return value of sorted() cannot be upcast

Bug Report

Mypy allows the return value of list() to be upcasted. eg. list[int] -> list[object] (or list[int | None]). Mypy does not permit the same behaviour with the return value of sorted(). Like list(), sorted() is a builtin, creates a new list, and does not retain a reference to the returned value. Mypy should allow the return value of sorted() to be upcast, because it is safe to do so.

To Reproduce

# file: foo.py
ints: list[int] = [1,2,3]
objects: list[object] = sorted(ints) # error!

Command line:

python -m mypy foo.py

Expected Behavior

That no error should be reported, much like if list() were used instead of sorted(). ie:

ints: list[int] = [1, 2, 3]
objects: list[object] = list(ints)

# undesirable work around 
objects2: list[object] = list(sorted(ints))

Actual Behavior

foo.py:11: error: Incompatible types in assignment (expression has type "list[int]", variable has type "list[object]")  [assignment]
foo.py:11: note: "List" is invariant -- see https://mypy.readthedocs.io/en/stable/common_issues.html#variance
foo.py:11: note: Consider using "Sequence" instead, which is covariant
Found 1 error in 1 file (checked 1 source file)

Your Environment

• Mypy version used: 1.10.0
• Mypy command-line flags: none
• Mypy configuration options from mypy.ini (and other config files): none
• Python version used: 3.12.0

Start by running python -m mypy foo.py with the reproduction in the issue, then inspect how mypy handles the return types of list() and sorted(). Trace the relevant builtin and generic-list type checking paths; done means the shown sorted(ints) assignment produces no error without requiring the list(sorted(ints)) workaround.