Add a testcase for PR6501 (too many/too few arguments to a function call).

llvm-svn: 101800

clang/test/Sema/exprs.c

@@ -128,3 +128,9 @@ void test17(int x) {
   x = sizeof(x/0);  // no warning.
 }
 
+// PR6501
+void test18_a(int a);
+void test18(int b) {
+  test18_a(b, b); // expected-error {{too many arguments to function call, expected 1, have 2}}
+  test18_a(); // expected-error {{too few arguments to function call, expected 1, have 0}}
+}