bors 989190874f Auto merge of #76538 - fusion-engineering-forks:check-useless-unstable-trait-impl, r=lcnr ... Warn for #[unstable] on trait impls when it has no effect. Earlier today I sent a PR with an `#[unstable]` attribute on a trait `impl`, but was informed that this attribute has no effect there. (comment: https://github.com/rust-lang/rust/pull/76525#issuecomment-689678895, issue: https://github.com/rust-lang/rust/issues/55436) This PR adds a warning for this situation. Trait `impl` blocks with `#[unstable]` where both the type and the trait are stable will result in a warning: ``` warning: An `#[unstable]` annotation here has no effect. See issue #55436 <https://github.com/rust-lang/rust/issues/55436> for more information. --> library/std/src/panic.rs:235:1 | 235 | #[unstable(feature = "integer_atomics", issue = "32976")] | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ``` --- It detects three problems in the existing code: 1. A few `RefUnwindSafe` implementations for the atomic integer types in `library/std/src/panic.rs`. Example: d92155bf6a/library/std/src/panic.rs (L235-L236) 2. An implementation of `Error` for `LayoutErr` in `library/std/srd/error.rs`: d92155bf6a/library/std/src/error.rs (L392-L397) 3. `From` implementations for `Waker` and `RawWaker` in `library/alloc/src/task.rs`. Example: d92155bf6a/library/alloc/src/task.rs (L36-L37) Case 3 interesting: It has a bound with an `#[unstable]` trait (`W: Wake`), so appears to have much effect on stable code. It does however break similar blanket implementations. It would also have immediate effect if `Wake` was implemented for any stable type. (Which is not the case right now, but there are no warnings in place to prevent it.) Whether this case is a problem or not is not clear to me. If it isn't, adding a simple `c.visit_generics(..);` to this PR will stop the warning for this case.		2020-09-12 18:01:33 +00:00
..
alloc	Auto merge of #76538 - fusion-engineering-forks:check-useless-unstable-trait-impl, r=lcnr	2020-09-12 18:01:33 +00:00
backtrace@4083a90168	std: Switch from libbacktrace to gimli	2020-07-28 16:34:01 -07:00
core	Rollup merge of #76615 - GuillaumeGomez:missing-examples-binary-ops, r=jyn514	2020-09-12 10:43:24 +02:00
panic_abort	Rollup merge of #75990 - rylev:arm-fastfail, r=alexcrichton	2020-08-30 01:43:54 +02:00
panic_unwind	Auto merge of #70212 - Amanieu:catch_foreign, r=Mark-Simulacrum	2020-08-28 01:20:17 +00:00
proc_macro	Respect -Z proc-macro-backtrace flag for panics inside libproc_macro	2020-09-03 12:13:26 -04:00
profiler_builtins	Fix warning whe building profiler_builtins crate	2020-09-04 15:10:29 +02:00
rtstartup
rustc-std-workspace-alloc
rustc-std-workspace-core
rustc-std-workspace-std
std	Auto merge of #76538 - fusion-engineering-forks:check-useless-unstable-trait-impl, r=lcnr	2020-09-12 18:01:33 +00:00
stdarch@78891cdf29	fix broken git commit in stdarch	2020-08-03 15:52:30 +08:00
term
test	Prefer https link for wikipedia URLs	2020-08-23 10:02:42 +00:00
unwind	Add back unwinding support for Sony PSP	2020-08-08 02:14:40 -04:00