diff options
| -rw-r--r-- | compiler/rustc_infer/src/infer/opaque_types.rs | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/compiler/rustc_infer/src/infer/opaque_types.rs b/compiler/rustc_infer/src/infer/opaque_types.rs index eab5e5a5fb4..d5e65705b28 100644 --- a/compiler/rustc_infer/src/infer/opaque_types.rs +++ b/compiler/rustc_infer/src/infer/opaque_types.rs @@ -551,14 +551,16 @@ impl<'a, 'tcx> Instantiator<'a, 'tcx> { let predicate = predicate.subst(tcx, substs); debug!(?predicate); - // Replace all other mentions of the same opaque type with the hidden type, - // as the bounds must hold on the hidden type after all. let predicate = predicate.fold_with(&mut BottomUpFolder { tcx, ty_op: |ty| match *ty.kind() { + // Replace all other mentions of the same opaque type with the hidden type, + // as the bounds must hold on the hidden type after all. ty::Opaque(def_id2, substs2) if def_id == def_id2 && substs == substs2 => { ty_var } + // Instantiate nested instances of `impl Trait`. + ty::Opaque(..) => self.instantiate_opaque_types_in_map(ty), _ => ty, }, lt_op: |lt| lt, @@ -589,10 +591,6 @@ impl<'a, 'tcx> Instantiator<'a, 'tcx> { return tcx.ty_error(); } } - // Change the predicate to refer to the type variable, - // which will be the concrete type instead of the opaque type. - // This also instantiates nested instances of `impl Trait`. - let predicate = self.instantiate_opaque_types_in_map(predicate); let cause = traits::ObligationCause::new(self.value_span, self.body_id, traits::OpaqueType); |