error[E0277]: `NotDebug` doesn't implement `Debug` --> $DIR/dbg-macro-requires-debug.rs:6:23 | LL | let _: NotDebug = dbg!(NotDebug); | ^^^^^^^^^^^^^^ `NotDebug` cannot be formatted using `{:?}` | = help: the trait `Debug` is not implemented for `NotDebug` = note: add `#[derive(Debug)]` to `NotDebug` or manually `impl Debug for NotDebug` = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `dbg` (in Nightly builds, run with -Z macro-backtrace for more info) help: consider annotating `NotDebug` with `#[derive(Debug)]` | LL | #[derive(Debug)] | error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.