Remove special handling of obsolete impl Trait for .. syntax
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Some changes occurred in src/tools/clippy cc @rust-lang/clippy Some changes occurred in src/tools/rustfmt cc @rust-lang/rustfmt |
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Best reviewed one commit at a time. |
nnethercote
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impl Trait for .. syntax errors. ErrorGuaranteed to ast::TyKind::Err.
Noratrieb
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Feb 14, 2024
| @@ -588,15 +588,8 @@ impl<'a> Parser<'a> { | |||
| let has_for = self.eat_keyword(kw::For); | |||
| let missing_for_span = self.prev_token.span.between(self.token.span); | |||
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| let ty_second = if self.token == token::DotDot { | |||
| // We need to report this error after `cfg` expansion for compatibility reasons | |||
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This suggests that we intend the following (historically wrongly gated 😭) to pass:
#[cfg(dont)]
impl Trait for .. {}given that this should have emitted a future compat warning (from a quick test it doesn't seem to do that though????, I might be doing it wrong though)
but this is a breaking change (a probably justified one, but one)
maybe this should just use some dummy node in the meantime to not block this
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This was referenced Feb 14, 2024
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This is related to #65860. |
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@bors try |
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Add an `ErrorGuaranteed` to `ast::TyKind::Err`. This makes it more like `hir::TyKind::Err`, and avoids a `span_delayed_bug` call in `LoweringContext::lower_ty_direct`. r? `@oli-obk`
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☀️ Try build successful - checks-actions |
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@craterbot check |
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I don't want to hold up the |
nnethercote
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ErrorGuaranteed to ast::TyKind::Err.impl Trait for .. syntax
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🚧 Experiment ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more |
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🎉 Experiment
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The crater run has 77 failures, which boil down to three crates. crossbeamMost of the failures are from this crate, versions 0.2.9, 0.2.10, 0.3.0, which are all over six years old. Current version is 0.8.4. dimensionedWe see a few failures with version 0.6.0, which is seven years old. Current version is 0.8.0, which is two years old. The crate has 220,000 downloads for all time. packedWe see a couple of failures with version 0.4.2, which is the latest version, but over seven years old. The crate has 21,000 downloads for all time. |
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☔ The latest upstream changes (presumably #121400) made this pull request unmergeable. Please resolve the merge conflicts. |
The ancient (pre-1.0) RFC 19 suggested using `impl Trait for ..` syntax
for default traits. That was later changed to `auto trait Trait {}`
syntax. The parser has special treatment for the `..` syntax, suggesting
the `auto` syntax.
Given that default traits have not be stabilized and the `..` syntax is
so old, the special case seems unnecessary, and it gets in the way of
adding `ErrorGuaranteed` to `TyKind::Err`. This commit removes it and
the tests.
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The failing line from #[cfg(feature = "nightly")]
unsafe impl ZerosValid for .. {} |
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The job Click to see the possible cause of the failure (guessed by this bot) |
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After some discussion with @tmandry I have decided that removing this is more trouble than it is worth, given that it's a pretty tiny chunk of code in the compiler. |
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The ancient (pre-1.0) RFC 19 suggested using
impl Trait for ..syntax for default traits. That was later changed toauto trait Trait {}syntax. The parser has special treatment for the..syntax, suggesting theautosyntax.Given that default traits have not be stabilized and the
..syntax is so old, the special case seems unnecessary, and it gets in the way of addingErrorGuaranteedtoTyKind::Err. This commit removes it and the tests.r? @oli-obk