Add support for GetCollectionType on LINQ Select() expression

Author: mythz

src/ServiceStack.Text/PlatformExtensions.cs

@@ -535,7 +535,8 @@ public static Delegate CreateDelegate(this MethodInfo methodInfo, Type delegateT
 
         public static Type GetCollectionType(this Type type)
         {
-            return type.GetElementType() ?? type.GetGenericArguments().FirstOrDefault();
+            return type.GetElementType() 
+                ?? type.GetGenericArguments().LastOrDefault(); //new[] { str }.Select(x => new Type()) => WhereSelectArrayIterator<string,Type>
         }
 
         static Dictionary<string, Type> GenericTypeCache = new Dictionary<string, Type>();

tests/ServiceStack.Text.Tests/ReflectionExtensionTests.cs

@@ -120,6 +120,16 @@ public void Can_get_method_from_type()
             helloVoidBoolIntDelegate(testInstance, true, 5);
             Assert.That(testInstance.Result, Is.EqualTo("Hello True 5"));
         }
+
+        [Test]
+        public void Does_GetCollectionType()
+        {
+            Assert.That(new[] { new TestModel() }.GetType().GetCollectionType(), Is.EqualTo(typeof(TestModel)));
+            Assert.That(new[] { new TestModel() }.ToList().GetType().GetCollectionType(), Is.EqualTo(typeof(TestModel)));
+            Assert.That(new[] { new TestModel() }.Select(x => x).GetType().GetCollectionType(), Is.EqualTo(typeof(TestModel)));
+            Assert.That(new[] { "" }.Select(x => new TestModel()).GetType().GetCollectionType(), Is.EqualTo(typeof(TestModel)));
+        }
+
     }
 
     public class GenericType<T> { }