error: using opaque C++ type by value is not supported
 --> tests/ui/by_value_not_supported.rs:4:9
  |
4 |         c: C,
  |         ^^^^

error: using opaque Rust type by value is not supported
 --> tests/ui/by_value_not_supported.rs:5:9
  |
5 |         r: R,
  |         ^^^^

error: using C++ string by value is not supported
 --> tests/ui/by_value_not_supported.rs:6:9
  |
6 |         s: CxxString,
  |         ^^^^^^^^^^^^

error: needs a cxx::ExternType impl in order to be used as a field of `S`, argument of `f` or return value of `f`
  --> tests/ui/by_value_not_supported.rs:10:9
   |
10 |         type C;
   |         ^^^^^^

error: passing opaque C++ type by value is not supported
  --> tests/ui/by_value_not_supported.rs:16:14
   |
16 |         fn f(c: C) -> C;
   |              ^^^^

error: returning opaque C++ type by value is not supported
  --> tests/ui/by_value_not_supported.rs:16:23
   |
16 |         fn f(c: C) -> C;
   |                       ^

error: passing opaque Rust type by value is not supported
  --> tests/ui/by_value_not_supported.rs:17:14
   |
17 |         fn g(r: R) -> R;
   |              ^^^^

error: returning opaque Rust type by value is not supported
  --> tests/ui/by_value_not_supported.rs:17:23
   |
17 |         fn g(r: R) -> R;
   |                       ^

error: passing C++ string by value is not supported
  --> tests/ui/by_value_not_supported.rs:18:14
   |
18 |         fn h(s: CxxString) -> CxxString;
   |              ^^^^^^^^^^^^

error: returning C++ string by value is not supported
  --> tests/ui/by_value_not_supported.rs:18:31
   |
18 |         fn h(s: CxxString) -> CxxString;
   |                               ^^^^^^^^^