error[E0308]: mismatched types --> src/lib.rs:6:1 | 5 | #[bench] | -------- in this attribute macro expansion 6 | fn b(_: &mut test::bench::Bencher) {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expected `&mut Bencher`, found `TestDescAndFn` | expected due to this | constant defined here | `b` is interpreted as a constant, not a new binding | help: introduce a new binding instead: `other_b` error[E0308]: mismatched types --> src/lib.rs:6:1 | 5 | #[bench] | -------- in this attribute macro expansion 6 | fn b(_: &mut test::bench::Bencher) {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expected `&mut Bencher`, found `TestDescAndFn` | arguments to this function are incorrect | note: function defined here --> src/lib.rs:6:4 | 6 | fn b(_: &mut test::bench::Bencher) {} | ^ ---------------------------- For more information about this error, try `rustc --explain E0308`.