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Auto merge of #9092 - tamaroning:fix-needless-match, r=llogiq

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Fix false positives of needless_match

closes: #9084
made needless_match take into account arm in the form of `_ if => ...`

changelog: none
This commit is contained in:
bors 2022-08-21 13:22:21 +00:00
commit cc637bacfa
4 changed files with 127 additions and 3 deletions
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22
clippy_lints/src/matches/needless_match.rs
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@ -8,7 +8,7 @@ use clippy_utils::{
};
use rustc_errors::Applicability;
use rustc_hir::LangItem::OptionNone;
use rustc_hir::{Arm, BindingAnnotation, Expr, ExprKind, FnRetTy, Node, Pat, PatKind, Path, QPath};
use rustc_hir::{Arm, BindingAnnotation, Expr, ExprKind, FnRetTy, Guard, Node, Pat, PatKind, Path, QPath};
use rustc_lint::LateContext;
use rustc_span::sym;
use rustc_typeck::hir_ty_to_ty;
@ -65,8 +65,26 @@ pub(crate) fn check_if_let<'tcx>(cx: &LateContext<'tcx>, ex: &Expr<'_>, if_let:
fn check_all_arms(cx: &LateContext<'_>, match_expr: &Expr<'_>, arms: &[Arm<'_>]) -> bool {
for arm in arms {
let arm_expr = peel_blocks_with_stmt(arm.body);
if let Some(guard_expr) = &arm.guard {
match guard_expr {
// gives up if `pat if expr` can have side effects
Guard::If(if_cond) => {
if if_cond.can_have_side_effects() {
return false;
}
},
// gives up `pat if let ...` arm
Guard::IfLet(_) => {
return false;
},
};
}
if let PatKind::Wild = arm.pat.kind {
return eq_expr_value(cx, match_expr, strip_return(arm_expr));
if !eq_expr_value(cx, match_expr, strip_return(arm_expr)) {
return false;
}
} else if !pat_same_as_expr(arm.pat, arm_expr) {
return false;
}