From 2bf6e7880ddab107219ec493952dc8d74c749a5b Mon Sep 17 00:00:00 2001
From: Nadrieril <nadrieril+git@gmail.com>
Date: Mon, 13 Sep 2021 15:44:30 +0100
Subject: [PATCH] Remove some unreachable code
---
.../src/thir/pattern/check_match.rs | 31 +++++++------------
1 file changed, 11 insertions(+), 20 deletions(-)
diff --git a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
index 4c51b9207bb..724ac545315 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
@@ -190,7 +190,7 @@ impl<'tcx> MatchVisitor<'_, 'tcx> {
let scrut_ty = self.typeck_results.expr_ty_adjusted(scrut);
let report = compute_match_usefulness(&cx, &arms, scrut.hir_id, scrut_ty);
- report_arm_reachability(&cx, &report, |_, arm_span, arm_hir_id, catchall| {
+ report_arm_reachability(&cx, &report, |arm_span, arm_hir_id, catchall| {
match source {
hir::MatchSource::ForLoopDesugar | hir::MatchSource::Normal => {
unreachable_pattern(cx.tcx, arm_span, arm_hir_id, catchall);
@@ -434,23 +434,14 @@ fn check_let_reachability<'p, 'tcx>(
let arms = [MatchArm { pat, hir_id: pat_id, has_guard: false }];
let report = compute_match_usefulness(&cx, &arms, pat_id, pat.ty);
- report_arm_reachability(&cx, &report, |arm_index, arm_span, arm_hir_id, _| {
- match let_source(cx.tcx, pat_id) {
- LetSource::IfLet | LetSource::WhileLet => {
- match arm_index {
- // The arm with the user-specified pattern.
- 0 => unreachable_pattern(cx.tcx, arm_span, arm_hir_id, None),
- // The arm with the wildcard pattern.
- 1 => irrefutable_let_pattern(cx.tcx, pat_id, arm_span),
- _ => bug!(),
- }
- }
- LetSource::IfLetGuard if arm_index == 0 => {
- unreachable_pattern(cx.tcx, arm_span, arm_hir_id, None);
- }
- _ => {}
+ match let_source(cx.tcx, pat_id) {
+ LetSource::IfLet | LetSource::WhileLet | LetSource::IfLetGuard => {
+ report_arm_reachability(&cx, &report, |arm_span, arm_hir_id, _| {
+ unreachable_pattern(cx.tcx, arm_span, arm_hir_id, None)
+ });
}
- });
+ _ => {}
+ }
if report.non_exhaustiveness_witnesses.is_empty() {
// The match is exhaustive, i.e. the `if let` pattern is irrefutable.
@@ -464,13 +455,13 @@ fn report_arm_reachability<'p, 'tcx, F>(
report: &UsefulnessReport<'p, 'tcx>,
unreachable: F,
) where
- F: Fn(usize, Span, HirId, Option<Span>),
+ F: Fn(Span, HirId, Option<Span>),
{
use Reachability::*;
let mut catchall = None;
- for (arm_index, (arm, is_useful)) in report.arm_usefulness.iter().enumerate() {
+ for (arm, is_useful) in report.arm_usefulness.iter() {
match is_useful {
- Unreachable => unreachable(arm_index, arm.pat.span, arm.hir_id, catchall),
+ Unreachable => unreachable(arm.pat.span, arm.hir_id, catchall),
Reachable(unreachables) if unreachables.is_empty() => {}
// The arm is reachable, but contains unreachable subpatterns (from or-patterns).
Reachable(unreachables) => {