1error[E0277]: `NonError` doesn't implement `std::fmt::Display`
2 --> tests/ui/result_no_display.rs:4:19
3  |
44 |         fn f() -> Result<()>;
5  |                   ^^^^^^^^^^ `NonError` cannot be formatted with the default formatter
6  |
7  = help: the trait `std::fmt::Display` is not implemented for `NonError`
8  = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
9