+ (&ty::GeneratorWitnessMIR(a_id, a_substs), &ty::GeneratorWitnessMIR(b_id, b_substs))
+ if a_id == b_id =>
+ {
+ // All GeneratorWitness types with the same id represent
+ // the (anonymous) type of the same generator expression. So
+ // all of their regions should be equated.
+ let substs = relation.relate(a_substs, b_substs)?;
+ Ok(tcx.mk_generator_witness_mir(a_id, substs))
+ }
+