Hey /u/TonyTheTerrible, would you mind PMing me with your MTG Arena display name (including the numbers after the #) so we can take a look at what's going on here?

(Edit) If anyone else sees this and is having the same issue, please send me your username and include details on which styles/cards you're seeing the issue with. We are investigating. Thank you!

Hey /u/Dexelele, would you mind PMing me with your MTG Arena display name (including the numbers after the #) so we can take a look at what's going on here?

(Edit) If anyone else sees this and is having the same issue, please send me your username and include details on which styles/cards you're seeing the issue with. We are investigating. Thank you!

OK, looking at both your client log and the server log for the match, it appears that your opponent did mistakenly play their [[Blacklance Paragon]] too early, while a [[Massacre Girl]] trigger was on the stack.

Here is a game state in your log that shows that the Paragon's trigger is on the stack at the same time as the Massacre Girl's trigger. You can see that the stack has two things in it:

{ "zoneId": 27, "type": "ZoneType_Stack", "visibility": "Visibility_Public", "objectInstanceIds": [ 372, 368 ] }

And that object 372 is an ability instance:

{ "instanceId": 372, "grpId": 136250, "type": "GameObjectType_Ability", "zoneId...

I'll look into this tomorrow. I could imagine how this bug could occur, so let's see if I'm right. #wotc_staff

We need to have Resolution Time Actions Windows like Electrodominance's promote actions because:

A) the default assumption is that no action is legal (except pass)

B) it gives other abilities the opportunity to step in and prune the action (e.g. [[Teferi, Time Raveler]])

and C) Most of these windows specify an alternate cost for you to pay ("without paying its mana cost" for Electrodominance), which also means that we need to prune actions that have a different alternative cost.

#wotc_staff

I like to think about it this way - there isn't a rule that says you can't cast Sorceries or other non-Flash spells at non-sorcery times. Rather, during those times, there simply isn't any rule saying you CAN cast those cards.

That's kind of how the underlying code works, too. The game proposes all the cards in your hand as castable (as well as other cards that abilities give you permission to cast). The default assumption during the Pruning step is that no proposed action can be performed, but certain rules Promote actions past pruning such as Prune_Promote_CastSorcerySpeed say "this is a cast action, the stack is empty, and it's your main phase, so the game says you can do this." And Prune_Promote_CastInstantSpeed says "this is a cast action for an Instant, so the game says you can do this."

Electrodominance itself adds a rule for the cards it proposes saying "this action was proposed by me, so I say you can do this." #wotc_staff