shallow resolve in orphan check

1 files changed, 12 insertions, 0 deletions

diff --git a/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs
index 8425d68ab59..1710746ae50 100644
--- a/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs
@@ -27,6 +27,7 @@ use rustc_span::DUMMY_SP;
 use std::io::Write;
 use std::ops::ControlFlow;
 
+use crate::traits::coherence;
 use crate::traits::vtable::{count_own_vtable_entries, prepare_vtable_segments, VtblSegment};
 
 use super::inspect::ProofTreeBuilder;
@@ -942,6 +943,17 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         }
     }
 
+    pub(super) fn trait_ref_is_knowable(
+        &mut self,
+        param_env: ty::ParamEnv<'tcx>,
+        trait_ref: ty::TraitRef<'tcx>,
+    ) -> Result<bool, NoSolution> {
+        let infcx = self.infcx;
+        let lazily_normalize_ty = |ty| self.structurally_normalize_ty(param_env, ty);
+        coherence::trait_ref_is_knowable(infcx, trait_ref, lazily_normalize_ty)
+            .map(|is_knowable| is_knowable.is_ok())
+    }
+
     pub(super) fn can_define_opaque_ty(&self, def_id: impl Into<DefId>) -> bool {
         self.infcx.can_define_opaque_ty(def_id)
     }