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cf2e7f6f45
The issue here is that the constraint solver was deciding on FixKind::RelabelCallTuple as the fix for the problem and emitting the diagnostic, even though there were two different fixes possible. CSDiags has the infrastructure to support doing doing the right thing here, but is only being used for ApplyExprs, not SubscriptExprs. The solution is to fix both problems: remove FixKind::RelabelCallTuple, to let CSDiags handle the problem, and enhance CSDiags to treat SubscriptExpr more commonly with ApplyExpr. This improves several cases where the solver was picking one solution randomly and suggesting that as a fix, instead of listing that there are multiple different solutions.
685 lines
24 KiB
C++
685 lines
24 KiB
C++
//===--- Constraint.cpp - Constraint in the Type Checker ------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See http://swift.org/LICENSE.txt for license information
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// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the \c Constraint class and its related types,
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// which is used by the constraint-based type checker to describe a
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// constraint that must be solved.
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//
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//===----------------------------------------------------------------------===//
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#include "Constraint.h"
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#include "ConstraintSystem.h"
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#include "swift/AST/Types.h"
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#include "swift/Basic/Fallthrough.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Support/SaveAndRestore.h"
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#include <algorithm>
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using namespace swift;
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using namespace constraints;
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Constraint::Constraint(ConstraintKind kind, ArrayRef<Constraint *> constraints,
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ConstraintLocator *locator,
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ArrayRef<TypeVariableType *> typeVars)
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: Kind(kind), HasRestriction(false), HasFix(false), IsActive(false),
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RememberChoice(false), IsFavored(false), NumTypeVariables(typeVars.size()),
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Nested(constraints), Locator(locator)
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{
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assert(kind == ConstraintKind::Disjunction);
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std::uninitialized_copy(typeVars.begin(), typeVars.end(),
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getTypeVariablesBuffer().begin());
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}
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Constraint::Constraint(ConstraintKind Kind, Type First, Type Second,
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DeclName Member, ConstraintLocator *locator,
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ArrayRef<TypeVariableType *> typeVars)
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: Kind(Kind), HasRestriction(false), HasFix(false), IsActive(false),
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RememberChoice(false), IsFavored(false), NumTypeVariables(typeVars.size()),
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Types { First, Second, Member }, Locator(locator)
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{
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switch (Kind) {
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case ConstraintKind::Bind:
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case ConstraintKind::Equal:
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case ConstraintKind::BindParam:
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case ConstraintKind::Subtype:
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case ConstraintKind::Conversion:
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case ConstraintKind::ExplicitConversion:
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case ConstraintKind::ArgumentConversion:
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case ConstraintKind::ArgumentTupleConversion:
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case ConstraintKind::OperatorArgumentTupleConversion:
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case ConstraintKind::OperatorArgumentConversion:
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case ConstraintKind::ConformsTo:
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case ConstraintKind::CheckedCast:
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case ConstraintKind::SelfObjectOfProtocol:
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case ConstraintKind::DynamicTypeOf:
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case ConstraintKind::OptionalObject:
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assert(!First.isNull());
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assert(!Second.isNull());
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assert(!Member && "Relational constraint cannot have a member");
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break;
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case ConstraintKind::ApplicableFunction:
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assert(First->is<FunctionType>()
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&& "The left-hand side type should be a function type");
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assert(!Member && "Relational constraint cannot have a member");
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break;
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case ConstraintKind::TypeMember:
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case ConstraintKind::ValueMember:
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case ConstraintKind::UnresolvedValueMember:
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assert(Member && "Member constraint has no member");
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break;
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case ConstraintKind::Archetype:
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case ConstraintKind::Class:
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case ConstraintKind::BridgedToObjectiveC:
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assert(!Member && "Type property cannot have a member");
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assert(Second.isNull() && "Type property with second type");
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break;
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case ConstraintKind::Defaultable:
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assert(!First.isNull());
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assert(!Second.isNull());
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assert(!Member && "Defaultable constraint cannot have a member");
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break;
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case ConstraintKind::BindOverload:
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llvm_unreachable("Wrong constructor for overload binding constraint");
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case ConstraintKind::Disjunction:
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llvm_unreachable("Disjunction constraints should use create()");
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}
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std::copy(typeVars.begin(), typeVars.end(), getTypeVariablesBuffer().begin());
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}
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Constraint::Constraint(Type type, OverloadChoice choice,
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ConstraintLocator *locator,
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ArrayRef<TypeVariableType *> typeVars)
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: Kind(ConstraintKind::BindOverload),
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HasRestriction(false), HasFix(false), IsActive(false),
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RememberChoice(false), IsFavored(false), NumTypeVariables(typeVars.size()),
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Overload{type, choice}, Locator(locator)
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{
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std::copy(typeVars.begin(), typeVars.end(), getTypeVariablesBuffer().begin());
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}
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Constraint::Constraint(ConstraintKind kind,
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ConversionRestrictionKind restriction,
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Type first, Type second, ConstraintLocator *locator,
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ArrayRef<TypeVariableType *> typeVars)
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: Kind(kind), Restriction(restriction),
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HasRestriction(true), HasFix(false), IsActive(false),
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RememberChoice(false), IsFavored(false), NumTypeVariables(typeVars.size()),
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Types{ first, second, Identifier() }, Locator(locator)
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{
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assert(!first.isNull());
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assert(!second.isNull());
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std::copy(typeVars.begin(), typeVars.end(), getTypeVariablesBuffer().begin());
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}
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Constraint::Constraint(ConstraintKind kind, Fix fix,
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Type first, Type second, ConstraintLocator *locator,
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ArrayRef<TypeVariableType *> typeVars)
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: Kind(kind), TheFix(fix.getKind()), FixData(fix.getData()),
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HasRestriction(false), HasFix(true),
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IsActive(false), RememberChoice(false), IsFavored(false),
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NumTypeVariables(typeVars.size()),
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Types{ first, second, Identifier() }, Locator(locator)
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{
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assert(!first.isNull());
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assert(!second.isNull());
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std::copy(typeVars.begin(), typeVars.end(), getTypeVariablesBuffer().begin());
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}
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ProtocolDecl *Constraint::getProtocol() const {
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assert((Kind == ConstraintKind::ConformsTo ||
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Kind == ConstraintKind::SelfObjectOfProtocol)
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&& "Not a conformance constraint");
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return Types.Second->castTo<ProtocolType>()->getDecl();
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}
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Constraint *Constraint::clone(ConstraintSystem &cs) const {
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switch (getKind()) {
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case ConstraintKind::Bind:
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case ConstraintKind::Equal:
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case ConstraintKind::BindParam:
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case ConstraintKind::Subtype:
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case ConstraintKind::Conversion:
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case ConstraintKind::ExplicitConversion:
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case ConstraintKind::ArgumentConversion:
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case ConstraintKind::ArgumentTupleConversion:
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case ConstraintKind::OperatorArgumentTupleConversion:
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case ConstraintKind::OperatorArgumentConversion:
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case ConstraintKind::ConformsTo:
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case ConstraintKind::CheckedCast:
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case ConstraintKind::DynamicTypeOf:
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case ConstraintKind::SelfObjectOfProtocol:
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case ConstraintKind::ApplicableFunction:
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case ConstraintKind::OptionalObject:
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return create(cs, getKind(), getFirstType(), getSecondType(),
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DeclName(), getLocator());
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case ConstraintKind::BindOverload:
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return createBindOverload(cs, getFirstType(), getOverloadChoice(),
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getLocator());
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case ConstraintKind::ValueMember:
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case ConstraintKind::UnresolvedValueMember:
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case ConstraintKind::TypeMember:
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return create(cs, getKind(), getFirstType(), Type(), getMember(),
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getLocator());
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case ConstraintKind::Defaultable:
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return create(cs, getKind(), getFirstType(), getSecondType(),
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getMember(), getLocator());
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case ConstraintKind::Archetype:
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case ConstraintKind::Class:
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case ConstraintKind::BridgedToObjectiveC:
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return create(cs, getKind(), getFirstType(), Type(), DeclName(),
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getLocator());
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case ConstraintKind::Disjunction:
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return createDisjunction(cs, getNestedConstraints(), getLocator());
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}
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}
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void Constraint::print(llvm::raw_ostream &Out, SourceManager *sm) const {
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if (Kind == ConstraintKind::Disjunction) {
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Out << "disjunction";
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if (shouldRememberChoice())
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Out << " (remembered)";
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if (Locator) {
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Out << " [[";
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Locator->dump(sm, Out);
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Out << "]]";
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}
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Out << ":";
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bool first = true;
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for (auto constraint : getNestedConstraints()) {
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if (first)
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first = false;
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else
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Out << " or ";
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constraint->print(Out, sm);
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}
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return;
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}
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Types.First->print(Out);
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bool skipSecond = false;
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switch (Kind) {
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case ConstraintKind::Bind: Out << " bind "; break;
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case ConstraintKind::Equal: Out << " equal "; break;
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case ConstraintKind::BindParam: Out << " bind param "; break;
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case ConstraintKind::Subtype: Out << " subtype "; break;
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case ConstraintKind::Conversion: Out << " conv "; break;
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case ConstraintKind::ExplicitConversion: Out << " expl conv "; break;
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case ConstraintKind::ArgumentConversion: Out << " arg conv "; break;
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case ConstraintKind::ArgumentTupleConversion:
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Out << " arg tuple conv "; break;
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case ConstraintKind::OperatorArgumentTupleConversion:
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Out << " operator arg tuple conv "; break;
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case ConstraintKind::OperatorArgumentConversion:
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Out << " operator arg conv "; break;
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case ConstraintKind::ConformsTo: Out << " conforms to "; break;
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case ConstraintKind::CheckedCast: Out << " checked cast to "; break;
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case ConstraintKind::SelfObjectOfProtocol: Out << " Self type of "; break;
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case ConstraintKind::ApplicableFunction: Out << " applicable fn "; break;
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case ConstraintKind::DynamicTypeOf: Out << " dynamicType type of "; break;
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case ConstraintKind::OptionalObject:
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Out << " optional with object type "; break;
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case ConstraintKind::BindOverload: {
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Out << " bound to ";
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auto overload = getOverloadChoice();
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auto printDecl = [&] {
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auto decl = overload.getDecl();
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decl->dumpRef(Out);
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Out << " : " << decl->getType();
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if (!sm || !decl->getLoc().isValid()) return;
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Out << " at ";
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decl->getLoc().print(Out, *sm);
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};
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switch (overload.getKind()) {
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case OverloadChoiceKind::Decl:
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Out << "decl ";
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printDecl();
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break;
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case OverloadChoiceKind::TypeDecl:
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Out << "type decl ";
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printDecl();
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break;
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case OverloadChoiceKind::DeclViaDynamic:
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Out << "decl-via-dynamic ";
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printDecl();
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break;
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case OverloadChoiceKind::DeclViaBridge:
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Out << "decl-via-bridge ";
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printDecl();
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break;
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case OverloadChoiceKind::DeclViaUnwrappedOptional:
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Out << "decl-via-unwrapped-optional ";
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printDecl();
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break;
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case OverloadChoiceKind::BaseType:
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Out << "base type";
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break;
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case OverloadChoiceKind::TupleIndex:
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Out << "tuple index " << overload.getTupleIndex();
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break;
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}
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skipSecond = true;
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break;
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}
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case ConstraintKind::ValueMember:
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Out << "[." << Types.Member << ": value] == ";
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break;
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case ConstraintKind::UnresolvedValueMember:
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Out << "[(implicit) ." << Types.Member << ": value] == ";
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break;
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case ConstraintKind::TypeMember:
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Out << "[." << Types.Member << ": type] == ";
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break;
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case ConstraintKind::Archetype:
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Out << " is an archetype";
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skipSecond = true;
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break;
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case ConstraintKind::Class:
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Out << " is a class";
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skipSecond = true;
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break;
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case ConstraintKind::BridgedToObjectiveC:
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Out << " is bridged to an Objective-C type";
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skipSecond = true;
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break;
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case ConstraintKind::Defaultable:
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Out << " can default to ";
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break;
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case ConstraintKind::Disjunction:
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llvm_unreachable("disjunction handled above");
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}
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if (!skipSecond)
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Types.Second->print(Out);
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if (auto restriction = getRestriction()) {
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Out << ' ' << getName(*restriction);
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}
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if (auto fix = getFix()) {
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Out << ' ';
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fix->print(Out, nullptr);
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}
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if (Locator) {
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Out << " [[";
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Locator->dump(sm, Out);
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Out << "]];";
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}
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}
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void Constraint::dump(SourceManager *sm) const {
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print(llvm::errs(), sm);
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llvm::errs() << "\n";
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}
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void Constraint::dump(ConstraintSystem *CS) const {
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// Print all type variables as $T0 instead of _ here.
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llvm::SaveAndRestore<bool> X(CS->getASTContext().LangOpts.
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DebugConstraintSolver, true);
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dump(&CS->getASTContext().SourceMgr);
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}
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StringRef swift::constraints::getName(ConversionRestrictionKind kind) {
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switch (kind) {
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case ConversionRestrictionKind::TupleToTuple:
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return "[tuple-to-tuple]";
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case ConversionRestrictionKind::ScalarToTuple:
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return "[scalar-to-tuple]";
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case ConversionRestrictionKind::TupleToScalar:
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return "[tuple-to-scalar]";
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case ConversionRestrictionKind::DeepEquality:
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return "[deep equality]";
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case ConversionRestrictionKind::Superclass:
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return "[superclass]";
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case ConversionRestrictionKind::LValueToRValue:
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return "[lvalue-to-rvalue]";
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case ConversionRestrictionKind::Existential:
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return "[existential]";
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case ConversionRestrictionKind::MetatypeToExistentialMetatype:
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return "[metatype-to-existential-metatype]";
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case ConversionRestrictionKind::ValueToOptional:
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return "[value-to-optional]";
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case ConversionRestrictionKind::OptionalToOptional:
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return "[optional-to-optional]";
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case ConversionRestrictionKind::ImplicitlyUnwrappedOptionalToOptional:
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return "[unchecked-optional-to-optional]";
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case ConversionRestrictionKind::OptionalToImplicitlyUnwrappedOptional:
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return "[optional-to-unchecked-optional]";
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case ConversionRestrictionKind::ClassMetatypeToAnyObject:
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return "[class-metatype-to-object]";
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case ConversionRestrictionKind::ExistentialMetatypeToAnyObject:
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return "[existential-metatype-to-object]";
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case ConversionRestrictionKind::ProtocolMetatypeToProtocolClass:
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return "[protocol-metatype-to-object]";
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case ConversionRestrictionKind::ArrayToPointer:
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return "[array-to-pointer]";
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case ConversionRestrictionKind::StringToPointer:
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return "[string-to-pointer]";
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case ConversionRestrictionKind::InoutToPointer:
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return "[inout-to-pointer]";
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case ConversionRestrictionKind::PointerToPointer:
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return "[pointer-to-pointer]";
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case ConversionRestrictionKind::ForceUnchecked:
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return "[force-unchecked]";
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case ConversionRestrictionKind::ArrayUpcast:
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return "[array-upcast]";
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case ConversionRestrictionKind::DictionaryUpcast:
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return "[dictionary-upcast]";
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case ConversionRestrictionKind::SetUpcast:
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return "[set-upcast]";
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case ConversionRestrictionKind::BridgeToNSError:
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return "[bridge-to-nserror]";
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case ConversionRestrictionKind::BridgeToObjC:
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return "[bridge-to-objc]";
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case ConversionRestrictionKind::BridgeFromObjC:
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return "[bridge-from-objc]";
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case ConversionRestrictionKind::CFTollFreeBridgeToObjC:
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return "[cf-toll-free-bridge-to-objc]";
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case ConversionRestrictionKind::ObjCTollFreeBridgeToCF:
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return "[objc-toll-free-bridge-to-cf]";
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}
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llvm_unreachable("bad conversion restriction kind");
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}
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Fix Fix::getRelabelTuple(ConstraintSystem &cs, FixKind kind,
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ArrayRef<Identifier> names) {
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assert(isRelabelTupleKind(kind) && "Not a tuple-relabel fix");
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Fix result(kind, cs.RelabelTupleNames.size());
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auto &allocator = cs.getAllocator();
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// Copy the names and indices.
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Identifier *namesCopy = allocator.Allocate<Identifier>(names.size());
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memcpy(namesCopy, names.data(), names.size() * sizeof(Identifier));
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cs.RelabelTupleNames.push_back({namesCopy, names.size()});
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return result;
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}
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Fix Fix::getForcedDowncast(ConstraintSystem &cs, Type toType) {
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unsigned index = cs.FixedTypes.size();
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cs.FixedTypes.push_back(toType);
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return Fix(FixKind::ForceDowncast, index);
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}
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ArrayRef<Identifier> Fix::getRelabelTupleNames(ConstraintSystem &cs) const {
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assert(isRelabelTuple());
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return cs.RelabelTupleNames[Data];
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}
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Type Fix::getTypeArgument(ConstraintSystem &cs) const {
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assert(getKind() == FixKind::ForceDowncast);
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return cs.FixedTypes[Data];
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}
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StringRef Fix::getName(FixKind kind) {
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switch (kind) {
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case FixKind::None:
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return "prevent fixes";
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case FixKind::ForceOptional:
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return "fix: force optional";
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case FixKind::ForceDowncast:
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return "fix: force downcast";
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case FixKind::AddressOf:
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return "fix: add address-of";
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case FixKind::RemoveNullaryCall:
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return "fix: remove nullary call";
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case FixKind::TupleToScalar:
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return "fix: tuple-to-scalar";
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case FixKind::ScalarToTuple:
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return "fix: scalar-to-tuple";
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case FixKind::OptionalToBoolean:
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return "fix: convert optional to boolean";
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case FixKind::FromRawToInit:
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return "fix: fromRaw(x) to init(rawValue:x)";
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case FixKind::AllZerosToInit:
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return "fix: x.allZeros to x()";
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case FixKind::ToRawToRawValue:
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return "fix: toRaw() to rawValue";
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case FixKind::CoerceToCheckedCast:
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return "fix: as to as!";
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}
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}
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void Fix::print(llvm::raw_ostream &Out, ConstraintSystem *cs) const {
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Out << "[" << getName(getKind());
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if (isRelabelTuple() && cs) {
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Out << " to ";
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for (auto name : getRelabelTupleNames(*cs))
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Out << name << ":";
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}
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if (getKind() == FixKind::ForceDowncast && cs) {
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Out << " as! ";
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Out << getTypeArgument(*cs).getString();
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}
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Out << "]";
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}
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void Fix::dump(ConstraintSystem *cs) const {
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print(llvm::errs(), cs);
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llvm::errs() << "\n";
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}
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/// Recursively gather the set of type variables referenced by this constraint.
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static void
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gatherReferencedTypeVars(Constraint *constraint,
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SmallVectorImpl<TypeVariableType *> &typeVars) {
|
|
switch (constraint->getKind()) {
|
|
case ConstraintKind::Disjunction:
|
|
for (auto nested : constraint->getNestedConstraints())
|
|
gatherReferencedTypeVars(nested, typeVars);
|
|
return;
|
|
|
|
case ConstraintKind::ApplicableFunction:
|
|
case ConstraintKind::Bind:
|
|
case ConstraintKind::BindParam:
|
|
case ConstraintKind::ArgumentConversion:
|
|
case ConstraintKind::Conversion:
|
|
case ConstraintKind::ExplicitConversion:
|
|
case ConstraintKind::ArgumentTupleConversion:
|
|
case ConstraintKind::OperatorArgumentTupleConversion:
|
|
case ConstraintKind::OperatorArgumentConversion:
|
|
case ConstraintKind::CheckedCast:
|
|
case ConstraintKind::Equal:
|
|
case ConstraintKind::Subtype:
|
|
case ConstraintKind::TypeMember:
|
|
case ConstraintKind::UnresolvedValueMember:
|
|
case ConstraintKind::ValueMember:
|
|
case ConstraintKind::DynamicTypeOf:
|
|
case ConstraintKind::OptionalObject:
|
|
case ConstraintKind::Defaultable:
|
|
constraint->getSecondType()->getTypeVariables(typeVars);
|
|
SWIFT_FALLTHROUGH;
|
|
|
|
case ConstraintKind::Archetype:
|
|
case ConstraintKind::BindOverload:
|
|
case ConstraintKind::Class:
|
|
case ConstraintKind::BridgedToObjectiveC:
|
|
case ConstraintKind::ConformsTo:
|
|
case ConstraintKind::SelfObjectOfProtocol:
|
|
constraint->getFirstType()->getTypeVariables(typeVars);
|
|
|
|
// Special case: the base type of an overloading binding.
|
|
if (constraint->getKind() == ConstraintKind::BindOverload) {
|
|
if (auto baseType = constraint->getOverloadChoice().getBaseType()) {
|
|
baseType->getTypeVariables(typeVars);
|
|
}
|
|
}
|
|
|
|
break;
|
|
}
|
|
}
|
|
|
|
/// Unique the given set of type variables.
|
|
static void uniqueTypeVariables(SmallVectorImpl<TypeVariableType *> &typeVars) {
|
|
// Remove any duplicate type variables.
|
|
llvm::SmallPtrSet<TypeVariableType *, 4> knownTypeVars;
|
|
typeVars.erase(std::remove_if(typeVars.begin(), typeVars.end(),
|
|
[&](TypeVariableType *typeVar) {
|
|
return !knownTypeVars.insert(typeVar).second;
|
|
}),
|
|
typeVars.end());
|
|
}
|
|
|
|
Constraint *Constraint::create(ConstraintSystem &cs, ConstraintKind kind,
|
|
Type first, Type second, DeclName member,
|
|
ConstraintLocator *locator) {
|
|
// Collect type variables.
|
|
SmallVector<TypeVariableType *, 4> typeVars;
|
|
if (first->hasTypeVariable())
|
|
first->getTypeVariables(typeVars);
|
|
if (second && second->hasTypeVariable())
|
|
second->getTypeVariables(typeVars);
|
|
uniqueTypeVariables(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, locator, typeVars);
|
|
}
|
|
|
|
Constraint *Constraint::createBindOverload(ConstraintSystem &cs, Type type,
|
|
OverloadChoice choice,
|
|
ConstraintLocator *locator) {
|
|
// Collect type variables.
|
|
SmallVector<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, locator, typeVars);
|
|
}
|
|
|
|
Constraint *Constraint::createRestricted(ConstraintSystem &cs,
|
|
ConstraintKind kind,
|
|
ConversionRestrictionKind restriction,
|
|
Type first, Type second,
|
|
ConstraintLocator *locator) {
|
|
// Collect type variables.
|
|
SmallVector<TypeVariableType *, 4> typeVars;
|
|
if (first->hasTypeVariable())
|
|
first->getTypeVariables(typeVars);
|
|
if (second->hasTypeVariable())
|
|
second->getTypeVariables(typeVars);
|
|
uniqueTypeVariables(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,
|
|
Fix fix,
|
|
Type first, Type second,
|
|
ConstraintLocator *locator) {
|
|
// Collect type variables.
|
|
SmallVector<TypeVariableType *, 4> typeVars;
|
|
if (first->hasTypeVariable())
|
|
first->getTypeVariables(typeVars);
|
|
if (second->hasTypeVariable())
|
|
second->getTypeVariables(typeVars);
|
|
uniqueTypeVariables(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::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.
|
|
SmallVector<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");
|
|
|
|
// If there is a single constraint, this isn't a disjunction at all.
|
|
if (constraints.size() == 1) {
|
|
assert(!rememberChoice && "simplified an important disjunction?");
|
|
return constraints.front();
|
|
}
|
|
|
|
// Create the disjunction constraint.
|
|
uniqueTypeVariables(typeVars);
|
|
unsigned size = totalSizeToAlloc<TypeVariableType*>(typeVars.size());
|
|
void *mem = cs.getAllocator().Allocate(size, alignof(Constraint));
|
|
auto disjunction = new (mem) Constraint(ConstraintKind::Disjunction,
|
|
cs.allocateCopy(constraints), locator, typeVars);
|
|
disjunction->RememberChoice = (bool) rememberChoice;
|
|
return disjunction;
|
|
}
|
|
|
|
void *Constraint::operator new(size_t bytes, ConstraintSystem& cs,
|
|
size_t alignment) {
|
|
return ::operator new (bytes, cs, alignment);
|
|
}
|