dart2js: type analysis: yield escapes its argument

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

Index: pkg/compiler/lib/src/inferrer/builder.dart
diff --git a/pkg/compiler/lib/src/inferrer/builder.dart b/pkg/compiler/lib/src/inferrer/builder.dart
index 90493aa4398736cc1a8fd4c9f59755f592f686fd..ba2db3bf79e112a08eef80a4e5be561e80b236d1 100644
--- a/pkg/compiler/lib/src/inferrer/builder.dart
+++ b/pkg/compiler/lib/src/inferrer/builder.dart
@@ -2289,6 +2289,11 @@ class ElementGraphBuilder extends ast.Visitor<TypeInformation>
     return inferrer.registerAwait(node, futureType);
   }
 
+  TypeInformation visitYield(ast.Yield node) {
+    TypeInformation operandType = node.expression.accept(this);
+    return inferrer.registerYield(node, operandType);
+  }
+
   TypeInformation handleTypeLiteralInvoke(ast.NodeList arguments) {
     // This is reached when users forget to put a `new` in front of a type
     // literal. The emitter will generate an actual call (even though it is