Improve OutOfRangeException message

PkmnLib.Static/Utils/Errors/OutOfRange.cs

@@ -6,9 +6,20 @@ namespace PkmnLib.Static.Utils.Errors;
 /// </summary>
 public class OutOfRangeException : Exception
 {
+    private readonly string _hint;
+    private readonly int _index;
+    private readonly int _max;
+
     /// <inheritdoc cref="OutOfRangeException"/>
     public OutOfRangeException(string hint, int index, int max)
-        : base($"{hint} index {index} is out of range. Must be between 0 and {max - 1}.")
     {
+        _hint = hint;
+        _index = index;
+        _max = max;
     }
+
+    /// <inheritdoc />
+    public override string Message => _max == 0
+        ? $"{_hint} index {_index} is out of range. Collection is empty."
+        : $"{_hint} index {_index} is out of range. Must be between 0 and {_max - 1}.";
 }

Plugins/PkmnLib.Plugin.Gen7/PkmnLib.Plugin.Gen7.csproj

@@ -4,6 +4,7 @@
         <TargetFramework>netstandard2.1</TargetFramework>
         <Nullable>enable</Nullable>
         <LangVersion>12</LangVersion>
+        <WarningsAsErrors>nullable</WarningsAsErrors>
     </PropertyGroup>
 
     <ItemGroup>