Merge pull request #40474 from apple/revert-40440-prefer-swift-type

Revert "lookup: prefer Swift types over Clang ones when multiple types are present in lookup"

Author: nkcsgexi

lib/Sema/TypeCheckType.cpp

@@ -1423,21 +1423,6 @@ static void diagnoseAmbiguousMemberType(Type baseTy, SourceRange baseRange,
   }
 }
 
-static LookupTypeResult preferSwiftTypes(LookupTypeResult results) {
-  if (results.size() == 1)
-    return results;
-  LookupTypeResult newResults;
-  for (auto cur: results) {
-    if (cur.Member->getClangNode()) {
-      continue;
-    }
-    newResults.addResult(cur);
-  }
-  if (newResults.size() == 1)
-    return newResults;
-  return results;
-}
-
 /// Resolve the given identifier type representation as a qualified
 /// lookup within the given parent type, returning the type it
 /// references.
@@ -1548,9 +1533,6 @@ static Type resolveNestedIdentTypeComponent(TypeResolution resolution,
     memberTypes = TypeChecker::lookupMemberType(
         DC, parentTy, comp->getNameRef(), lookupOptions);
 
-  // Prefer Swift types over Clang types.
-  memberTypes = preferSwiftTypes(memberTypes);
-
   // Name lookup was ambiguous. Complain.
   // FIXME: Could try to apply generic arguments first, and see whether
   // that resolves things. But do we really want that to succeed?