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Constraint.cpp
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//===--- Constraint.cpp - Constraint in the Type Checker ------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file implements the \c Constraint class and its related types,
// which is used by the constraint-based type checker to describe a
// constraint that must be solved.
//
//===----------------------------------------------------------------------===//
#include "swift/AST/Types.h"
#include "swift/Basic/Compiler.h"
#include "swift/Sema/Constraint.h"
#include "swift/Sema/ConstraintSystem.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
using namespace swift;
using namespace constraints;
Constraint::Constraint(ConstraintKind kind, ArrayRef<Constraint *> constraints,
bool isIsolated, ConstraintLocator *locator,
SmallPtrSetImpl<TypeVariableType *> &typeVars)
: Kind(kind), HasRestriction(false), IsActive(false), IsDisabled(false),
IsDisabledForPerformance(false), RememberChoice(false), IsFavored(false),
IsIsolated(isIsolated), NumTypeVariables(typeVars.size()),
Nested(constraints), Locator(locator) {
assert(kind == ConstraintKind::Disjunction ||
kind == ConstraintKind::Conjunction);
#ifndef NDEBUG
if (isIsolated)
assert(kind == ConstraintKind::Conjunction &&
"Isolation applies only to conjunctions");
#endif
std::uninitialized_copy(typeVars.begin(), typeVars.end(),
getTypeVariablesBuffer().begin());
}
Constraint::Constraint(ConstraintKind Kind, Type First, Type Second,
ConstraintLocator *locator,
SmallPtrSetImpl<TypeVariableType *> &typeVars)
: Kind(Kind), HasRestriction(false), IsActive(false), IsDisabled(false),
IsDisabledForPerformance(false), RememberChoice(false), IsFavored(false),
IsIsolated(false),
NumTypeVariables(typeVars.size()), Types{First, Second, Type()},
Locator(locator) {
switch (Kind) {
case ConstraintKind::Bind:
case ConstraintKind::Equal:
case ConstraintKind::BindParam:
case ConstraintKind::BindToPointerType:
case ConstraintKind::Subtype:
case ConstraintKind::Conversion:
case ConstraintKind::BridgingConversion:
case ConstraintKind::ArgumentConversion:
case ConstraintKind::OperatorArgumentConversion:
case ConstraintKind::SubclassOf:
case ConstraintKind::ConformsTo:
case ConstraintKind::LiteralConformsTo:
case ConstraintKind::TransitivelyConformsTo:
case ConstraintKind::CheckedCast:
case ConstraintKind::SelfObjectOfProtocol:
case ConstraintKind::DynamicTypeOf:
case ConstraintKind::EscapableFunctionOf:
case ConstraintKind::OpenedExistentialOf:
case ConstraintKind::OptionalObject:
case ConstraintKind::OneWayEqual:
case ConstraintKind::OneWayBindParam:
case ConstraintKind::UnresolvedMemberChainBase:
case ConstraintKind::PropertyWrapper:
case ConstraintKind::BindTupleOfFunctionParams:
case ConstraintKind::PackElementOf:
case ConstraintKind::ShapeOf:
case ConstraintKind::ExplicitGenericArguments:
case ConstraintKind::SameShape:
assert(!First.isNull());
assert(!Second.isNull());
break;
case ConstraintKind::ApplicableFunction:
case ConstraintKind::DynamicCallableApplicableFunction:
assert(First->is<FunctionType>()
&& "The left-hand side type should be a function type");
trailingClosureMatching = 0;
break;
case ConstraintKind::ValueMember:
case ConstraintKind::UnresolvedValueMember:
case ConstraintKind::ValueWitness:
llvm_unreachable("Wrong constructor for member constraint");
case ConstraintKind::Defaultable:
case ConstraintKind::FallbackType:
assert(!First.isNull());
assert(!Second.isNull());
break;
case ConstraintKind::BindOverload:
llvm_unreachable("Wrong constructor for overload binding constraint");
case ConstraintKind::Disjunction:
llvm_unreachable("Disjunction constraints should use create()");
case ConstraintKind::Conjunction:
llvm_unreachable("Conjunction constraints should use create()");
case ConstraintKind::KeyPath:
case ConstraintKind::KeyPathApplication:
llvm_unreachable("Key path constraint takes three types");
case ConstraintKind::SyntacticElement:
llvm_unreachable("Syntactic element constraint should use create()");
}
std::uninitialized_copy(typeVars.begin(), typeVars.end(),
getTypeVariablesBuffer().begin());
}
Constraint::Constraint(ConstraintKind Kind, Type First, Type Second, Type Third,
ConstraintLocator *locator,
SmallPtrSetImpl<TypeVariableType *> &typeVars)
: Kind(Kind), HasRestriction(false), IsActive(false), IsDisabled(false),
IsDisabledForPerformance(false), RememberChoice(false), IsFavored(false),
IsIsolated(false),
NumTypeVariables(typeVars.size()), Types{First, Second, Third},
Locator(locator) {
switch (Kind) {
case ConstraintKind::Bind:
case ConstraintKind::Equal:
case ConstraintKind::BindParam:
case ConstraintKind::BindToPointerType:
case ConstraintKind::Subtype:
case ConstraintKind::Conversion:
case ConstraintKind::BridgingConversion:
case ConstraintKind::ArgumentConversion:
case ConstraintKind::OperatorArgumentConversion:
case ConstraintKind::SubclassOf:
case ConstraintKind::ConformsTo:
case ConstraintKind::LiteralConformsTo:
case ConstraintKind::TransitivelyConformsTo:
case ConstraintKind::CheckedCast:
case ConstraintKind::SelfObjectOfProtocol:
case ConstraintKind::DynamicTypeOf:
case ConstraintKind::EscapableFunctionOf:
case ConstraintKind::OpenedExistentialOf:
case ConstraintKind::OptionalObject:
case ConstraintKind::ApplicableFunction:
case ConstraintKind::DynamicCallableApplicableFunction:
case ConstraintKind::ValueMember:
case ConstraintKind::ValueWitness:
case ConstraintKind::UnresolvedValueMember:
case ConstraintKind::Defaultable:
case ConstraintKind::BindOverload:
case ConstraintKind::Disjunction:
case ConstraintKind::Conjunction:
case ConstraintKind::OneWayEqual:
case ConstraintKind::OneWayBindParam:
case ConstraintKind::FallbackType:
case ConstraintKind::UnresolvedMemberChainBase:
case ConstraintKind::PropertyWrapper:
case ConstraintKind::SyntacticElement:
case ConstraintKind::BindTupleOfFunctionParams:
case ConstraintKind::PackElementOf:
case ConstraintKind::ShapeOf:
case ConstraintKind::ExplicitGenericArguments:
case ConstraintKind::SameShape:
llvm_unreachable("Wrong constructor");
case ConstraintKind::KeyPath:
case ConstraintKind::KeyPathApplication:
assert(!First.isNull());
assert(!Second.isNull());
assert(!Third.isNull());
break;
}
std::uninitialized_copy(typeVars.begin(), typeVars.end(),
getTypeVariablesBuffer().begin());
}
Constraint::Constraint(ConstraintKind kind, Type first, Type second,
DeclNameRef member, DeclContext *useDC,
FunctionRefKind functionRefKind,
ConstraintLocator *locator,
SmallPtrSetImpl<TypeVariableType *> &typeVars)
: Kind(kind), HasRestriction(false), IsActive(false), IsDisabled(false),
IsDisabledForPerformance(false), RememberChoice(false), IsFavored(false),
IsIsolated(false),
NumTypeVariables(typeVars.size()), Member{first, second, {member}, useDC},
Locator(locator) {
assert(kind == ConstraintKind::ValueMember ||
kind == ConstraintKind::UnresolvedValueMember);
TheFunctionRefKind = static_cast<unsigned>(functionRefKind);
assert(getFunctionRefKind() == functionRefKind);
assert(member && "Member constraint has no member");
assert(useDC && "Member constraint has no use DC");
std::copy(typeVars.begin(), typeVars.end(), getTypeVariablesBuffer().begin());
}
Constraint::Constraint(ConstraintKind kind, Type first, Type second,
ValueDecl *requirement, DeclContext *useDC,
FunctionRefKind functionRefKind,
ConstraintLocator *locator,
SmallPtrSetImpl<TypeVariableType *> &typeVars)
: Kind(kind), HasRestriction(false), IsActive(false), IsDisabled(false),
IsDisabledForPerformance(false), RememberChoice(false), IsFavored(false),
IsIsolated(false), NumTypeVariables(typeVars.size()), Locator(locator) {
Member.First = first;
Member.Second = second;
Member.Member.Ref = requirement;
Member.UseDC = useDC;
TheFunctionRefKind = static_cast<unsigned>(functionRefKind);
assert(kind == ConstraintKind::ValueWitness);
assert(getFunctionRefKind() == functionRefKind);
assert(requirement && "Value witness constraint has no requirement");
assert(useDC && "Member constraint has no use DC");
std::copy(typeVars.begin(), typeVars.end(), getTypeVariablesBuffer().begin());
}
Constraint::Constraint(Type type, OverloadChoice choice, DeclContext *useDC,
ConstraintFix *fix, ConstraintLocator *locator,
SmallPtrSetImpl<TypeVariableType *> &typeVars)
: Kind(ConstraintKind::BindOverload), TheFix(fix), HasRestriction(false),
IsActive(false), IsDisabled(bool(fix)), IsDisabledForPerformance(false),
RememberChoice(false), IsFavored(false), IsIsolated(false),
NumTypeVariables(typeVars.size()), Overload{type, choice, useDC},
Locator(locator) {
std::copy(typeVars.begin(), typeVars.end(), getTypeVariablesBuffer().begin());
}
Constraint::Constraint(ConstraintKind kind,
ConversionRestrictionKind restriction, Type first,
Type second, ConstraintLocator *locator,
SmallPtrSetImpl<TypeVariableType *> &typeVars)
: Kind(kind), Restriction(restriction), HasRestriction(true),
IsActive(false), IsDisabled(false), IsDisabledForPerformance(false),
RememberChoice(false), IsFavored(false), IsIsolated(false),
NumTypeVariables(typeVars.size()), Types{first, second, Type()},
Locator(locator) {
assert(!first.isNull());
assert(!second.isNull());
std::copy(typeVars.begin(), typeVars.end(), getTypeVariablesBuffer().begin());
}
Constraint::Constraint(ConstraintKind kind, ConstraintFix *fix, Type first,
Type second, ConstraintLocator *locator,
SmallPtrSetImpl<TypeVariableType *> &typeVars)
: Kind(kind), TheFix(fix), HasRestriction(false), IsActive(false),
IsDisabled(false), IsDisabledForPerformance(false), RememberChoice(false),
IsFavored(false), IsIsolated(false),
NumTypeVariables(typeVars.size()), Types{first, second, Type()},
Locator(locator) {
assert(!first.isNull());
assert(!second.isNull());
std::copy(typeVars.begin(), typeVars.end(), getTypeVariablesBuffer().begin());
}
Constraint::Constraint(ASTNode node, ContextualTypeInfo context,
bool isDiscarded, ConstraintLocator *locator,
SmallPtrSetImpl<TypeVariableType *> &typeVars)
: Kind(ConstraintKind::SyntacticElement), TheFix(nullptr),
HasRestriction(false), IsActive(false), IsDisabled(false),
IsDisabledForPerformance(false), RememberChoice(false), IsFavored(false),
IsIsolated(false),
NumTypeVariables(typeVars.size()), SyntacticElement{node, context,
isDiscarded},
Locator(locator) {
std::copy(typeVars.begin(), typeVars.end(), getTypeVariablesBuffer().begin());
}
ProtocolDecl *Constraint::getProtocol() const {
assert((Kind == ConstraintKind::ConformsTo ||
Kind == ConstraintKind::LiteralConformsTo ||
Kind == ConstraintKind::SelfObjectOfProtocol ||
Kind == ConstraintKind::TransitivelyConformsTo)
&& "Not a conformance constraint");
return Types.Second->castTo<ProtocolType>()->getDecl();
}
Constraint *Constraint::clone(ConstraintSystem &cs) const {
switch (getKind()) {
case ConstraintKind::Bind:
case ConstraintKind::Equal:
case ConstraintKind::BindParam:
case ConstraintKind::BindToPointerType:
case ConstraintKind::Subtype:
case ConstraintKind::Conversion:
case ConstraintKind::BridgingConversion:
case ConstraintKind::ArgumentConversion:
case ConstraintKind::OperatorArgumentConversion:
case ConstraintKind::SubclassOf:
case ConstraintKind::ConformsTo:
case ConstraintKind::LiteralConformsTo:
case ConstraintKind::TransitivelyConformsTo:
case ConstraintKind::CheckedCast:
case ConstraintKind::DynamicTypeOf:
case ConstraintKind::EscapableFunctionOf:
case ConstraintKind::OpenedExistentialOf:
case ConstraintKind::SelfObjectOfProtocol:
case ConstraintKind::DynamicCallableApplicableFunction:
case ConstraintKind::OptionalObject:
case ConstraintKind::Defaultable:
case ConstraintKind::OneWayEqual:
case ConstraintKind::OneWayBindParam:
case ConstraintKind::FallbackType:
case ConstraintKind::UnresolvedMemberChainBase:
case ConstraintKind::PropertyWrapper:
case ConstraintKind::BindTupleOfFunctionParams:
case ConstraintKind::PackElementOf:
case ConstraintKind::ShapeOf:
case ConstraintKind::ExplicitGenericArguments:
case ConstraintKind::SameShape:
return create(cs, getKind(), getFirstType(), getSecondType(), getLocator());
case ConstraintKind::ApplicableFunction:
return createApplicableFunction(
cs, getFirstType(), getSecondType(), getTrailingClosureMatching(),
getLocator());
case ConstraintKind::BindOverload:
return createBindOverload(cs, getFirstType(), getOverloadChoice(),
getOverloadUseDC(), getLocator());
case ConstraintKind::ValueMember:
case ConstraintKind::UnresolvedValueMember:
return createMember(cs, getKind(), getFirstType(), getSecondType(),
getMember(), getMemberUseDC(), getFunctionRefKind(),
getLocator());
case ConstraintKind::ValueWitness:
return createValueWitness(
cs, getKind(), getFirstType(), getSecondType(), getRequirement(),
getMemberUseDC(), getFunctionRefKind(), getLocator());
case ConstraintKind::Disjunction:
return createDisjunction(
cs, getNestedConstraints(), getLocator(),
static_cast<RememberChoice_t>(shouldRememberChoice()));
case ConstraintKind::Conjunction:
return createConjunction(cs, getNestedConstraints(), IsIsolated,
getLocator(), getTypeVariables());
case ConstraintKind::KeyPath:
case ConstraintKind::KeyPathApplication:
return create(cs, getKind(), getFirstType(), getSecondType(), getThirdType(),
getLocator());
case ConstraintKind::SyntacticElement:
return createSyntacticElement(cs, getSyntacticElement(), getLocator(),
isDiscardedElement());
}
llvm_unreachable("Unhandled ConstraintKind in switch.");
}
void Constraint::print(llvm::raw_ostream &Out, SourceManager *sm,
unsigned indent, bool skipLocator) const {
// Print all type variables as $T0 instead of _ here.
PrintOptions PO;
PO.PrintTypesForDebugging = true;
if (Kind == ConstraintKind::Disjunction ||
Kind == ConstraintKind::Conjunction) {
Out << (Kind == ConstraintKind::Disjunction ? "disjunction"
: "conjunction");
if (shouldRememberChoice())
Out << " (remembered)";
if (isIsolated())
Out << " (isolated)";
if (Locator) {
Out << " @ ";
Locator->dump(sm, Out);
}
Out << ":\n";
// Sort constraints by favored, unmarked, disabled
// for printing only.
std::vector<Constraint *> sortedConstraints(getNestedConstraints().begin(),
getNestedConstraints().end());
llvm::sort(sortedConstraints,
[](const Constraint *lhs, const Constraint *rhs) {
if (lhs->isFavored() != rhs->isFavored())
return lhs->isFavored();
if (lhs->isDisabled() != rhs->isDisabled())
return rhs->isDisabled();
return false;
});
interleave(
sortedConstraints,
[&](Constraint *constraint) {
Out.indent(indent + 2);
if (constraint->isDisabled())
Out << "> [disabled] ";
else if (constraint->isFavored())
Out << "> [favored] ";
else
Out << "> ";
constraint->print(Out, sm, indent,
/*skipLocator=*/constraint->getLocator() ==
Locator);
},
[&] { Out << "\n"; });
return;
}
if (Kind == ConstraintKind::SyntacticElement) {
auto *locator = getLocator();
auto element = getSyntacticElement();
if (auto patternBindingElt =
locator
->getLastElementAs<LocatorPathElt::PatternBindingElement>()) {
auto *patternBinding = cast<PatternBindingDecl>(element.get<Decl *>());
Out << "pattern binding element @ ";
Out << patternBindingElt->getIndex() << " : ";
Out << '\n';
patternBinding->getPattern(patternBindingElt->getIndex())->dump(Out, indent);
} else {
Out << "syntactic element ";
Out << '\n';
element.dump(Out, indent);
}
return;
}
Out << getFirstType()->getString(PO);
bool skipSecond = false;
switch (Kind) {
case ConstraintKind::Bind: Out << " bind "; break;
case ConstraintKind::Equal: Out << " equal "; break;
case ConstraintKind::BindParam: Out << " bind param "; break;
case ConstraintKind::BindToPointerType: Out << " bind to pointer "; break;
case ConstraintKind::Subtype: Out << " subtype "; break;
case ConstraintKind::Conversion: Out << " conv "; break;
case ConstraintKind::BridgingConversion: Out << " bridging conv "; break;
case ConstraintKind::ArgumentConversion: Out << " arg conv "; break;
case ConstraintKind::OperatorArgumentConversion:
Out << " operator arg conv "; break;
case ConstraintKind::SubclassOf: Out << " subclass of "; break;
case ConstraintKind::ConformsTo: Out << " conforms to "; break;
case ConstraintKind::LiteralConformsTo: Out << " literal conforms to "; break;
case ConstraintKind::TransitivelyConformsTo: Out << " transitive conformance to "; break;
case ConstraintKind::CheckedCast: Out << " checked cast to "; break;
case ConstraintKind::SelfObjectOfProtocol: Out << " Self type of "; break;
case ConstraintKind::ApplicableFunction: Out << " applicable fn "; break;
case ConstraintKind::DynamicCallableApplicableFunction:
Out << " dynamic callable applicable fn "; break;
case ConstraintKind::DynamicTypeOf: Out << " dynamicType type of "; break;
case ConstraintKind::EscapableFunctionOf: Out << " @escaping type of "; break;
case ConstraintKind::OpenedExistentialOf: Out << " opened archetype of "; break;
case ConstraintKind::OneWayEqual: Out << " one-way bind to "; break;
case ConstraintKind::OneWayBindParam: Out << " one-way bind param to "; break;
case ConstraintKind::FallbackType:
Out << " can fallback to ";
break;
case ConstraintKind::UnresolvedMemberChainBase:
Out << " unresolved member chain base ";
break;
case ConstraintKind::PropertyWrapper:
Out << " property wrapper with wrapped value of ";
break;
case ConstraintKind::KeyPath:
Out << " key path from ";
Out << getSecondType()->getString(PO);
Out << " → ";
Out << getThirdType()->getString(PO);
skipSecond = true;
break;
case ConstraintKind::KeyPathApplication:
Out << " key path projecting ";
Out << getSecondType()->getString(PO);
Out << " → ";
Out << getThirdType()->getString(PO);
skipSecond = true;
break;
case ConstraintKind::OptionalObject:
Out << " optional with object type "; break;
case ConstraintKind::BindOverload: {
Out << " bound to ";
auto overload = getOverloadChoice();
auto printDecl = [&] {
auto decl = overload.getDecl();
decl->dumpRef(Out);
Out << " : " << decl->getInterfaceType();
};
switch (overload.getKind()) {
case OverloadChoiceKind::Decl:
Out << "decl ";
printDecl();
break;
case OverloadChoiceKind::DeclViaDynamic:
Out << "decl-via-dynamic ";
printDecl();
break;
case OverloadChoiceKind::DeclViaBridge:
Out << "decl-via-bridge ";
printDecl();
break;
case OverloadChoiceKind::DeclViaUnwrappedOptional:
Out << "decl-via-unwrapped-optional ";
printDecl();
break;
case OverloadChoiceKind::DynamicMemberLookup:
case OverloadChoiceKind::KeyPathDynamicMemberLookup:
Out << "dynamic member lookup '" << overload.getName() << "'";
break;
case OverloadChoiceKind::TupleIndex:
Out << "tuple index " << overload.getTupleIndex();
break;
case OverloadChoiceKind::MaterializePack:
Out << "materialize pack";
break;
case OverloadChoiceKind::KeyPathApplication:
Out << "key path application";
break;
}
skipSecond = true;
break;
}
case ConstraintKind::ValueMember:
Out << "[." << getMember() << ": value] == ";
break;
case ConstraintKind::UnresolvedValueMember:
Out << "[(implicit) ." << getMember() << ": value] == ";
break;
case ConstraintKind::ValueWitness: {
auto requirement = getRequirement();
auto selfNominal = requirement->getDeclContext()->getSelfNominalTypeDecl();
Out << "[." << selfNominal->getName() << "::" << requirement->getName()
<< ": witness] == ";
break;
}
case ConstraintKind::Defaultable:
Out << " can default to ";
break;
case ConstraintKind::BindTupleOfFunctionParams:
Out << " bind tuple of function params to ";
break;
case ConstraintKind::PackElementOf:
Out << " element of pack expansion pattern ";
break;
case ConstraintKind::ShapeOf:
Out << " shape of ";
break;
case ConstraintKind::SameShape:
Out << " same-shape ";
break;
case ConstraintKind::ExplicitGenericArguments:
Out << " explicit generic argument binding ";
break;
case ConstraintKind::Disjunction:
llvm_unreachable("disjunction handled above");
case ConstraintKind::Conjunction:
llvm_unreachable("conjunction handled above");
case ConstraintKind::SyntacticElement:
llvm_unreachable("syntactic element handled above");
}
if (!skipSecond)
Out << getSecondType()->getString(PO);
if (auto restriction = getRestriction()) {
Out << ' ' << getName(*restriction);
}
if (getKind() == ConstraintKind::ApplicableFunction) {
if (auto trailingClosureMatching = getTrailingClosureMatching()) {
switch (*trailingClosureMatching) {
case TrailingClosureMatching::Forward:
Out << " [forward scan]";
break;
case TrailingClosureMatching::Backward:
Out << " [backward scan]";
break;
}
}
}
if (auto *fix = getFix()) {
Out << ' ';
fix->print(Out);
}
if (Locator && !skipLocator) {
Out << " @ ";
Locator->dump(sm, Out);
}
}
void Constraint::dump(SourceManager *sm) const {
print(llvm::errs(), sm);
llvm::errs() << "\n";
}
void Constraint::dump(ConstraintSystem *CS) const {
// Disable MSVC warning: only for use within the debugger.
#if SWIFT_COMPILER_IS_MSVC
#pragma warning(push)
#pragma warning(disable: 4996)
#endif
dump(&CS->getASTContext().SourceMgr);
#if SWIFT_COMPILER_IS_MSVC
#pragma warning(pop)
#endif
}
StringRef swift::constraints::getName(ConversionRestrictionKind kind) {
switch (kind) {
case ConversionRestrictionKind::DeepEquality:
return "[deep equality]";
case ConversionRestrictionKind::Superclass:
return "[superclass]";
case ConversionRestrictionKind::Existential:
return "[existential]";
case ConversionRestrictionKind::MetatypeToExistentialMetatype:
return "[metatype-to-existential-metatype]";
case ConversionRestrictionKind::ExistentialMetatypeToMetatype:
return "[existential-metatype-to-metatype]";
case ConversionRestrictionKind::ValueToOptional:
return "[value-to-optional]";
case ConversionRestrictionKind::OptionalToOptional:
return "[optional-to-optional]";
case ConversionRestrictionKind::ClassMetatypeToAnyObject:
return "[class-metatype-to-object]";
case ConversionRestrictionKind::ExistentialMetatypeToAnyObject:
return "[existential-metatype-to-object]";
case ConversionRestrictionKind::ProtocolMetatypeToProtocolClass:
return "[protocol-metatype-to-object]";
case ConversionRestrictionKind::ArrayToPointer:
return "[array-to-pointer]";
case ConversionRestrictionKind::ArrayToCPointer:
return "[array-to-c-pointer]";
case ConversionRestrictionKind::StringToPointer:
return "[string-to-pointer]";
case ConversionRestrictionKind::InoutToPointer:
return "[inout-to-pointer]";
case ConversionRestrictionKind::InoutToCPointer:
return "[inout-to-c-pointer]";
case ConversionRestrictionKind::PointerToPointer:
return "[pointer-to-pointer]";
case ConversionRestrictionKind::PointerToCPointer:
return "[pointer-to-c-pointer]";
case ConversionRestrictionKind::ArrayUpcast:
return "[array-upcast]";
case ConversionRestrictionKind::DictionaryUpcast:
return "[dictionary-upcast]";
case ConversionRestrictionKind::SetUpcast:
return "[set-upcast]";
case ConversionRestrictionKind::HashableToAnyHashable:
return "[hashable-to-anyhashable]";
case ConversionRestrictionKind::CFTollFreeBridgeToObjC:
return "[cf-toll-free-bridge-to-objc]";
case ConversionRestrictionKind::ObjCTollFreeBridgeToCF:
return "[objc-toll-free-bridge-to-cf]";
case ConversionRestrictionKind::CGFloatToDouble:
return "[CGFloat-to-Double]";
case ConversionRestrictionKind::DoubleToCGFloat:
return "[Double-to-CGFloat]";
}
llvm_unreachable("bad conversion restriction kind");
}
/// Recursively gather the set of type variables referenced by this constraint.
static void
gatherReferencedTypeVars(Constraint *constraint,
SmallPtrSetImpl<TypeVariableType *> &typeVars) {
switch (constraint->getKind()) {
case ConstraintKind::Disjunction:
for (auto nested : constraint->getNestedConstraints())
gatherReferencedTypeVars(nested, typeVars);
return;
case ConstraintKind::Conjunction:
typeVars.insert(constraint->getTypeVariables().begin(),
constraint->getTypeVariables().end());
return;
case ConstraintKind::KeyPath:
case ConstraintKind::KeyPathApplication:
constraint->getThirdType()->getTypeVariables(typeVars);
LLVM_FALLTHROUGH;
case ConstraintKind::ApplicableFunction:
case ConstraintKind::DynamicCallableApplicableFunction:
case ConstraintKind::Bind:
case ConstraintKind::BindParam:
case ConstraintKind::BindToPointerType:
case ConstraintKind::ArgumentConversion:
case ConstraintKind::Conversion:
case ConstraintKind::BridgingConversion:
case ConstraintKind::OperatorArgumentConversion:
case ConstraintKind::CheckedCast:
case ConstraintKind::Equal:
case ConstraintKind::Subtype:
case ConstraintKind::UnresolvedValueMember:
case ConstraintKind::ValueMember:
case ConstraintKind::ValueWitness:
case ConstraintKind::DynamicTypeOf:
case ConstraintKind::EscapableFunctionOf:
case ConstraintKind::OpenedExistentialOf:
case ConstraintKind::OptionalObject:
case ConstraintKind::Defaultable:
case ConstraintKind::SubclassOf:
case ConstraintKind::ConformsTo:
case ConstraintKind::LiteralConformsTo:
case ConstraintKind::TransitivelyConformsTo:
case ConstraintKind::SelfObjectOfProtocol:
case ConstraintKind::OneWayEqual:
case ConstraintKind::OneWayBindParam:
case ConstraintKind::FallbackType:
case ConstraintKind::UnresolvedMemberChainBase:
case ConstraintKind::PropertyWrapper:
case ConstraintKind::BindTupleOfFunctionParams:
case ConstraintKind::PackElementOf:
case ConstraintKind::ShapeOf:
case ConstraintKind::ExplicitGenericArguments:
case ConstraintKind::SameShape:
constraint->getFirstType()->getTypeVariables(typeVars);
constraint->getSecondType()->getTypeVariables(typeVars);
break;
case ConstraintKind::BindOverload:
constraint->getFirstType()->getTypeVariables(typeVars);
// Special case: the base type of an overloading binding.
if (auto baseType = constraint->getOverloadChoice().getBaseType()) {
baseType->getTypeVariables(typeVars);
}
break;
case ConstraintKind::SyntacticElement:
typeVars.insert(constraint->getTypeVariables().begin(),
constraint->getTypeVariables().end());
break;
}
}
unsigned Constraint::countResolvedArgumentTypes(ConstraintSystem &cs) const {
auto *argumentFuncType = cs.getAppliedDisjunctionArgumentFunction(this);
if (!argumentFuncType)
return 0;
return llvm::count_if(argumentFuncType->getParams(), [&](const AnyFunctionType::Param arg) {
auto argType = cs.getFixedTypeRecursive(arg.getPlainType(), /*wantRValue=*/true);
return !argType->isTypeVariableOrMember();
});
}
bool Constraint::isExplicitConversion() const {
assert(Kind == ConstraintKind::Disjunction);
if (auto *locator = getLocator())
return isExpr<CoerceExpr>(locator->getAnchor());
return false;
}
Constraint *Constraint::create(ConstraintSystem &cs, ConstraintKind kind,
Type first, Type second,
ConstraintLocator *locator,
ArrayRef<TypeVariableType *> extraTypeVars) {
// Collect type variables.
SmallPtrSet<TypeVariableType *, 4> typeVars;
if (first->hasTypeVariable())
first->getTypeVariables(typeVars);
if (second && second->hasTypeVariable())
second->getTypeVariables(typeVars);
typeVars.insert(extraTypeVars.begin(), extraTypeVars.end());
// Conformance constraints expect an existential on the right-hand side.
assert((kind != ConstraintKind::ConformsTo &&
kind != ConstraintKind::TransitivelyConformsTo &&
kind != ConstraintKind::SelfObjectOfProtocol) ||
second->isExistentialType());
// Literal protocol conformances expect a protocol.
assert((kind != ConstraintKind::LiteralConformsTo) ||
second->is<ProtocolType>());
// Create the constraint.
unsigned size = totalSizeToAlloc<TypeVariableType*>(typeVars.size());
void *mem = cs.getAllocator().Allocate(size, alignof(Constraint));
return ::new (mem) Constraint(kind, first, second, locator, typeVars);
}
Constraint *Constraint::create(ConstraintSystem &cs, ConstraintKind kind,
Type first, Type second, Type third,
ConstraintLocator *locator,
ArrayRef<TypeVariableType *> extraTypeVars) {
// Collect type variables.
SmallPtrSet<TypeVariableType *, 4> typeVars(extraTypeVars.begin(),
extraTypeVars.end());
if (first->hasTypeVariable())
first->getTypeVariables(typeVars);
if (second->hasTypeVariable())
second->getTypeVariables(typeVars);
if (third->hasTypeVariable())
third->getTypeVariables(typeVars);
unsigned size = totalSizeToAlloc<TypeVariableType*>(typeVars.size());
void *mem = cs.getAllocator().Allocate(size, alignof(Constraint));
return ::new (mem) Constraint(kind,
first, second, third,
locator, typeVars);
}
Constraint *Constraint::createMemberOrOuterDisjunction(
ConstraintSystem &cs, ConstraintKind kind, Type first, Type second,
DeclNameRef member, DeclContext *useDC, FunctionRefKind functionRefKind,
ArrayRef<OverloadChoice> outerAlternatives, ConstraintLocator *locator) {
auto memberConstraint = createMember(cs, kind, first, second, member,
useDC, functionRefKind, locator);
if (outerAlternatives.empty())
return memberConstraint;
SmallVector<Constraint *, 4> constraints;
constraints.push_back(memberConstraint);
memberConstraint->setFavored();
for (auto choice : outerAlternatives) {
constraints.push_back(
Constraint::createBindOverload(cs, first, choice, useDC, locator));
}
return Constraint::createDisjunction(cs, constraints, locator, ForgetChoice);
}
Constraint *Constraint::createMember(ConstraintSystem &cs, ConstraintKind kind,
Type first, Type second,
DeclNameRef member, DeclContext *useDC,
FunctionRefKind functionRefKind,
ConstraintLocator *locator) {
// Collect type variables.
SmallPtrSet<TypeVariableType *, 4> typeVars;
if (first->hasTypeVariable())
first->getTypeVariables(typeVars);
if (second->hasTypeVariable())
second->getTypeVariables(typeVars);
// Create the constraint.
unsigned size = totalSizeToAlloc<TypeVariableType*>(typeVars.size());
void *mem = cs.getAllocator().Allocate(size, alignof(Constraint));
return new (mem) Constraint(kind, first, second, member, useDC,
functionRefKind, locator, typeVars);
}
Constraint *Constraint::createValueWitness(
ConstraintSystem &cs, ConstraintKind kind, Type first, Type second,
ValueDecl *requirement, DeclContext *useDC,
FunctionRefKind functionRefKind, ConstraintLocator *locator) {
assert(kind == ConstraintKind::ValueWitness);
// Collect type variables.
SmallPtrSet<TypeVariableType *, 4> typeVars;
if (first->hasTypeVariable())
first->getTypeVariables(typeVars);
if (second->hasTypeVariable())
second->getTypeVariables(typeVars);
// Create the constraint.
unsigned size = totalSizeToAlloc<TypeVariableType*>(typeVars.size());
void *mem = cs.getAllocator().Allocate(size, alignof(Constraint));
return new (mem) Constraint(kind, first, second, requirement, useDC,
functionRefKind, locator, typeVars);
}
Constraint *Constraint::createBindOverload(ConstraintSystem &cs, Type type,
OverloadChoice choice,
DeclContext *useDC,
ConstraintLocator *locator) {
return createFixedChoice(cs, type, choice, useDC, /*fix=*/nullptr, locator);
}
Constraint *Constraint::createRestricted(ConstraintSystem &cs,
ConstraintKind kind,
ConversionRestrictionKind restriction,
Type first, Type second,
ConstraintLocator *locator) {
// Collect type variables.
SmallPtrSet<TypeVariableType *, 4> typeVars;
if (first->hasTypeVariable())
first->getTypeVariables(typeVars);
if (second->hasTypeVariable())
second->getTypeVariables(typeVars);
// Create the constraint.
unsigned size = totalSizeToAlloc<TypeVariableType*>(typeVars.size());
void *mem = cs.getAllocator().Allocate(size, alignof(Constraint));
return new (mem) Constraint(kind, restriction, first, second, locator,
typeVars);
}
Constraint *Constraint::createFixed(ConstraintSystem &cs, ConstraintKind kind,
ConstraintFix *fix, Type first, Type second,
ConstraintLocator *locator) {
// Collect type variables.
SmallPtrSet<TypeVariableType *, 4> typeVars;
if (first->hasTypeVariable())
first->getTypeVariables(typeVars);
if (second->hasTypeVariable())
second->getTypeVariables(typeVars);
// Create the constraint.
unsigned size = totalSizeToAlloc<TypeVariableType*>(typeVars.size());
void *mem = cs.getAllocator().Allocate(size, alignof(Constraint));
return new (mem) Constraint(kind, fix, first, second, locator, typeVars);
}
Constraint *Constraint::createFixedChoice(ConstraintSystem &cs, Type type,
OverloadChoice choice,
DeclContext *useDC,
ConstraintFix *fix,
ConstraintLocator *locator) {
// Collect type variables.
SmallPtrSet<TypeVariableType *, 4> typeVars;
if (type->hasTypeVariable())
type->getTypeVariables(typeVars);
if (auto baseType = choice.getBaseType()) {
baseType->getTypeVariables(typeVars);
}
// Create the constraint.
unsigned size = totalSizeToAlloc<TypeVariableType *>(typeVars.size());
void *mem = cs.getAllocator().Allocate(size, alignof(Constraint));
return new (mem) Constraint(type, choice, useDC, fix, locator, typeVars);
}
Constraint *Constraint::createDisjunction(ConstraintSystem &cs,
ArrayRef<Constraint *> constraints,
ConstraintLocator *locator,
RememberChoice_t rememberChoice) {
// Unwrap any disjunctions inside the disjunction constraint; we only allow
// disjunctions at the top level.
SmallPtrSet<TypeVariableType *, 4> typeVars;
bool unwrappedAny = false;
SmallVector<Constraint *, 1> unwrapped;
unsigned index = 0;
for (auto constraint : constraints) {
// Gather type variables from this constraint.
gatherReferencedTypeVars(constraint, typeVars);
// If we have a nested disjunction, unwrap it.
if (constraint->getKind() == ConstraintKind::Disjunction) {
// If we haven't unwrapped anything before, copy all of the constraints
// we skipped.
if (!unwrappedAny) {
unwrapped.append(constraints.begin(), constraints.begin() + index);
unwrappedAny = true;
}
// Add all of the constraints in the disjunction.
unwrapped.append(constraint->getNestedConstraints().begin(),
constraint->getNestedConstraints().end());
} else if (unwrappedAny) {
// Since we unwrapped constraints before, add this constraint.
unwrapped.push_back(constraint);
}
++index;
}
// If we unwrapped anything, our list of constraints is the unwrapped list.
if (unwrappedAny)
constraints = unwrapped;
assert(!constraints.empty() && "Empty disjunction constraint");