fixes #202, check IndexExpression

lib/runtime/dart/collection.js

Index: lib/runtime/dart/collection.js
diff --git a/lib/runtime/dart/collection.js b/lib/runtime/dart/collection.js
index df4e3980b46cd3b87d342d29bf4aae0e5adc9059..15d4434848798f3995d528ad4681940bfc4ad21b 100644
--- a/lib/runtime/dart/collection.js
+++ b/lib/runtime/dart/collection.js
@@ -79,7 +79,7 @@ var math = dart.lazyImport(math);
       static from(other) {
         let result = HashMap$(K, V).new();
         other.forEach(dart.fn((k, v) => {
-          result.set(k, dart.as(v, V));
+          result.set(dart.as(k, K), dart.as(v, V));
         }));
         return result;
       }
@@ -1218,7 +1218,7 @@ var math = dart.lazyImport(math);
       static from(other) {
         let result = LinkedHashMap$(K, V).new();
         other.forEach(dart.fn((k, v) => {
-          result.set(k, dart.as(v, V));
+          result.set(dart.as(k, K), dart.as(v, V));

[Jennifer Messerly, 2015/06/02 23:29:47]

pretty neat how these just got figured out automagically

         }));
         return result;
       }
@@ -3324,7 +3324,7 @@ var math = dart.lazyImport(math);
           isValidKey = null;
         let result = new (SplayTreeMap$(K, V))();
         other.forEach(dart.fn((k, v) => {
-          result.set(k, dart.as(v, V));
+          result.set(dart.as(k, K), dart.as(v, V));
         }));
         return result;
       }