Add mark::check! and mark::hit!

crates/hir_def/src/nameres/path_resolution.rs

@@ -65,6 +65,7 @@ impl ResolvePathResult {
 impl DefMap {
     pub(super) fn resolve_name_in_extern_prelude(&self, name: &Name) -> PerNs {
         if name == &name!(self) {
+            mark::hit!(extern_crate_self_as);
             return PerNs::types(
                 ModuleId { krate: self.krate, local_id: self.root }.into(),
                 Visibility::Public,

crates/hir_def/src/nameres/tests/diagnostics.rs

@@ -63,6 +63,7 @@ fn unresolved_extern_crate() {
 
 #[test]
 fn extern_crate_self_as() {
+    mark::check!(extern_crate_self_as);
     check_diagnostics(
         r"
         //- /lib.rs