Validation of `@required` params (#26182).

pkg/analyzer/lib/src/generated/error.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 analyzer.src.generated.error;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart' show AstNode;
 import 'package:analyzer/dart/ast/token.dart';
@@ skipping 2665 matching lines @@
     HintCode.DEPRECATED_MEMBER_USE,
     HintCode.DUPLICATE_IMPORT,
     HintCode.DIVISION_OPTIMIZATION,
     HintCode.IS_DOUBLE,
     HintCode.IS_INT,
     HintCode.IS_NOT_DOUBLE,
     HintCode.IS_NOT_INT,
     HintCode.IMPORT_DEFERRED_LIBRARY_WITH_LOAD_FUNCTION,
     HintCode.INVALID_ASSIGNMENT,
     HintCode.INVALID_USE_OF_PROTECTED_MEMBER,
+    HintCode.MISSING_REQUIRED_PARAM,
     HintCode.MISSING_RETURN,
     HintCode.NULL_AWARE_IN_CONDITION,
     HintCode.OVERRIDE_ON_NON_OVERRIDING_GETTER,
     HintCode.OVERRIDE_ON_NON_OVERRIDING_METHOD,
     HintCode.OVERRIDE_ON_NON_OVERRIDING_SETTER,
     HintCode.OVERRIDE_EQUALS_BUT_NOT_HASH_CODE,
     HintCode.TYPE_CHECK_IS_NOT_NULL,
     HintCode.TYPE_CHECK_IS_NULL,
     HintCode.UNDEFINED_GETTER,
     HintCode.UNDEFINED_METHOD,
@@ skipping 869 matching lines @@
    *
    * Parameters:
    * 0: the name of the member
    * 1: the name of the defining class
    */
   static const HintCode INVALID_USE_OF_PROTECTED_MEMBER = const HintCode(
       'INVALID_USE_OF_PROTECTED_MEMBER',
       "The member '{0}' can only be used within instance members of subclasses of '{1}'");
 
   /**
+   * Generate a hint for a constructor, function or method invocation where a
+   * required parameter is missing.
+   *
+   * Parameters:
+   * 0: the name of the parameter
+   * 1: an optional reason
+   */
+  static const HintCode MISSING_REQUIRED_PARAM = const HintCode(
+      'MISSING_REQUIRED_PARAM', "The parameter '{0}' is required. {1}");
+
+  /**
    * Generate a hint for methods or functions that have a return type, but do
    * not have a non-void return statement on all branches. At the end of methods
    * or functions with no return, Dart implicitly returns `null`, avoiding these
    * implicit returns is considered a best practice.
    *
    * Parameters:
    * 0: the name of the declared return type
    */
   static const HintCode MISSING_RETURN = const HintCode(
       'MISSING_RETURN',
@@ skipping 2163 matching lines @@
    * Initialize a newly created error code to have the given [name].
    */
   const TodoCode(String name) : super(name, "{0}");
 
   @override
   ErrorSeverity get errorSeverity => ErrorSeverity.INFO;
 
   @override
   ErrorType get type => ErrorType.TODO;
 }