When casting a ranged spell within melee reach of an enemy, if the spell doesn't require a ranged attack roll, are there any downsides (assuming the enemy doesn't have the Mage Slayer feat)?
Originally, when I read this:
Ranged Attacks in Close Combat
Aiming a ranged attack is more difficult when a foe is next to you. When you make a ranged attack with a weapon, a spell, or some other means, you have disadvantage on the attack roll if you are within 5 feet of a hostile creature who can see you and who isn’t incapacitated.
PHB 195
I thought all ranged spells were at a disadvantage or somehow penalised when cast in melee range of an enemy. But then I read this:
Making attacks
If there’s ever any question whether something you’re doing counts as an attack, the rule is simple: if you’re making an attack roll, you’re making an attack.
PHB, 194
And I'm thinking that, since non-attack spells don't make attack rolls, there's no disadvantage to be had. So, unless I'm missing something, there's really no penalty to casting non-attack ranged spells within reach of an enemy.
Best Answer
No. There are no downsides at all (again provided the enemy doesn't have Mage Slayer or some other specific feature) to casting in melee if the spell does not have an attack roll.
For all intents and purposes it's not an attack.
There are several other rules that govern attacks that don't work with spells that don't have attack rolls. For instance, you can't crit with them.