-Fix merging null with complex type and MergeNullValueHandling.Ignore

Src/Newtonsoft.Json.Tests/Linq/MergeTests.cs

@@ -596,5 +596,70 @@ namespace Newtonsoft.Json.Tests.Linq
             Assert.IsNotNull(source["Property5"]);
             Assert.AreEqual(JTokenType.Null, source["Property5"].Type);
         }
+
+        [Test]
+        public void MergeNullValueHandling_Array()
+        {
+            string originalJson = @"{
+  ""Bar"": [
+    ""a"",
+    ""b"",
+    ""c""
+  ]
+}";
+            string newJson = @"{
+  ""Bar"": null
+}";
+
+            JObject oldFoo = JObject.Parse(originalJson);
+            JObject newFoo = JObject.Parse(newJson);
+
+            oldFoo.Merge(newFoo, new JsonMergeSettings
+            {
+                MergeNullValueHandling = MergeNullValueHandling.Ignore
+            });
+
+            StringAssert.AreEqual(originalJson, oldFoo.ToString());
+
+            oldFoo.Merge(newFoo, new JsonMergeSettings
+            {
+                MergeNullValueHandling = MergeNullValueHandling.Merge
+            });
+
+            StringAssert.AreEqual(newJson, newFoo.ToString());
+        }
+
+        [Test]
+        public void MergeNullValueHandling_Object()
+        {
+            string originalJson = @"{
+  ""Bar"": {}
+}";
+            string newJson = @"{
+  ""Bar"": null
+}";
+
+            JObject oldFoo = JObject.Parse(originalJson);
+            JObject newFoo = JObject.Parse(newJson);
+
+            oldFoo.Merge(newFoo, new JsonMergeSettings
+            {
+                MergeNullValueHandling = MergeNullValueHandling.Ignore
+            });
+
+            StringAssert.AreEqual(originalJson, oldFoo.ToString());
+
+            oldFoo.Merge(newFoo, new JsonMergeSettings
+            {
+                MergeNullValueHandling = MergeNullValueHandling.Merge
+            });
+
+            StringAssert.AreEqual(newJson, newFoo.ToString());
+        }
+
+        public class Foo
+        {
+            public IEnumerable<string> Bar { get; set; }
+        }
     }
 }

Src/Newtonsoft.Json/Linq/JObject.cs

@@ -190,17 +190,13 @@ namespace Newtonsoft.Json.Linq
                 else if (contentItem.Value != null)
                 {
                     JContainer existingContainer = existingProperty.Value as JContainer;
-                    if (existingContainer == null)
+                    if (existingContainer == null || existingContainer.Type != contentItem.Value.Type)
                     {
                         if (contentItem.Value.Type != JTokenType.Null || settings?.MergeNullValueHandling == MergeNullValueHandling.Merge)
                         {
                             existingProperty.Value = contentItem.Value;
                         }
                     }
-                    else if (existingContainer.Type != contentItem.Value.Type)
-                    {
-                        existingProperty.Value = contentItem.Value;
-                    }
                     else
                     {
                         existingContainer.Merge(contentItem.Value, settings);