error: associated function in `impl` without body --> $DIR/issue-95023.rs:6:5 | LL | fn foo(&self) -> Self::B<{N}>; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^- | | | help: provide a definition for the function: `{ }` error[E0407]: method `foo` is not a member of trait `Fn` --> $DIR/issue-95023.rs:6:5 | LL | fn foo(&self) -> Self::B<{N}>; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not a member of trait `Fn` error[E0183]: manual implementations of `Fn` are experimental --> $DIR/issue-95023.rs:3:6 | LL | impl Fn(&isize) for Error { | ^^^^^^^^^^ manual implementations of `Fn` are experimental | = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable error[E0229]: associated type bindings are not allowed here --> $DIR/issue-95023.rs:3:6 | LL | impl Fn(&isize) for Error { | ^^^^^^^^^^ associated type not allowed here error[E0220]: associated type `B` not found for `Self` --> $DIR/issue-95023.rs:6:44 | LL | fn foo(&self) -> Self::B<{N}>; | ^ associated type `B` not found error: aborting due to 5 previous errors Some errors have detailed explanations: E0183, E0220, E0229, E0407. For more information about an error, try `rustc --explain E0183`.