IRGen: Reduce type witnesses in hasDependentTypeWitness()

Author: slavapestov

lib/IRGen/GenProto.cpp

@@ -1006,6 +1006,8 @@ static bool hasDependentTypeWitness(
   if (!DC->isGenericContext())
     return false;
 
+  auto genericSig = conformance->getGenericSignature();
+
   // Check whether any of the associated types are dependent.
   if (conformance->forEachTypeWitness(
         [&](AssociatedTypeDecl *requirement, Type type,
@@ -1015,7 +1017,7 @@ static bool hasDependentTypeWitness(
             return false;
 
           // RESILIENCE: this could be an opaque conformance
-          return type->getCanonicalType()->hasTypeParameter();
+          return type->getReducedType(genericSig)->hasTypeParameter();
        },
        /*useResolver=*/true)) {
     return true;