Merge pull request #2024 from dart-lang/avoid-returning-null-for-future-highlight

Improve the highlight range for avoid_returning_null_for_future
diff --git a/lib/src/rules/avoid_returning_null_for_future.dart b/lib/src/rules/avoid_returning_null_for_future.dart
index 8997353..2de2a77 100644
--- a/lib/src/rules/avoid_returning_null_for_future.dart
+++ b/lib/src/rules/avoid_returning_null_for_future.dart
@@ -74,7 +74,7 @@
       throw StateError('unexpected type');
     }
     if (returnType != null && returnType.isDartAsyncFuture && !isAsync) {
-      rule.reportLint(node);
+      rule.reportLint(expression);
     }
   }
 }