"{}".format(1, bar=2) # F522 "{bar}{}".format(1, bar=2, spam=3) # F522 "{bar:{spam}}".format(bar=2, spam=3) # No issues "{bar:{spam}}".format(bar=2, spam=3, eggs=4, ham=5) # F522 ('' .format(x=2)) # F522 # https://github.com/astral-sh/ruff/issues/18806 # The fix here is unsafe because the unused argument has side effect "Hello, {name}".format(greeting=print(1), name="World") # The fix here is safe because the unused argument has no side effect, # even though the used argument has a side effect "Hello, {name}".format(greeting="Pikachu", name=print(1))