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docs/test: add error-docs and UI test for E0711

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Ezra Shaw 2023-01-08 21:36:19 +13:00
parent ecc0507fdd
commit 24ce65c8d6
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4 changed files with 64 additions and 1 deletions
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2
compiler/rustc_error_codes/src/error_codes.rs
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@ -436,6 +436,7 @@ E0713: include_str!("./error_codes/E0713.md"),
E0714: include_str!("./error_codes/E0714.md"),
E0715: include_str!("./error_codes/E0715.md"),
E0716: include_str!("./error_codes/E0716.md"),
E0711: include_str!("./error_codes/E0711.md"),
E0717: include_str!("./error_codes/E0717.md"),
E0718: include_str!("./error_codes/E0718.md"),
E0719: include_str!("./error_codes/E0719.md"),
@ -640,7 +641,6 @@ E0791: include_str!("./error_codes/E0791.md"),
// E0702, // replaced with a generic attribute input check
// E0707, // multiple elided lifetimes used in arguments of `async fn`
// E0709, // multiple different lifetimes used in arguments of `async fn`
E0711, // a feature has been declared with conflicting stability attributes, internal error code
// E0721, // `await` keyword
// E0723, // unstable feature in `const` context
// E0738, // Removed; errored on `#[track_caller] fn`s in `extern "Rust" { ... }`.

30
compiler/rustc_error_codes/src/error_codes/E0711.md Normal file
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@ -0,0 +1,30 @@
#### This error code is internal to the compiler and will not be emitted with normal Rust code.
Feature declared with conflicting stability requirements.
```compile_fail,E0711
// NOTE: this attribute is perma-unstable and should *never* be used outside of
// stdlib and the compiler.
#![feature(staged_api)]
#![stable(feature = "...", since = "1.0.0")]
#[stable(feature = "foo", since = "1.0.0")]
fn foo_stable_1_0_0() {}
// error: feature `foo` is declared stable since 1.29.0
#[stable(feature = "foo", since = "1.29.0")]
fn foo_stable_1_29_0() {}
// error: feature `foo` is declared unstable
#[unstable(feature = "foo", issue = "none")]
fn foo_unstable() {}
```
In the above example, the `foo` feature is first defined to be stable since
1.0.0, but is then re-declared stable since 1.29.0. This discrepancy in
versions causes an error. Furthermore, `foo` is then re-declared as unstable,
again the conflict causes an error.
This error can be fixed by splitting the feature, this allows any
stability requirements and removes any possibility of conflict.