error[E0369]: binary operation `==` cannot be applied to type `for<'a> fn(&'a i32) -> &'a i32 {foo}` --> $DIR/issue-77910-2.rs:7:12 | LL | if foo == y {} | --- ^^ - _ | | | for<'a> fn(&'a i32) -> &'a i32 {foo} | help: use parentheses to call this function | LL | if foo(/* &i32 */) == y {} | ++++++++++++ error: aborting due to previous error For more information about this error, try `rustc --explain E0369`.