Have static proxy not always failing PeVerify

Author: fredericDelaporte

src/NHibernate/Proxy/NHibernateProxyBuilder.cs

@@ -96,7 +96,7 @@ public TypeInfo CreateProxyType(System.Type baseType, IReadOnlyCollection<System
 			var customAttributeBuilder = new CustomAttributeBuilder(serializableConstructor, Array.Empty<object>());
 			typeBuilder.SetCustomAttribute(customAttributeBuilder);
 
-			ImplementDeserializationConstructor(typeBuilder);
+			ImplementDeserializationConstructor(typeBuilder, parentType);
 			ImplementGetObjectData(typeBuilder, proxyInfoField, lazyInitializerField);
 
 			var proxyType = typeBuilder.CreateTypeInfo();
@@ -169,13 +169,24 @@ private static void ImplementConstructor(TypeBuilder typeBuilder, System.Type pa
 			IL.Emit(OpCodes.Ret);
 		}
 
-		private static void ImplementDeserializationConstructor(TypeBuilder typeBuilder)
+		private static void ImplementDeserializationConstructor(TypeBuilder typeBuilder, System.Type parentType)
 		{
 			var parameterTypes = new[] {typeof (SerializationInfo), typeof (StreamingContext)};
 			var constructor = typeBuilder.DefineConstructor(constructorAttributes, CallingConventions.Standard, parameterTypes);
 			constructor.SetImplementationFlags(MethodImplAttributes.IL | MethodImplAttributes.Managed);
 
 			var IL = constructor.GetILGenerator();
+
+			constructor.SetImplementationFlags(MethodImplAttributes.IL | MethodImplAttributes.Managed);
+
+			var baseConstructor = parentType.GetConstructor(BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public, null, System.Type.EmptyTypes, null);
+			// if there is no default constructor, or the default constructor is private/internal, call System.Object constructor
+			// this works, but the generated assembly will fail PeVerify (cannot use in medium trust for example)
+			if (baseConstructor == null || baseConstructor.IsPrivate || baseConstructor.IsAssembly)
+				baseConstructor = ObjectConstructor;
+			IL.Emit(OpCodes.Ldarg_0);
+			IL.Emit(OpCodes.Call, baseConstructor);
+
 			//Everything is done in NHibernateProxyObjectReference, so just return data.
 			IL.Emit(OpCodes.Ret);
 		}