python / python/mypy

error: Expression is of type "Any", not "Any" (Using `Any` as a `type`)

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bug
Dominant language
Python
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Description

Here is a minimum reproducible example of this bug:

from typing import Any, assert_type

def foo[T](typ: type[T]) -> T: ...

assert_type(foo(Any), Any)

reveal_type(foo(Any), Any)
reveal_type(Any)

which produces this output:

error: Expression is of type "Any", not "Any"  [assert-type]
note: Revealed type is "typing.Any"
note: Revealed type is "def () -> typing.Any"

I did not expect this to cause any mypy errors.
Or, it would say that Any is not a type.

Your Environment

  • Mypy version used: mypy 1.19.1 (compiled: yes)
  • Mypy command-line flags: NA
  • Mypy configuration options from mypy.ini (and other config files): NA
  • Python version used: 3.13.9 (also reproduced in 3.14.3)

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

No repository file or test is named. Start by running the provided reproducer against mypy 1.19.1, then trace how Any is handled when passed to type[T] and by assert_type; done means the example produces no erroneous assert-type error while retaining the revealed types.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
devtools
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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