X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=compiler%2Frustc_trait_selection%2Fsrc%2Ftraits%2Fselect%2Fcandidate_assembly.rs;h=0c5d764e79d0cb25a472294b607a3dbb71ce5e48;hb=a11e2b1f755e392e7c776b98e76aa86a30b7b22e;hp=db86041f6180b5efdc49a71aebda28ba7a8d2020;hpb=c77f0a42d3de096aa0ebac4aa73449864f3afdfb;p=rust.git

diff --git a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
index db86041f618..0c5d764e79d 100644
--- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
@@ -254,6 +254,7 @@ pub(super) fn assemble_candidates<'o>(
         };
 
         if obligation.predicate.skip_binder().self_ty().is_ty_var() {
+            debug!(ty = ?obligation.predicate.skip_binder().self_ty(), "ambiguous inference var or opaque type");
             // Self is a type variable (e.g., `_: AsRef<str>`).
             //
             // This is somewhat problematic, as the current scheme can't really