error: inherent impls cannot be `default` --> $DIR/validation.rs:7:14 | LL | default impl S {} | ------- ^ inherent impl for this type | | | `default` because of this | = note: only trait implementations may be annotated with `default` warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes --> $DIR/validation.rs:2:12 | LL | #![feature(specialization)] | ^^^^^^^^^^^^^^ | = note: see issue #31844 for more information = help: consider using `min_specialization` instead, which is more stable and complete = note: `#[warn(incomplete_features)]` on by default error: impls of auto traits cannot be default --> $DIR/validation.rs:9:21 | LL | default unsafe impl Send for S {} | ------- ^^^^ auto trait | | | default because of this error: impls of auto traits cannot be default --> $DIR/validation.rs:10:15 | LL | default impl !Send for Z {} | ------- ^^^^ auto trait | | | default because of this error[E0750]: negative impls cannot be default impls --> $DIR/validation.rs:10:1 | LL | default impl !Send for Z {} | ^^^^^^^ ^ error[E0750]: negative impls cannot be default impls --> $DIR/validation.rs:14:1 | LL | default impl !Tr for S {} | ^^^^^^^ ^ error: aborting due to 5 previous errors; 1 warning emitted For more information about this error, try `rustc --explain E0750`.