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69b71e4410
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.
20 lines
363 B
Rust
20 lines
363 B
Rust
// Anti-regression test to demonstrate that at least we mitigated breakage from adding a new
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// `#[align]` built-in attribute.
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//
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// See https://github.com/rust-lang/rust/issues/143834.
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//@ check-pass
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// Needs edition >= 2018 macro use behavior.
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//@ edition: 2018
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macro_rules! align {
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() => {
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/* .. */
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};
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}
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pub(crate) use align;
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fn main() {}
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