Requeue generators for re-traversal so we pick up regeneratorRuntime - fixes T6676

packages/babel-plugin-transform-regenerator/src/visit.js

@@ -129,6 +129,11 @@ exports.visitor = {
       if (wasGeneratorFunction && t.isExpression(node)) {
         path.replaceWith(t.callExpression(util.runtimeProperty("mark"), [node]));
       }
+
+      // Generators are processed in 'exit' handlers so that regenerator only has to run on
+      // an ES5 AST, but that means traversal will not pick up newly inserted references
+      // to things like 'regeneratorRuntime'. To avoid this, we explicitly re-queue.
+      path.requeue();
     }
   }
 };