Feature Request: No Useless List Unpack-Repack

[Skylion007]

Description

Saw this is in a discussion on RUFF: astral-sh/ruff#7618

Thread just mentions this construct[*x] as opposed to just calling list(x). Not only is the later more readable, I would assume it's more efficient because lack of arg unpack (we should benchmark it though)? You may want to add a rule to flag this weird construct.

[adamchainz]

Sounds sensible but let’s not assume and do a benchmark first. dicts can also be constructed via unpack so the rule could cover both.

[adamchainz]

Unpacking is faster, presumably because it doesn't need to look up the name list. So, let's leave this.

In [1]: items = list(range(10))

In [2]: %timeit list(items)
52.1 ns ± 0.144 ns per loop (mean ± std. dev. of 7 runs, 10,000,000 loops each)

In [3]: %timeit [*items]
34.5 ns ± 0.173 ns per loop (mean ± std. dev. of 7 runs, 10,000,000 loops each)