diff options
| -rw-r--r-- | compiler/rustc_infer/src/infer/canonical/query_response.rs | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/compiler/rustc_infer/src/infer/canonical/query_response.rs b/compiler/rustc_infer/src/infer/canonical/query_response.rs index 9d2e065afa3..b948067e750 100644 --- a/compiler/rustc_infer/src/infer/canonical/query_response.rs +++ b/compiler/rustc_infer/src/infer/canonical/query_response.rs @@ -505,12 +505,9 @@ impl<'tcx> InferCtxt<'tcx> { let b = instantiate_value(self.tcx, &result_args, b); debug!(?a, ?b, "constrain opaque type"); // We use equate here instead of, for example, just registering the - // opaque type's hidden value directly, because we may be instantiating - // a query response that was canonicalized in an InferCtxt that had - // a different defining anchor. In that case, we may have inferred - // `NonLocalOpaque := LocalOpaque` but can only instantiate it in - // the other direction as `LocalOpaque := NonLocalOpaque`. Using eq - // here allows us to try both directions (in `InferCtxt::handle_opaque_type`). + // opaque type's hidden value directly, because the hidden type may have been an inference + // variable that got constrained to the opaque type itself. In that case we want to equate + // the generic args of the opaque with the generic params of its hidden type version. obligations.extend( self.at(cause, param_env) .eq( |