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Fix ignored unused outer label when inner label shadows and is broken multiple times

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This commit is contained in:
Kyle Stachowicz 2018-05-15 20:32:43 -07:00
parent 0f274122ee
commit 4de4e61864
1 changed files with 6 additions and 8 deletions

14
src/librustc_lint/unused.rs

@ -472,7 +472,7 @@ declare_lint! {
}
#[derive(Clone)]
pub struct UnusedLabel(pub Vec<ast::Label>);
pub struct UnusedLabel(pub Vec<(ast::Label, bool)>);
impl UnusedLabel {
pub fn new() -> Self {
@ -493,11 +493,11 @@ impl EarlyLintPass for UnusedLabel {
| ast::ExprKind::WhileLet(_, _, _, Some(label))
| ast::ExprKind::ForLoop(_, _, _, Some(label))
| ast::ExprKind::Loop(_, Some(label)) => {
self.0.push(label);
self.0.push((label, false));
}
ast::ExprKind::Break(Some(label), _) | ast::ExprKind::Continue(Some(label)) => {
if let Some(index) = self.0.iter().rposition(|&l| l.ident == label.ident) {
self.0.remove(index);
if let Some((_, ref mut was_used)) = self.0.iter_mut().rev().find(|(l, _)| label == *l) {
*was_used = true;
}
}
_ => {}
@ -510,11 +510,9 @@ impl EarlyLintPass for UnusedLabel {
| ast::ExprKind::WhileLet(_, _, _, Some(label))
| ast::ExprKind::ForLoop(_, _, _, Some(label))
| ast::ExprKind::Loop(_, Some(label)) => {
if let Some(unused_label) = self.0.pop() {
if label.ident == unused_label.ident {
if let Some((_, was_used)) = self.0.pop() {
if !was_used {
ctxt.span_lint(UNUSED_LABEL, label.ident.span, "unused label");
} else {
self.0.push(unused_label);
}
}
},