Any damage dice delivered by a critical hit—as opposed to a saving throw—are rolled twice.
This has reminded me of another situation that happened recently; if an Imp were to attack with it's stinger with an attack roll of 20, it clearly doubles the piercing damage die, but what about the poison damage die (assuming the target fails their save against it)?
I previously assumed to double the poison damage die too, but this quote might imply that it isn't, if I'm reading the "as opposed to a saving throw" bit right.
Is that right? The poison damage die shouldn't be doubled in this case? Or is the part about the saving throw just describing spells like acid splash or fireball, where no attack roll exists so there cannot be a critical hit?
To clear that up a bit, does the part reading "as opposed to a saving throw" mean:
1) The poison damage from the Imp would be unaffected because there's a saving throw to determine the amount of damage;
2) The poison damage from the Imp would be affected because this part of the quote is just describing attacks without attack rolls;
Which is the correct interpretation?