Fix CreateInstance of string on .NET Core

Author: xplicit

src/ServiceStack.Text/ReflectionExtensions.cs

@@ -466,7 +466,11 @@ public static EmptyCtorDelegate GetConstructorMethod(string typeName)
 
         public static EmptyCtorDelegate GetConstructorMethodToCache(Type type)
         {
-            if (type.IsInterface())
+            if (type == typeof(string))
+            {
+                return () => String.Empty;
+            }
+            else if (type.IsInterface())
             {
                 if (type.HasGenericType())
                 {
@@ -550,9 +554,6 @@ public static EmptyCtorDelegate GetConstructorMethodToCache(Type type)
             return System.Linq.Expressions.Expression.Lambda<EmptyCtorDelegate>(
                 System.Linq.Expressions.Expression.New(type)).Compile();
 #else
-            if (type == typeof(string))
-                return () => String.Empty;
-
             //Anonymous types don't have empty constructors
             return () => FormatterServices.GetUninitializedObject(type);
 #endif

tests/ServiceStack.Text.Tests/ReflectionExtensionTests.cs

@@ -53,6 +53,12 @@ public void Only_serializes_public_readable_properties()
 			Serialize(model);
 		}
 
+        [Test]
+        public void Can_create_instance_of_string()
+        {
+            Assert.That(typeof(string).CreateInstance(), Is.EqualTo(String.Empty));
+        }
+
         [Test]
         public void Can_create_instances_of_common_collections()
         {