Unrolled build for rust-lang#126927

Rollup merge of rust-lang#126927 - workingjubilee:vaargsafe-is-unsafe, r=joboet core: VaArgSafe is an unsafe trait `T: VaArgSafe` is relied on for soundness. Safe impls promise nothing. Therefore this must be an unsafe trait. Slightly pedantic, as only core can impl this, but we *could* choose to unseal the trait. That would allow soundly (but unsafely) implementing this for e.g. a `#[repr(C)] struct` that should be passable by varargs. Relates to rust-lang#44930
rust-lang-ci · Jun 25, 2024 · 6fc046e · 6fc046e
2 parents c290e9d 050595a
commit 6fc046e
Showing 1 changed file with 5 additions and 4 deletions.
diff --git a/library/core/src/ffi/mod.rs b/library/core/src/ffi/mod.rs
@@ -484,7 484,7 @@ mod sealed_trait {
  all supported platforms",
  issue = "44930"
  )]
- pub trait VaArgSafe {}
  pub unsafe trait VaArgSafe {}
 }
 
 macro_rules! impl_va_arg_safe {
@@ -494,7 494,7 @@ macro_rules! impl_va_arg_safe {
  reason = "the `c_variadic` feature has not been properly tested on \
  all supported platforms",
  issue = "44930")]
- impl sealed_trait::VaArgSafe for $t {}
  unsafe impl sealed_trait::VaArgSafe for $t {}
  ) 
  }
 }
@@ -509,14 509,15 @@ impl_va_arg_safe! {f64}
  all supported platforms",
  issue = "44930"
 )]
-impl<T> sealed_trait::VaArgSafe for *mut T {}
 unsafe impl<T> sealed_trait::VaArgSafe for *mut T {}
 
 #[unstable(
  feature = "c_variadic",
  reason = "the `c_variadic` feature has not been properly tested on \
  all supported platforms",
  issue = "44930"
 )]
-impl<T> sealed_trait::VaArgSafe for *const T {}
 unsafe impl<T> sealed_trait::VaArgSafe for *const T {}
 
 #[unstable(
  feature = "c_variadic",