test: fix the added test case at pr #rust-lang#20432 to properly test the issue rust-lang#20215

Author: sgasho

crates/ide-assists/src/handlers/add_missing_impl_members.rs

@@ -2433,29 +2433,31 @@ pub enum State {
     Inactive,
 }
 
+use State::*;
+
 pub trait Checker {
     fn check(&self) -> State;
 
     fn is_active(&self) -> bool {
         match self.check() {
-            State::Active => true,
-            State::Inactive => false,
+            Active => true,
+            Inactive => false,
         }
     }
 }
 //- /main.rs crate:a deps:b
 struct MyChecker;
 
 impl b::Checker for MyChecker {
-    fn check(&self) -> lib::State {
+    fn check(&self) -> b::State {
         todo!();
     }$0
 }"#,
             r#"
 struct MyChecker;
 
 impl b::Checker for MyChecker {
-    fn check(&self) -> lib::State {
+    fn check(&self) -> b::State {
         todo!();
     }