Dont use typing_extensions.Literal; fix stuff

README.md

@@ -232,11 +232,12 @@ ParseError: shape-(3,) doesn't match shape-type (B=2,)
 #### Support for `Literal` dimensions:
 
 ```python
+from typing import Literal as L
+
 from phantom_tensors import parse
 from phantom_tensors.torch import Tensor
 
 import torch as tr
-from typing_extensions import Literal as L
 
 parse(tr.zeros(1, 3), Tensor[L[1], L[3]])  # static + runtime: OK
 parse(tr.zeros(2, 3), Tensor[L[1], L[3]])  #  # Runtime: ParseError - mismatch at dim 0

pyproject.toml

@@ -183,7 +183,7 @@ deps =
        numpy
        phantom-types
 
-commands = pyright tests/ src/ --pythonversion=3.8
+commands = pyright tests/ src/ --pythonversion=3.8 -p pyrightconfig_py38.json
            pyright tests/ src/ --pythonversion=3.9
            pyright tests/ src/ --pythonversion=3.10
            pyright tests/ src/ --pythonversion=3.11

pyrightconfig_py38.json

@@ -0,0 +1 @@
+{}

src/phantom_tensors/_internals/utils.py

@@ -1,9 +1,9 @@
 # pyright: strict
 
 import abc
-from typing import Any, Tuple, Type
+from typing import Any, Literal, Tuple, Type
 
-from typing_extensions import Literal, Protocol, TypeGuard, TypeVarTuple, Unpack
+from typing_extensions import Protocol, TypeGuard, TypeVarTuple, Unpack
 
 _Ts = TypeVarTuple("_Ts")
 

tests/test_prototype.py

@@ -1,9 +1,9 @@
 import re
-from typing import Any, NewType, TypeVar
+from typing import Any, Literal as L, NewType, TypeVar
 
 import pytest
 from pytest import param
-from typing_extensions import Literal as L, TypeVarTuple, Unpack as U
+from typing_extensions import TypeVarTuple, Unpack as U
 
 import phantom_tensors
 from phantom_tensors import dim_binding_scope, parse

tests/test_type_properties.py

@@ -1,11 +1,10 @@
 from __future__ import annotations
 
 import sys
-from typing import Tuple
+from typing import Literal, Tuple
 
 import pytest
 from hypothesis import assume, given
-from typing_extensions import Literal
 
 
 @pytest.mark.xfail(
@@ -15,9 +14,6 @@ def test_literal_singlet_tuple_same_as_scalar():
     assert Literal[(1,)] is Literal[1]  # type: ignore
 
 
-@pytest.mark.xfail(
-    sys.version_info < (3, 8), reason="Literal identity introduced in 3.8"
-)
 @given(...)
 def test_literals_can_check_by_identity(a: Tuple[int, ...], b: Tuple[int, ...]):
     assume(len(a))