[BUG] Types are being enforced on non-cdef classes

[da-woods]

Describe the bug +To Reproduce

From the users mailing list (https://groups.google.com/g/cython-users/c/R4YQzdIOPSQ):

class BaseModel:
    pass

class Field:
    def __init__(self, *args, **kwds):
        pass

class ServiceRow(BaseModel):
    """An individual record."""

    service_id: int = Field(..., description="The ID for the service.", alias="id")
    name: str = Field(..., description="Displayable Name for the service.")

Fails at runtime with

name: str = Field(..., description="Displayable Name for the service.")
TypeError: Expected str, got Field

Generated C code includes

if (!(likely(PyString_CheckExact(__pyx_t_2))||((__pyx_t_2) == Py_None) || __Pyx_RaiseUnexpectedTypeError("str", __pyx_t_2))) __PYX_ERR(0, 12, __pyx_L1_error)

Expected behavior

It's just regular Python code - it shouldn't enforce the types

Environment (please complete the following information):

• OS: Linux
• Python version 3.8.9
• Cython version: 3.0a7

Additional context

Bisect suggests b2b81c9 (slightly unsurprisingly).

[stevenj]

I can also add that

# cython: annotation_typing=False

added to the top of the file does not seem to work around the issue either.