`tuple[*Ts]` subtype with extra type parameter not gradually assignable to itself

This demonstrates the issue:

from typing import Any

class Array[DataT, *ShapeTs](tuple[*ShapeTs]): ...

type Float2D = Array[float, *tuple[int, int]]  # or Array[float, int, int]
type FloatND = Array[float, *tuple[Any, ...]]

def from_2d(a: Float2D) -> FloatND:
    return a  # mypy: ✅, pyright: ✅

def into_2d(a: FloatND) -> Float2D:
    return a  # mypy: ❌, pyright: ✅

https://mypy-play.net/?mypy=latest&python=3.13&flags=strict&gist=1b95c702df6de35fa3f61aa7b5dfef16

from typing import Any

class Array[*ShapeTs](tuple[*ShapeTs]): ...

type Float2D = Array[*tuple[int, int]]  # or Array[int, int]
type FloatND = Array[*tuple[Any, ...]]

def from_2d(a: Float2D) -> FloatND:
    return a  # mypy: ✅, pyright: ✅

def into_2d(a: FloatND) -> Float2D:
    return a  # mypy: ✅, pyright: ✅

from typing import Any

class Array[float, *ShapeTs]: ...

type Float2D = Array[float, *tuple[int, int]]  # or Array[float, int, int]
type FloatND = Array[float, *tuple[Any, ...]]

def from_2d(a: Float2D) -> FloatND:
    return a  # mypy: ✅, pyright: ✅

def into_2d(a: FloatND) -> Float2D:
    return a  # mypy: ✅, pyright: ✅

Potentially related issues:

• #18665
• #19106
• #19109
• #19110
• #19860
• #19858

Comienza ejecutando las dos reproducciones de Python en los ejemplos enlazados de mypy-play con mypy 3.13 strict settings, comparando las asignaciones from_2d e into_2d y las variantes sin DataT o sin la clase base de tupla. Revisa los issues relacionados #18665, #19106, #19109, #19110, #19860 y #19858; se considera terminado cuando la asignación problemática se gestione de forma coherente sin romper los casos que ya funcionan.