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Sema: Better fix for <rdar://problem/36449760>

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This commit is contained in:
Slava Pestov
2018-07-10 12:27:28 -07:00
parent 3ae11e6536
commit 4878889c1e
2 changed files with 32 additions and 57 deletions
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87
lib/Sema/ConstraintSystem.cpp
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@@ -1053,31 +1053,6 @@ ConstraintSystem::getTypeOfReference(ValueDecl *value,
return { valueType, valueType };
}
static Type getInnermostConformingType(TypeChecker &TC, DeclContext *DC,
ProtocolDecl *protocol) {
do {
if (DC->isTypeContext()) {
if (protocol == DC->getAsProtocolOrProtocolExtensionContext())
return DC->mapTypeIntoContext(DC->getProtocolSelfType());
auto *NTD = DC->getAsNominalTypeOrNominalTypeExtensionContext();
auto type = NTD->getDeclaredType();
ConformanceCheckOptions options;
options |= ConformanceCheckFlags::InExpression;
options |= ConformanceCheckFlags::SuppressDependencyTracking;
options |= ConformanceCheckFlags::SkipConditionalRequirements;
auto result =
TC.conformsToProtocol(type, protocol, NTD->getDeclContext(), options);
if (result)
return DC->getDeclaredTypeInContext();
}
} while ((DC = DC->getParent()));
return nullptr;
}
/// Bind type variables for archetypes that are determined from
/// context.
///
@@ -1093,10 +1068,10 @@ static Type getInnermostConformingType(TypeChecker &TC, DeclContext *DC,
///
/// A final case we have to handle, even though it is invalid, is
/// when a type is nested inside another protocol. We bind the
/// protocol type variable for the protocol Self to its archetype
/// in protocol context. This of course makes no sense, but we
/// can't leave the type variable dangling, because then we crash
/// later.
/// protocol type variable for the protocol Self to an unresolved
/// type, since it will conform to anything. This of course makes
/// no sense, but we can't leave the type variable dangling,
/// because then we crash later.
///
/// If we ever do want to allow nominal types to be nested inside
/// protocols, the key is to set their declared type to a
@@ -1117,43 +1092,43 @@ static void bindArchetypesFromContext(
auto *genericEnv = cs.DC->getGenericEnvironmentOfContext();
auto bindContextArchetype = [&](Type paramTy, Type contextTy) {
auto found = replacements.find(cast<GenericTypeParamType>(
paramTy->getCanonicalType()));
// We might not have a type variable for this generic parameter
// because either we're opening up an UnboundGenericType,
// in which case we only want to infer the innermost generic
// parameters, or because this generic parameter was constrained
// away into a concrete type.
if (found != replacements.end()) {
auto typeVar = found->second;
cs.addConstraint(ConstraintKind::Bind, typeVar, contextTy,
locatorPtr);
}
};
// Find the innermost non-type context.
for (const auto *parentDC = outerDC;
!parentDC->isModuleScopeContext();
parentDC = parentDC->getParent()) {
if (parentDC->isTypeContext() &&
(parentDC == outerDC ||
!parentDC->getAsProtocolOrProtocolExtensionContext()))
if (parentDC->isTypeContext()) {
if (parentDC != outerDC && parentDC->getAsProtocolOrProtocolExtensionContext()) {
auto selfTy = parentDC->getSelfInterfaceType();
auto contextTy = cs.TC.Context.TheUnresolvedType;
bindContextArchetype(selfTy, contextTy);
}
continue;
}
// If it's not generic, there's nothing to do.
auto *genericSig = parentDC->getGenericSignatureOfContext();
if (!genericSig)
break;
for (auto *paramTy : genericSig->getGenericParams()) {
auto found = replacements.find(cast<GenericTypeParamType>(
paramTy->getCanonicalType()));
// We might not have a type variable for this generic parameter
// because either we're opening up an UnboundGenericType,
// in which case we only want to infer the innermost generic
// parameters, or because this generic parameter was constrained
// away into a concrete type.
if (found != replacements.end()) {
Type contextTy;
if (genericEnv) {
contextTy = genericEnv->mapTypeIntoContext(paramTy);
} else {
auto *protocol = parentDC->getAsProtocolOrProtocolExtensionContext();
contextTy = getInnermostConformingType(cs.TC, cs.DC, protocol);
}
assert(contextTy);
auto typeVar = found->second;
cs.addConstraint(ConstraintKind::Bind, typeVar, contextTy,
locatorPtr);
}
Type contextTy = genericEnv->mapTypeIntoContext(paramTy);
bindContextArchetype(paramTy, contextTy);
}
break;