-Fixed serializing generated types with duplicate property names

.gitignore

@@ -13,6 +13,7 @@ _ReSharper.*
 *.ReSharper.user
 *.resharper.user
 .vs/
+.vscode/
 *.lock.json
 *.nuget.props
 *.nuget.targets

Src/Newtonsoft.Json.Tests/App.config

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<configuration>
+  <runtime>
+    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
+      <dependentAssembly>
+        <assemblyIdentity name="System.ValueTuple" publicKeyToken="cc7b13ffcd2ddd51" />
+        <bindingRedirect oldVersion="0.0.0.0-4.4.0.0" newVersion="4.0.2.0" />
+      </dependentAssembly>
+    </assemblyBinding>
+  </runtime>
+</configuration>

Src/Newtonsoft.Json.Tests/Issues/Issue1620.cs

@@ -0,0 +1,105 @@
+#region License
+// Copyright (c) 2007 James Newton-King
+//
+// Permission is hereby granted, free of charge, to any person
+// obtaining a copy of this software and associated documentation
+// files (the "Software"), to deal in the Software without
+// restriction, including without limitation the rights to use,
+// copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following
+// conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+// OTHER DEALINGS IN THE SOFTWARE.
+#endregion
+
+#if !(NET20 || NET35 || NET40)
+using Moq;
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Dynamic;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using System.Runtime.Serialization;
+using Newtonsoft.Json.Linq;
+using Newtonsoft.Json.Serialization;
+using Newtonsoft.Json.Utilities;
+#if PORTABLE && !NETSTANDARD2_0
+using BindingFlags = Newtonsoft.Json.Utilities.BindingFlags;
+#else
+using BindingFlags = System.Reflection.BindingFlags;
+#endif
+#if DNXCORE50
+using Xunit;
+using Test = Xunit.FactAttribute;
+using Assert = Newtonsoft.Json.Tests.XUnitAssert;
+#else
+using NUnit.Framework;
+#endif
+
+namespace Newtonsoft.Json.Tests.Issues
+{
+    [TestFixture]
+    public class Issue1620 : TestFixtureBase
+    {
+        [Test]
+        public void Test_SerializeMock()
+        {
+            Mock<IFoo> mock = new Mock<IFoo>();
+            IFoo foo = mock.Object;
+
+            string json = JsonConvert.SerializeObject(foo, new JsonSerializerSettings() { Converters = { new FooConverter() } });
+            Assert.AreEqual(@"""foo""", json);
+        }
+
+        [Test]
+        public void Test_GetFieldsAndProperties()
+        {
+            Mock<IFoo> mock = new Mock<IFoo>();
+            IFoo foo = mock.Object;
+
+            List<MemberInfo> properties = ReflectionUtils.GetFieldsAndProperties(foo.GetType(), BindingFlags.Instance | BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic).ToList();
+
+            Assert.AreEqual(1, properties.Count(p => p.Name == "Mock"));
+        }
+
+        public interface IFoo
+        {
+        }
+
+        public class Foo : IFoo
+        {
+        }
+
+        public class FooConverter : JsonConverter
+        {
+            public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+            {
+                writer.WriteValue("foo");
+            }
+
+            public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+            {
+                return new Foo();
+            }
+
+            public override bool CanConvert(Type objectType)
+            {
+                return typeof(IFoo).GetTypeInfo().IsAssignableFrom(objectType);
+            }
+        }
+    }
+}
+#endif

Src/Newtonsoft.Json.Tests/Newtonsoft.Json.Tests.csproj

@@ -55,6 +55,7 @@
     <PackageReference Include="System.Buffers" Version="4.4.0" />
     <PackageReference Include="System.Collections.Immutable" Version="1.4.0" />
     <PackageReference Include="System.ValueTuple" Version="4.4.0" />
+    <PackageReference Include="Moq" Version="4.8.1" />
     <Reference Include="Microsoft.CSharp" />
     <Reference Include="System.Web" />
     <Reference Include="System.Data.Linq" />
@@ -77,6 +78,7 @@
     <PackageReference Include="System.Buffers" Version="4.4.0" />
     <PackageReference Include="System.Collections.Immutable" Version="1.4.0" />
     <PackageReference Include="System.ValueTuple" Version="4.4.0" />
+    <PackageReference Include="Moq" Version="4.8.1" />
     <Reference Include="Microsoft.CSharp" />
     <Reference Include="System.Web" />
     <Reference Include="System.Data.Linq" />
@@ -99,6 +101,7 @@
     <PackageReference Include="System.Buffers" Version="4.4.0" />
     <PackageReference Include="System.Collections.Immutable" Version="1.4.0" />
     <PackageReference Include="System.ValueTuple" Version="4.4.0" />
+    <PackageReference Include="Moq" Version="4.8.1" />
     <Reference Include="Microsoft.CSharp" />
     <Reference Include="System.Web" />
     <Reference Include="System.Data.Linq" />
@@ -165,6 +168,7 @@
     <PackageReference Include="System.Xml.XmlSerializer" Version="4.3.0" />
     <PackageReference Include="System.ValueTuple" Version="4.4.0" />
     <PackageReference Include="Autofac" Version="4.6.2" />
+    <PackageReference Include="Moq" Version="4.8.1" />
     <PackageReference Include="xunit" Version="2.3.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.3.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.5.0" />
@@ -185,6 +189,7 @@
     <PackageReference Include="System.Xml.XmlSerializer" Version="4.3.0" />
     <PackageReference Include="System.ValueTuple" Version="4.4.0" />
     <PackageReference Include="Autofac" Version="4.6.2" />
+    <PackageReference Include="Moq" Version="4.8.1" />
     <PackageReference Include="xunit" Version="2.3.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.3.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.5.0" />
@@ -204,6 +209,7 @@
     <PackageReference Include="System.Xml.XmlSerializer" Version="4.3.0" />
     <PackageReference Include="System.ValueTuple" Version="4.4.0" />
     <PackageReference Include="Autofac" Version="4.6.2" />
+    <PackageReference Include="Moq" Version="4.8.1" />
     <PackageReference Include="xunit" Version="2.3.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.3.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.5.0" />

Src/Newtonsoft.Json/Utilities/ReflectionUtils.cs

@@ -652,7 +652,7 @@ namespace Newtonsoft.Json.Utilities
                 }
                 else
                 {
-                    IList<MemberInfo> resolvedMembers = new List<MemberInfo>();
+                    List<MemberInfo> resolvedMembers = new List<MemberInfo>();
                     foreach (MemberInfo memberInfo in groupedMember)
                     {
                         // this is a bit hacky
@@ -664,6 +664,13 @@ namespace Newtonsoft.Json.Utilities
                         }
                         else if (!IsOverridenGenericMember(memberInfo, bindingAttr) || memberInfo.Name == "Item")
                         {
+                            // two members with the same name were declared on a type
+                            // this can be done via IL emit, e.g. Moq
+                            if (resolvedMembers.Any(m => m.DeclaringType == memberInfo.DeclaringType))
+                            {
+                                continue;
+                            }
+
                             resolvedMembers.Add(memberInfo);
                         }
                     }

Src/Newtonsoft.Json/Utilities/TypeExtensions.cs

@@ -363,20 +363,33 @@ namespace Newtonsoft.Json.Utilities
             return properties.Where(p => TestAccessibility(p, bindingFlags));
         }
 
+        private static bool ContainsMemberName(IEnumerable<MemberInfo> members, string name)
+        {
+            foreach (MemberInfo memberInfo in members)
+            {
+                if (memberInfo.Name == name)
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
         private static IList<MemberInfo> GetMembersRecursive(this TypeInfo type)
         {
             TypeInfo t = type;
-            IList<MemberInfo> members = new List<MemberInfo>();
+            List<MemberInfo> members = new List<MemberInfo>();
             while (t != null)
             {
                 foreach (MemberInfo member in t.DeclaredMembers)
                 {
-                    if (!members.Any(p => p.Name == member.Name))
+                    if (!ContainsMemberName(members, member.Name))
                     {
                         members.Add(member);
                     }
                 }
-                t = (t.BaseType != null) ? t.BaseType.GetTypeInfo() : null;
+                t = t.BaseType?.GetTypeInfo();
             }
 
             return members;
@@ -385,17 +398,17 @@ namespace Newtonsoft.Json.Utilities
         private static IList<PropertyInfo> GetPropertiesRecursive(this TypeInfo type)
         {
             TypeInfo t = type;
-            IList<PropertyInfo> properties = new List<PropertyInfo>();
+            List<PropertyInfo> properties = new List<PropertyInfo>();
             while (t != null)
             {
                 foreach (PropertyInfo member in t.DeclaredProperties)
                 {
-                    if (!properties.Any(p => p.Name == member.Name))
+                    if (!ContainsMemberName(properties, member.Name))
                     {
                         properties.Add(member);
                     }
                 }
-                t = (t.BaseType != null) ? t.BaseType.GetTypeInfo() : null;
+                t = t.BaseType?.GetTypeInfo();
             }
 
             return properties;
@@ -404,17 +417,17 @@ namespace Newtonsoft.Json.Utilities
         private static IList<FieldInfo> GetFieldsRecursive(this TypeInfo type)
         {
             TypeInfo t = type;
-            IList<FieldInfo> fields = new List<FieldInfo>();
+            List<FieldInfo> fields = new List<FieldInfo>();
             while (t != null)
             {
                 foreach (FieldInfo member in t.DeclaredFields)
                 {
-                    if (!fields.Any(p => p.Name == member.Name))
+                    if (!ContainsMemberName(fields, member.Name))
                     {
                         fields.Add(member);
                     }
                 }
-                t = (t.BaseType != null) ? t.BaseType.GetTypeInfo() : null;
+                t = t.BaseType?.GetTypeInfo();
             }
 
             return fields;