Fix a crash related to obsolete factory syntax.

dart/lib/compiler/implementation/tree/unparser.dart

Index: dart/lib/compiler/implementation/tree/unparser.dart
diff --git a/dart/lib/compiler/implementation/tree/unparser.dart b/dart/lib/compiler/implementation/tree/unparser.dart
index 8eda6371f0e8af805c210d71917a21d30d29440d..da5868d13441f417b43deb7c4c1354504f49bf01 100644
--- a/dart/lib/compiler/implementation/tree/unparser.dart
+++ b/dart/lib/compiler/implementation/tree/unparser.dart
@@ -271,9 +271,11 @@ class Unparser implements Visitor {
     if (spacesNeeded) sb.add(' ');
     // Also add a space for sequences like x + +1 and y - -y.
     if (opString === '-' || opString === '+') {
-      Token beginToken = node.argumentsNode.getBeginToken();
-      if (beginToken !== null && beginToken.stringValue === opString) {
-        sb.add(' ');
+      if (node.argumentsNode != null) {

[karlklose, 2012/10/15 07:59:26]

You could add this condition to the if above.

[Lasse Reichstein Nielsen, 2012/10/15 08:34:37]

And eventually remove the '+' case when we drop support for that.

+        Token beginToken = node.argumentsNode.getBeginToken();
+        if (beginToken !== null && beginToken.stringValue === opString) {
+          sb.add(' ');
+        }
       }
     }
     visit(node.argumentsNode);