From d6f4a96257f01e11fbec61eb1eab3d073f453d93 Mon Sep 17 00:00:00 2001
From: Oliver Booth <me@olivr.me>
Date: Sun, 27 Jun 2021 13:14:42 +0100
Subject: [PATCH] (#42) Validate lower <= upper

---
 X10D/src/ComparableExtensions/ComparableExtensions.cs | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/X10D/src/ComparableExtensions/ComparableExtensions.cs b/X10D/src/ComparableExtensions/ComparableExtensions.cs
index a38de3b..dd7615e 100644
--- a/X10D/src/ComparableExtensions/ComparableExtensions.cs
+++ b/X10D/src/ComparableExtensions/ComparableExtensions.cs
@@ -45,12 +45,21 @@ namespace X10D
         /// </example>
         public static bool Between<T1, T2, T3>(this T1 value, T2 lower, T3 upper)
             where T1 : IComparable<T2>, IComparable<T3>
+            where T2 : IComparable<T3>
+            where T3 : IComparable<T2>
         {
             if (value is null)
             {
                 throw new ArgumentNullException(nameof(value));
             }
             
+            if (lower.GreaterThan(upper))
+            {
+                throw new ArgumentException(
+                    string.Format(ExceptionMessages.LowerCannotBeGreaterThanUpper, lower, upper),
+                    nameof(lower));
+            }
+
             return value.CompareTo(lower) > 0 && value.CompareTo(upper) < 0;
         }