| error[E0392]: parameter `T` is never used | |
| --> $DIR/issue-17904-2.rs:4:12 | |
| | | |
| LL | struct Foo<T> where T: Copy; | |
| | ^ unused parameter | |
| | | |
| = help: consider removing `T` or using a marker such as `std::marker::PhantomData` | |
| error: aborting due to previous error | |
| For more information about this error, try `rustc --explain E0392`. |