[FOLD] add tests

Author: sdkrystian

clang/test/SemaCXX/dependent-typeof.cpp

@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+template<bool B>
+void f() {
+  decltype(B) x = false;
+  __typeof__(B) y = false;
+  !x;
+  !y;
+}