bjoernager/rust
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Handle all arbitrary loop nesting in break type errors

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This commit is contained in:
Esteban Küber 2023-09-25 21:57:22 +00:00
parent 58adfd84e2
commit 3747ef5d6f
3 changed files with 137 additions and 8 deletions
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27
compiler/rustc_hir_typeck/src/demand.rs
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@ -583,7 +583,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
// loop, so we need to account for that.
direct = !direct;
}
if let hir::ExprKind::Loop(_, label, _, span) = parent.kind
if let hir::ExprKind::Loop(block, label, _, span) = parent.kind
&& (destination.label == label || direct)
{
if let Some((reason_span, message)) =
@ -594,25 +594,39 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
span,
format!("this loop is expected to be of type `{expected}`"),
);
break 'outer;
} else {
// Locate all other `break` statements within the same `loop` that might
// have affected inference.
struct FindBreaks<'tcx> {
label: Option<rustc_ast::Label>,
uses: Vec<&'tcx hir::Expr<'tcx>>,
nest_depth: usize,
}
impl<'tcx> Visitor<'tcx> for FindBreaks<'tcx> {
fn visit_expr(&mut self, ex: &'tcx hir::Expr<'tcx>) {
let nest_depth = self.nest_depth;
if let hir::ExprKind::Loop(_, label, _, _) = ex.kind {
if label == self.label {
// Account for `'a: loop { 'a: loop {...} }`.
return;
}
self.nest_depth += 1;
}
if let hir::ExprKind::Break(destination, _) = ex.kind
&& self.label == destination.label
&& (self.label == destination.label
// Account for `loop { 'a: loop { loop { break; } } }`.
|| destination.label.is_none() && self.nest_depth == 0)
{
self.uses.push(ex);
}
hir::intravisit::walk_expr(self, ex);
self.nest_depth = nest_depth;
}
}
let mut expr_finder = FindBreaks { label, uses: vec![] };
expr_finder.visit_expr(parent);
let mut expr_finder = FindBreaks { label, uses: vec![], nest_depth: 0 };
expr_finder.visit_block(block);
let mut exit = false;
for ex in expr_finder.uses {
let hir::ExprKind::Break(_, val) = ex.kind else {
continue;
@ -631,10 +645,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
ex.span,
format!("expected because of this `break`"),
);
exit = true;
}
}
if exit {
break 'outer;
}
}
break 'outer;
}
}
}