rust/tests/ui/asm/naked-with-invalid-repr-attr.rs
Jieyou Xu 69b71e4410
Mitigate #[align] name resolution ambiguity regression with a rename
From `#[align]` -> `#[rustc_align]`. Attributes starting with `rustc`
are always perma-unstable and feature-gated by `feature(rustc_attrs)`.

See regression RUST-143834.

For the underlying problem where even introducing new feature-gated
unstable built-in attributes can break user code such as

```rs
macro_rules! align {
    () => {
        /* .. */
    };
}

pub(crate) use align; // `use` here becomes ambiguous
```

refer to RUST-134963.

Since the `#[align]` attribute is still feature-gated by
`feature(fn_align)`, we can rename it as a mitigation. Note that
`#[rustc_align]` will obviously mean that current unstable user code
using `feature(fn_aling)` will need additionally `feature(rustc_attrs)`,
but this is a short-term mitigation to buy time, and is expected to be
changed to a better name with less collision potential.

See
<https://rust-lang.zulipchat.com/#narrow/channel/238009-t-compiler.2Fmeetings/topic/.5Bweekly.5D.202025-07-17/near/529290371>
where mitigation options were considered.
2025-07-19 01:42:30 +08:00

53 lines
1.3 KiB
Rust

//@ needs-asm-support
// FIXME(#82232, #143834): temporarily renamed to mitigate `#[align]` nameres ambiguity
#![feature(rustc_attrs)]
#![feature(fn_align)]
#![crate_type = "lib"]
use std::arch::naked_asm;
#[repr(C)]
//~^ ERROR attribute should be applied to a struct, enum, or union [E0517]
#[unsafe(naked)]
extern "C" fn example1() {
//~^ NOTE not a struct, enum, or union
naked_asm!("")
}
#[repr(transparent)]
//~^ ERROR attribute should be applied to a struct, enum, or union [E0517]
#[unsafe(naked)]
extern "C" fn example2() {
//~^ NOTE not a struct, enum, or union
naked_asm!("")
}
#[repr(C)]
//~^ ERROR attribute should be applied to a struct, enum, or union [E0517]
#[rustc_align(16)]
#[unsafe(naked)]
extern "C" fn example3() {
//~^ NOTE not a struct, enum, or union
naked_asm!("")
}
// note: two errors because of packed and C
#[repr(C, packed)]
//~^ ERROR attribute should be applied to a struct or union [E0517]
//~| ERROR attribute should be applied to a struct, enum, or union [E0517]
#[unsafe(naked)]
extern "C" fn example4() {
//~^ NOTE not a struct, enum, or union
//~| NOTE not a struct or union
naked_asm!("")
}
#[repr(u8)]
//~^ ERROR attribute should be applied to an enum [E0517]
#[unsafe(naked)]
extern "C" fn example5() {
//~^ NOTE not an enum
naked_asm!("")
}