| error[E0308]: mismatched types |
| --> $DIR/universal-mismatched-type.rs:4:5 |
| | |
| LL | fn foo(x: impl Debug) -> String { |
| | ---------- ------ expected `std::string::String` because of return type |
| | | |
| | this type parameter |
| LL | x |
| | ^ expected struct `std::string::String`, found type parameter `impl Debug` |
| | |
| = note: expected struct `std::string::String` |
| found type parameter `impl Debug` |
| = help: type parameters must be constrained to match other types |
| = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters |
| |
| error: aborting due to previous error |
| |
| For more information about this error, try `rustc --explain E0308`. |
