thiserror 2.0.18

derive(Error)
Documentation
1
2
3
4
5
error: #[error(fmt = ...)] is only supported in enums; for a struct, handwrite your own Display impl
 --> tests/ui/struct-with-fmt.rs:4:1
  |
4 | #[error(fmt = core::fmt::Octal::fmt)]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^