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Change const trait bound syntax from ~const to [const]

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This commit is contained in:
Oli Scherer
2025-03-11 12:08:45 +00:00
parent 18f4cb1110
commit eb7245a864
234 changed files with 1382 additions and 1319 deletions
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8
compiler/rustc_hir_analysis/src/impl_wf_check/min_specialization.rs
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@@ -402,22 +402,22 @@ fn check_predicates<'tcx>(
/// as some predicate on the base impl (`predicate2`).
///
/// This basically just checks syntactic equivalence, but is a little more
/// forgiving since we want to equate `T: Tr` with `T: ~const Tr` so this can work:
/// forgiving since we want to equate `T: Tr` with `T: [const] Tr` so this can work:
///
/// ```ignore (illustrative)
/// #[rustc_specialization_trait]
/// trait Specialize { }
///
/// impl<T: Bound> Tr for T { }
/// impl<T: ~const Bound + Specialize> const Tr for T { }
/// impl<T: [const] Bound + Specialize> const Tr for T { }
/// ```
///
/// However, we *don't* want to allow the reverse, i.e., when the bound on the
/// specializing impl is not as const as the bound on the base impl:
///
/// ```ignore (illustrative)
/// impl<T: ~const Bound> const Tr for T { }
/// impl<T: Bound + Specialize> const Tr for T { } // should be T: ~const Bound
/// impl<T: [const] Bound> const Tr for T { }
/// impl<T: Bound + Specialize> const Tr for T { } // should be T: [const] Bound
/// ```
///
/// So we make that check in this function and try to raise a helpful error message.