Empty Harmony Annotations Cause ArguementException: No Target Method Found

[RobbinBob]

Ran into an issue where defining a class and then using the [HarmonyPatch] attribute on that class, to mark the class or contents as a patch, then completing the attributes on the individual methods. Doing it this way causes it to throw an ArguementException error as the empty HarmonyPatch attribute is not treated as a flag and instead causes it to fail.

Incomplete code example showing a class with that attribute workflow:

[HarmonyPatch] // Seems to error here
internal static class PatchContainer
{
  [HarmonyPrefix]
  [HarmonyPatch(typeof(Type...), nameof(Method...))]
  private static bool SomeMethod_Prefix()...

This workflow should be fine as HarmonyX wiki specifies it replicates the same system Harmony uses, even pointing to documentation showcasing this workflow

[ManlyMarco]

How are you patching? Does the exact same code run fine under normal Harmony?

[RobbinBob]

Using .PatchAll

Yes it works fine on regular harmony

[Akilaydin]

Faced the same issue.

This is working

[HarmonyPatch(typeof(ItemEventTracker), nameof(ItemEventTracker.OnChestOpened))]
    public class ItemEventTracker_Patches
    {
        static void Postfix(MonoBehaviour sender, EventArgs eventArgs)
        {
            //Some logic here
        }
    }

This is not working

[HarmonyPatch(typeof(ItemEventTracker))]
    public static class ItemEventTracker_Patches
    {
        [HarmonyPatch(nameof(ItemEventTracker.OnChestOpened))]
        [HarmonyPostfix]
        static void Postfix(MonoBehaviour sender, EventArgs eventArgs)
        {
          //some logic here
 
        }
    }

Not working example throws

System.ArgumentException: No target method specified for class OriGames.SoulStonesForAll.ItemEventTracker_Patches (declaringType=GameEventTracking.ItemEventTracker, methodName =, methodType=, argumentTypes=NULL)
  at HarmonyLib.PatchProcessor.PrepareType () [0x00301] in <c855157390e846558602c247f342bc0d>:0

Tried to remove [HarmonyPostfix].
Tried to remove static keyword from the class.