error: associated function in `impl` without body --> $DIR/issue-95023.rs:8:5 | 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:8:5 | 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 item constraints are not allowed here --> $DIR/issue-95023.rs:3:6 | LL | impl Fn(&isize) for Error { | ^^^^^^^^^^ associated item constraint not allowed here | help: parenthesized trait syntax expands to `Fn<(&isize,), Output=()>` --> $DIR/issue-95023.rs:3:6 | LL | impl Fn(&isize) for Error { | ^^^^^^^^^^ error[E0277]: expected a `FnMut(&isize)` closure, found `Error` --> $DIR/issue-95023.rs:3:21 | LL | impl Fn(&isize) for Error { | ^^^^^ expected an `FnMut(&isize)` closure, found `Error` | = help: the trait `FnMut(&isize)` is not implemented for `Error` note: required by a bound in `Fn` --> $SRC_DIR/core/src/ops/function.rs:LL:COL error[E0046]: not all trait items implemented, missing: `call` --> $DIR/issue-95023.rs:3:1 | LL | impl Fn(&isize) for Error { | ^^^^^^^^^^^^^^^^^^^^^^^^^ missing `call` in implementation | = help: implement the missing item: `fn call(&self, _: (&isize,)) -> >::Output { todo!() }` error[E0220]: associated type `B` not found for `Self` --> $DIR/issue-95023.rs:8:44 | LL | fn foo(&self) -> Self::B<{ N }>; | ^ help: `Self` has the following associated type: `Output` error: aborting due to 7 previous errors Some errors have detailed explanations: E0046, E0183, E0220, E0229, E0277, E0407. For more information about an error, try `rustc --explain E0046`.