dart2js: type analysis: yield escapes its argument

pkg/compiler/lib/src/inferrer/inferrer_engine.dart

Index: pkg/compiler/lib/src/inferrer/inferrer_engine.dart
diff --git a/pkg/compiler/lib/src/inferrer/inferrer_engine.dart b/pkg/compiler/lib/src/inferrer/inferrer_engine.dart
index d42541c6c991d526ba4c03afb89b64823530b954..fa5a147e666eafada8ea0229281546a2826fb062 100644
--- a/pkg/compiler/lib/src/inferrer/inferrer_engine.dart
+++ b/pkg/compiler/lib/src/inferrer/inferrer_engine.dart
@@ -919,6 +919,18 @@ class InferrerEngine {
   }
 
   /**
+   * Registers a call to yield with an expression of type [argumentType] as
+   * argument.
+   */
+  TypeInformation registerYield(ast.Node node, TypeInformation argument) {
+    YieldTypeInformation info =
+        new YieldTypeInformation(types.currentMember, node);
+    info.addAssignment(argument);
+    types.allocatedTypes.add(info);
+    return info;
+  }
+
+  /**
    * Registers that [caller] calls [closure] with [arguments].
    *
    * [sideEffects] will be updated to incorporate the potential