Fix for exception in FixProcessor._addFix_illegalAsyncReturnType.

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

Index: pkg/analysis_server/test/services/correction/fix_test.dart
diff --git a/pkg/analysis_server/test/services/correction/fix_test.dart b/pkg/analysis_server/test/services/correction/fix_test.dart
index 72134291fc46b05df19c6a8bd569a98adb30ed31..b9b68572ed932a35be08a129674d021e1d615ce1 100644
--- a/pkg/analysis_server/test/services/correction/fix_test.dart
+++ b/pkg/analysis_server/test/services/correction/fix_test.dart
@@ -2600,6 +2600,22 @@ main() {
 ''');
   }
 
+  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;