reveal_type(x) where x: Tuple[int, ...] doesn't show "..."

[gvanrossum]

Bug Report

Using reveal_type() on a variable whose type is a variable-length tuple shows misleading output.

While it's different from the output for a fixed-length tuple (which shows Tuple[builtins.int]), it doesn't clearly indicate that the type is variable-length.

Note that with PEP 585 accepted, eventually we'll have to use builtins.tuple (or, I'd recomment, plain tuple) for both situations.

To Reproduce

from typing import Tuple
a: Tuple[int, ...]
reveal_type(a)

Expected Behavior

t.py:3: note: Revealed type is 'builtins.tuple[builtins.int, ...]'

or

t.py:3: note: Revealed type is 'Tuple[builtins.int, ...]'

Actual Behavior

t.py:3: note: Revealed type is 'builtins.tuple[builtins.int]'

Your Environment

Master or 0.782, no flags.

[hauntsaninja]

It looks like mypy uses builtins.tuple as a homogenous tuple type:

mypy/mypy/typeanal.py

Line 290 in b884a39

if len(t.args) == 2 and isinstance(t.args[1], EllipsisType):

Seems possibly worrisome for transitioning to the PEP 585 world, eg #9459