Big merge from experimental to bleeding edge.

sdk/lib/_internal/compiler/implementation/resolution/scope.dart

Index: sdk/lib/_internal/compiler/implementation/resolution/scope.dart
diff --git a/sdk/lib/_internal/compiler/implementation/resolution/scope.dart b/sdk/lib/_internal/compiler/implementation/resolution/scope.dart
index af5b0e768b56ecacb59bfba935c01e9472a7436d..92e7840bba0fb8006b60e62bfbdfb5a20d3a1cc8 100644
--- a/sdk/lib/_internal/compiler/implementation/resolution/scope.dart
+++ b/sdk/lib/_internal/compiler/implementation/resolution/scope.dart
@@ -104,13 +104,13 @@ class MethodScope extends MutableScope {
   MethodScope(Scope parent, this.element)
       : super(parent);
 
-  String toString() => 'MethodScope($element${elements.keys})';
+  String toString() => 'MethodScope($element${elements.keys.toList()})';
 }
 
 class BlockScope extends MutableScope {
   BlockScope(Scope parent) : super(parent);
 
-  String toString() => 'BlockScope(${elements.keys})';
+  String toString() => 'BlockScope(${elements.keys.toList()})';
 }
 
 /**