diff --git a/compiler/rustc_borrowck/src/region_infer/opaque_types.rs b/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
index d354ecd1438..407bbf48813 100644
--- a/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
+++ b/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
@@ -299,7 +299,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                             infcx
                                 .report_mismatched_types(
                                     &ObligationCause::misc(instantiated_ty.span, body_id),
-                                    self.tcx.mk_opaque(def_id, id_substs),
+                                    self.tcx.mk_opaque(def_id.to_def_id(), id_substs),
                                     definition_ty,
                                     err,
                                 )