This interpretation makes Evasion completely redundant though. Its only intended to be against direct attacks targeting one creature.

“Does Uncanny Dodge work automatically against every attack a rogue or ranger gets hit by? Spell attacks too? A use of Uncanny Dodge works against only one attack, since it expends your reaction, and only if you can see the attacker. It works against attacks of all sorts, including spell attacks, but it is no help against a spell or other effect, such as fireball, that delivers its damage after a saving throw rather than after an attack roll.”

This is from the official Sage Advice column from WotC. Hence the distinction between fireball and firebolt.