AssertionError: unexpected type <class 'mypy.types.ParamSpecType'>

[itamarst]

Consider the following module:

from typing import Callable, ParamSpec, TypeVar

_P = ParamSpec("_P")
_T = TypeVar("_T")

def execute(
    func: Callable[_P, _T], *args: _P.args, **kwargs: _P.kwargs
) -> _T:
    return func(*args, **kwargs)

I can check it with mypy, but not compile it with mypyc:

$ mypy repro.py 
Success: no issues found in 1 source file
$ mypyc repro.py 
Traceback (most recent call last):
  File "mypyc/irbuild/builder.py", line 266, in accept
  File "mypy/nodes.py", line 787, in accept
  File "mypyc/irbuild/visitor.py", line 179, in visit_func_def
  File "mypyc/irbuild/function.py", line 99, in transform_func_def
  File "mypyc/irbuild/function.py", line 284, in gen_func_item
  File "mypyc/irbuild/env_class.py", line 102, in load_env_registers
  File "mypyc/irbuild/env_class.py", line 179, in add_args_to_env
  File "mypyc/irbuild/env_class.py", line 165, in num_bitmap_args
  File "mypyc/irbuild/builder.py", line 1233, in type_to_rtype
  File "mypyc/irbuild/mapper.py", line 153, in type_to_rtype
repro.py:6: AssertionError: unexpected type <class 'mypy.types.ParamSpecType'>

Versions:

Python 3.11.9
mypy 1.9.0 (compiled: yes)
mypyc 1.9.0 (compiled: yes)