diff options
| -rw-r--r-- | compiler/rustc_feature/src/unstable.rs | 2 | ||||
| -rw-r--r-- | compiler/rustc_span/src/symbol.rs | 1 | ||||
| -rw-r--r-- | src/doc/unstable-book/src/language-features/explicit-extern-abis.md | 23 |
3 files changed, 26 insertions, 0 deletions
diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs index 36e375c778d..d0ac822ba26 100644 --- a/compiler/rustc_feature/src/unstable.rs +++ b/compiler/rustc_feature/src/unstable.rs @@ -477,6 +477,8 @@ declare_features! ( (incomplete, ergonomic_clones, "1.87.0", Some(132290)), /// Allows exhaustive pattern matching on types that contain uninhabited types. (unstable, exhaustive_patterns, "1.13.0", Some(51085)), + /// Disallows `extern` without an explicit ABI. + (unstable, explicit_extern_abis, "CURRENT_RUSTC_VERSION", Some(134986)), /// Allows explicit tail calls via `become` expression. (incomplete, explicit_tail_calls, "1.72.0", Some(112788)), /// Allows using `aapcs`, `efiapi`, `sysv64` and `win64` as calling conventions diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs index d1f3eb16e4e..0a2e4e4977f 100644 --- a/compiler/rustc_span/src/symbol.rs +++ b/compiler/rustc_span/src/symbol.rs @@ -916,6 +916,7 @@ symbols! { expf16, expf32, expf64, + explicit_extern_abis, explicit_generic_args_with_impl_trait, explicit_tail_calls, export_name, diff --git a/src/doc/unstable-book/src/language-features/explicit-extern-abis.md b/src/doc/unstable-book/src/language-features/explicit-extern-abis.md new file mode 100644 index 00000000000..ba622466ba7 --- /dev/null +++ b/src/doc/unstable-book/src/language-features/explicit-extern-abis.md @@ -0,0 +1,23 @@ +# `explicit_extern_abis` + +The tracking issue for this feature is: #134986 + +------ + +Disallow `extern` without an explicit ABI. We should write `extern "C"` +(or another ABI) instead of just `extern`. + +By making the ABI explicit, it becomes much clearer that "C" is just one of the +possible choices, rather than the "standard" way for external functions. +Removing the default makes it easier to add a new ABI on equal footing as "C". + +```rust,editionfuture,compile_fail +#![feature(explicit_extern_abis)] + +extern fn function1() {} // ERROR `extern` declarations without an explicit ABI + // are disallowed + +extern "C" fn function2() {} // compiles + +extern "aapcs" fn function3() {} // compiles +``` |