fix assertion

Author: changkhothuychung

clang/lib/Parse/ParseExpr.cpp

@@ -2222,8 +2222,9 @@ ExprResult Parser::ParseUnaryExprOrTypeTraitExpression() {
   assert(Tok.isOneOf(tok::kw_sizeof, tok::kw___datasizeof, tok::kw___alignof,
                      tok::kw_alignof, tok::kw__Alignof, tok::kw_vec_step,
                      tok::kw___builtin_omp_required_simd_align,
-                     tok::kw___builtin_vectorelements, tok::kw__Countof) &&
-         "Not a sizeof/alignof/vec_step expression!");
+                     tok::kw___builtin_vectorelements, tok::kw__Countof) ||
+         (getLangOpts().Reflection && Tok.is(tok::caretcaret)) &&
+             "Not a sizeof/alignof/vec_step expression!");
   Token OpTok = Tok;
   ConsumeToken();