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Auto merge of #9368 - nahuakang:improve-equatable-if-let, r=flip1995

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Improvement for  `equatable_if_let`

fixes #9221

This PR makes sure that enums or structs not implementing `PartialEq` trait but still using the `if let` patterns can be linted to be rewritten with `matches!`.

If you added a new lint, here's a checklist for things that will be
checked during review or continuous integration.

- \[ ] Followed [lint naming conventions][lint_naming]
- \[x] Added passing UI tests (including committed `.stderr` file)
- \[x] `cargo test` passes locally
- \[ ] Executed `cargo dev update_lints`
- \[ ] Added lint documentation
- \[x] Run `cargo dev fmt`

---

changelog: Improve [`equatable_if_let`] with additional `matches!` suggestions.
This commit is contained in:
bors 2022-10-23 15:31:46 +00:00
commit 628a79d6b6
4 changed files with 65 additions and 22 deletions
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27
clippy_lints/src/equatable_if_let.rs
View file

@ -1,7 +1,6 @@
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::source::snippet_with_context;
use clippy_utils::ty::implements_trait;
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir::{Expr, ExprKind, Pat, PatKind};
use rustc_lint::{LateContext, LateLintPass, LintContext};
@ -67,16 +66,14 @@ fn is_structural_partial_eq<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>, other: T
impl<'tcx> LateLintPass<'tcx> for PatternEquality {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
if_chain! {
if !in_external_macro(cx.sess(), expr.span);
if let ExprKind::Let(let_expr) = expr.kind;
if unary_pattern(let_expr.pat);
if !in_external_macro(cx.sess(), expr.span)
&& let ExprKind::Let(let_expr) = expr.kind
&& unary_pattern(let_expr.pat) {
let exp_ty = cx.typeck_results().expr_ty(let_expr.init);
let pat_ty = cx.typeck_results().pat_ty(let_expr.pat);
if is_structural_partial_eq(cx, exp_ty, pat_ty);
then {
let mut applicability = Applicability::MachineApplicable;
let mut applicability = Applicability::MachineApplicable;
if is_structural_partial_eq(cx, exp_ty, pat_ty) {
let pat_str = match let_expr.pat.kind {
PatKind::Struct(..) => format!(
"({})",
@ -96,6 +93,20 @@ impl<'tcx> LateLintPass<'tcx> for PatternEquality {
),
applicability,
);
} else {
span_lint_and_sugg(
cx,
EQUATABLE_IF_LET,
expr.span,
"this pattern matching can be expressed using `matches!`",
"try",
format!(
"matches!({}, {})",
snippet_with_context(cx, let_expr.init.span, expr.span.ctxt(), "..", &mut applicability).0,
snippet_with_context(cx, let_expr.pat.span, expr.span.ctxt(), "..", &mut applicability).0,
),
applicability,
);
}
}
}