Fix for exception in FixProcessor._addFix_illegalAsyncReturnType.

pkg/analysis_server/test/services/correction/fix_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library test.services.correction.fix;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
 import 'package:analysis_server/plugin/edit/fix/fix_dart.dart';
@@ skipping 2582 matching lines @@
 ''');
     await assertHasFix(
         DartFixKind.INSERT_SEMICOLON,
         '''
 main() {
   print(0);
 }
 ''');
   }
 
+  test_illegalAsyncReturnType_adjacentNodes() async {
+    errorFilter = (AnalysisError error) {
+      return error.errorCode == StaticTypeWarningCode.ILLEGAL_ASYNC_RETURN_TYPE;
+    };
+    resolveTestUnit('''
+import 'dart:async';
+var v;int main() async => 0;
+''');
+    await assertHasFix(
+        DartFixKind.REPLACE_RETURN_TYPE_FUTURE,
+        '''
+import 'dart:async';
+var v;Future<int> main() async => 0;
+''');
+  }
+
   test_illegalAsyncReturnType_asyncLibrary_import() async {
     errorFilter = (AnalysisError error) {
       return error.errorCode == StaticTypeWarningCode.ILLEGAL_ASYNC_RETURN_TYPE;
     };
     resolveTestUnit('''
 library main;
 int main() async {
 }
 ''');
     await assertHasFix(
@@ skipping 2077 matching lines @@
       int offset = resultCode.indexOf(search);
       positions.add(new Position(testFile, offset));
     }
     return positions;
   }
 
   void _performAnalysis() {
     while (context.performAnalysisTask().hasMoreWork);
   }
 }