Review feedback

Author: gregomni

lib/Sema/TypeCheckProtocol.cpp

@@ -885,9 +885,9 @@ swift::matchWitness(TypeChecker &tc,
         return missingRequirementMatch(type);
 
       type = type->mapTypeOutOfContext();
-      if (auto typeParamTy = type->getAs<GenericTypeParamType>())
+      if (type->hasTypeParameter())
         if (auto env = conformance->getGenericEnvironment())
-          if (auto assocType = env->mapTypeIntoContext(typeParamTy))
+          if (auto assocType = env->mapTypeIntoContext(type))
             return missingRequirementMatch(assocType);
 
       auto reqSubMap = reqEnvironment.getRequirementToSyntheticMap();

lib/Sema/TypeCheckProtocol.h

@@ -79,6 +79,9 @@ class CheckTypeWitnessResult {
   bool isConformanceRequirement() const {
     return Requirement->isExistentialType();
   }
+  bool isSuperclassRequirement() const {
+    return !isConformanceRequirement();
+  }
   bool isError() const {
     return Requirement->is<ErrorType>();
   }

lib/Sema/TypeCheckProtocolInference.cpp

@@ -1747,16 +1747,16 @@ bool AssociatedTypeInference::diagnoseNoSolutions(
           if (failed.Result.isError())
             continue;
 
-          if (!failed.TypeWitness->is<NominalType>() &&
+          if (!failed.TypeWitness->getAnyNominal() &&
               failed.Result.isConformanceRequirement()) {
             diags.diagnose(failed.Witness,
                            diag::associated_type_witness_conform_impossible,
                            assocType->getName(), failed.TypeWitness,
                            failed.Result.getRequirement());
             continue;
           }
-          if (!failed.TypeWitness->is<ClassType>() &&
-              !failed.Result.isConformanceRequirement()) {
+          if (!failed.TypeWitness->getClassOrBoundGenericClass() &&
+              failed.Result.isSuperclassRequirement()) {
             diags.diagnose(failed.Witness,
                            diag::associated_type_witness_inherit_impossible,
                            assocType->getName(), failed.TypeWitness,