When you add one of the Handler attributes to a procedure, your procedure should match the expected signature for that Handler-type.
For example:
[MessageHandler]
procedure MyMessageHandler()
begin

end;

Will raise the following error message:
```
The signature of procedure 'MyMessageHandler' does not match the signature required by attribute 'MessageHandler'. The expected signature is: MyMessageHandler(Message: Text[1024]). AL(AL0241)

Here's a picture of this: https://i.imgur.com/vJnjqDd.png

This also shows an option to apply a *Quick Fix*, however there are no options for this yet.
It would be nice to see an option that automatically lets us fix the signature of procedures in such situations.