Document some serious badness in our evaluation of the type traits: we need to be sure we have complete types in many cases

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@124428 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index df4103a..ca104ef 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -2219,6 +2219,8 @@
 
 static bool EvaluateUnaryTypeTrait(Sema &Self, UnaryTypeTrait UTT, QualType T,
                                    SourceLocation KeyLoc) {
+  // FIXME: For many of these traits, we need a complete type before we can 
+  // check these properties.
   assert(!T->isDependentType() &&
          "Cannot evaluate traits for dependent types.");
   ASTContext &C = Self.Context;