Add another test for #3177

Author: catamorphism

src/test/compile-fail/issue-3177-mutable-struct.rs

@@ -0,0 +1,11 @@
+// xfail-test
+// error-pattern: instantiating a type parameter with an incompatible type
+struct S<T: Const> {
+    s: T,
+    mut cant_nest: ()
+}
+
+fn main() {
+    let a1  = ~S{ s: true, cant_nest: () };
+    let _a2 = ~S{ s: move a1, cant_nest: () };
+}