1 error[E0404]: expected trait, found type alias `Foo`
2 --> $DIR/issue-3907.rs:20:6
4 LL | impl Foo for S { //~ ERROR expected trait, found type alias `Foo`
5 | ^^^ type aliases cannot be used for traits
6 help: possible better candidate is found in another module, you can import it into scope
8 LL | use issue_3907::Foo;
11 error: aborting due to previous error
13 For more information about this error, try `rustc --explain E0404`.