RFC: Resolution based tree-shaking.

dart/lib/compiler/implementation/elements/elements.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.
 
 #library('elements');
 
 #import('../tree/tree.dart');
 #import('../scanner/scannerlib.dart');
 #import('../leg.dart');  // TODO(karlklose): we only need type.
 #import('../util/util.dart');
@@ skipping 105 matching lines @@
   bool isMember() =>
       enclosingElement !== null && enclosingElement.kind === ElementKind.CLASS;
   bool isInstanceMember() => false;
   bool isFactoryConstructor() => modifiers !== null && modifiers.isFactory();
   bool isGenerativeConstructor() => kind === ElementKind.GENERATIVE_CONSTRUCTOR;
   bool isCompilationUnit() {
     return kind === ElementKind.COMPILATION_UNIT ||
            kind === ElementKind.LIBRARY;
   }
   bool isClass() => kind === ElementKind.CLASS;
+  bool isPrefix() => kind === ElementKind.PREFIX;
   bool isVariable() => kind === ElementKind.VARIABLE;
   bool isParameter() => kind === ElementKind.PARAMETER;
   bool isStatement() => kind === ElementKind.STATEMENT;
   bool isTypedef() => kind === ElementKind.TYPEDEF;
   bool isTypeVariable() => kind === ElementKind.TYPE_VARIABLE;
   bool isField() => kind === ElementKind.FIELD;
   bool isGetter() => kind === ElementKind.GETTER;
   bool isSetter() => kind === ElementKind.SETTER;
+  bool isAccessor() => isGetter() || isSetter();
+  bool isForeign() => kind === ElementKind.FOREIGN;
   bool impliesType() => (kind.category & ElementCategory.IMPLIES_TYPE) != 0;
   bool isExtendable() => (kind.category & ElementCategory.IS_EXTENDABLE) != 0;
 
+  bool isTopLevel() => enclosingElement.isCompilationUnit();
+
   bool isAssignable() {
     if (modifiers != null && modifiers.isFinal()) return false;
     if (isFunction() || isGenerativeConstructor()) return false;
     return true;
   }
 
   Token position() => null;
 
   Token findMyName(Token token) {
     for (Token t = token; t.kind !== EOF_TOKEN; t = t.next) {
@@ skipping 34 matching lines @@
     return null;
   }
 
   Element getEnclosingMember() {
     for (Element e = this; e !== null; e = e.enclosingElement) {
       if (e.isMember()) return e;
     }
     return null;
   }
 
-  toString() => '$kind(${name.slowToString()})';
+  Element getOutermostEnclosingMemberOrTopLevel() {
+    for (Element e = this; e !== null; e = e.enclosingElement) {
+      if (e.isMember() || e.isTopLevel()) {
+        return e;
+      }
+    }
+    return null;
+  }
+
+  toString() {
+    if (!isTopLevel()) {
+      String holderName = enclosingElement.name.slowToString();
+      return '$kind($holderName#${name.slowToString()})';
+    } else {
+      return '$kind(${name.slowToString()})';
+    }
+  }
 
   bool _isNative = false;
   void setNative() { _isNative = true; }
   bool isNative() => _isNative;
 }
 
 class ContainerElement extends Element {
   ContainerElement(name, kind, enclosingElement) :
     super(name, kind, enclosingElement);
 
@@ skipping 583 matching lines @@
 
   /**
    * Runs through all members of this class.
    *
    * The enclosing class is passed to the callback. This is useful when
    * [includeSuperMembers] is [:true:].
    */
   void forEachMember([void f(ClassElement enclosingClass, Element member),
                       includeBackendMembers = false,
                       includeSuperMembers = false]) {
+    Set<ClassElement> seen = new Set<ClassElement>();
     ClassElement classElement = this;
     do {
+      if (seen.contains(classElement)) return;
+      seen.add(classElement);
       for (Element element in classElement.members) {
         f(classElement, element);
       }
       if (includeBackendMembers) {
         for (Element element in classElement.backendMembers) {
           f(classElement, element);
         }
       }
       classElement = includeSuperMembers ? classElement.superclass : null;
     } while(classElement !== null);
@@ skipping 228 matching lines @@
   final Node node;
   Type bound;
   Type type;
   TypeVariableElement(name, Element enclosing, this.node, this.type,
                       [this.bound])
     : super(name, ElementKind.TYPE_VARIABLE, enclosing);
   Type computeType(compiler) => type;
   Node parseNode(compiler) => node;
   toString() => "${enclosingElement.toString()}.${name.slowToString()}";
 }