error[E0277]: `Foo` doesn't implement `Debug` --> $DIR/no-debug.rs:10:27 | LL | println!("{:?} {:?}", Foo, Bar); | ^^^ `Foo` cannot be formatted using `{:?}` | = help: the trait `Debug` is not implemented for `Foo` = note: add `#[derive(Debug)]` to `Foo` or manually `impl Debug for Foo` = note: this error originates in the macro `$crate::format_args_nl` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0277]: `Bar` doesn't implement `Debug` --> $DIR/no-debug.rs:10:32 | LL | println!("{:?} {:?}", Foo, Bar); | ^^^ `Bar` cannot be formatted using `{:?}` because it doesn't implement `Debug` | = help: the trait `Debug` is not implemented for `Bar` = note: this error originates in the macro `$crate::format_args_nl` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0277]: `Foo` doesn't implement `std::fmt::Display` --> $DIR/no-debug.rs:11:23 | LL | println!("{} {}", Foo, Bar); | ^^^ `Foo` cannot be formatted with the default formatter | = help: the trait `std::fmt::Display` is not implemented for `Foo` = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead = note: this error originates in the macro `$crate::format_args_nl` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0277]: `Bar` doesn't implement `std::fmt::Display` --> $DIR/no-debug.rs:11:28 | LL | println!("{} {}", Foo, Bar); | ^^^ `Bar` cannot be formatted with the default formatter | = help: the trait `std::fmt::Display` is not implemented for `Bar` = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead = note: this error originates in the macro `$crate::format_args_nl` (in Nightly builds, run with -Z macro-backtrace for more info) error: aborting due to 4 previous errors For more information about this error, try `rustc --explain E0277`.