Prepare CompilationUnitElementDelta in IncrementalCompilationUnitElementBuilder.

pkg/analyzer/lib/src/generated/ast.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.
 
 // This code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine.ast;
 
 import 'dart:collection';
@@ skipping 4757 matching lines @@
    */
   bool get _directivesAreBeforeDeclarations {
     if (_directives.isEmpty || _declarations.isEmpty) {
       return true;
     }
     Directive lastDirective = _directives[_directives.length - 1];
     CompilationUnitMember firstDeclaration = _declarations[0];
     return lastDirective.offset < firstDeclaration.offset;
   }
 
+  /**
+   * Replaces contents of this [CompilationUnit] with the given [other].
+   */
+  void replaceWith(CompilationUnit other) {

[Brian Wilkerson, 2015/06/02 15:50:41]

I really don't think we want to add this to the public API, and certainly not
with the current semantics that the parent of the child nodes doesn't change.

Is that an important semantic to preserve? If not, perhaps this could be moved
to Incremental...Builder and the setters invoked to preserve the parent/child
relationships.

[scheglov, 2015/06/02 17:13:11]

Oops... You're right.
Removing it.

+    beginToken = other.beginToken;
+    _scriptTag = other._scriptTag;
+    _directives = other._directives;
+    _declarations = other._declarations;
+    element = other.element;
+    lineInfo = other.lineInfo;
+  }
+
   @override
   accept(AstVisitor visitor) => visitor.visitCompilationUnit(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     _safelyVisitChild(_scriptTag, visitor);
     if (_directivesAreBeforeDeclarations) {
       _directives.accept(visitor);
       _declarations.accept(visitor);
     } else {
@@ skipping 15268 matching lines @@
   }
 
   @override
   accept(AstVisitor visitor) => visitor.visitYieldStatement(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     _safelyVisitChild(_expression, visitor);
   }
 }