error: at least one trait must be specified --> $DIR/issue-86719.rs:7:14 | LL | type E = impl ; | ^^^^ error[E0407]: method `foo` is not a member of trait `Bar` --> $DIR/issue-86719.rs:8:5 | LL | / fn foo() -> Self::E { LL | | |_| true LL | | } | |_____^ not a member of trait `Bar` error[E0282]: type annotations needed --> $DIR/issue-86719.rs:9:10 | LL | |_| true | ^ | help: consider giving this closure parameter an explicit type | LL | |_: _| true | +++ error: aborting due to 3 previous errors Some errors have detailed explanations: E0282, E0407. For more information about an error, try `rustc --explain E0282`.