[Sema] Fix assertion hit while trying to do constant evaluation for a dependent expression

inside a GNU statement expression.

rdar://16064952

llvm-svn: 201468

clang/lib/AST/ExprConstant.cpp

@@ -8028,6 +8028,8 @@ static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) {
 /// an object can indirectly refer to subobjects which were initialized earlier.
 static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, const LValue &This,
                             const Expr *E, bool AllowNonLiteralTypes) {
+  if (E->isTypeDependent() || E->isValueDependent())
+    return false;
   if (!AllowNonLiteralTypes && !CheckLiteralType(Info, E, &This))
     return false;
 

clang/test/SemaCXX/constant-expression.cpp

@@ -133,3 +133,11 @@ namespace test4 {
   // equivalent to "const int x = 42;" as per C++03 8.5/p13.
   typedef A<i> Ai; // ok
 }
+
+// rdar://16064952
+namespace rdar16064952 {
+  template < typename T > void fn1() {
+   T b;
+   unsigned w = ({int a = b.val[sizeof(0)]; 0; }); // expected-warning {{use of GNU statement expression extension}}
+  }
+}