diff --git a/Src/Newtonsoft.Json/Serialization/ExpressionValueProvider.cs b/Src/Newtonsoft.Json/Serialization/ExpressionValueProvider.cs
index ae1e7cba..47102d5e 100644
--- a/Src/Newtonsoft.Json/Serialization/ExpressionValueProvider.cs
+++ b/Src/Newtonsoft.Json/Serialization/ExpressionValueProvider.cs
@@ -75,7 +75,7 @@ namespace Newtonsoft.Json.Serialization
                     if (!ReflectionUtils.IsNullable(ReflectionUtils.GetMemberUnderlyingType(_memberInfo)))
                         throw new JsonSerializationException("Incompatible value. Cannot set {0} to null.".FormatWith(CultureInfo.InvariantCulture, _memberInfo));
                 }
-                else if (!ReflectionUtils.GetMemberUnderlyingType(_memberInfo).IsInstanceOfType(value))
+                else if (!ReflectionUtils.GetMemberUnderlyingType(_memberInfo).IsAssignableFrom(value.GetType()))
                 {
                     throw new JsonSerializationException("Incompatible value. Cannot set {0} to type {1}.".FormatWith(CultureInfo.InvariantCulture, _memberInfo, value.GetType()));
                 }