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Fix a bug with inlining self-conformances.

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This commit is contained in:
John McCall
2018-11-16 22:49:07 -05:00
parent 5c205b4573
commit cd2b558280
3 changed files with 65 additions and 53 deletions
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99
lib/AST/Module.cpp
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@@ -570,6 +570,57 @@ void ModuleDecl::getDisplayDecls(SmallVectorImpl<Decl*> &Results) const {
FORWARD(getDisplayDecls, (Results));
}
Optional<ProtocolConformanceRef>
ModuleDecl::lookupExistentialConformance(Type type, ProtocolDecl *protocol) {
assert(type->isExistentialType());
// If the existential type cannot be represented or the protocol does not
// conform to itself, there's no point in looking further.
if (!protocol->existentialConformsToSelf())
return None;
auto layout = type->getExistentialLayout();
// Due to an IRGen limitation, witness tables cannot be passed from an
// existential to an archetype parameter, so for now we restrict this to
// @objc protocols.
if (!layout.isObjC()) {
return None;
}
// If the existential is class-constrained, the class might conform
// concretely.
if (auto superclass = layout.explicitSuperclass) {
if (auto result = lookupConformance(superclass, protocol))
return result;
}
// Otherwise, the existential might conform abstractly.
for (auto proto : layout.getProtocols()) {
auto *protoDecl = proto->getDecl();
// If we found the protocol we're looking for, return an abstract
// conformance to it.
if (protoDecl == protocol)
return ProtocolConformanceRef(protocol);
// If the protocol has a superclass constraint, we might conform
// concretely.
if (auto superclass = protoDecl->getSuperclass()) {
if (auto result = lookupConformance(superclass, protocol))
return result;
}
// Now check refined protocols.
if (protoDecl->inheritsFrom(protocol))
return ProtocolConformanceRef(protocol);
}
// We didn't find our protocol in the existential's list; it doesn't
// conform.
return None;
}
Optional<ProtocolConformanceRef>
ModuleDecl::lookupConformance(Type type, ProtocolDecl *protocol) {
ASTContext &ctx = getASTContext();
@@ -609,52 +660,8 @@ ModuleDecl::lookupConformance(Type type, ProtocolDecl *protocol) {
// An existential conforms to a protocol if the protocol is listed in the
// existential's list of conformances and the existential conforms to
// itself.
if (type->isExistentialType()) {
// If the existential type cannot be represented or the protocol does not
// conform to itself, there's no point in looking further.
if (!protocol->existentialConformsToSelf())
return None;
auto layout = type->getExistentialLayout();
// Due to an IRGen limitation, witness tables cannot be passed from an
// existential to an archetype parameter, so for now we restrict this to
// @objc protocols.
if (!layout.isObjC())
return None;
// If the existential is class-constrained, the class might conform
// concretely.
if (auto superclass = layout.explicitSuperclass) {
if (auto result = lookupConformance(superclass, protocol))
return result;
}
// Otherwise, the existential might conform abstractly.
for (auto proto : layout.getProtocols()) {
auto *protoDecl = proto->getDecl();
// If we found the protocol we're looking for, return an abstract
// conformance to it.
if (protoDecl == protocol)
return ProtocolConformanceRef(protocol);
// If the protocol has a superclass constraint, we might conform
// concretely.
if (auto superclass = protoDecl->getSuperclass()) {
if (auto result = lookupConformance(superclass, protocol))
return result;
}
// Now check refined protocols.
if (protoDecl->inheritsFrom(protocol))
return ProtocolConformanceRef(protocol);
}
// We didn't find our protocol in the existential's list; it doesn't
// conform.
return None;
}
if (type->isExistentialType())
return lookupExistentialConformance(type, protocol);
// Type variables have trivial conformances.
if (type->isTypeVariableOrMember())