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make non-PartialEq-typed consts as patterns a hard error

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This commit is contained in:
Ralf Jung 2024-02-08 20:08:19 +01:00
parent e9f9594913
commit 5b7786cd1d
8 changed files with 27 additions and 112 deletions
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52
compiler/rustc_lint_defs/src/builtin.rs
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@ -32,7 +32,6 @@ declare_lint_pass! {
CONFLICTING_REPR_HINTS,
CONST_EVALUATABLE_UNCHECKED,
CONST_ITEM_MUTATION,
CONST_PATTERNS_WITHOUT_PARTIAL_EQ,
DEAD_CODE,
DEPRECATED,
DEPRECATED_CFG_ATTR_CRATE_TYPE_NAME,
@ -2342,57 +2341,6 @@ declare_lint! {
};
}
declare_lint! {
/// The `const_patterns_without_partial_eq` lint detects constants that are used in patterns,
/// whose type does not implement `PartialEq`.
///
/// ### Example
///
/// ```rust,compile_fail
/// #![deny(const_patterns_without_partial_eq)]
///
/// trait EnumSetType {
/// type Repr;
/// }
///
/// enum Enum8 { }
/// impl EnumSetType for Enum8 {
/// type Repr = u8;
/// }
///
/// #[derive(PartialEq, Eq)]
/// struct EnumSet<T: EnumSetType> {
/// __enumset_underlying: T::Repr,
/// }
///
/// const CONST_SET: EnumSet<Enum8> = EnumSet { __enumset_underlying: 3 };
///
/// fn main() {
/// match CONST_SET {
/// CONST_SET => { /* ok */ }
/// _ => panic!("match fell through?"),
/// }
/// }
/// ```
///
/// {{produces}}
///
/// ### Explanation
///
/// Previous versions of Rust accepted constants in patterns, even if those constants' types
/// did not have `PartialEq` implemented. The compiler falls back to comparing the value
/// field-by-field. In the future we'd like to ensure that pattern matching always
/// follows `PartialEq` semantics, so that trait bound will become a requirement for
/// matching on constants.
pub CONST_PATTERNS_WITHOUT_PARTIAL_EQ,
Warn,
"constant in pattern does not implement `PartialEq`",
@future_incompatible = FutureIncompatibleInfo {
reason: FutureIncompatibilityReason::FutureReleaseErrorReportInDeps,
reference: "issue #116122 <https://github.com/rust-lang/rust/issues/116122>",
};
}
declare_lint! {
/// The `ambiguous_associated_items` lint detects ambiguity between
/// [associated items] and [enum variants].