Given

set([name for project in projects for name in await get_users(project)])

Ruff outputs

Unnecessary list comprehension (rewrite as a set comprehension) Ruff (C403)

But doing so leads to a runtime error

TypeError: 'async_generator' object is not iterable.

Note that C403 is not triggered by using list() instead of brackets on the comprehension, but it still causes the same runtime error.

Ruff: 0.8.0
Python 3.11