[Sema] Remove assert in TreeTransform<Derived>::TransformObjCObjectType

[ahatanak]

Summary

The assert is triggered when there is a template function whose return type is a protocol without an object type (e.g., "<P1>"). clang treats such a protocol as a synonym for "id<P1>" and sets ObjCObjectTypeLocInfo::HasBaseTypeAsWritten to false in Sema::actOnObjCProtocolQualifierType, which later causes an assert in TreeTransform<Derived>::TransformObjCObjectType.

assert(TL.hasBaseTypeAsWritten() && "Can't be dependent");

I'm not sure what hasBaseTypeAsWritten is used for. But it seemed to me that it doesn't necessarily indicate whether the type is a dependent type, so I've removed the assert.

[ahatanak]

Note that the test case currently asserts. The patch that is currently under review in http://reviews.llvm.org/D16843 has to be applied first.

[ahatanak]

Is this OK to commit?

I've committed the patch to fix the TypeLocBuilder bug in r261260.

[doug.gregor]

LGTM, sorry for the delay.

[ahatanak]

Thanks, I'll commit this shortly.

cfe/trunk/lib/Sema/TreeTransform.h

Result = getDerived().RebuildObjCObjectType(
                TL.getProtocolLocs(),
                TL.getProtocolRAngleLoc());
 
     if (Result.isNull())
       return QualType();
   }
 
   ObjCObjectTypeLoc NewT = TLB.push<ObjCObjectTypeLoc>(Result);
-  assert(TL.hasBaseTypeAsWritten() && "Can't be dependent");
   NewT.setHasBaseTypeAsWritten(true);
   NewT.setTypeArgsLAngleLoc(TL.getTypeArgsLAngleLoc());
   for (unsigned i = 0, n = TL.getNumTypeArgs(); i != n; ++i)
     NewT.setTypeArgTInfo(i, NewTypeArgInfos[i]);
   NewT.setTypeArgsRAngleLoc(TL.getTypeArgsRAngleLoc());
   NewT.setProtocolLAngleLoc(TL.getProtocolLAngleLoc());
   for (unsigned i = 0, n = TL.getNumProtocols(); i != n; ++i)
     NewT.setProtocolLoc(i, TL.getProtocolLoc(i));

cfe/trunk/test/SemaObjCXX/base-type-as-written.mm

+// RUN: %clang_cc1 -fsyntax-only -verify %s
+// Make sure we don't crash in TreeTransform<Derived>::TransformObjCObjectType.
+
+@protocol P1
+@end
+
+template <class T1><P1> foo1(T1) { // expected-warning {{protocol has no object type specified; defaults to qualified 'id'}}
+  foo1(0);
+}