error[E0369]: binary operation `==` cannot be applied to type `for<'r> fn(&'r i32) -> &'r i32 {foo}` --> $DIR/issue-77910-1.rs:8:5 | LL | assert_eq!(foo, y); | ^^^^^^^^^^^^^^^^^^ | | | for<'r> fn(&'r i32) -> &'r i32 {foo} | _ | = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0277]: `for<'r> fn(&'r i32) -> &'r i32 {foo}` doesn't implement `Debug` --> $DIR/issue-77910-1.rs:8:5 | LL | fn foo(s: &i32) -> &i32 { | --- consider calling this function ... LL | assert_eq!(foo, y); | ^^^^^^^^^^^^^^^^^^ `for<'r> fn(&'r i32) -> &'r i32 {foo}` cannot be formatted using `{:?}` because it doesn't implement `Debug` | = help: the trait `Debug` is not implemented for `for<'r> fn(&'r i32) -> &'r i32 {foo}` = help: use parentheses to call the function: `foo(s)` = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info) error: aborting due to 2 previous errors Some errors have detailed explanations: E0277, E0369. For more information about an error, try `rustc --explain E0277`.