First take on support of library private names.

lib/compiler/implementation/tree/unparser.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.
 
 class Unparser implements Visitor {
   final Renamer renamer;
   StringBuffer sb;
 
   Unparser([this.renamer = const Renamer()]);
 
@@ skipping 88 matching lines @@
       sb.add(' ');
     }
     if (node.getOrSet !== null) {
       add(node.getOrSet.value);
       sb.add(' ');
     }
     // TODO(antonm): that's a workaround as currently FunctionExpression
     // names are modelled with Send and it emits operator[] as only
     // operator, without [] which are expected to be emitted with
     // arguments.
-    emitName(Identifier name) {
-      final newName = renamer.renameIdentifier(name);
-      if (newName === null) {
-        visit(name);
-      } else {
-        sb.add(newName);
-      }
-    }
     if (node.name is Send) {
       Send send = node.name;
       assert(send is !SendSet);
       if (!send.isOperator) {
         // Looks like a factory method.
-        emitName(send.receiver);
+        visit(send.receiver);
         sb.add('.');
       } else {
         visit(send.receiver);
         if (send.selector.token.kind === KEYWORD_TOKEN) sb.add(' ');
       }
       visit(send.selector);
     } else {
-      if (node.name !== null) emitName(node.name);
+      visit(node.name);
     }
     visit(node.parameters);
     visit(node.initializers);
     visit(node.body);
   }
 
   visitIdentifier(Identifier node) {
-    add(node.token.value);
+    String newName = renamer.renameIdentifier(node);
+    if (newName === null) {
+      add(node.token.value);
+    } else {
+      sb.add(newName);
+    }
   }
 
   visitIf(If node) {
     add(node.ifToken.value);
     visit(node.condition);
     visit(node.thenPart);
     if (node.hasElsePart) {
       addToken(node.elseToken);
       visit(node.elsePart);
     }
@@ skipping 361 matching lines @@
       sb.add(' ');
     }
     visit(node.name);
     if (node.typeParameters !== null) {
       visit(node.typeParameters);
     }
     visit(node.formals);
     add(node.endToken.value);
   }
 }