Fix proxy generation for private protected constructors

src/Castle.Core.Tests/DynamicProxy.Tests/BasicClassProxyTestCase.cs

@@ -380,6 +380,21 @@ public void ClassProxyShouldCallProtectedDefaultConstructor()
 			Assert.AreEqual("Something", ((ClassWithProtectedDefaultConstructor)proxy2).SomeString);
 		}
 
+		[Test]
+		public void ClassProxyShouldHaveDefaultConstructorWhenBaseClassHasPrivateProtected()
+		{
+			object proxy = generator.CreateClassProxy<ClassWithPrivateProtectedConstructor>();
+			Assert.IsNotNull(Activator.CreateInstance(proxy.GetType()));
+		}
+
+		[Test]
+		public void ClassProxyShouldCallPrivateProtectedDefaultConstructor()
+		{
+			object proxy = generator.CreateClassProxy<ClassWithPrivateProtectedConstructor>();
+			object proxy2 = Activator.CreateInstance(proxy.GetType());
+			Assert.AreEqual("Something", ((ClassWithPrivateProtectedConstructor)proxy2).SomeString);
+		}
+
 		[Test]
 		public void ClassImplementingInterfaceVitrually()
 		{

src/Castle.Core.Tests/DynamicProxy.Tests/Classes/ClassWithPrivateProtectedConstructor.cs

@@ -0,0 +1,32 @@
+// Copyright 2004-2020 Castle Project - http://www.castleproject.org/
+// 
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// 
+//     http://www.apache.org/licenses/LICENSE-2.0
+// 
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+namespace Castle.DynamicProxy.Tests.Classes
+{
+	public class ClassWithPrivateProtectedConstructor
+	{
+		private protected ClassWithPrivateProtectedConstructor()
+		{
+			_someString = "Something";
+		}
+
+		private string _someString = string.Empty;
+
+		public string SomeString
+		{
+			get { return _someString; }
+			set { _someString = value; }
+		}
+	}
+}

src/Castle.Core/DynamicProxy/Generators/BaseProxyGenerator.cs

@@ -281,7 +281,7 @@ protected void GenerateConstructors(ClassEmitter emitter, Type baseType, params
 
 			foreach (var constructor in constructors)
 			{
-				if (!IsConstructorVisible(constructor))
+				if (!ProxyUtil.IsAccessibleMethod(constructor))
 				{
 					continue;
 				}
@@ -409,14 +409,6 @@ protected Type ObtainProxyType(CacheKey cacheKey, Func<string, INamingScope, Typ
 			return proxyType;
 		}
 
-		private bool IsConstructorVisible(ConstructorInfo constructor)
-		{
-			return constructor.IsPublic ||
-				constructor.IsFamily ||
-				constructor.IsFamilyOrAssembly ||
-				(constructor.IsAssembly && ProxyUtil.AreInternalsVisibleToDynamicProxy(constructor.DeclaringType.GetTypeInfo().Assembly));
-		}
-
 		private bool OverridesEqualsAndGetHashCode(Type type)
 		{
 			var equalsMethod = type.GetMethod("Equals", BindingFlags.Public | BindingFlags.Instance);