Correct scope resolution

src/polymer-expressions.js

Index: src/polymer-expressions.js 
diff --git a/src/polymer-expressions.js b/src/polymer-expressions.js 
index b09ab3febdd283da90618ce1fc695c60f5891fc2..e8765f2a90dc298fe249ea76d14e02a88892010e 100644 
--- a/src/polymer-expressions.js 
+++ b/src/polymer-expressions.js 
@@ -115,6 +115,9 @@ 
 }, 
 
 setValue: function(model, newValue) { 
+ if (this.path.length == 1); 
+ model = findScope(model, this.path[0]); 
+ 
 return this.path.setValueFrom(model, newValue); 
 } 
 }; 
@@ -508,18 +511,35 @@ 
 mixedCaseEventTypes[e.toLowerCase()] = e; 
 }); 
 
+ function getReceiver(model, path) { 
+ if (path.length == 0) 
+ return undefined; 
+ 
+ if (path.length == 1) 
+ return model; 
+ 
+ for (var i = 0; model != null && i < path.length - 1; i++) { 
+ model = model[path[i]]; 
+ } 
+ 
+ return model; 
+ } 
+ 
 function prepareEventBinding(path, name) { 
 var eventType = name.substring(3); 
 eventType = mixedCaseEventTypes[eventType] || eventType; 
 
 return function(model, node, oneTime) { 
 var fn = path.getValueFrom(model); 
+ var receiver = getReceiver(model, path); 
 
 function handler(e) { 
- if (!oneTime) 
+ if (!oneTime) { 
 fn = path.getValueFrom(model); 
+ receiver = getReceiver(model, path); 
+ } 
 
- fn.apply(model, [e, e.detail, e.currentTarget]); 
+ fn.apply(receiver, [e, e.detail, e.currentTarget]); 
 
 if (Platform && typeof Platform.flush == 'function') 
 Platform.flush(); 
@@ -546,6 +566,14 @@ 
 
 function PolymerExpressions() {} 
 
+ function findScope(model, prop) { 
+ while (model.__parentScope && !model.hasOwnProperty(prop)) { 
+ model = model.__parentScope; 
+ } 
+ 
+ return model; 
+ } 
+ 
 PolymerExpressions.prototype = { 
 // "built-in" filters 
 styleObject: function(value) { 
@@ -577,8 +605,8 @@ 
 }, 
 
 prepareBinding: function(pathString, name, node) { 
+ var path = Path.get(pathString); 
 if (isEventHandler(name)) { 
- var path = Path.get(pathString); 
 if (!path.valid) { 
 console.error('on-* bindings must be simple path expressions'); 
 return; 
@@ -587,8 +615,22 @@ 
 return prepareEventBinding(path, name); 
 } 
 
- if (Path.get(pathString).valid) 
+ if (path.valid) { 
+ if (path.length == 1) { 
+ return function(model, node, oneTime) { 
+ if (oneTime) 
+ return path.getValueFrom(model); 
+ 
+ // Special-case dynamic single-property bindings which do not 
+ // directly reference a scope object such that they bind directly to 
+ // the root scope 
+ var scope = findScope(model, path[0]); 
+ return new PathObserver(scope, path); 
+ } 
+ } 
+ 
 return; // bail out early if pathString is simple path. 
+ } 
 
 return prepareBinding(pathString, name, node, this); 
 }, 
@@ -602,9 +644,13 @@ 
 template.templateInstance.model : 
 template.model; 
 
+ var indexName = template.polymerExpressionIndexIdent_; 
+ 
 return function(model) { 
 var scope = Object.create(parentScope); 
 scope[scopeName] = model; 
+ scope[indexName] = undefined; 
+ scope.__parentScope = parentScope; 
 return scope; 
 }; 
 }