1 files changed, 3 insertions, 3 deletions
diff --git a/src/SMAPI/Events/ModMessageReceivedEventArgs.cs b/src/SMAPI/Events/ModMessageReceivedEventArgs.cs
index 671bdf38..84a27d18 100644
--- a/src/SMAPI/Events/ModMessageReceivedEventArgs.cs
+++ b/src/SMAPI/Events/ModMessageReceivedEventArgs.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using StardewModdingAPI.Framework.Networking;
 using StardewModdingAPI.Toolkit.Serialization;
@@ -47,8 +45,10 @@ namespace StardewModdingAPI.Events
         /// <summary>Read the message data into the given model type.</summary>
         /// <typeparam name="TModel">The message model type.</typeparam>
         public TModel ReadAs<TModel>()
+            where TModel : notnull
         {
-            return this.Message.Data.ToObject<TModel>(this.JsonHelper.GetSerializer());
+            return this.Message.Data.ToObject<TModel>(this.JsonHelper.GetSerializer())
+                ?? throw new InvalidOperationException($"Can't read empty mod message data as a {typeof(TModel).FullName} value.");
         }
     }
 }