fix #299

NiL.JS/BaseLibrary/Promise.cs

@@ -188,7 +188,7 @@ private void callbackInvoke()
 
         public static Promise resolve(JSValue data)
         {
-            return data.As<Promise>() ?? new Promise(fromResult(data));
+            return data.Value as Promise ?? new Promise(fromResult(data));
         }
 
         public static Promise reject(JSValue data)

Tests/Fuzz/Bug_299.cs

@@ -0,0 +1,44 @@
+using System;
+using System.Threading.Tasks;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using NiL.JS;
+using NiL.JS.BaseLibrary;
+using NiL.JS.Core;
+using NiL.JS.Extensions;
+
+namespace Tests.Fuzz
+{
+    [TestClass]
+    public sealed class Bug_299
+    {
+        [TestMethod]
+        public async Task Promise_299()
+        {
+            var script = Script.Parse(
+                @"
+export default class Test {
+    async run(params) {
+        return params;
+    }
+}
+"
+            );
+            var context = new GlobalContext();
+            var module = new Module($"main.js", script, context);
+            module.Run();
+
+            var ctor = module.Exports.Default.As<Function>();
+            var instance = ctor.Construct(new Arguments());
+            var run = instance.GetProperty("run").As<Function>();
+
+            var param = JSON.parse("{}");
+            var result = run.MakeDelegate<Func<JSValue, JSValue>>()(param);
+            if (result.Value is Promise promise)
+            {
+                result = await promise.Task;
+            }
+
+            Assert.AreEqual(param, result);
+        }
+    }
+}