Add unwrap method for QueryResult

It was what was already being done but with worse diagnostics

Author: rsmyth-ecmi

compiler/rustc_query_system/src/query/plumbing.rs

@@ -44,6 +44,18 @@ enum QueryResult {
     Poisoned,
 }
 
+impl QueryResult {
+
+    /// Unwraps the query job and if poisoned will raise a [`FatalError`]
+    fn unwrap(self) -> QueryJob {
+        match self {
+            Self::Started(job) => job,
+            Self::Poisoned => FatalError.raise(),
+        }
+    }
+
+}
+
 impl<K> QueryState<K>
 where
     K: Eq + Hash + Copy + Debug,
@@ -169,10 +181,7 @@ where
 
         let job = {
             let mut lock = state.active.lock_shard_by_value(&key);
-            match lock.remove(&key).unwrap() {
-                QueryResult::Started(job) => job,
-                QueryResult::Poisoned => panic!(),
-            }
+            lock.remove(&key).unwrap().unwrap()
         };
 
         job.signal_complete();
@@ -190,10 +199,8 @@ where
         let state = self.state;
         let job = {
             let mut shard = state.active.lock_shard_by_value(&self.key);
-            let job = match shard.remove(&self.key).unwrap() {
-                QueryResult::Started(job) => job,
-                QueryResult::Poisoned => panic!(),
-            };
+            let job = shard.remove(&self.key).unwrap().unwrap();
+            
             shard.insert(self.key, QueryResult::Poisoned);
             job
         };