Impossible for Smeargle to sketch Sleep Talk?

Hi, I posted this elsewhere but haven’t been able to find an answer so far, I’m hoping someone here knows!

I am playing gen 2 (on cartridge) and wanted to get Smeargle to learn Sleep Talk. To do so I’ve tried 3 different approaches, all of which have had the same outcome. Step 1, encounter Smeargle (of course), step 2:

Inall3 cases, opposing Smeargle tries Sketch which is followed by ‘It didn’t affect [my Pokemon]!". It then proceeds to use Struggle on future turns because it has no PP.

So I am coming to the conclusion it isn’t possible for it to learn Sleep Talk (in this gen at least), since even if it needed another move first, no trainers/wild Pokemon (as far as I’m aware) use Sleep Talk in the game so a Smeargle belonging to me, already knowing other moves, would never be able to sketch the desired move. On the other hand, I can’t find this documented anywhere, so perhaps I am doing something wrong.

Most likely this will involve knowing more about the game mechanics/code than I do – would love to hear some thoughts!

Pleaselog inorregisterto add a comment.

Metronome, Mirror Move, Mimic, Sleep Talk, Transform, and Sketch itself all run asnippet of codewhose effect is to say “You know how there’s normally a variable in memory keeping track of the last move I used, for purposes such as Counter, Conversion2, and Sketch? Well, this move is specificallynot supposed to beexposed to those effects, so instead of keeping this move in the history, scrub it so the game thinks I haven’t used any move at all instead.”

That call makes their intentions pretty blatant.