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[Generic signature builder] Substitute requirements instead of threading a PA around.

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This essentially undoes the implementation in 51da51dfc0, which
implicitly did a substitution of the Self type in a protocol's
requirement signature by threading around the replacement PA. This is
brittle because every part of the code needs to take and pass around the
argument. By preemptively substituting, the whole requirement is in the
right form from the time it enters `addRequirement`.

The infrastructure here also allows simplifying some code.
This commit is contained in:
Huon Wilson
2017-02-10 18:39:21 -08:00
parent dd597cce74
commit f1dba0e7e8
3 changed files with 69 additions and 66 deletions
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101
lib/AST/GenericSignatureBuilder.cpp
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@@ -1019,12 +1019,8 @@ LazyResolver *GenericSignatureBuilder::getLazyResolver() const {
return Context.getLazyResolver();
}
auto GenericSignatureBuilder::resolveArchetype(Type type, PotentialArchetype *basePA)
-> PotentialArchetype * {
auto GenericSignatureBuilder::resolveArchetype(Type type) -> PotentialArchetype * {
if (auto genericParam = type->getAs<GenericTypeParamType>()) {
if (basePA)
return basePA;
unsigned index = GenericParamKey(genericParam).findIndexIn(
Impl->GenericParams);
if (index < Impl->GenericParams.size())
@@ -1034,7 +1030,7 @@ auto GenericSignatureBuilder::resolveArchetype(Type type, PotentialArchetype *ba
}
if (auto dependentMember = type->getAs<DependentMemberType>()) {
auto base = resolveArchetype(dependentMember->getBase(), basePA);
auto base = resolveArchetype(dependentMember->getBase());
if (!base)
return nullptr;
@@ -1112,9 +1108,15 @@ bool GenericSignatureBuilder::addConformanceRequirement(PotentialArchetype *PAT,
if (Proto->isRequirementSignatureComputed()) {
auto reqSig = Proto->getRequirementSignature();
for (auto req : reqSig->getRequirements()) {
auto concreteSelf = T->getDependentType({}, /*allowUnresolved=*/true);
auto subMap = SubstitutionMap::getProtocolSubstitutions(
Proto, concreteSelf, ProtocolConformanceRef(Proto));
for (auto rawReq : reqSig->getRequirements()) {
auto req = rawReq.subst(subMap);
assert(req && "substituting Self in requirement shouldn't fail");
RequirementSource InnerSource(Kind, Source.getLoc());
addRequirement(req, InnerSource, T, Visited);
addRequirement(*req, InnerSource, Visited);
}
} else {
// Conformances to inherit protocols are explicit in a protocol requirement
@@ -1333,9 +1335,8 @@ bool GenericSignatureBuilder::addSameTypeRequirementBetweenArchetypes(
Type concrete2 = T2->getConcreteType();
if (concrete1 && concrete2) {
bool mismatch =
addSameTypeRequirement(concrete1, concrete2, Source, nullptr,
[&](Type type1, Type type2) {
bool mismatch = addSameTypeRequirement(
concrete1, concrete2, Source, [&](Type type1, Type type2) {
Diags.diagnose(Source.getLoc(),
diag::requires_same_type_conflict,
T1->getDependentType(/*FIXME: */{ }, true), type1,
@@ -1411,9 +1412,8 @@ bool GenericSignatureBuilder::addSameTypeRequirementToConcrete(
// If we've already been bound to a type, we're either done, or we have a
// problem.
if (auto oldConcrete = T->getConcreteType()) {
bool mismatch =
addSameTypeRequirement(oldConcrete, Concrete, Source, nullptr,
[&](Type type1, Type type2) {
bool mismatch = addSameTypeRequirement(
oldConcrete, Concrete, Source, [&](Type type1, Type type2) {
Diags.diagnose(Source.getLoc(),
diag::requires_same_type_conflict,
T->getDependentType(/*FIXME: */{ }, true), type1,
@@ -1486,30 +1486,25 @@ bool GenericSignatureBuilder::addSameTypeRequirementToConcrete(
}
bool GenericSignatureBuilder::addSameTypeRequirement(
Type type1, Type type2,
RequirementSource source,
PotentialArchetype *basePA,
llvm::function_ref<void(Type, Type)> diagnoseMismatch) {
Type type1, Type type2, RequirementSource source,
llvm::function_ref<void(Type, Type)> diagnoseMismatch) {
// Local class to handle matching the two sides of the same-type constraint.
class ReqTypeMatcher : public TypeMatcher<ReqTypeMatcher> {
GenericSignatureBuilder &builder;
RequirementSource source;
PotentialArchetype *basePA;
llvm::function_ref<void(Type, Type)> diagnoseMismatch;
public:
ReqTypeMatcher(GenericSignatureBuilder &builder,
RequirementSource source,
PotentialArchetype *basePA,
ReqTypeMatcher(GenericSignatureBuilder &builder, RequirementSource source,
llvm::function_ref<void(Type, Type)> diagnoseMismatch)
: builder(builder), source(source), basePA(basePA),
diagnoseMismatch(diagnoseMismatch) { }
: builder(builder), source(source), diagnoseMismatch(diagnoseMismatch) {
}
bool mismatch(TypeBase *firstType, TypeBase *secondType,
Type sugaredFirstType) {
// Find the potential archetypes.
PotentialArchetype *pa1 = builder.resolveArchetype(firstType, basePA);
PotentialArchetype *pa2 = builder.resolveArchetype(secondType, basePA);
PotentialArchetype *pa1 = builder.resolveArchetype(firstType);
PotentialArchetype *pa2 = builder.resolveArchetype(secondType);
// If both sides of the requirement are type parameters, equate them.
if (pa1 && pa2)
@@ -1527,7 +1522,7 @@ bool GenericSignatureBuilder::addSameTypeRequirement(
diagnoseMismatch(sugaredFirstType, secondType);
return false;
}
} matcher(*this, source, basePA, diagnoseMismatch);
} matcher(*this, source, diagnoseMismatch);
return !matcher.match(type1, type2);
}
@@ -1697,17 +1692,16 @@ bool GenericSignatureBuilder::addRequirement(const RequirementRepr &Req) {
bool GenericSignatureBuilder::addRequirement(const Requirement &req,
RequirementSource source) {
llvm::SmallPtrSet<ProtocolDecl *, 8> Visited;
return addRequirement(req, source, nullptr, Visited);
return addRequirement(req, source, Visited);
}
bool GenericSignatureBuilder::addRequirement(
const Requirement &req, RequirementSource source,
PotentialArchetype *basePA,
llvm::SmallPtrSetImpl<ProtocolDecl *> &Visited) {
switch (req.getKind()) {
case RequirementKind::Superclass: {
// FIXME: Diagnose this.
PotentialArchetype *pa = resolveArchetype(req.getFirstType(), basePA);
PotentialArchetype *pa = resolveArchetype(req.getFirstType());
if (!pa) return false;
assert(req.getSecondType()->getClassOrBoundGenericClass());
@@ -1716,7 +1710,7 @@ bool GenericSignatureBuilder::addRequirement(
case RequirementKind::Layout: {
// FIXME: Diagnose this.
PotentialArchetype *pa = resolveArchetype(req.getFirstType(), basePA);
PotentialArchetype *pa = resolveArchetype(req.getFirstType());
if (!pa) return false;
return addLayoutRequirement(pa, req.getLayoutConstraint(), source);
@@ -1724,7 +1718,7 @@ bool GenericSignatureBuilder::addRequirement(
case RequirementKind::Conformance: {
// FIXME: Diagnose this.
PotentialArchetype *pa = resolveArchetype(req.getFirstType(), basePA);
PotentialArchetype *pa = resolveArchetype(req.getFirstType());
if (!pa) return false;
SmallVector<ProtocolDecl *, 4> conformsTo;
@@ -1744,7 +1738,7 @@ bool GenericSignatureBuilder::addRequirement(
case RequirementKind::SameType:
return addSameTypeRequirement(
req.getFirstType(), req.getSecondType(), source, basePA,
req.getFirstType(), req.getSecondType(), source,
[&](Type type1, Type type2) {
if (source.getLoc().isValid())
Diags.diagnose(source.getLoc(),
@@ -1804,25 +1798,21 @@ public:
// Handle the requirements.
RequirementSource source(RequirementSource::Inferred, Loc);
for (const auto &req : genericSig->getRequirements()) {
switch (req.getKind()) {
case RequirementKind::SameType: {
auto firstType = req.getFirstType().subst(
getTypeSubstitution,
Builder.getLookupConformanceFn());
if (!firstType)
break;
for (const auto &rawReq : genericSig->getRequirements()) {
auto req =
rawReq.subst(getTypeSubstitution, Builder.getLookupConformanceFn());
if (!req)
continue;
switch (req->getKind()) {
case RequirementKind::SameType: {
auto firstType = req->getFirstType();
auto firstPA = Builder.resolveArchetype(firstType);
if (firstPA && isOuterArchetype(firstPA))
return Action::Continue;
auto secondType = req.getSecondType().subst(
getTypeSubstitution,
Builder.getLookupConformanceFn());
if (!secondType)
break;
auto secondType = req->getSecondType();
auto secondPA = Builder.resolveArchetype(secondType);
if (firstPA && secondPA) {
@@ -1843,12 +1833,7 @@ public:
case RequirementKind::Superclass:
case RequirementKind::Layout:
case RequirementKind::Conformance: {
auto subjectType = req.getFirstType().subst(
getTypeSubstitution,
Builder.getLookupConformanceFn());
if (!subjectType)
break;
auto subjectType = req->getFirstType();
auto subjectPA = Builder.resolveArchetype(subjectType);
if (!subjectPA) {
break;
@@ -1857,19 +1842,19 @@ public:
if (isOuterArchetype(subjectPA))
return Action::Continue;
if (req.getKind() == RequirementKind::Conformance) {
auto proto = req.getSecondType()->castTo<ProtocolType>();
if (req->getKind() == RequirementKind::Conformance) {
auto proto = req->getSecondType()->castTo<ProtocolType>();
if (Builder.addConformanceRequirement(subjectPA, proto->getDecl(),
source)) {
return Action::Stop;
}
} else if (req.getKind() == RequirementKind::Layout) {
if (Builder.addLayoutRequirement(subjectPA, req.getLayoutConstraint(),
source)) {
} else if (req->getKind() == RequirementKind::Layout) {
if (Builder.addLayoutRequirement(
subjectPA, req->getLayoutConstraint(), source)) {
return Action::Stop;
}
} else {
if (Builder.addSuperclassRequirement(subjectPA, req.getSecondType(),
if (Builder.addSuperclassRequirement(subjectPA, req->getSecondType(),
source)) {
return Action::Stop;
}