Merged migrated compile-fail tests and ui tests. Fixes #46841.

src/test/ui/structs/struct-duplicate-comma.rs

@@ -0,0 +1,27 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags: -Z parse-only
+
+// Issue #50974
+
+struct Foo {
+    a: u8,
+    b: u8
+}
+
+fn main() {
+    let bar = Foo {
+        a: 0,,
+          //~^ ERROR expected identifier
+        b: 42
+    };
+}
+