--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/test/Sema/void_arg.c	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,26 @@
+/* RUN: %clang_cc1 -fsyntax-only %s -verify
+ */
+
+typedef void Void;
+
+void foo() {
+  int X;
+  
+  X = sizeof(int (void a));    // expected-error {{argument may not have 'void' type}}
+  X = sizeof(int (int, void)); // expected-error {{must be the first and only parameter}}
+  X = sizeof(int (void, ...)); // expected-error {{must be the first and only parameter}}
+
+  X = sizeof(int (Void a));    // expected-error {{argument may not have 'void' type}}
+  X = sizeof(int (int, Void)); // expected-error {{must be the first and only parameter}}
+  X = sizeof(int (Void, ...)); // expected-error {{must be the first and only parameter}}
+
+  // Accept these.
+  X = sizeof(int (void));
+  X = sizeof(int (Void));
+}
+
+// this is ok.
+void bar(Void) {
+}
+
+void f(const void);            // expected-error {{parameter must not have type qualifiers}}