Fixing GetEnumerableElementType bug

Author: SteveWilkes

ReadableExpressions.UnitTests/Extensions/WhenAccessingTypeInformation.cs

@@ -30,6 +30,12 @@ public void ShouldEvaluateANonGenericListAsEnumerable()
             typeof(IList).IsEnumerable().ShouldBeTrue();
         }
 
+        [Fact]
+        public void ShouldEvaluateANonGenericEnumerableAsEnumerable()
+        {
+            typeof(IEnumerable).IsEnumerable().ShouldBeTrue();
+        }
+
         [Fact]
         public void ShouldNotEvaluateAStringAsEnumerable()
         {

ReadableExpressions/Extensions/PublicTypeExtensions.cs

@@ -345,13 +345,14 @@ public static Type GetEnumerableElementType(this Type enumerableType)
 
             if (enumerableType.IsGenericType())
             {
-                return InternalEnumerableExtensions.Last(enumerableType.GetGenericTypeArguments());
+                return enumerableType.GetGenericTypeArguments().Last();
             }
 
-            var enumerableInterfaceType = InternalEnumerableExtensions.FirstOrDefault(enumerableType
-                    .GetAllInterfaces(), interfaceType => interfaceType.IsClosedTypeOf(typeof(IEnumerable<>)));
+            var enumerableInterfaceType = enumerableType
+                .GetAllInterfaces()
+                .FirstOrDefault(interfaceType => interfaceType.IsClosedTypeOf(typeof(IEnumerable<>)));
 
-            return InternalEnumerableExtensions.First(enumerableInterfaceType?.GetGenericTypeArguments()) ?? typeof(object);
+            return enumerableInterfaceType?.GetGenericTypeArguments().First() ?? typeof(object);
         }
 
         /// <summary>
@@ -360,19 +361,15 @@ public static Type GetEnumerableElementType(this Type enumerableType)
         /// <param name="type">The type for which to make the determination.</param>
         /// <returns>True if the given <paramref name="type"/> can be null, otherwise false.</returns>
         public static bool CanBeNull(this Type type)
-        {
-            return type.IsClass() || type.IsInterface() || type.IsNullableType();
-        }
+            => type.IsClass() || type.IsInterface() || type.IsNullableType();
 
         /// <summary>
         /// Returns a value indicating if the given <paramref name="type"/> is a Nullable{T}.
         /// </summary>
         /// <param name="type">The type for which to make the determination.</param>
         /// <returns>True if the given <paramref name="type"/> is a Nullable{T}, otherwise false.</returns>
         public static bool IsNullableType(this Type type)
-        {
-            return Nullable.GetUnderlyingType(type) != null;
-        }
+            => Nullable.GetUnderlyingType(type) != null;
 
         /// <summary>
         /// Gets the underlying non-nullable Type of this <paramref name="type"/>, or returns this