Support symbol literals.

sdk/lib/_internal/compiler/implementation/tree/nodes.dart

 // Copyright (c) 2012, 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.
 
 part of tree;
 
 abstract class Visitor<R> {
   const Visitor();
 
   R visitNode(Node node);
@@ skipping 58 matching lines @@
   R visitSend(Send node) => visitExpression(node);
   R visitSendSet(SendSet node) => visitSend(node);
   R visitStatement(Statement node) => visitNode(node);
   R visitStringNode(StringNode node) => visitExpression(node);
   R visitStringInterpolation(StringInterpolation node) => visitStringNode(node);
   R visitStringInterpolationPart(StringInterpolationPart node) {
     return visitNode(node);
   }
   R visitSwitchCase(SwitchCase node) => visitNode(node);
   R visitSwitchStatement(SwitchStatement node) => visitStatement(node);
+  R visitLiteralSymbol(LiteralSymbol node) => visitExpression(node);
   R visitThrow(Throw node) => visitExpression(node);
   R visitTryStatement(TryStatement node) => visitStatement(node);
   R visitTypeAnnotation(TypeAnnotation node) => visitNode(node);
   R visitTypedef(Typedef node) => visitNode(node);
   R visitTypeVariable(TypeVariable node) => visitNode(node);
   R visitVariableDefinitions(VariableDefinitions node) => visitStatement(node);
   R visitWhile(While node) => visitLoop(node);
 }
 
 Token firstBeginToken(Node first, Node second) {
@@ skipping 851 matching lines @@
   }
 
   Token getBeginToken() {
     if (constKeyword != null) return constKeyword;
     return firstBeginToken(typeArguments, elements);
   }
 
   Token getEndToken() => elements.getEndToken();
 }
 
+class LiteralSymbol extends Expression {
+  final Token hashToken;
+  final NodeList identifiers;
+
+  LiteralSymbol(this.hashToken, this.identifiers);
+
+  LiteralSymbol asLiteralSymbol() => this;
+
+  void visitChildren(Visitor visitor) {
+    if (identifiers != null) identifiers.accept(visitor);
+  }
+
+  accept(Visitor visitor) => visitor.visitLiteralSymbol(this);
+
+  Token getBeginToken() => hashToken;
+
+  Token getEndToken() => identifiers.getEndToken();
+
+  String get slowNameString => '${identifiers}';
+}
+
 class Identifier extends Expression {
   final Token token;
 
   SourceString get source => token.value;
 
   Identifier(Token this.token);
 
   bool isThis() => identical(source.stringValue, 'this');
 
   bool isSuper() => identical(source.stringValue, 'super');
@@ skipping 1092 matching lines @@
  * argument).
  *
  * TODO(ahe): This method is controversial, the team needs to discuss
  * if top-level methods are acceptable and what naming conventions to
  * use.
  */
 initializerDo(Node node, f(Node node)) {
   SendSet send = node.asSendSet();
   if (send != null) return f(send.arguments.head);
 }