRestrictionKind::ImplicitlyUnwrappedOptionalToOptional:
case ConversionRestrictionKind::OptionalToOptional:
return coerceOptionalToOptional(expr, toType, locator, typeFromPattern);
case ConversionRestrictionKind::ForceUnchecked: {
auto valueTy = fromType->getImplicitlyUnwrappedOptionalObjectType();
assert(valueTy);
expr = coerceImplicitlyUnwrappedOptionalToValue(expr, valueTy, locator);
return coerceToType(expr, toType, locator);
}
case ConversionRestrictionKind::ArrayUpcast: {
// Look through implicitly unwrapped optionals.
if (auto objTy= cs.lookThroughImplicitlyUnwrappedOptionalType(fromType)) {
expr = coerceImplicitlyUnwrappedOptionalToValue(expr, objTy, locator);
}
// Build the value conversion.
auto conv = buildElementConversion(*this, expr->getLoc(), cs.getType(expr),
toType, locator, 0);
// Form the upcast.
return
cs.cacheType(
new (tc.Context) CollectionUpcastConversionExpr(expr, toType,
{}, conv));
}
case ConversionRestrictionKind::HashableToAnyHashable: {
// Look through implicitly unwrapped optionals.
if (auto objTy
= cs.lookThroughImplicitlyUnwrappedOptionalType(cs.getType(expr))) {
expr = coerceImplicitlyUnwrappedOptionalToValue(expr, objTy, locator);
}
// We want to check conformance on the rvalue, as that's what has
// the Hashable conformance
expr = cs.coerceToRValue(expr);
// Find the conformance of the source type to Hashable.
auto hashable = tc.Context.getProtocol(KnownProtocolKind::Hashable);
auto conformance =
tc.conformsToProtocol(cs.getType(expr), hashable, cs.DC,
(ConformanceCheckFlags::InExpression |
ConformanceCheckFlags::Used));
assert(conformance && "must conform to Hashable");
return cs.cacheType(
new (tc.Context) AnyHashableErasureExpr(expr, toType, *conformance));
}
case ConversionRestrictionKind::DictionaryUpcast: {
// Look through implicitly unwrapped optionals.
if (auto objTy
= cs.lookThroughImplicitlyUnwrappedOptionalType(cs.getType(expr))) {
expr = coerceImplicitlyUnwrappedOptionalToValue(expr, objTy, locator);
}
// Build the key and value conversions.
auto keyConv = buildElementConversion(
*this, expr->getLoc(), cs.getType(expr), toType, locator, 0);
auto valueConv = buildElementConversion(
*this, expr->getLoc(), cs.getType(expr), toType, locator, 1);
// If the source key and value types are object types, this is an upcast.
// Otherwise, it's bridged.
Type sourceKey, sourceValue;
std::tie(sourceKey, sourceValue) = *cs.isDictionaryType(cs.getType(expr));
return cs.cacheType(new (tc.Context) CollectionUpcastConversionExpr(
expr, toType, keyConv, valueConv));
}
case ConversionRestrictionKind::SetUpcast: {
// Look through implicitly unwrapped optionals.
if (auto objTy
= cs.lookThroughImplicitlyUnwrappedOptionalType(cs.getType(expr))) {
expr = coerceImplicitlyUnwrappedOptionalToValue(expr, objTy, locator);
}
// Build the value conversion.
auto conv = buildElementConversion(*this, expr->getLoc(), cs.getType(expr),
toType, locator, 0);
return cs.cacheType(new (tc.Context) CollectionUpcastConversionExpr(
expr, toType, {}, conv));
}
case ConversionRestrictionKind::InoutToPointer: {
OptionalTypeKind optionalKind;
Type unwrappedTy = toType;
if (Type unwrapped = toType->getAnyOptionalObjectType(optionalKind))
unwrappedTy = unwrapped;
PointerTypeKind pointerKind;
auto toEltType = unwrappedTy->getAnyPointerElementType(pointerKind);
assert(toEltType && "not a pointer type?"); (void) toEltType;
if (pointerKind == PTK_UnsafePointer) {
// Overwrite the l-value access kind to be read-only if we're
// converting to a non-mutable pointer type.
auto *E = cast<InOutExpr>(expr->getValueProvidingExpr())->getSubExpr();
cs.propagateLValueAccessKind(E,
AccessKind::Read, /*overwrite*/ true);
}
tc.requirePointerArgumentIntrinsics(expr->getLoc());
Expr *result =
cs.cacheType(new (tc.Context) InOutToPointerExpr(expr, unwrappedTy));
if (optionalKind != OTK_None)
result = cs.cacheType(new (tc.Context)
InjectIntoOptionalExpr(result, toType));
return result;
}
case ConversionRestrictionKind::ArrayToPointer: {
OptionalTypeKind optionalKind;
Type unwrappedTy = toType;
if (Type unwrapped = toType->getAnyOptionalObjectType(optionalKind))
unwrappedTy = unwrapped;
tc.requirePointerArgumentIntrinsics(expr->getLoc());
Expr *result =
cs.cacheType(new (tc.Context) ArrayToPointerExpr(expr, unwrappedTy));
if (optionalKind != OTK_None)
result = cs.cacheType(new (tc.Context)
InjectIntoOptionalExpr(result, toType));
return result;
}
case ConversionRestrictionKind::StringToPointer: {
OptionalTypeKind optionalKind;
Type unwrappedTy = toType;
if (Type unwrapped = toType->getAnyOptionalObjectType(optionalKind))
unwrappedTy = unwrapped;
tc.requirePointerArgumentIntrinsics(expr->getLoc());
Expr *result =
cs.cacheType(new (tc.Context) StringToPointerExpr(expr, unwrappedTy));
if (optionalKind != OTK_None)
result = cs.cacheType(new (tc.Context)
InjectIntoOptionalExpr(result, toType));
return result;
}
case ConversionRestrictionKind::PointerToPointer: {
tc.requirePointerArgumentIntrinsics(expr->getLoc());
Type unwrappedToTy = toType->getAnyOptionalObjectType();
// Optional to optional.
if (Type unwrappedFromTy = cs.getType(expr)->getAnyOptionalObjectType()) {
assert(unwrappedToTy && "converting optional to non-optional");
Expr *boundOptional = cs.cacheType(
new (tc.Context) BindOptionalExpr(expr, SourceLoc(),
/*depth*/ 0, unwrappedFromTy));
Expr *converted = cs.cacheType(new (tc.Context) PointerToPointerExpr(
boundOptional, unwrappedToTy));
Expr *rewrapped = cs.cacheType(
new (tc.Context) InjectIntoOptionalExpr(converted, toType));
return cs.cacheType(new (tc.Context)
OptionalEvaluationExpr(rewrapped, toType));
}
// Non-optional to optional.
if (unwrappedToTy) {
Expr *converted = cs.cacheType(
new (tc.Context) PointerToPointerExpr(expr, unwrappedToTy));
return cs.cacheType(new (tc.Context)
InjectIntoOptionalExpr(converted, toType));
}
// Non-optional to non-optional.
return cs.cacheType(new (tc.Context) PointerToPointerExpr(expr, toType));
}
case ConversionRestrictionKind::BridgeToObjC: {
Expr *objcExpr = bridgeToObjectiveC(expr);
if (!objcExpr)
return nullptr;
return coerceToType(objcExpr, toType, locator);
}
case ConversionRestrictionKind::BridgeFromObjC:
return forceBridgeFromObjectiveC(expr, toType);
case ConversionRestrictionKind::CFTollFreeBridgeToObjC: {
auto foreignClass = fromType->getClassOrBoundGenericClass();
auto objcType = foreignClass->getAttrs().getAttribute<ObjCBridgedAttr>()
->getObjCClass()->getDeclaredInterfaceType();
auto asObjCClass = cs.cacheType(
new (tc.Context) ForeignObjectConversionExpr(expr, objcType));
return coerceToType(asObjCClass, toType, locator);
}
case ConversionRestrictionKind::ObjCTollFreeBridgeToCF: {
auto foreignClass = toType->getClassOrBoundGenericClass();
auto objcType = foreignClass->getAttrs().getAttribute<ObjCBridgedAttr>()
->getObjCClass()->getDeclaredInterfaceType();
Expr *result = coerceToType(expr, objcType, locator);
if (!result)
return nullptr;
return cs.cacheType(new (tc.Context)
ForeignObjectConversionExpr(result, toType));
}
}
}
// Tuple-to-scalar conversion.
if (auto fromTuple = fromType->getAs<TupleType>()) {
if (fromTuple->getNumElements() == 1 &&
!fromTuple->getElement(0).isVararg() &&
!toType->is<TupleType>()) {
expr = cs.cacheType(new (cs.getASTContext())
TupleElementExpr(
expr,
expr->getLoc(),
0,
expr->getLoc(),
fromTuple->getElementType(0)));
expr->setImplicit(true);
return expr;
}
}
// Coercions from an lvalue: load or perform implicit address-of. We perform
// these coercions first because they are often the first step in a multi-step
// coercion.
if (auto fromLValue = fromType->getAs<LValueType>()) {
if (auto *toIO = toType->getAs<InOutType>()) {
(void)toIO;
// In an 'inout' operator like "++i", the operand is converted from
// an implicit lvalue to an inout argument.
assert(toIO->getObjectType()->isEqual(fromLValue->getObjectType()));
cs.propagateLValueAccessKind(expr, AccessKind::ReadWrite);
return cs.cacheType(new (tc.Context)
InOutExpr(expr->getStartLoc(), expr, toType,
/*isImplicit*/ true));
}
// If we're actually turning this into an lvalue tuple element, don't
// load.
bool performLoad = true;
if (auto toTuple = toType->getAs<TupleType>()) {
int scalarIdx = toTuple->getElementForScalarInit();
if (scalarIdx >= 0 &&
toTuple->getElementType(scalarIdx)->is<InOutType>())
performLoad = false;
}
if (performLoad) {
// Load from the lvalue.
cs.propagateLValueAccessKind(expr, AccessKind::Read);
expr = cs.cacheType(new (tc.Context)
LoadExpr(expr, fromLValue->getObjectType()));
// Coerce the result.
return coerceToType(expr, toType, locator);
}
}
// Coercions to tuple type.
if (auto toTuple = toType->getAs<TupleType>()) {
// Coerce from a tuple to a tuple.
if (auto fromTuple = fromType->getAs<TupleType>()) {
SmallVector<int, 4> sources;
SmallVector<unsigned, 4> variadicArgs;
if (!computeTupleShuffle(fromTuple, toTuple, sources, variadicArgs)) {
return coerceTupleToTuple(expr, fromTuple, toTuple,
locator, sources, variadicArgs);
}
}
// Coerce scalar to tuple.
int toScalarIdx = toTuple->getElementForScalarInit();
if (toScalarIdx != -1) {
return coerceScalarToTuple(expr, toTuple, toScalarIdx, locator);
}
}
// Coercion from a subclass to a superclass.
if (fromType->mayHaveSuperclass() &&
toType->getClassOrBoundGenericClass()) {
for (auto fromSuperClass = tc.getSuperClassOf(fromType);
fromSuperClass;
fromSuperClass = tc.getSuperClassOf(fromSuperClass)) {
if (fromSuperClass->isEqual(toType)) {
// Coercion from archetype to its (concrete) superclass.
if (auto fromArchetype = fromType->getAs<ArchetypeType>()) {
expr = cs.cacheType(new (tc.Context) ArchetypeToSuperExpr(
expr, fromArchetype->getSuperclass()));
// If we succeeded, use the coerced result.
if (cs.getType(expr)->isEqual(toType))
return expr;
}
// Coercion from subclass to superclass.
return cs.cacheType(new (tc.Context) DerivedToBaseExpr(expr, toType));
}
}
}
// Coercions to function type.
if (auto toFunc = toType->getAs<FunctionType>()) {
// Coercion to an autoclosure type produces an implicit closure.
// FIXME: The type checker is more lenient, and allows @autoclosures to
// be subtypes of non-@autoclosures, which is bogus.
if (toFunc->isAutoClosure()) {
// Convert the value to the expected result type of the function.
expr = coerceToType(expr, toFunc->getResult(),
locator.withPathElement(ConstraintLocator::Load));
// We'll set discriminator values on all the autoclosures in a
// later pass.
auto discriminator = AutoClosureExpr::InvalidDiscriminator;
auto closure = cs.cacheType(
new (tc.Context) AutoClosureExpr(expr, toType, discriminator, dc));
closure->setParameterList(ParameterList::createEmpty(tc.Context));
// Compute the capture list, now that we have analyzed the expression.
tc.ClosuresWithUncomputedCaptures.push_back(closure);
return closure;
}
// Coercion from one function type to another, this produces a
// FunctionConversionExpr in its full generality.
if (auto fromFunc = fromType->getAs<FunctionType>()) {
// If toType is a NoEscape or NoReturn function type and the expression is
// a ClosureExpr, propagate these bits onto the ClosureExpr. Do not
// *remove* any bits that are already on the closure though.
// Note that in this case, we do not want to propagate the 'throws' bit
// to the closure type, as the closure has already been analyzed for
// throwing subexpressions. We also don't want to change the convention
// of the original closure.
auto fromEI = fromFunc->getExtInfo(), toEI = toFunc->getExtInfo();
if (toEI.isNoEscape() && !fromEI.isNoEscape()) {
swift::AnyFunctionType::ExtInfo newEI(fromEI.getRepresentation(),
toEI.isAutoClosure(),
toEI.isNoEscape() | fromEI.isNoEscape(),
toEI.throws() & fromEI.throws());
auto newToType = FunctionType::get(fromFunc->getInput(),
fromFunc->getResult(), newEI);
if (applyTypeToClosureExpr(cs, expr, newToType)) {
fromFunc = newToType;
// Propagating the bits in might have satisfied the entire
// conversion. If so, we're done, otherwise keep converting.
if (fromFunc->isEqual(toType))
return expr;
}
}
maybeDiagnoseUnsupportedFunctionConversion(cs, expr, toFunc);
return cs.cacheType(new (tc.Context)
FunctionConversionExpr(expr, toType));
}
}
// Coercions from a type to an existential type.
if (toType->isAnyExistentialType()) {
return coerceExistential(expr, toType, locator);
}
if (toType->getAnyOptionalObjectType() &&
cs.getType(expr)->getAnyOptionalObjectType()) {
return coerceOptionalToOptional(expr, toType, locator, typeFromPattern);
}
// Coercion to Optional<T>.
if (auto toGenericType = toType->getAs<BoundGenericType>()) {
if (toGenericType->getDecl()->classifyAsOptionalType()) {
tc.requireOptionalIntrinsics(expr->getLoc());
Type valueType = toGenericType->getGenericArgs()[0];
expr = coerceToType(expr, valueType, locator);
if (!expr) return nullptr;
auto *result =
cs.cacheType(new (tc.Context) InjectIntoOptionalExpr(expr, toType));
diagnoseOptionalInjection(result);
return result;
}
}
// Coercion from one metatype to another.
if (fromType->is<MetatypeType>()) {
auto toMeta = toType->castTo<MetatypeType>();
return cs.cacheType(new (tc.Context) MetatypeConversionExpr(expr, toMeta));
}
// Look through ImplicitlyUnwrappedOptional<T> before coercing expression.
if (auto ty = cs.lookThroughImplicitlyUnwrappedOptionalType(fromType)) {
expr = coerceImplicitlyUnwrappedOptionalToValue(expr, ty, locator);
return coerceToType(expr, toType, locator);
}
// Conversion to/from UnresolvedType.
if (fromType->is<UnresolvedType>() || toType->is<UnresolvedType>())
return cs.cacheType(new (tc.Context)
UnresolvedTypeConversionExpr(expr, toType));
llvm_unreachable("Unhandled coercion");
}
/// Adjust the given type to become the self type when referring to
/// the given member.
static Type adjustSelfTypeForMember(Type baseTy, ValueDecl *member,
AccessSemantics semantics,
DeclContext *UseDC) {
auto baseObjectTy = baseTy->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->getInterfaceType()->getAs<AnyFunctionType>()->getInput();
if (selfTy->is<InOutType>()) {
// Unless we're looking at a nonmutating existential member. In which
// case, the member will be modeled as an inout but ExistentialMemberRef
// and ArchetypeMemberRef want to take the base as an rvalue.
if (auto *fd = dyn_cast<FuncDecl>(func))
if (!fd->isMutating() && baseObjectTy->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 that requires the base to be mutable.
if (auto *SD = dyn_cast<AbstractStorageDecl>(member)) {
bool isSettableFromHere = SD->isSettable(UseDC)
&& (!UseDC->getASTContext().LangOpts.EnableAccessControl
|| SD->isSetterAccessibleFrom(UseDC));
// If neither the property's getter nor its setter are mutating, the base
// can be an rvalue.
if (!SD->isGetterMutating()
&& (!isSettableFromHere || SD->isSetterNonMutating()))
return baseObjectTy;
// If we're calling an accessor, keep the base as an inout type, because the
// getter may be mutating.
if (SD->hasAccessorFunctions() && baseTy->is<InOutType>() &&
semantics != AccessSemantics::DirectToStorage)
return InOutType::get(baseObjectTy);
}
// Accesses to non-function members in value types are done through an @lvalue
// type.
if (baseTy->is<InOutType>())
return LValueType::get(baseObjectTy);
// Accesses to members in values of reference type (classes, metatypes) are
// always done through a the reference to self. Accesses to value types with
// a non-mutable self are also done through the base type.
return baseTy;
}
Expr *
ExprRewriter::coerceObjectArgumentToType(Expr *expr,
Type baseTy, ValueDecl *member,
AccessSemantics semantics,
ConstraintLocatorBuilder locator) {
Type toType = adjustSelfTypeForMember(baseTy, member, semantics, dc);
// If our expression already has the right type, we're done.
Type fromType = cs.getType(expr);
if (fromType->isEqual(toType))
return expr;
// If we're coercing to an rvalue type, just do it.
if (!toType->is<InOutType>())
return coerceToType(expr, toType, locator);
assert(fromType->is<LValueType>() && "Can only convert lvalues to inout");
auto &ctx = cs.getTypeChecker().Context;
// Use InOutExpr to convert it to an explicit inout argument for the
// receiver.
cs.propagateLValueAccessKind(expr, AccessKind::ReadWrite);
return cs.cacheType(new (ctx) InOutExpr(expr->getStartLoc(), expr, toType,
/*isImplicit*/ true));
}
Expr *ExprRewriter::convertLiteral(Expr *literal,
Type type,
Type openedType,
ProtocolDecl *protocol,
TypeOrName literalType,
DeclName literalFuncName,
ProtocolDecl *builtinProtocol,
TypeOrName builtinLiteralType,
DeclName builtinLiteralFuncName,
bool (*isBuiltinArgType)(Type),
Diag<> brokenProtocolDiag,
Diag<> brokenBuiltinProtocolDiag) {
auto &tc = cs.getTypeChecker();
// If coercing a literal to an unresolved type, we don't try to look up the
// witness members, just do it.
if (type->is<UnresolvedType>()) {
// Instead of updating the literal expr in place, allocate a new node. This
// avoids issues where Builtin types end up on expr nodes and pollute
// diagnostics.
literal = cast<LiteralExpr>(literal)->shallowClone(tc.Context);
// The literal expression has this type.
cs.setType(literal, type);
return literal;
}
// Check whether this literal type conforms to the builtin protocol.
Optional<ProtocolConformanceRef> builtinConformance;
if (builtinProtocol &&
(builtinConformance =
tc.conformsToProtocol(type, builtinProtocol, cs.DC,
ConformanceCheckFlags::InExpression))) {
// Find the builtin argument type we'll use.
Type argType;
if (builtinLiteralType.is<Type>())
argType = builtinLiteralType.get<Type>();
else
argType = tc.getWitnessType(type, builtinProtocol,
*builtinConformance,
builtinLiteralType.get<Identifier>(),
brokenBuiltinProtocolDiag);
if (!argType)
return nullptr;
// Make sure it's of an appropriate builtin type.
if (isBuiltinArgType && !isBuiltinArgType(argType)) {
tc.diagnose(builtinProtocol->getLoc(), brokenBuiltinProtocolDiag);
return nullptr;
}
// Instead of updating the literal expr in place, allocate a new node. This
// avoids issues where Builtin types end up on expr nodes and pollute
// diagnostics.
literal = cast<LiteralExpr>(literal)->shallowClone(tc.Context);
// The literal expression has this type.
cs.setType(literal, argType);
// Call the builtin conversion operation.
// FIXME: Bogus location info.
Expr *base =
cs.cacheType(TypeExpr::createImplicitHack(literal->getLoc(), type,
tc.Context));
Expr *result = tc.callWitness(base, dc,
builtinProtocol, *builtinConformance,
builtinLiteralFuncName,
literal,
brokenBuiltinProtocolDiag);
if (result)
cs.setType(result, type);
return result;
}
// This literal type must conform to the (non-builtin) protocol.
assert(protocol && "requirements should have stopped recursion");
auto conformance = tc.conformsToProtocol(type, protocol, cs.DC,
ConformanceCheckFlags::InExpression);
assert(conformance && "must conform to literal protocol");
// Figure out the (non-builtin) argument type if there is one.
Type argType;
if (literalType.is<Identifier>() &&
literalType.get<Identifier>().empty()) {
// If there is no argument to the constructor function, then just pass in
// the empty tuple.
literal =
cs.cacheType(
TupleExpr::createEmpty(tc.Context, literal->getLoc(),
literal->getLoc(),
/*implicit*/!literal->getLoc().isValid()));
} else {
// Otherwise, figure out the type of the constructor function and coerce to
// it.
if (literalType.is<Type>())
argType = literalType.get<Type>();
else
argType = tc.getWitnessType(type, protocol, *conformance,
literalType.get<Identifier>(),
brokenProtocolDiag);
if (!argType)
return nullptr;
// If the argument type is in error, we're done.
if (argType->hasError() || argType->getCanonicalType()->hasError())
return nullptr;
// Convert the literal to the non-builtin argument type via the
// builtin protocol, first.
// FIXME: Do we need an opened type here?
literal = convertLiteral(literal, argType, argType, nullptr, Identifier(),
Identifier(), builtinProtocol,
builtinLiteralType, builtinLiteralFuncName,
isBuiltinArgType, brokenProtocolDiag,
brokenBuiltinProtocolDiag);
if (!literal)
return nullptr;
}
// Convert the resulting expression to the final literal type.
// FIXME: Bogus location info.
Expr *base =
cs.cacheType(TypeExpr::createImplicitHack(literal->getLoc(), type,
tc.Context));
literal = tc.callWitness(base, dc,
protocol, *conformance, literalFuncName,
literal, brokenProtocolDiag);
if (literal)
cs.setType(literal, type);
return literal;
}
Expr *ExprRewriter::convertLiteralInPlace(Expr *literal,
Type type,
ProtocolDecl *protocol,
Identifier literalType,
DeclName literalFuncName,
ProtocolDecl *builtinProtocol,
DeclName builtinLiteralFuncName,
Diag<> brokenProtocolDiag,
Diag<> brokenBuiltinProtocolDiag) {
auto &tc = cs.getTypeChecker();
// If coercing a literal to an unresolved type, we don't try to look up the
// witness members, just do it.
if (type->is<UnresolvedType>()) {
// Instead of updating the literal expr in place, allocate a new node. This
// avoids issues where Builtin types end up on expr nodes and pollute
// diagnostics.
literal = cast<LiteralExpr>(literal)->shallowClone(tc.Context);
// The literal expression has this type.
cs.setType(literal, type);
return literal;
}
// Check whether this literal type conforms to the builtin protocol. If so,
// initialize via the builtin protocol.
Optional<ProtocolConformanceRef> builtinConformance;
if (builtinProtocol &&
(builtinConformance =
tc.conformsToProtocol(type, builtinProtocol, cs.DC,
ConformanceCheckFlags::InExpression))) {
// Find the witness that we'll use to initialize the type via a builtin
// literal.
auto witness = findNamedWitnessImpl<AbstractFunctionDecl>(
tc, dc, type->getRValueType(), builtinProtocol,
builtinLiteralFuncName, brokenBuiltinProtocolDiag,
*builtinConformance);
if (!witness)
return nullptr;
// Form a reference to the builtin conversion function.
// FIXME: Bogus location info.
Expr *base =
cs.cacheType(TypeExpr::createImplicitHack(literal->getLoc(), type,
tc.Context));
Expr *unresolvedDot = new (tc.Context) UnresolvedDotExpr(
base, SourceLoc(),
witness->getFullName(),
DeclNameLoc(base->getEndLoc()),
/*Implicit=*/true);
(void)tc.typeCheckExpression(unresolvedDot, dc);
cs.cacheExprTypes(unresolvedDot);
ConcreteDeclRef builtinRef = unresolvedDot->getReferencedDecl();
if (!builtinRef) {
tc.diagnose(base->getLoc(), brokenBuiltinProtocolDiag);
return nullptr;
}
// Set the builtin initializer.
if (auto stringLiteral = dyn_cast<StringLiteralExpr>(literal))
stringLiteral->setBuiltinInitializer(builtinRef);
else {
cast<MagicIdentifierLiteralExpr>(literal)
->setBuiltinInitializer(builtinRef);
}
// The literal expression has this type.
cs.setType(literal, type);
return literal;
}
// This literal type must conform to the (non-builtin) protocol.
assert(protocol && "requirements should have stopped recursion");
auto conformance = tc.conformsToProtocol(type, protocol, cs.DC,
ConformanceCheckFlags::InExpression);
assert(conformance && "must conform to literal protocol");
// Dig out the literal type and perform a builtin literal conversion to it.
if (!literalType.empty()) {
// Extract the literal type.
Type builtinLiteralType = tc.getWitnessType(type, protocol, *conformance,
literalType,
brokenProtocolDiag);
if (!builtinLiteralType)
return nullptr;
// Perform the builtin conversion.
if (!convertLiteralInPlace(literal, builtinLiteralType, nullptr,
Identifier(), DeclName(), builtinProtocol,
builtinLiteralFuncName, brokenProtocolDiag,
brokenBuiltinProtocolDiag))
return nullptr;
}
// Find the witness that we'll use to initialize the literal value.
auto witness = findNamedWitnessImpl<AbstractFunctionDecl>(
tc, dc, type->getRValueType(), protocol,
literalFuncName, brokenProtocolDiag,
conformance);
if (!witness)
return nullptr;
// Form a reference to the conversion function.
// FIXME: Bogus location info.
Expr *base =
cs.cacheType(TypeExpr::createImplicitHack(literal->getLoc(), type,
tc.Context));
Expr *unresolvedDot = new (tc.Context) UnresolvedDotExpr(
base, SourceLoc(),
witness->getFullName(),
DeclNameLoc(base->getEndLoc()),
/*Implicit=*/true);
(void)tc.typeCheckExpression(unresolvedDot, dc);
cs.cacheExprTypes(unresolvedDot);
ConcreteDeclRef ref = unresolvedDot->getReferencedDecl();
if (!ref) {
tc.diagnose(base->getLoc(), brokenProtocolDiag);
return nullptr;
}
// Set the initializer.
if (auto stringLiteral = dyn_cast<StringLiteralExpr>(literal))
stringLiteral->setInitializer(ref);
else
cast<MagicIdentifierLiteralExpr>(literal)->setInitializer(ref);
// The literal expression has this type.
cs.setType(literal, type);
return literal;
}
/// Determine whether the given type refers to a non-final class (or
/// dynamic self of one).
static bool isNonFinalClass(Type type) {
if (auto dynamicSelf = type->getAs<DynamicSelfType>())
type = dynamicSelf->getSelfType();
if (auto classDecl = type->getClassOrBoundGenericClass())
return !classDecl->isFinal();
if (auto archetype = type->getAs<ArchetypeType>())
if (auto super = archetype->getSuperclass())
return isNonFinalClass(super);
return false;
}
// Non-required constructors may not be not inherited. Therefore when
// constructing a class object, either the metatype must be statically
// derived (rather than an arbitrary value of metatype type) or the referenced
// constructor must be required.
bool
TypeChecker::diagnoseInvalidDynamicConstructorReferences(Expr *base,
DeclNameLoc memberRefLoc,
AnyMetatypeType *metaTy,
ConstructorDecl *ctorDecl,
bool SuppressDiagnostics) {
auto ty = metaTy->getInstanceType();
// FIXME: The "hasClangNode" check here is a complete hack.
if (isNonFinalClass(ty) &&
!base->isStaticallyDerivedMetatype() &&
!ctorDecl->hasClangNode() &&
!(ctorDecl->isRequired() ||
ctorDecl->getDeclContext()->getAsProtocolOrProtocolExtensionContext())) {
if (SuppressDiagnostics)
return false;
diagnose(memberRefLoc, diag::dynamic_construct_class, ty)
.highlight(base->getSourceRange());
auto ctor = cast<ConstructorDecl>(ctorDecl);
diagnose(ctorDecl, diag::note_nonrequired_initializer,
ctor->isImplicit(), ctor->getFullName());
// Constructors cannot be called on a protocol metatype, because there is no
// metatype to witness it.
} else if (isa<ConstructorDecl>(ctorDecl) &&
isa<MetatypeType>(metaTy) &&
ty->isExistentialType()) {
if (SuppressDiagnostics)
return false;
if (base->isStaticallyDerivedMetatype()) {
diagnose(memberRefLoc, diag::construct_protocol_by_name, ty)
.highlight(base->getSourceRange());
} else {
diagnose(memberRefLoc, diag::construct_protocol_value, metaTy)
.highlight(base->getSourceRange());
}
}
return true;
}
Expr *ExprRewriter::finishApply(ApplyExpr *apply, Type openedType,
ConstraintLocatorBuilder locator) {
TypeChecker &tc = cs.getTypeChecker();
auto fn = apply->getFn();
// The function is always an rvalue.
fn = cs.coerceToRValue(fn);
assert(fn && "Rvalue conversion failed?");
if (!fn)
return nullptr;
// Handle applications that look through ImplicitlyUnwrappedOptional<T>.
if (auto fnTy = cs.lookThroughImplicitlyUnwrappedOptionalType(cs.getType(fn)))
fn = coerceImplicitlyUnwrappedOptionalToValue(fn, fnTy, locator);
// If we're applying a function that resulted from a covariant
// function conversion, strip off that conversion.
// FIXME: It would be nicer if we could build the ASTs properly in the
// first shot.
Type covariantResultType;
if (auto covariant = dyn_cast<CovariantFunctionConversionExpr>(fn)) {
// Strip off one layer of application from the covariant result.
covariantResultType
= cs.getType(covariant)->castTo<AnyFunctionType>()->getResult();
// Use the subexpression as the function.
fn = covariant->getSubExpr();
}
apply->setFn(fn);
// Check whether the argument is 'super'.
bool isSuper = apply->getArg()->isSuperExpr();
// For function application, convert the argument to the input type of
// the function.
SmallVector<Identifier, 2> argLabelsScratch;
if (auto fnType = cs.getType(fn)->getAs<FunctionType>()) {
auto origArg = apply->getArg();
bool hasTrailingClosure =
isa<CallExpr>(apply) && cast<CallExpr>(apply)->hasTrailingClosure();
Expr *arg = coerceCallArguments(origArg, fnType->getInput(),
apply,
apply->getArgumentLabels(argLabelsScratch),
hasTrailingClosure,
locator.withPathElement(
ConstraintLocator::ApplyArgument));
if (!arg) {
return nullptr;
}
apply->setArg(arg);
cs.setType(apply, fnType->getResult());
apply->setIsSuper(isSuper);
Expr *result = tc.substituteInputSugarTypeForResult(apply);
// Try closing the existential, if there is one.
closeExistential(result);
// If we have a covariant result type, perform the conversion now.
if (covariantResultType) {
if (covariantResultType->is<FunctionType>())
result = cs.cacheType(new (tc.Context) CovariantFunctionConversionExpr(
result, covariantResultType));
else
result = cs.cacheType(new (tc.Context) CovariantReturnConversionExpr(
result, covariantResultType));
}
// Extract all arguments.
auto *CEA = arg;
if (auto *TSE = dyn_cast<TupleShuffleExpr>(CEA))
CEA = TSE->getSubExpr();
// The argument is either a ParenExpr or TupleExpr.
ArrayRef<Expr *> arguments;
ArrayRef<TypeBase *> types;
SmallVector<Expr *, 1> Scratch;
if (auto *TE = dyn_cast<TupleExpr>(CEA))
arguments = TE->getElements();
else if (auto *PE = dyn_cast<ParenExpr>(CEA)) {
Scratch.push_back(PE->getSubExpr());
arguments = makeArrayRef(Scratch);
}
else {
Scratch.push_back(apply->getArg());
arguments = makeArrayRef(Scratch);
}
for (auto arg: arguments) {
bool isNoEscape = false;
while (1) {
if (auto AFT = cs.getType(arg)->getAs<AnyFunctionType>()) {
isNoEscape = isNoEscape || AFT->isNoEscape();
}
if (auto conv = dyn_cast<ImplicitConversionExpr>(arg))
arg = conv->getSubExpr();
else if (auto *PE = dyn_cast<ParenExpr>(arg))
arg = PE->getSubExpr();
else
break;
}
if (!isNoEscape) {
if (auto DRE = dyn_cast<DeclRefExpr>(arg))
if (auto FD = dyn_cast<FuncDecl>(DRE->getDecl())) {
tc.addEscapingFunctionAsArgument(FD, apply);
}
}
}
return result;
}
// If this is an UnresolvedType in the system, preserve it.
if (cs.getType(fn)->is<UnresolvedType>()) {
cs.setType(apply, cs.getType(fn));
return apply;
}
// We have a type constructor.
auto metaTy = cs.getType(fn)->castTo<AnyMetatypeType>();
auto ty = metaTy->getInstanceType();
// If this is an UnresolvedType in the system, preserve it.
if (ty->is<UnresolvedType>()) {
cs.setType(apply, ty);
return apply;
}
// If the metatype value isn't a type expression, the user should reference
// '.init' explicitly, for clarity.
if (!fn->isTypeReference()) {
cs.TC.diagnose(apply->getArg()->getStartLoc(),
diag::missing_init_on_metatype_initialization)
.fixItInsert(apply->getArg()->getStartLoc(), ".init");
}
// If we're "constructing" a tuple type, it's simply a conversion.
if (auto tupleTy = ty->getAs<TupleType>()) {
// FIXME: Need an AST to represent this properly.
return coerceToType(apply->getArg(), tupleTy, locator);
}
// We're constructing a value of nominal type. Look for the constructor or
// enum element to use.
assert(ty->getNominalOrBoundGenericNominal() || ty->is<DynamicSelfType>() ||
ty->isExistentialType() || ty->is<ArchetypeType>());
auto ctorLocator = cs.getConstraintLocator(
locator.withPathElement(ConstraintLocator::ApplyFunction)
.withPathElement(ConstraintLocator::ConstructorMember));
auto selected = getOverloadChoiceIfAvailable(ctorLocator);
// We have the constructor.
auto choice = selected->choice;
auto decl = choice.getDecl();
// Consider the constructor decl reference expr 'implicit', but the
// constructor call expr itself has the apply's 'implicitness'.
bool isDynamic = choice.getKind() == OverloadChoiceKind::DeclViaDynamic;
Expr *declRef = buildMemberRef(fn,
selected->openedFullType,
/*DotLoc=*/SourceLoc(),
decl, DeclNameLoc(fn->getEndLoc()),
selected->openedType,
locator,
ctorLocator,
/*Implicit=*/true,
choice.getFunctionRefKind(),
AccessSemantics::Ordinary,
isDynamic);
if (!declRef)
return nullptr;
declRef->setImplicit(apply->isImplicit());
apply->setFn(declRef);
// Tail-recur to actually call the constructor.
return finishApply(apply, openedType, locator);
}
// Return the precedence-yielding parent of 'expr', along with the index of
// 'expr' as the child of that parent. The precedence-yielding parent is the
// nearest ancestor of 'expr' which imposes a minimum precedence on 'expr'.
// Right now that just means skipping over TupleExpr instances that only exist
// to hold arguments to binary operators.
static std::pair<Expr *, unsigned> getPrecedenceParentAndIndex(Expr *expr,
Expr *rootExpr)
{
auto parentMap = rootExpr->getParentMap();
auto it = parentMap.find(expr);
if (it == parentMap.end()) {
return { nullptr, 0 };
}
Expr *parent = it->second;
// Handle all cases where the answer isn't just going to be { parent, 0 }.
if (auto tuple = dyn_cast<TupleExpr>(parent)) {
// Get index of expression in tuple.
auto tupleElems = tuple->getElements();
auto elemIt = std::find(tupleElems.begin(), tupleElems.end(), expr);
assert(elemIt != tupleElems.end() && "expr not found in parent TupleExpr");
unsigned index = elemIt - tupleElems.begin();
it = parentMap.find(parent);
if (it != parentMap.end()) {
Expr *gparent = it->second;
// Was this tuple just constructed for a binop?
if (isa<BinaryExpr>(gparent)) {
return { gparent, index };
}
}
// Must be a tuple literal, function arg list, collection, etc.
return { parent, index };
} else if (auto ifExpr = dyn_cast<IfExpr>(parent)) {
unsigned index;
if (expr == ifExpr->getCondExpr()) {
index = 0;
} else if (expr == ifExpr->getThenExpr()) {
index = 1;
} else if (expr == ifExpr->getElseExpr()) {
index = 2;
} else {
llvm_unreachable("expr not found in parent IfExpr");
}
return { ifExpr, index };
} else if (auto assignExpr = dyn_cast<AssignExpr>(parent)) {
unsigned index;
if (expr == assignExpr->getSrc()) {
index = 0;
} else if (expr == assignExpr->getDest()) {
index = 1;
} else {
llvm_unreachable("expr not found in parent AssignExpr");
}
return { assignExpr, index };
}
return { parent, 0 };
}
/// Return true if, when replacing "<expr>" with "<expr> op <something>",
/// parentheses must be added around "<expr>" to allow the new operator
/// to bind correctly.
static bool exprNeedsParensInsideFollowingOperator(TypeChecker &TC,
DeclContext *DC, Expr *expr,
PrecedenceGroupDecl *followingPG) {
if (expr->isInfixOperator()) {
auto exprPG = TC.lookupPrecedenceGroupForInfixOperator(DC, expr);
if (!exprPG) return true;
return TC.Context.associateInfixOperators(exprPG, followingPG)
!= Associativity::Left;
}
// We want to parenthesize a 'try?' on the LHS, but we don't care about
// capturing the new operator inside a 'try' or 'try!'.
if (isa<OptionalTryExpr>(expr))
return true;
return false;
}
/// Return true if, when replacing "<expr>" with "<expr> op <something>"
/// within the given root expression, parentheses must be added around
/// the new operator to prevent it from binding incorrectly in the
/// surrounding context.
static bool exprNeedsParensOutsideFollowingOperator(TypeChecker &TC,
DeclContext *DC, Expr *expr,
Expr *rootExpr,
PrecedenceGroupDecl *followingPG) {
Expr *parent;
unsigned index;
std::tie(parent, index) = getPrecedenceParentAndIndex(expr, rootExpr);
if (!parent || isa<TupleExpr>(parent) || isa<ParenExpr>(parent)) {
return false;
}
if (parent->isInfixOperator()) {
auto parentPG = TC.lookupPrecedenceGroupForInfixOperator(DC, parent);
if (!parentPG) return true;
// If the index is 0, this is on the LHS of the parent.
if (index == 0) {
return TC.Context.associateInfixOperators(followingPG, parentPG)
!= Associativity::Left;
} else {
return TC.Context.associateInfixOperators(parentPG, followingPG)
!= Associativity::Right;
}
}
return true;
}
// Return true if, when replacing "<expr>" with "<expr> as T", parentheses need
// to be added around <expr> first in order to maintain the correct precedence.
static bool exprNeedsParensBeforeAddingAs(TypeChecker &TC, DeclContext *DC,
Expr *expr) {
auto asPG =
TC.lookupPrecedenceGroup(DC, DC->getASTContext().Id_CastingPrecedence,
SourceLoc());
if (!asPG) return true;
return exprNeedsParensInsideFollowingOperator(TC, DC, expr, asPG);
}
// Return true if, when replacing "<expr>" with "<expr> as T", parentheses need
// to be added around the new expression in order to maintain the correct
// precedence.
static bool exprNeedsParensAfterAddingAs(TypeChecker &TC, DeclContext *DC,
Expr *expr, Expr *rootExpr) {
auto asPG =
TC.lookupPrecedenceGroup(DC, DC->getASTContext().Id_CastingPrecedence,
SourceLoc());
if (!asPG) return true;
return exprNeedsParensOutsideFollowingOperator(TC, DC, expr, rootExpr, asPG);
}
static bool exprNeedsParensInsidePostfixOperator(TypeChecker &TC,
DeclContext *DC,
Expr *expr) {
// Prefix and infix operators will bind outside of a postfix operator.
// Postfix operators will get token-merged with a new postfix operator.
return (isa<PrefixUnaryExpr>(expr) ||
isa<PostfixUnaryExpr>(expr) ||
isa<OptionalEvaluationExpr>(expr) ||
expr->isInfixOperator());
}
namespace {
class ExprWalker : public ASTWalker {
ExprRewriter &Rewriter;
SmallVector<ClosureExpr *, 4> closuresToTypeCheck;
public:
ExprWalker(ExprRewriter &Rewriter) : Rewriter(Rewriter) { }
~ExprWalker() {
// If we're re-typechecking an expression for diagnostics, don't
// visit closures that have non-single expression bodies.
if (Rewriter.SkipClosures)
return;
auto &cs = Rewriter.getConstraintSystem();
auto &tc = cs.getTypeChecker();
for (auto *closure : closuresToTypeCheck)
tc.typeCheckClosureBody(closure);
}
std::pair<bool, Expr *> walkToExprPre(Expr *expr) override {
// For closures, update the parameter types and check the body.
if (auto closure = dyn_cast<ClosureExpr>(expr)) {
Rewriter.simplifyExprType(expr);
auto &cs = Rewriter.getConstraintSystem();
auto &tc = cs.getTypeChecker();
// Coerce the pattern, in case we resolved something.
auto fnType = cs.getType(closure)->castTo<FunctionType>();
auto *params = closure->getParameters();
if (tc.coerceParameterListToType(params, closure, fnType))
return { false, nullptr };
// If this is a single-expression closure, convert the expression
// in the body to the result type of the closure.
if (closure->hasSingleExpressionBody()) {
// Enter the context of the closure when type-checking the body.
llvm::SaveAndRestore<DeclContext *> savedDC(Rewriter.dc, closure);
Expr *body = closure->getSingleExpressionBody()->walk(*this);
if (!body)
return { false, nullptr };
if (body != closure->getSingleExpressionBody())
closure->setSingleExpressionBody(body);
if (body) {
// A single-expression closure with a non-Void expression type
// coerces to a Void-returning function type.
if (fnType->getResult()->isVoid() && !cs.getType(body)->isVoid()) {
closure = Rewriter.coerceClosureExprToVoid(closure);
// A single-expression closure with a Never expression type
// coerces to any other function type.
} else if (!fnType->getResult()->isUninhabited() &&
cs.getType(body)->isUninhabited()) {
closure = Rewriter.coerceClosureExprFromNever(closure);
} else {
body = Rewriter.coerceToType(body,
fnType->getResult(),
cs.getConstraintLocator(
closure,
ConstraintLocator::ClosureResult));
if (!body)
return { false, nullptr };
closure->setSingleExpressionBody(body);
}
}
} else {
// For other closures, type-check the body once we've finished with
// the expression.
closuresToTypeCheck.push_back(closure);
}
tc.ClosuresWithUncomputedCaptures.push_back(closure);
return { false, closure };
}
Rewriter.walkToExprPre(expr);
return { true, expr };
}
Expr *walkToExprPost(Expr *expr) override {
Expr *result = Rewriter.walkToExprPost(expr);
auto &cs = Rewriter.getConstraintSystem();
if (result && cs.hasType(result))
Rewriter.checkForImportedUsedConformances(cs.getType(result));
return result;
}
/// \brief Ignore statements.
std::pair<bool, Stmt *> walkToStmtPre(Stmt *stmt) override {
return { false, stmt };
}
/// \brief Ignore declarations.
bool walkToDeclPre(Decl *decl) override { return false; }
};
}
Expr *ConstraintSystem::coerceToRValue(Expr *expr) {
// Can't load from an inout value.
if (auto *iot = getType(expr)->getAs<InOutType>()) {
// Emit a fixit if we can find the & expression that turned this into an
// inout.
auto &tc = getTypeChecker();
if (auto addrOf =
dyn_cast<InOutExpr>(expr->getSemanticsProvidingExpr())) {
tc.diagnose(expr->getLoc(), diag::load_of_explicit_lvalue,
iot->getObjectType())
.fixItRemove(SourceRange(addrOf->getLoc()));
return coerceToRValue(addrOf->getSubExpr());
} else {
tc.diagnose(expr->getLoc(), diag::load_of_explicit_lvalue,
iot->getObjectType());
return expr;
}
}
// If we already have an rvalue, we're done, otherwise emit a load.
if (auto lvalueTy = getType(expr)->getAs<LValueType>()) {
propagateLValueAccessKind(expr, AccessKind::Read);
return cacheType(new (getASTContext())
LoadExpr(expr, lvalueTy->getObjectType()));
}
return expr;
}
/// Emit the fixes computed as part of the solution, returning true if we were
/// able to emit an error message, or false if none of the fixits worked out.
bool ConstraintSystem::applySolutionFixes(Expr *E, const Solution &solution) {
bool diagnosed = false;
for (unsigned i = 0, e = solution.Fixes.size(); i != e; ++i)
diagnosed |= applySolutionFix(E, solution, i);
return diagnosed;
}
/// \brief Apply the specified Fix # to this solution, producing a fixit hint
/// diagnostic for it and returning true. If the fixit hint turned out to be
/// bogus, this returns false and doesn't emit anything.
bool ConstraintSystem::applySolutionFix(Expr *expr,
const Solution &solution,
unsigned fixNo) {
auto &fix = solution.Fixes[fixNo];
// Some fixes need more information from the locator.
ConstraintLocator *locator = fix.second;
// In the case of us having applied a type member constraint against a
// synthesized type variable during diagnostic generation, we may not have
// a valid locator.
if (!locator)
return false;
// Resolve the locator to a specific expression.
SourceRange range;
bool isSubscriptMember =
(!locator->getPath().empty() &&
locator->getPath().back().getKind() == ConstraintLocator::SubscriptMember);
ConstraintLocator *resolved = simplifyLocator(*this, locator, range);
// If we didn't manage to resolve directly to an expression, we don't
// have a great diagnostic to give, so bail.
if (!resolved || !resolved->getAnchor() ||
!resolved->getPath().empty())
return false;
Expr *affected = resolved->getAnchor();
// FIXME: Work around an odd locator representation that doesn't separate the
// base of a subscript member from the member access.
if (isSubscriptMember) {
if (auto subscript = dyn_cast<SubscriptExpr>(affected))
affected = subscript->getBase();
}
switch (fix.first.getKind()) {
case FixKind::None:
llvm_unreachable("no-fix marker should never make it into solution");
case FixKind::ForceOptional: {
const Expr *unwrapped = affected->getValueProvidingExpr();
auto type = solution.simplifyType(TC, getType(affected))
->getRValueObjectType();
if (auto tryExpr = dyn_cast<OptionalTryExpr>(unwrapped)) {
TC.diagnose(tryExpr->getTryLoc(), diag::missing_unwrap_optional_try,
type)
.fixItReplace({tryExpr->getTryLoc(), tryExpr->getQuestionLoc()},
"try!");
} else {
auto diag = TC.diagnose(affected->getLoc(),
diag::missing_unwrap_optional, type);
bool parensNeeded =
exprNeedsParensInsidePostfixOperator(TC, DC, affected);
if (parensNeeded) {
diag.fixItInsert(affected->getStartLoc(), "(")
.fixItInsertAfter(affected->getEndLoc(), ")!");
} else {
diag.fixItInsertAfter(affected->getEndLoc(), "!");
}
}
return true;
}
case FixKind::OptionalChaining: {
auto type = solution.simplifyType(TC, getType(affected))
->getRValueObjectType();
auto diag = TC.diagnose(affected->getLoc(),
diag::missing_unwrap_optional, type);
diag.fixItInsertAfter(affected->getEndLoc(), "?");
return true;
}
case FixKind::ForceDowncast: {
auto fromType = solution.simplifyType(TC, getType(affected))
->getRValueObjectType();
Type toType = solution.simplifyType(TC,
fix.first.getTypeArgument(*this));
bool useAs = TC.isExplicitlyConvertibleTo(fromType, toType, DC);
bool useAsBang = !useAs && TC.checkedCastMaySucceed(fromType, toType,
DC);
if (!useAs && !useAsBang)
return false;
bool needsParensInside = exprNeedsParensBeforeAddingAs(TC, DC, affected);
bool needsParensOutside = exprNeedsParensAfterAddingAs(TC, DC, affected,
expr);
llvm::SmallString<2> insertBefore;
llvm::SmallString<32> insertAfter;
if (needsParensOutside) {
insertBefore += "(";
}
if (needsParensInside) {
insertBefore += "(";
insertAfter += ")";
}
insertAfter += useAs ? " as " : " as! ";
insertAfter += toType.getString();
if (needsParensOutside)
insertAfter += ")";
auto diagID = useAs ? diag::missing_explicit_conversion
: diag::missing_forced_downcast;
auto diag = TC.diagnose(affected->getLoc(), diagID, fromType, toType);
if (!insertBefore.empty()) {
diag.fixItInsert(affected->getStartLoc(), insertBefore);
}
diag.fixItInsertAfter(affected->getEndLoc(), insertAfter);
return true;
}
case FixKind::AddressOf: {
auto type = solution.simplifyType(TC, getType(affected))
->getRValueObjectType();
TC.diagnose(affected->getLoc(), diag::missing_address_of, type)
.fixItInsert(affected->getStartLoc(), "&");
return true;
}
case FixKind::CoerceToCheckedCast: {
if (auto *coerceExpr = dyn_cast<CoerceExpr>(locator->getAnchor())) {
Expr *subExpr = coerceExpr->getSubExpr();
auto fromType =
solution.simplifyType(TC, getType(subExpr))->getRValueType();
auto toType =
solution.simplifyType(TC, coerceExpr->getCastTypeLoc().getType());
auto castKind = TC.typeCheckCheckedCast(
fromType, toType, DC,
coerceExpr->getLoc(),
subExpr->getSourceRange(),
coerceExpr->getCastTypeLoc().getSourceRange(),
[&](Type commonTy) -> bool {
return TC.convertToType(subExpr, commonTy, DC);
},
/*suppressDiagnostics=*/ true);
switch (castKind) {
// Invalid cast.
case CheckedCastKind::Unresolved:
// Fix didn't work, let diagnoseFailureForExpr handle this.
return false;
case CheckedCastKind::Coercion:
llvm_unreachable("Coercions handled in other disjunction branch");
// Valid casts.
case CheckedCastKind::ArrayDowncast:
case CheckedCastKind::DictionaryDowncast:
case CheckedCastKind::SetDowncast:
case CheckedCastKind::ValueCast:
case CheckedCastKind::BridgeFromObjectiveC:
TC.diagnose(coerceExpr->getLoc(), diag::missing_forced_downcast,
fromType, toType)
.highlight(coerceExpr->getSourceRange())
.fixItReplace(coerceExpr->getLoc(), "as!");
return true;
}
}
return false;
}
}
// FIXME: It would be really nice to emit a follow-up note showing where
// we got the other type information from, e.g., the parameter we're
// initializing.
return false;
}
/// \brief Apply a given solution to the expression, producing a fully
/// type-checked expression.
Expr *ConstraintSystem::applySolution(Solution &solution, Expr *expr,
Type convertType,
bool discardedExpr,
bool suppressDiagnostics,
bool skipClosures) {
// If any fixes needed to be applied to arrive at this solution, resolve
// them to specific expressions.
if (!solution.Fixes.empty()) {
// If we can diagnose the problem with the fixits that we've pre-assumed,
// do so now.
if (applySolutionFixes(expr, solution))
return nullptr;
// If we didn't manage to diagnose anything well, so fall back to
// diagnosing mining the system to construct a reasonable error message.
diagnoseFailureForExpr(expr);
return nullptr;
}
ExprRewriter rewriter(*this, solution, suppressDiagnostics, skipClosures);
ExprWalker walker(rewriter);
// Apply the solution to the expression.
auto result = expr->walk(walker);
if (!result)
return nullptr;
// If we're supposed to convert the expression to some particular type,
// do so now.
if (convertType) {
result = rewriter.coerceToType(result, convertType,
getConstraintLocator(expr));
if (!result)
return nullptr;
} else if (getType(result)->isLValueType() && !discardedExpr) {
// We referenced an lvalue. Load it.
result = rewriter.coerceToType(result, getType(result)->getRValueType(),
getConstraintLocator(expr));
}
if (result)
rewriter.finalize(result);
return result;
}
Expr *ConstraintSystem::applySolutionShallow(const Solution &solution,
Expr *expr,
bool suppressDiagnostics) {
ExprRewriter rewriter(*this, solution, suppressDiagnostics,
/*skipClosures=*/false);
rewriter.walkToExprPre(expr);
Expr *result = rewriter.walkToExprPost(expr);
if (result)
rewriter.finalize(result);
return result;
}
Expr *Solution::coerceToType(Expr *expr, Type toType,
ConstraintLocator *locator,
bool ignoreTopLevelInjection,
Optional<Pattern*> typeFromPattern) const {
auto &cs = getConstraintSystem();
ExprRewriter rewriter(cs, *this,
/*suppressDiagnostics=*/false,
/*skipClosures=*/false);
Expr *result = rewriter.coerceToType(expr, toType, locator, typeFromPattern);
if (!result)
return nullptr;
// If we were asked to ignore top-level optional injections, mark
// the top-level injection (if any) as "diagnosed".
if (ignoreTopLevelInjection) {
if (auto injection = dyn_cast<InjectIntoOptionalExpr>(
result->getSemanticsProvidingExpr())) {
rewriter.DiagnosedOptionalInjections.insert(injection);
}
}
rewriter.finalize(result);
return result;
}
// Determine whether this is a variadic witness.
static bool isVariadicWitness(AbstractFunctionDecl *afd) {
unsigned index = 0;
if (afd->getImplicitSelfDecl())
++index;
for (auto param : *afd->getParameterList(index))
if (param->isVariadic())
return true;
return false;
}
static bool argumentNamesMatch(Type argTy, ArrayRef<Identifier> names) {
auto tupleType = argTy->getAs<TupleType>();
if (!tupleType)
return names.size() == 1 && names[0].empty();
if (tupleType->getNumElements() != names.size())
return false;
for (unsigned i = 0, n = tupleType->getNumElements(); i != n; ++i) {
if (tupleType->getElement(i).getName() != names[i])
return false;
}
return true;
}
Expr *TypeChecker::callWitness(Expr *base, DeclContext *dc,
ProtocolDecl *protocol,
ProtocolConformanceRef conformance,
DeclName name,
MutableArrayRef<Expr *> arguments,
Diag<> brokenProtocolDiag) {
// Construct an empty constraint system and solution.
ConstraintSystem cs(*this, dc, ConstraintSystemOptions());
cs.cacheExprTypes(base);
for (auto *e : arguments) {
cs.cacheExprTypes(e);
}
// Find the witness we need to use.
auto type = cs.getType(base);
assert(!type->hasTypeVariable() &&
"Building call to witness with unresolved base type!");
if (auto metaType = type->getAs<AnyMetatypeType>())
type = metaType->getInstanceType();
auto witness = findNamedWitnessImpl<AbstractFunctionDecl>(
*this, dc, type->getRValueType(), protocol,
name, brokenProtocolDiag);
if (!witness)
return nullptr;
// Form a syntactic expression that describes the reference to the
// witness.
// FIXME: Egregious hack.
auto unresolvedDot = new (Context) UnresolvedDotExpr(
base, SourceLoc(),
witness->getFullName(),
DeclNameLoc(base->getEndLoc()),
/*Implicit=*/true);
unresolvedDot->setFunctionRefKind(FunctionRefKind::SingleApply);
auto dotLocator = cs.getConstraintLocator(unresolvedDot);
// Form a reference to the witness itself.
Type openedFullType, openedType;
std::tie(openedFullType, openedType)
= cs.getTypeOfMemberReference(cs.getType(base), witness,
/*isTypeReference=*/false,
/*isDynamicResult=*/false,
FunctionRefKind::DoubleApply,
dotLocator);
// Form the call argument.
// FIXME: Standardize all callers to always provide all argument names,
// rather than hack around this.
CallExpr *call;
auto argLabels = witness->getFullName().getArgumentNames();
if (arguments.size() == 1 &&
(isVariadicWitness(witness) ||
argumentNamesMatch(cs.getType(arguments[0]), argLabels))) {
call = CallExpr::create(Context, unresolvedDot, arguments[0], { },
{ }, /*hasTrailingClosure=*/false,
/*implicit=*/true);
} else {
// The tuple should have the source range enclosing its arguments unless
// they are invalid or there are no arguments.
SourceLoc TupleStartLoc = base->getStartLoc();
SourceLoc TupleEndLoc = base->getEndLoc();
if (arguments.size() > 0) {
SourceLoc AltStartLoc = arguments.front()->getStartLoc();
SourceLoc AltEndLoc = arguments.back()->getEndLoc();
if (AltStartLoc.isValid() && AltEndLoc.isValid()) {
TupleStartLoc = AltStartLoc;
TupleEndLoc = AltEndLoc;
}
}
call = CallExpr::create(Context, unresolvedDot,
TupleStartLoc,
arguments, argLabels, { },
TupleEndLoc,
/*trailingClosure=*/nullptr,
/*implicit=*/true);
}
cs.cacheExprTypes(call);
// Add the conversion from the argument to the function parameter type.
cs.addConstraint(ConstraintKind::ArgumentTupleConversion,
cs.getType(call->getArg()),
openedType->castTo<FunctionType>()->getInput(),
cs.getConstraintLocator(call,
ConstraintLocator::ApplyArgument));
// Solve the system.
SmallVector<Solution, 1> solutions;
// If the system failed to produce a solution, post any available diagnostics.
if (cs.solve(solutions) || solutions.size() != 1) {
cs.salvage(solutions, base);
return nullptr;
}
Solution &solution = solutions.front();
ExprRewriter rewriter(cs, solution,
/*suppressDiagnostics=*/false,
/*skipClosures=*/false);
auto memberRef = rewriter.buildMemberRef(base, openedFullType,
base->getStartLoc(),
witness,
DeclNameLoc(base->getEndLoc()),
openedType, dotLocator, dotLocator,
/*Implicit=*/true,
FunctionRefKind::SingleApply,
AccessSemantics::Ordinary,
/*isDynamic=*/false);
call->setFn(memberRef);
// Call the witness.
Expr *result = rewriter.finishApply(call, openedType,
cs.getConstraintLocator(call));
if (!result)
return nullptr;
rewriter.finalize(result);
return result;
}
/// \brief Convert an expression via a builtin protocol.
///
/// \param solution The solution to the expression's constraint system,
/// which must have included a constraint that the expression's type
/// conforms to the give \c protocol.
/// \param expr The expression to convert.
/// \param locator The locator describing where the conversion occurs.
/// \param builtinName The name of the builtin method to use for the
/// last step of the conversion.
/// \param brokenBuiltinDiag Diagnostic to emit if the builtin definition
/// is broken.
///
/// \returns the converted expression.
static Expr *convertViaMember(const Solution &solution, Expr *expr,
ConstraintLocator *locator,
Identifier builtinName,
Diag<> brokenBuiltinDiag) {
auto &cs = solution.getConstraintSystem();
// FIXME: Cache name.
auto &tc = cs.getTypeChecker();
auto &ctx = tc.Context;
auto type = cs.getType(expr);
// Look for the builtin name. If we don't have it, we need to call the
// general name via the witness table.
NameLookupOptions lookupOptions = defaultMemberLookupOptions;
if (isa<AbstractFunctionDecl>(cs.DC))
lookupOptions |= NameLookupFlags::KnownPrivate;
auto members = tc.lookupMember(cs.DC, type->getRValueType(), builtinName,
lookupOptions);
// Find the builtin method.
if (members.size() != 1) {
tc.diagnose(expr->getLoc(), brokenBuiltinDiag);
return nullptr;
}
FuncDecl *builtinMethod = dyn_cast<FuncDecl>(members[0].Decl);
if (!builtinMethod) {
tc.diagnose(expr->getLoc(), brokenBuiltinDiag);
return nullptr;
}
// Form a reference to the builtin method.
Expr *memberRef = new (ctx) MemberRefExpr(expr, SourceLoc(),
builtinMethod,
DeclNameLoc(expr->getLoc()),
/*Implicit=*/true);
bool failed = tc.typeCheckExpressionShallow(memberRef, cs.DC);
cs.cacheType(memberRef);
assert(!failed && "Could not reference witness?");
(void)failed;
// Call the builtin method.
expr = CallExpr::createImplicit(ctx, memberRef, { }, { });
failed = tc.typeCheckExpressionShallow(expr, cs.DC);
cs.cacheType(expr);
assert(!failed && "Could not call witness?");
(void)failed;
return expr;
}
Expr *
Solution::convertBooleanTypeToBuiltinI1(Expr *expr, ConstraintLocator *locator) const {
auto &cs = getConstraintSystem();
auto &tc = cs.getTypeChecker();
auto result = convertViaMember(*this, expr, locator,
tc.Context.Id_getBuiltinLogicValue,
diag::broken_bool);
if (result && !cs.getType(result)->isBuiltinIntegerType(1)) {
tc.diagnose(expr->getLoc(), diag::broken_bool);
return nullptr;
}
return result;
}
Expr *Solution::convertOptionalToBool(Expr *expr,
ConstraintLocator *locator) const {
auto &cs = getConstraintSystem();
auto &tc = cs.getTypeChecker();
tc.requireOptionalIntrinsics(expr->getLoc());
// Match the optional value against its `Some` case.
auto &ctx = tc.Context;
auto isSomeExpr = new (ctx) EnumIsCaseExpr(expr, ctx.getOptionalSomeDecl());
cs.setType(isSomeExpr, tc.lookupBoolType(cs.DC));
return isSomeExpr;
}