Type expression arguments aren't recognized as `TypeForm` when the parameter type is a union containing a `TypeForm`

A type expression passed as a call argument is only recognized as a TypeForm when the parameter type is exactly TypeForm[...]. With a union such as TypeForm[T] | None, the argument is evaluated as a value expression instead.

from typing import Annotated, TypeVar
from typing_extensions import TypeForm

T = TypeVar('T')

def f(t: TypeForm[T]) -> T: ...
def g(t: TypeForm[T] | None) -> T: ...

reveal_type(f(Annotated[int, 'meta']))  # int
reveal_type(g(Annotated[int, 'meta']))  # Argument 1 to "g" has incompatible type "<typing special form>"; expected "TypeForm[Never] | None"  [arg-type]

The same happens with int | str, Literal[...], Optional[...] or a string annotation. Assigning the same expression to a variable annotated TypeForm[int] | None works, so this is specific to call arguments.

Playground: https://mypy-play.net/?mypy=latest&python=3.14&gist=9ccf3597617fe30ec3d718ee9cdb1d9d.

Your Environment

• Mypy version used: 2.3.1
• Python version used: 3.14

Inizia con la riproduzione minima nell’issue e confronta i parametri TypeForm diretti con TypeForm all’interno di unions, includendo Optional e le annotazioni di tipo string. Traccia l’analisi degli argomenti della chiamata di mypy, quindi aggiungi un test di regressione che confermi che questi argomenti vengono riconosciuti e rivelano il tipo previsto senza una diagnostica di incompatibilità.