Switch a cast to a dyn_cast and check the pointer before using.  Fixes a crash
in the following code:

void test4(bool (&x)(void)) {
  while (x);
}

llvm-svn: 145918
diff --git a/clang/test/SemaCXX/condition.cpp b/clang/test/SemaCXX/condition.cpp
index 21671fa..7854d51 100644
--- a/clang/test/SemaCXX/condition.cpp
+++ b/clang/test/SemaCXX/condition.cpp
@@ -52,3 +52,7 @@
   if (test3) // expected-warning {{address of function 'test3' will always evaluate to 'true'}}
     (void) 0;
 }
+
+void test4(bool (&x)(void)) {
+  while (x);
+}