add debug

Author: Kohei316

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -3291,6 +3291,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip(self))]
     fn suggest_use_candidates<F>(&self, candidates: Vec<DefId>, handle_candidates: F)
     where
         F: FnOnce(Vec<String>, Vec<String>, Span),
@@ -3329,6 +3330,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let prefix = if visible { "use " } else { "" };
             let postfix = if visible { ";" } else { "" };
             let path_strings = candidates.iter().map(|trait_did| {
+                debug!(
+                    "trait_did={:?} with_crate_prefix={:?}",
+                    trait_did,
+                    with_crate_prefix!(self.tcx.def_path_str(*trait_did))
+                );
                 format!(
                     "{prefix}{}{postfix}\n",
                     with_crate_prefix!(self.tcx.def_path_str(*trait_did)),