Fix generalizer bug

rust-lang · Feb 22, 2024 · 27da982 · 27da982
1 parent f5631bf
commit 27da982
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Showing 2 changed files with 5 additions and 16 deletions.
diff --git a/compiler/rustc_infer/src/infer/relate/generalize.rs b/compiler/rustc_infer/src/infer/relate/generalize.rs
@@ -108,16 +108,11 @@ impl<'tcx> InferCtxt<'tcx> {
  } else {
  // HACK: make sure that we `a_is_expected` continues to be
  // correct when relating the generalized type with the source.
- if target_is_expected == relation.a_is_expected() {
- relation.relate_with_variance(
- ambient_variance,
- ty::VarianceDiagInfo::default(),
- generalized_ty,
- source_ty,
- )?;
+ if target_is_expected {
+ relation.relate(generalized_ty, source_ty)?;
  } else {
  relation.relate_with_variance(
- ambient_variance.xform(ty::Contravariant),
+ ty::Contravariant,
  ty::VarianceDiagInfo::default(),
  source_ty,
  generalized_ty,

diff --git a/compiler/rustc_infer/src/infer/relate/type_relating.rs b/compiler/rustc_infer/src/infer/relate/type_relating.rs
@@ -125,18 +125,12 @@ impl<'tcx> TypeRelation<'tcx> for TypeRelating<'_, '_, 'tcx> {
  }
 
  (&ty::Infer(TyVar(a_vid)), _) => {
- infcx.instantiate_ty_var(
- self,
- self.a_is_expected,
- a_vid,
- self.ambient_variance,
- b,
- )?;
+ infcx.instantiate_ty_var(self, true, a_vid, self.ambient_variance, b)?;
  }
  (_, &ty::Infer(TyVar(b_vid))) => {
  infcx.instantiate_ty_var(
  self,
- !self.a_is_expected,
+ false,
  b_vid,
  self.ambient_variance.xform(ty::Contravariant),
  a,