unnecessary-literal-within-tuple-call (C409)

Derived from the flake8-comprehensions linter.

Fix is always available.

What it does

Checks for tuple calls that take unnecessary list or tuple literals as arguments. In preview, this also includes unnecessary list comprehensions within tuple calls.

Why is this bad?

It's unnecessary to use a list or tuple literal within a tuple() call, since there is a literal syntax for these types.

If a list literal was passed, then it should be rewritten as a tuple literal. Otherwise, if a tuple literal was passed, then the outer call to tuple() should be removed.

In preview, this rule also checks for list comprehensions within tuple() calls. If a list comprehension is found, it should be rewritten as a generator expression.

Examples

tuple([1, 2])
tuple((1, 2))
tuple([x for x in range(10)])

Use instead:

(1, 2)
(1, 2)
tuple(x for x in range(10))

Fix safety

This rule's fix is marked as unsafe, as it may occasionally drop comments when rewriting the call. In most cases, though, comments will be preserved.