error[E0277]: `Option<{integer}>` doesn't implement `std::fmt::Display` --> $DIR/format-args-argument-span.rs:13:21 | LL | println!("{x:?} {x} {x:?}"); | ^^^ `Option<{integer}>` cannot be formatted with the default formatter | = help: the trait `std::fmt::Display` is not implemented for `Option<{integer}>` = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0277]: `Option<{integer}>` doesn't implement `std::fmt::Display` --> $DIR/format-args-argument-span.rs:15:37 | LL | println!("{x:?} {x} {x:?}", x = Some(1)); | ^^^^^^^ `Option<{integer}>` cannot be formatted with the default formatter | = help: the trait `std::fmt::Display` is not implemented for `Option<{integer}>` = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0277]: `DisplayOnly` doesn't implement `Debug` --> $DIR/format-args-argument-span.rs:18:19 | LL | println!("{x} {x:?} {x}"); | ^^^^^ `DisplayOnly` cannot be formatted using `{:?}` | = help: the trait `Debug` is not implemented for `DisplayOnly` = note: add `#[derive(Debug)]` to `DisplayOnly` or manually `impl Debug for DisplayOnly` = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info) help: consider annotating `DisplayOnly` with `#[derive(Debug)]` | LL + #[derive(Debug)] LL | struct DisplayOnly; | error[E0277]: `DisplayOnly` doesn't implement `Debug` --> $DIR/format-args-argument-span.rs:20:35 | LL | println!("{x} {x:?} {x}", x = DisplayOnly); | ^^^^^^^^^^^ `DisplayOnly` cannot be formatted using `{:?}` | = help: the trait `Debug` is not implemented for `DisplayOnly` = note: add `#[derive(Debug)]` to `DisplayOnly` or manually `impl Debug for DisplayOnly` = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info) help: consider annotating `DisplayOnly` with `#[derive(Debug)]` | LL + #[derive(Debug)] LL | struct DisplayOnly; | error: aborting due to 4 previous errors For more information about this error, try `rustc --explain E0277`.