diff --git a/compiler/rustc_middle/src/ty/fold.rs b/compiler/rustc_middle/src/ty/fold.rs index 027d43d186a..57aa15f69a9 100644 --- a/compiler/rustc_middle/src/ty/fold.rs +++ b/compiler/rustc_middle/src/ty/fold.rs @@ -818,6 +818,9 @@ where value.fold_with(&mut Shifter::new(tcx, amount)) } +#[derive(Debug, PartialEq, Eq, Copy, Clone)] +struct FoundEscapingVars; + /// An "escaping var" is a bound var whose binder is not part of `t`. A bound var can be a /// bound region or a bound type. /// @@ -849,6 +852,8 @@ struct HasEscapingVarsVisitor { } impl<'tcx> TypeVisitor<'tcx> for HasEscapingVarsVisitor { + type BreakTy = FoundEscapingVars; + fn visit_binder<T: TypeFoldable<'tcx>>(&mut self, t: &Binder<T>) -> ControlFlow<Self::BreakTy> { self.outer_index.shift_in(1); let result = t.super_visit_with(self); @@ -863,7 +868,7 @@ impl<'tcx> TypeVisitor<'tcx> for HasEscapingVarsVisitor { // `outer_exclusive_binder` is always 1 higher than the // content in `t`). Therefore, `t` has some escaping vars. if t.outer_exclusive_binder > self.outer_index { - ControlFlow::BREAK + ControlFlow::Break(FoundEscapingVars) } else { ControlFlow::CONTINUE } @@ -874,7 +879,7 @@ impl<'tcx> TypeVisitor<'tcx> for HasEscapingVarsVisitor { // of outer index, then it escapes the binders we have // visited. if r.bound_at_or_above_binder(self.outer_index) { - ControlFlow::BREAK + ControlFlow::Break(FoundEscapingVars) } else { ControlFlow::CONTINUE } @@ -887,14 +892,16 @@ impl<'tcx> TypeVisitor<'tcx> for HasEscapingVarsVisitor { // const, as it has types/regions embedded in a lot of other // places. match ct.val { - ty::ConstKind::Bound(debruijn, _) if debruijn >= self.outer_index => ControlFlow::BREAK, + ty::ConstKind::Bound(debruijn, _) if debruijn >= self.outer_index => { + ControlFlow::Break(FoundEscapingVars) + } _ => ct.super_visit_with(self), } } fn visit_predicate(&mut self, predicate: ty::Predicate<'tcx>) -> ControlFlow<Self::BreakTy> { if predicate.inner.outer_exclusive_binder > self.outer_index { - ControlFlow::BREAK + ControlFlow::Break(FoundEscapingVars) } else { ControlFlow::CONTINUE }