Quick Fix for CAN_BE_NULL_AFTER_NULL_AWARE.

pkg/analyzer/lib/src/generated/resolver.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 engine.resolver;
 
 import 'dart:collection';
 
 import 'package:analyzer/src/generated/scanner.dart';
 
@@ skipping 201 matching lines @@
   @override
   Object visitMethodDeclaration(MethodDeclaration node) {
     // This was determined to not be a good hint, see: dartbug.com/16029
     //checkForOverridingPrivateMember(node);
     _checkForMissingReturn(node.returnType, node.body);
     return super.visitMethodDeclaration(node);
   }
 
   @override
   Object visitMethodInvocation(MethodInvocation node) {
-    _checkForCanBeNullAfterNullAware(node.realTarget);
+    _checkForCanBeNullAfterNullAware(node.realTarget, node.operator);
     return super.visitMethodInvocation(node);
   }
 
   @override
   Object visitPostfixExpression(PostfixExpression node) {
     _checkForDeprecatedMemberUse(node.bestElement, node);
     return super.visitPostfixExpression(node);
   }
 
   @override
   Object visitPrefixExpression(PrefixExpression node) {
     _checkForDeprecatedMemberUse(node.bestElement, node);
     return super.visitPrefixExpression(node);
   }
 
   @override
   Object visitPropertyAccess(PropertyAccess node) {
-    _checkForCanBeNullAfterNullAware(node.realTarget);
+    _checkForCanBeNullAfterNullAware(node.realTarget, node.operator);
     return super.visitPropertyAccess(node);
   }
 
   @override
   Object visitRedirectingConstructorInvocation(
       RedirectingConstructorInvocation node) {
     _checkForDeprecatedMemberUse(node.staticElement, node);
     return super.visitRedirectingConstructorInvocation(node);
   }
 
@@ skipping 207 matching lines @@
     bool problemReported = false;
     for (Expression argument in argumentList.arguments) {
       if (_checkForArgumentTypeNotAssignableForArgument(argument)) {
         problemReported = true;
       }
     }
     return problemReported;
   }
 
   /**
-   * Produce a hint if the given [expression] could have a value of `null`.
+   * Produce a hint if the given [target] could have a value of `null`.
    */
-  void _checkForCanBeNullAfterNullAware(Expression expression) {
-    if (expression is ParenthesizedExpression) {
-      _checkForCanBeNullAfterNullAware(expression.expression);
-    } else if (expression is MethodInvocation) {
-      if (expression.operator?.type == TokenType.QUESTION_PERIOD) {
+  void _checkForCanBeNullAfterNullAware(Expression target, Token operator) {
+    if (operator?.type == TokenType.QUESTION_PERIOD) {

[Brian Wilkerson, 2015/10/29 14:02:23]

It seems strange to have to repeat this test for a parenthesized expression when
the value of the operator will never change. Maybe it would be better to not use
recursion here. Your call.

+      return;
+    }
+    if (target is ParenthesizedExpression) {
+      _checkForCanBeNullAfterNullAware(target.expression, operator);
+    } else if (target is MethodInvocation) {
+      if (target.operator?.type == TokenType.QUESTION_PERIOD) {
         _errorReporter.reportErrorForNode(
-            HintCode.CAN_BE_NULL_AFTER_NULL_AWARE, expression);
+            HintCode.CAN_BE_NULL_AFTER_NULL_AWARE, target);
       }
-    } else if (expression is PropertyAccess) {
-      if (expression.operator.type == TokenType.QUESTION_PERIOD) {
+    } else if (target is PropertyAccess) {
+      if (target.operator.type == TokenType.QUESTION_PERIOD) {
         _errorReporter.reportErrorForNode(
-            HintCode.CAN_BE_NULL_AFTER_NULL_AWARE, expression);
+            HintCode.CAN_BE_NULL_AFTER_NULL_AWARE, target);
       }
     }
   }
 
   /**
    * Given some [Element], look at the associated metadata and report the use of the member if
    * it is declared as deprecated.
    *
    * @param element some element to check for deprecated use of
    * @param node the node use for the location of the error
@@ skipping 15603 matching lines @@
     nonFields.add(node);
     return null;
   }
 
   @override
   Object visitNode(AstNode node) => node.accept(TypeResolverVisitor_this);
 
   @override
   Object visitWithClause(WithClause node) => null;
 }