cool shit

Author: lcnr

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -1769,6 +1769,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
     /// *fairly arbitrary* choices about which candidate is actually used.
     ///
     /// For more details, look at the implementation of this method :)
+    #[instrument(level = "debug", skip(self), ret)]
     fn winnow_candidates(
         &mut self,
         has_non_region_infer: bool,
@@ -1854,7 +1855,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
         match alias_bound {
             Some(Some(index)) => return Some(ProjectionCandidate(index)),
             Some(None) => {}
-            None => {}
+            None => return None,
         }
 
         // Need to prioritize builtin trait object impls as `<dyn Any as Any>::type_id`
@@ -1868,8 +1869,8 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
             .try_reduce(|c1, c2| if has_non_region_infer { None } else { Some(c1.min(c2)) });
         match object_bound {
             Some(Some(index)) => return Some(ObjectCandidate(index)),
-            Some(None) => return None,
-            None => {}
+            Some(None) => {}
+            None => return None,
         }
 
         // Finally, handle overlapping user-written impls.