Is this really worth it?

-$attributes = $event->getAttributes(SomeAttribute::class);
+$attributes = $event->getAttributes()[SomeAttribute::class] ?? null;

@nicolas-grekas the difference is that the new argument has a generic signature, telling SA tools that all returned objects are an instance of the provided class name.
For the case of returning all attributes grouped by a class name, there is no interoperable way to indicate that in phpdoc (Psalm has a class-string-map type, but no other tool support it)

Wouldn't this work?
@return array<class-string<T>, list<T>>

@nicolas-grekas no. This won't work as it would force using the same T (and inferring it from somewhere).

That's precisely why Psalm introduced a class-string-map type, which would be exactly what we need here if it was interoperable.

Thank you @HypeMC.