warning: unmatched `}` found
  --> $DIR/broken_format.rs:1:32
   |
LL | #[diagnostic::on_unimplemented(message = "{{Test } thing")]
   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: `#[warn(unknown_or_malformed_diagnostic_attributes)]` on by default

warning: positional format arguments are not allowed here
  --> $DIR/broken_format.rs:6:32
   |
LL | #[diagnostic::on_unimplemented(message = "Test {}")]
   |                                ^^^^^^^^^^^^^^^^^^^
   |
   = help: only named format arguments with the name of one of the generic types are allowed in this context

warning: positional format arguments are not allowed here
  --> $DIR/broken_format.rs:11:32
   |
LL | #[diagnostic::on_unimplemented(message = "Test {1:}")]
   |                                ^^^^^^^^^^^^^^^^^^^^^
   |
   = help: only named format arguments with the name of one of the generic types are allowed in this context

warning: invalid format specifier
  --> $DIR/broken_format.rs:16:32
   |
LL | #[diagnostic::on_unimplemented(message = "Test {Self:123}")]
   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: no format specifier are supported in this position

warning: expected `'}'`, found `'!'`
  --> $DIR/broken_format.rs:21:32
   |
LL | #[diagnostic::on_unimplemented(message = "Test {Self:!}")]
   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^

warning: unmatched `}` found
  --> $DIR/broken_format.rs:21:32
   |
LL | #[diagnostic::on_unimplemented(message = "Test {Self:!}")]
   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^

warning: unmatched `}` found
  --> $DIR/broken_format.rs:1:32
   |
LL | #[diagnostic::on_unimplemented(message = "{{Test } thing")]
   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error[E0277]: {{Test } thing
  --> $DIR/broken_format.rs:35:13
   |
LL |     check_1(());
   |     ------- ^^ the trait `ImportantTrait1` is not implemented for `()`
   |     |
   |     required by a bound introduced by this call
   |
help: this trait has no implementations, consider adding one
  --> $DIR/broken_format.rs:4:1
   |
LL | trait ImportantTrait1 {}
   | ^^^^^^^^^^^^^^^^^^^^^
note: required by a bound in `check_1`
  --> $DIR/broken_format.rs:28:20
   |
LL | fn check_1(_: impl ImportantTrait1) {}
   |                    ^^^^^^^^^^^^^^^ required by this bound in `check_1`

warning: positional format arguments are not allowed here
  --> $DIR/broken_format.rs:6:32
   |
LL | #[diagnostic::on_unimplemented(message = "Test {}")]
   |                                ^^^^^^^^^^^^^^^^^^^
   |
   = help: only named format arguments with the name of one of the generic types are allowed in this context
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error[E0277]: Test {}
  --> $DIR/broken_format.rs:37:13
   |
LL |     check_2(());
   |     ------- ^^ the trait `ImportantTrait2` is not implemented for `()`
   |     |
   |     required by a bound introduced by this call
   |
help: this trait has no implementations, consider adding one
  --> $DIR/broken_format.rs:9:1
   |
LL | trait ImportantTrait2 {}
   | ^^^^^^^^^^^^^^^^^^^^^
note: required by a bound in `check_2`
  --> $DIR/broken_format.rs:29:20
   |
LL | fn check_2(_: impl ImportantTrait2) {}
   |                    ^^^^^^^^^^^^^^^ required by this bound in `check_2`

warning: positional format arguments are not allowed here
  --> $DIR/broken_format.rs:11:32
   |
LL | #[diagnostic::on_unimplemented(message = "Test {1:}")]
   |                                ^^^^^^^^^^^^^^^^^^^^^
   |
   = help: only named format arguments with the name of one of the generic types are allowed in this context
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error[E0277]: Test {1}
  --> $DIR/broken_format.rs:39:13
   |
LL |     check_3(());
   |     ------- ^^ the trait `ImportantTrait3` is not implemented for `()`
   |     |
   |     required by a bound introduced by this call
   |
help: this trait has no implementations, consider adding one
  --> $DIR/broken_format.rs:14:1
   |
LL | trait ImportantTrait3 {}
   | ^^^^^^^^^^^^^^^^^^^^^
note: required by a bound in `check_3`
  --> $DIR/broken_format.rs:30:20
   |
LL | fn check_3(_: impl ImportantTrait3) {}
   |                    ^^^^^^^^^^^^^^^ required by this bound in `check_3`

warning: invalid format specifier
  --> $DIR/broken_format.rs:16:32
   |
LL | #[diagnostic::on_unimplemented(message = "Test {Self:123}")]
   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: no format specifier are supported in this position
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error[E0277]: Test ()
  --> $DIR/broken_format.rs:41:13
   |
LL |     check_4(());
   |     ------- ^^ the trait `ImportantTrait4` is not implemented for `()`
   |     |
   |     required by a bound introduced by this call
   |
help: this trait has no implementations, consider adding one
  --> $DIR/broken_format.rs:19:1
   |
LL | trait ImportantTrait4 {}
   | ^^^^^^^^^^^^^^^^^^^^^
note: required by a bound in `check_4`
  --> $DIR/broken_format.rs:31:20
   |
LL | fn check_4(_: impl ImportantTrait4) {}
   |                    ^^^^^^^^^^^^^^^ required by this bound in `check_4`

warning: expected `'}'`, found `'!'`
  --> $DIR/broken_format.rs:21:32
   |
LL | #[diagnostic::on_unimplemented(message = "Test {Self:!}")]
   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

warning: unmatched `}` found
  --> $DIR/broken_format.rs:21:32
   |
LL | #[diagnostic::on_unimplemented(message = "Test {Self:!}")]
   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error[E0277]: Test {Self:!}
  --> $DIR/broken_format.rs:43:13
   |
LL |     check_5(());
   |     ------- ^^ the trait `ImportantTrait5` is not implemented for `()`
   |     |
   |     required by a bound introduced by this call
   |
help: this trait has no implementations, consider adding one
  --> $DIR/broken_format.rs:26:1
   |
LL | trait ImportantTrait5 {}
   | ^^^^^^^^^^^^^^^^^^^^^
note: required by a bound in `check_5`
  --> $DIR/broken_format.rs:32:20
   |
LL | fn check_5(_: impl ImportantTrait5) {}
   |                    ^^^^^^^^^^^^^^^ required by this bound in `check_5`

error: aborting due to 5 previous errors; 12 warnings emitted

For more information about this error, try `rustc --explain E0277`.