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Remove some unreachable code

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Nadrieril 2021-09-13 15:44:30 +01:00
parent 2e78c6bd99
commit 2bf6e7880d
1 changed files with 11 additions and 20 deletions
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31
compiler/rustc_mir_build/src/thir/pattern/check_match.rs
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@ -190,7 +190,7 @@ impl<'tcx> MatchVisitor<'_, 'tcx> {
let scrut_ty = self.typeck_results.expr_ty_adjusted(scrut); let scrut_ty = self.typeck_results.expr_ty_adjusted(scrut);
let report = compute_match_usefulness(&cx, &arms, scrut.hir_id, scrut_ty); 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 { match source {
hir::MatchSource::ForLoopDesugar | hir::MatchSource::Normal => { hir::MatchSource::ForLoopDesugar | hir::MatchSource::Normal => {
unreachable_pattern(cx.tcx, arm_span, arm_hir_id, catchall); 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 arms = [MatchArm { pat, hir_id: pat_id, has_guard: false }];
let report = compute_match_usefulness(&cx, &arms, pat_id, pat.ty); 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) {
match let_source(cx.tcx, pat_id) { LetSource::IfLet | LetSource::WhileLet | LetSource::IfLetGuard => {
LetSource::IfLet | LetSource::WhileLet => { report_arm_reachability(&cx, &report, |arm_span, arm_hir_id, _| {
match arm_index { unreachable_pattern(cx.tcx, arm_span, arm_hir_id, None)
// 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);
}
_ => {}
} }
}); _ => {}
}
if report.non_exhaustiveness_witnesses.is_empty() { if report.non_exhaustiveness_witnesses.is_empty() {
// The match is exhaustive, i.e. the `if let` pattern is irrefutable. // 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>, report: &UsefulnessReport<'p, 'tcx>,
unreachable: F, unreachable: F,
) where ) where
F: Fn(usize, Span, HirId, Option<Span>), F: Fn(Span, HirId, Option<Span>),
{ {
use Reachability::*; use Reachability::*;
let mut catchall = None; 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 { 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() => {} Reachable(unreachables) if unreachables.is_empty() => {}
// The arm is reachable, but contains unreachable subpatterns (from or-patterns). // The arm is reachable, but contains unreachable subpatterns (from or-patterns).
Reachable(unreachables) => { Reachable(unreachables) => {