fix

Author: angela-laar

lib/AST/GenericSignature.cpp

@@ -644,12 +644,13 @@ Type GenericSignatureImpl::getUpperBound(Type type,
   // If the class contains a type parameter that cannot be reduced,
   // try looking for a non-dependent superclass.
   if (Type superclass = getSuperclassBound(type)) {
-    do {
+    while (superclass->hasTypeParameter()) {
       superclass = getReducedType(superclass);
-      if (wantDependentBound || !superclass->hasTypeParameter()) {
+      if (wantDependentBound && !superclass->hasTypeParameter()) {
         break;
       }
-    } while ((superclass = superclass->getSuperclass()));
+      superclass = superclass->getSuperclass();
+    }
 
     if (superclass) {
       types.push_back(superclass);