Check that visibility upgrade path is hit

Author: Jonas Schievink

crates/ra_hir_def/src/nameres/collector.rs

@@ -625,7 +625,12 @@ impl DefCollector<'_> {
                                 panic!("`Tr as _` imports with unrelated visibilities {:?} and {:?} (trait {:?})", old_vis, vis, tr);
                             });
 
-                            max_vis != old_vis
+                            if max_vis == old_vis {
+                                false
+                            } else {
+                                mark::hit!(upgrade_underscore_visibility);
+                                true
+                            }
                         }
                     };
 

crates/ra_hir_def/src/nameres/tests.rs

@@ -619,6 +619,7 @@ use crate::reex::*;
 
 #[test]
 fn underscore_pub_crate_reexport() {
+    mark::check!(upgrade_underscore_visibility);
     check(
         r#"
 //- /main.rs crate:main deps:lib
@@ -629,9 +630,7 @@ use tr::Tr as _;
 pub use tr::Tr as _;
 
 mod tr {
-    pub trait Tr {
-        fn method(&self) {}
-    }
+    pub trait Tr {}
 }
     "#,
         expect![[r#"