bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Match ergonomics 2024: migration lint

Browse source 
Unfortunately, we can't always offer a machine-applicable suggestion when there are subpatterns from macro expansion.

Co-Authored-By: Guillaume Boisseau <Nadrieril@users.noreply.github.com>
This commit is contained in:
Jules Bertholet 2024-05-02 19:55:03 -04:00
parent 686bfc4c42
commit 9d92a7f355
No known key found for this signature in database
GPG key ID: 32034DAFC38C1BFC
17 changed files with 409 additions and 116 deletions
Download patch file Download diff file Expand all files Collapse all files

38
compiler/rustc_lint_defs/src/builtin.rs
View file

@ -38,7 +38,6 @@ declare_lint_pass! {
DEPRECATED_CFG_ATTR_CRATE_TYPE_NAME,
DEPRECATED_IN_FUTURE,
DEPRECATED_WHERE_CLAUSE_LOCATION,
DEREFERENCING_MUT_BINDING,
DUPLICATE_MACRO_ATTRIBUTES,
ELIDED_LIFETIMES_IN_ASSOCIATED_CONSTANT,
ELIDED_LIFETIMES_IN_PATHS,
@ -90,6 +89,7 @@ declare_lint_pass! {
RUST_2021_INCOMPATIBLE_OR_PATTERNS,
RUST_2021_PREFIXES_INCOMPATIBLE_SYNTAX,
RUST_2021_PRELUDE_COLLISIONS,
RUST_2024_INCOMPATIBLE_PAT,
SEMICOLON_IN_EXPRESSIONS_FROM_MACROS,
SINGLE_USE_LIFETIMES,
SOFT_UNSTABLE,
@ -1630,34 +1630,34 @@ declare_lint! {
}
declare_lint! {
/// The `dereferencing_mut_binding` lint detects a `mut x` pattern that resets the binding mode,
/// as this behavior will change in rust 2024.
/// The `rust_2024_incompatible_pat` lint
/// detects patterns whose meaning will change in the Rust 2024 edition.
///
/// ### Example
///
/// ```rust
/// # #![warn(dereferencing_mut_binding)]
/// let x = Some(123u32);
/// let _y = match &x {
/// Some(mut x) => {
/// x += 1;
/// x
/// }
/// None => 0,
/// };
/// ```rust,edition2021
/// #![feature(ref_pat_eat_one_layer_2024)]
/// #![warn(rust_2024_incompatible_pat)]
///
/// if let Some(&a) = &Some(&0u8) {
/// let _: u8 = a;
/// }
/// if let Some(mut _a) = &mut Some(0u8) {
/// _a = 7u8;
/// }
/// ```
///
/// {{produces}}
///
/// ### Explanation
///
/// Without the `mut`, `x` would have type `&u32`. Pre-2024, adding `mut` makes `x` have type
/// `u32`, which was deemed surprising. After edition 2024, adding `mut` will not change the
/// type of `x`. This lint warns users of editions before 2024 to update their code.
pub DEREFERENCING_MUT_BINDING,
/// In Rust 2024 and above, the `mut` keyword does not reset the pattern binding mode,
/// and nor do `&` or `&mut` patterns. The lint will suggest code that
/// has the same meaning in all editions.
pub RUST_2024_INCOMPATIBLE_PAT,
Allow,
"detects `mut x` bindings that change the type of `x`",
@feature_gate = sym::mut_preserve_binding_mode_2024;
"detects patterns whose meaning will change in Rust 2024",
@feature_gate = sym::ref_pat_eat_one_layer_2024;
// FIXME uncomment below upon stabilization
/*@future_incompatible = FutureIncompatibleInfo {
reason: FutureIncompatibilityReason::EditionSemanticsChange(Edition::Edition2024),