TM TS-2 and no Pokemon to de-evolve.

[Ardoptres]

I have Gengar active with a TM TS-1 attached to. My opponent has Machamp Lv. X active and some benched Uxies. I use Devoluter, but clearly, it has no effect. Since i attack for no effect, as in not meeting the requirement for the attack, am I allowed to use another attack of Gengars (if i have correct number of Energies attached, of course), does my turn end, or can't I attack at all, meaning i'm not even in the attacking fase.

Thanks in advance!

 

[PokePop]

The only requirements that are looked at to see if you can do an attack are that you have the correct energy attached and can discard any energy that is required to be discarded.
Other than that, nothing is required.

So, you meet the requirement of having enough, and the right kind of, energy attached (none in this case).

You don't get to choose another attack.
You do get to attack. It's just that the attack you chose does nothing in this case.

 

[Big Daddy Snorlax]

You may be confusing this with the "you can't play a Trainer for no effect" ruling. For example, you can't play an Energy Switch if you do not have any Energy attached to your Pokemon. Attacking is different, as Pop said, if you can legally do the attack (meet the energy requirements) the fact that it has no impact on the gamestate does not matter. You have attacked!

BDS