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791c449f7c
We should enable it again once the substitutions machinery and GenericSignatureBuilder always generate correct SubstitutionMaps. But for now let’s disable it to unblock the CI jobs. Should fix SR-4322 and rdar://31224655
486 lines
17 KiB
C++
486 lines
17 KiB
C++
//===--- SubstitutionMap.cpp - Type substitution map ----------------------===//
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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 - 2017 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 https://swift.org/LICENSE.txt for license information
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// See https://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 defines the SubstitutionMap class. A SubstitutionMap packages
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// together a set of replacement types and protocol conformances for
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// specializing generic types.
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//
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// SubstitutionMaps either have type parameters or archetypes as keys,
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// based on whether they were built from a GenericSignature or a
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// GenericEnvironment.
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//
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// To specialize a type, call Type::subst() with the right SubstitutionMap.
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//
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//===----------------------------------------------------------------------===//
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#include "swift/AST/ASTContext.h"
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#include "swift/AST/SubstitutionMap.h"
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#include "swift/AST/Decl.h"
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#include "swift/AST/Module.h"
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#include "swift/AST/ProtocolConformance.h"
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#include "swift/AST/Types.h"
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#include "llvm/Support/Debug.h"
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using namespace swift;
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bool SubstitutionMap::hasArchetypes() const {
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for (auto &entry : subMap)
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if (entry.second->hasArchetype())
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return true;
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return false;
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}
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bool SubstitutionMap::hasOpenedExistential() const {
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for (auto &entry : subMap)
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if (entry.second->hasOpenedExistential())
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return true;
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return false;
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}
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bool SubstitutionMap::hasDynamicSelf() const {
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for (auto &entry : subMap)
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if (entry.second->hasDynamicSelfType())
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return true;
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return false;
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}
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Type SubstitutionMap::lookupSubstitution(CanSubstitutableType type) const {
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auto known = subMap.find(type);
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if (known != subMap.end() && known->second)
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return known->second;
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// Not known.
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return Type();
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}
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void SubstitutionMap::
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addSubstitution(CanSubstitutableType type, Type replacement) {
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auto result = subMap.insert(std::make_pair(type, replacement));
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assert(result.second || result.first->second->isEqual(replacement));
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(void) result;
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}
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template<typename T>
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Optional<T> SubstitutionMap::forEachParent(
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CanType type,
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llvm::SmallPtrSetImpl<CanType> &visitedParents,
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llvm::function_ref<Optional<T>(CanType,
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AssociatedTypeDecl *)> fn) const {
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// If we've already visited the parents of this type, stop.
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if (!visitedParents.insert(type).second)
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return None;
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auto foundParents = parentMap.find(type.getPointer());
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if (foundParents != parentMap.end()) {
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for (auto parent : foundParents->second) {
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if (auto result = fn(parent.first, parent.second))
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return result;
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}
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}
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if (auto archetypeType = dyn_cast<ArchetypeType>(type))
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if (auto *parent = archetypeType->getParent())
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return fn(CanType(parent), archetypeType->getAssocType());
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if (auto memberType = dyn_cast<DependentMemberType>(type))
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return fn(CanType(memberType->getBase()), memberType->getAssocType());
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return None;
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}
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template<typename T>
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Optional<T> SubstitutionMap::forEachConformance(
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CanType type,
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llvm::SmallPtrSetImpl<CanType> &visitedParents,
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llvm::function_ref<Optional<T>(ProtocolConformanceRef)> fn) const{
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// Check for conformances for the type that apply to the original
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// substituted archetype.
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auto foundReplacement = conformanceMap.find(type.getPointer());
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if (foundReplacement != conformanceMap.end()) {
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for (auto conformance : foundReplacement->second) {
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if (auto found = fn(conformance))
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return found;
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}
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}
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// Local function to performance a (recursive) search for an associated type
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// of the given name in the given conformance and all inherited conformances.
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std::function<Optional<T>(ProtocolConformanceRef, DeclName,
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llvm::SmallPtrSetImpl<ProtocolDecl *> &)>
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searchInConformance;
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searchInConformance =
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[&](ProtocolConformanceRef conformance,
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DeclName associatedTypeName,
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llvm::SmallPtrSetImpl<ProtocolDecl *> &visited) -> Optional<T> {
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// Only visit a particular protocol once.
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auto proto = conformance.getRequirement();
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if (!visited.insert(proto).second) return None;
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// Check whether this protocol has an associated type with the
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// same name as the one we're looking for.
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AssociatedTypeDecl *protoAssocType = nullptr;
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for (auto member : proto->lookupDirect(associatedTypeName)) {
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protoAssocType = dyn_cast<AssociatedTypeDecl>(member);
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if (protoAssocType) break;
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}
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if (protoAssocType) {
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if (conformance.isAbstract()) {
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for (auto assocProto : protoAssocType->getConformingProtocols()) {
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if (auto found = fn(ProtocolConformanceRef(assocProto)))
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return found;
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}
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} else {
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auto sub = conformance.getConcrete()->getTypeWitnessSubstAndDecl(
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protoAssocType, nullptr).first;
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for (auto subConformance : sub.getConformances()) {
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if (auto found = fn(subConformance))
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return found;
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}
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}
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}
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// Search inherited conformances.
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for (auto inherited : proto->getInheritedProtocols()) {
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if (auto found = searchInConformance(conformance.getInherited(inherited),
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associatedTypeName,
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visited))
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return found;
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}
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return None;
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};
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// Check if we have conformances from one of our parent types.
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return forEachParent<ProtocolConformanceRef>(type, visitedParents,
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[&](CanType parent, AssociatedTypeDecl *assocType)
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-> Optional<ProtocolConformanceRef> {
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return forEachConformance<T>(parent, visitedParents,
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[&](ProtocolConformanceRef conformance) -> Optional<T> {
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llvm::SmallPtrSet<ProtocolDecl *, 4> visited;
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return searchInConformance(conformance, assocType->getFullName(),
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visited);
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});
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});
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}
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Optional<ProtocolConformanceRef>
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SubstitutionMap::lookupConformance(
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CanType type, ProtocolDecl *proto,
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llvm::SmallPtrSetImpl<CanType> *visitedParents) const {
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// Local function to either record an abstract conformance or return a
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// concrete conformance. This allows us to check multiple parents and
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// find the most specific conformance that applies.
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Optional<ProtocolConformanceRef> abstractConformance;
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auto recordOrReturn = [&](ProtocolConformanceRef conformance)
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-> Optional<ProtocolConformanceRef> {
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if (conformance.isAbstract()) {
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if (!abstractConformance)
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abstractConformance = conformance;
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return None;
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}
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return conformance;
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};
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llvm::SmallPtrSet<CanType, 4> visitedParentsStored;
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if (!visitedParents)
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visitedParents = &visitedParentsStored;
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auto concreteConformance =
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forEachConformance<ProtocolConformanceRef>(type, *visitedParents,
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[&](ProtocolConformanceRef conformance)
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-> Optional<ProtocolConformanceRef> {
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if (conformance.getRequirement() == proto)
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return recordOrReturn(conformance);
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if (conformance.getRequirement()->inheritsFrom(proto))
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return recordOrReturn(conformance.getInherited(proto));
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return None;
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});
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return concreteConformance ? concreteConformance : abstractConformance;
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}
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void SubstitutionMap::
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addConformance(CanType type, ProtocolConformanceRef conformance) {
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conformanceMap[type.getPointer()].push_back(conformance);
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}
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void SubstitutionMap::
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addParent(CanType type, CanType parent, AssociatedTypeDecl *assocType) {
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assert(type && parent && assocType);
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parentMap[type.getPointer()].push_back(std::make_pair(parent, assocType));
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}
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SubstitutionMap SubstitutionMap::subst(const SubstitutionMap &subMap) const {
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return subst(QuerySubstitutionMap{subMap},
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LookUpConformanceInSubstitutionMap(subMap));
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}
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SubstitutionMap SubstitutionMap::subst(TypeSubstitutionFn subs,
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LookupConformanceFn conformances) const {
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SubstitutionMap result(*this);
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for (auto iter = result.subMap.begin(),
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end = result.subMap.end();
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iter != end; ++iter) {
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iter->second = iter->second.subst(subs, conformances,
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SubstFlags::UseErrorType);
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}
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for (auto iter = result.conformanceMap.begin(),
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end = result.conformanceMap.end();
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iter != end; ++iter) {
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auto origType = Type(iter->first).subst(
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*this, SubstFlags::UseErrorType);
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for (auto citer = iter->second.begin(),
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cend = iter->second.end();
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citer != cend; ++citer) {
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*citer = citer->subst(origType, subs, conformances);
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}
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}
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result.verify();
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return result;
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}
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SubstitutionMap
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SubstitutionMap::getProtocolSubstitutions(ProtocolDecl *protocol,
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Type selfType,
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ProtocolConformanceRef conformance) {
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auto protocolSelfType = protocol->getSelfInterfaceType();
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return protocol->getGenericSignature()->getSubstitutionMap(
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[&](SubstitutableType *type) -> Type {
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if (type->isEqual(protocolSelfType))
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return selfType;
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// This will need to change if we ever support protocols
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// inside generic types.
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return Type();
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},
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[&](CanType origType, Type replacementType, ProtocolType *protoType)
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-> Optional<ProtocolConformanceRef> {
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if (origType->isEqual(protocolSelfType) &&
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protoType->getDecl() == protocol)
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return conformance;
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// This will need to change if we ever support protocols
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// inside generic types.
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return None;
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});
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}
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SubstitutionMap
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SubstitutionMap::getOverrideSubstitutions(const ValueDecl *baseDecl,
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const ValueDecl *derivedDecl,
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Optional<SubstitutionMap> derivedSubs,
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LazyResolver *resolver) {
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auto *baseClass = baseDecl->getDeclContext()
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->getAsClassOrClassExtensionContext();
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auto *derivedClass = derivedDecl->getDeclContext()
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->getAsClassOrClassExtensionContext();
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auto *baseSig = baseDecl->getInnermostDeclContext()
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->getGenericSignatureOfContext();
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auto *derivedSig = derivedDecl->getInnermostDeclContext()
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->getGenericSignatureOfContext();
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return getOverrideSubstitutions(baseClass, derivedClass,
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baseSig, derivedSig,
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derivedSubs,
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resolver);
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}
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SubstitutionMap
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SubstitutionMap::getOverrideSubstitutions(const ClassDecl *baseClass,
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const ClassDecl *derivedClass,
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GenericSignature *baseSig,
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GenericSignature *derivedSig,
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Optional<SubstitutionMap> derivedSubs,
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LazyResolver *resolver) {
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if (baseSig == nullptr)
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return SubstitutionMap();
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auto *M = baseClass->getParentModule();
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unsigned baseDepth = 0;
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SubstitutionMap baseSubMap;
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if (auto *baseClassSig = baseClass->getGenericSignature()) {
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baseDepth = baseClassSig->getGenericParams().back()->getDepth() + 1;
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auto derivedClassTy = derivedClass->getDeclaredInterfaceType();
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if (derivedSubs)
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derivedClassTy = derivedClassTy.subst(*derivedSubs);
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auto baseClassTy = derivedClassTy->getSuperclassForDecl(baseClass, resolver);
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baseSubMap = baseClassTy->getContextSubstitutionMap(M, baseClass);
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}
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unsigned origDepth = 0;
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if (auto *derivedClassSig = derivedClass->getGenericSignature())
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origDepth = derivedClassSig->getGenericParams().back()->getDepth() + 1;
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SubstitutionMap origSubMap;
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if (derivedSubs)
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origSubMap = *derivedSubs;
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else if (derivedSig) {
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origSubMap = derivedSig->getSubstitutionMap(
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[](SubstitutableType *type) -> Type { return type; },
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MakeAbstractConformanceForGenericType());
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}
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return combineSubstitutionMaps(baseSubMap, origSubMap,
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CombineSubstitutionMaps::AtDepth,
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baseDepth, origDepth,
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baseSig);
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}
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SubstitutionMap
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SubstitutionMap::combineSubstitutionMaps(const SubstitutionMap &firstSubMap,
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const SubstitutionMap &secondSubMap,
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CombineSubstitutionMaps how,
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unsigned firstDepthOrIndex,
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unsigned secondDepthOrIndex,
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GenericSignature *genericSig) {
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auto &ctx = genericSig->getASTContext();
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auto replaceGenericParameter = [&](Type type) -> Type {
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if (auto gp = type->getAs<GenericTypeParamType>()) {
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if (how == CombineSubstitutionMaps::AtDepth) {
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if (gp->getDepth() < firstDepthOrIndex)
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return Type();
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return GenericTypeParamType::get(
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gp->getDepth() + secondDepthOrIndex - firstDepthOrIndex,
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gp->getIndex(),
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ctx);
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}
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assert(how == CombineSubstitutionMaps::AtIndex);
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if (gp->getIndex() < firstDepthOrIndex)
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return Type();
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return GenericTypeParamType::get(
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gp->getDepth(),
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gp->getIndex() + secondDepthOrIndex - firstDepthOrIndex,
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ctx);
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}
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return type;
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};
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return genericSig->getSubstitutionMap(
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[&](SubstitutableType *type) {
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auto replacement = replaceGenericParameter(type);
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if (replacement)
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return Type(replacement).subst(secondSubMap);
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return Type(type).subst(firstSubMap);
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},
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[&](CanType type, Type substType, ProtocolType *conformedProtocol) {
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auto replacement = type.transform(replaceGenericParameter);
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if (replacement)
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return secondSubMap.lookupConformance(replacement->getCanonicalType(),
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conformedProtocol->getDecl());
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return firstSubMap.lookupConformance(type,
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conformedProtocol->getDecl());
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});
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}
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void SubstitutionMap::verify() const {
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// FIXME: Remove the conditional compilation once the substitutions
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// machinery and GenericSignatureBuilder always generate correct
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// SubstitutionMaps.
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#if 0 && !defined(NDEBUG)
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for (auto iter = conformanceMap.begin(), end = conformanceMap.end();
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iter != end; ++iter) {
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auto replacement = Type(iter->first).subst(*this, SubstFlags::UseErrorType);
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if (replacement->isTypeParameter() || replacement->is<ArchetypeType>() ||
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replacement->isTypeVariableOrMember() ||
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replacement->is<UnresolvedType>() || replacement->hasError())
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continue;
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// Check conformances of a concrete replacement type.
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for (auto citer = iter->second.begin(), cend = iter->second.end();
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citer != cend; ++citer) {
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// An existential type can have an abstract conformance to
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// AnyObject or an @objc protocol.
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if (citer->isAbstract() && replacement->isExistentialType()) {
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auto *proto = citer->getRequirement();
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assert((proto->isSpecificProtocol(KnownProtocolKind::AnyObject) ||
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proto->isObjC()) &&
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"an existential type can conform only to AnyObject or an "
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"@objc-protocol");
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continue;
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}
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// All of the conformances should be concrete.
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if (!citer->isConcrete()) {
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llvm::dbgs() << "Concrete replacement type:\n";
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replacement->dump(llvm::dbgs());
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llvm::dbgs() << "SubstitutionMap:\n";
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dump(llvm::dbgs());
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}
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assert(citer->isConcrete() && "Conformance should be concrete");
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}
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}
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#endif
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}
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void SubstitutionMap::dump(llvm::raw_ostream &out) const {
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out << "Substitutions:\n";
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for (const auto &sub : subMap) {
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out.indent(2);
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sub.first->print(out);
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out << " -> ";
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sub.second->print(out);
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out << "\n";
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}
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out << "\nConformance map:\n";
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for (const auto &conformances : conformanceMap) {
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out.indent(2);
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conformances.first->print(out);
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out << " -> [";
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interleave(conformances.second.begin(), conformances.second.end(),
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[&](ProtocolConformanceRef conf) {
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conf.dump(out);
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},
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[&] {
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out << ", ";
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});
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out << "]\n";
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}
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out << "\nParent map:\n";
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for (const auto &parent : parentMap) {
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out.indent(2);
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parent.first->print(out);
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out << " -> [";
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interleave(parent.second.begin(), parent.second.end(),
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[&](SubstitutionMap::ParentType parentType) {
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parentType.first->print(out);
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out << " @ ";
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out << parentType.second->getProtocol()->getName().str()
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<< "." << parentType.second->getName().str();
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},
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[&] {
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out << ", ";
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});
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out << "]\n";
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}
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}
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void SubstitutionMap::dump() const {
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return dump(llvm::errs());
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}
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