error: Mutable references to opaque Copy types are not yet supported.
  --> tests/ui/opaque-copy-type-mut-ref.rs:14:24
   |
14 |         fn some_method(&mut self);
   |                        ^^^^^^^^^

error: Mutable references to opaque Copy types are not yet supported.
  --> tests/ui/opaque-copy-type-mut-ref.rs:16:25
   |
16 |         fn some_method2(self: &mut SomeType);
   |                         ^^^^^^^^^^^^^^^^^^^

error: Mutable references to opaque Copy types are not yet supported.
  --> tests/ui/opaque-copy-type-mut-ref.rs:18:26
   |
18 |         fn some_function(arg: &mut SomeType);
   |                          ^^^^^^^^^^^^^^^^^^