AST: Handle new abstract conformances in ProtocolConformanceRef::subst()

Author: slavapestov

lib/AST/ProtocolConformanceRef.cpp

@@ -94,21 +94,20 @@ ProtocolConformanceRef::subst(Type origType, InFlightSubstitution &IFS) const {
     return getPack()->subst(IFS);
 
   // Handle abstract conformances below:
+  auto *proto = getProtocol();
 
   // If the type is an opaque archetype, the conformance will remain abstract,
   // unless we're specifically substituting opaque types.
   if (auto origArchetype = origType->getAs<ArchetypeType>()) {
     if (!IFS.shouldSubstituteOpaqueArchetypes()
         && isa<OpaqueTypeArchetypeType>(origArchetype)) {
-      return *this;
+      return forAbstract(origType.subst(IFS), proto);
     }
   }
 
   // Otherwise, compute the substituted type.
   auto substType = origType.subst(IFS);
 
-  auto *proto = getProtocol();
-
   // If the type is an existential, it must be self-conforming.
   if (substType->isExistentialType()) {
     auto optConformance =
@@ -119,7 +118,7 @@ ProtocolConformanceRef::subst(Type origType, InFlightSubstitution &IFS) const {
     return ProtocolConformanceRef::forInvalid();
   }
 
-  // Check the conformance map.
+  // Local conformance lookup into the substitution map.
   // FIXME: Pack element level?
   return IFS.lookupConformance(origType->getCanonicalType(), substType, proto,
                                /*level=*/0);