diff --git a/pre-pep.rst b/pre-pep.rst
index 2f442b5..57b2ebc 100644
--- a/pre-pep.rst
+++ b/pre-pep.rst
@@ -216,7 +216,7 @@ grabs the argument to a ``Pointer``).
 
 ::
 
-    type PointerArg[T: Pointer] = GetArg[T, Pointer, 0]
+    type PointerArg[T: Pointer] = GetArg[T, Pointer, Literal[0]]
 
 ``AdjustLink`` sticks a ``list`` around ``MultiLink``, using features
 we've discussed already.
@@ -559,8 +559,6 @@ to be imported, and it could also be used qualified as
         # *[... for t in ...] arguments
         | <ident>[<variadic-type-arg> +]
 
-        | <string-or-int-literal>  # Only accepted in arguments to new functions?
-
    # Type conditional checks are boolean compositions of
    # "subtype checking" and boolean Literal type checking.
    <type-bool> =
diff --git a/tests/test_fastapilike_2.py b/tests/test_fastapilike_2.py
index 7a33109..3c0ac80 100644
--- a/tests/test_fastapilike_2.py
+++ b/tests/test_fastapilike_2.py
@@ -46,7 +46,9 @@ class Field[T: FieldArgs](InitField[T]):
 ####
 
 # TODO: Should this go into the stdlib?
-type GetFieldItem[T: InitField, K] = GetAttr[GetArg[T, InitField, 0], K]
+type GetFieldItem[T: InitField, K] = GetAttr[
+    GetArg[T, InitField, Literal[0]], K
+]
 
 
 ##
diff --git a/tests/test_qblike.py b/tests/test_qblike.py
index 870d721..13b7393 100644
--- a/tests/test_qblike.py
+++ b/tests/test_qblike.py
@@ -37,7 +37,7 @@ class Link[T]:
 
 # Conditional type alias!
 type FilterLinks[T] = (
-    Link[PropsOnly[GetArg[T, Link, 0]]] if IsSub[T, Link] else T
+    Link[PropsOnly[GetArg[T, Link, Literal[0]]]] if IsSub[T, Link] else T
 )
 
 
diff --git a/tests/test_qblike_2.py b/tests/test_qblike_2.py
index 21ddb4d..e8f06f1 100644
--- a/tests/test_qblike_2.py
+++ b/tests/test_qblike_2.py
@@ -108,7 +108,7 @@ def select[ModelT, K: BaseTypedDict](
 grabs the argument to a ``Pointer``).
 
 """
-type PointerArg[T: Pointer] = GetArg[T, Pointer, 0]
+type PointerArg[T: Pointer] = GetArg[T, Pointer, Literal[0]]
 
 """
 ``AdjustLink`` sticks a ``list`` around ``MultiLink``, using features
diff --git a/tests/test_type_dir.py b/tests/test_type_dir.py
index 71387db..08da787 100644
--- a/tests/test_type_dir.py
+++ b/tests/test_type_dir.py
@@ -80,7 +80,7 @@ class Final(Mine, Ordinary, Wrapper[float], AnotherBase[float], Last[int]):
     pass
 
 
-type BaseArg[T] = GetArg[T, Base, 0] if IsSub[T, Base] else Never
+type BaseArg[T] = GetArg[T, Base, Literal[0]] if IsSub[T, Base] else Never
 
 
 type AllOptional[T] = NewProtocol[
diff --git a/tests/test_type_eval.py b/tests/test_type_eval.py
index ce9d1e6..ea99c9f 100644
--- a/tests/test_type_eval.py
+++ b/tests/test_type_eval.py
@@ -266,9 +266,9 @@ def test_type_from_union_02():
     d = eval_typing(FromUnion[UnlabeledTree])
     assert _is_generic_permutation(d, tuple[list[UnlabeledTree]])
 
-    d = eval_typing(GetArg[d, tuple, 0])
+    d = eval_typing(GetArg[d, tuple, Literal[0]])
     assert d == list[UnlabeledTree]
-    d = eval_typing(GetArg[d, list, 0])
+    d = eval_typing(GetArg[d, list, Literal[0]])
     assert d == list[UnlabeledTree]
     d = eval_typing(FromUnion[d])
     assert _is_generic_permutation(d, tuple[list[UnlabeledTree]])
@@ -278,9 +278,9 @@ def test_type_from_union_03():
     d = eval_typing(FromUnion[IntTree])
     assert _is_generic_permutation(d, tuple[int, list[IntTree]])
 
-    d = eval_typing(GetArg[d, tuple, 1])
+    d = eval_typing(GetArg[d, tuple, Literal[1]])
     assert d == list[IntTree]
-    d = eval_typing(GetArg[d, list, 0])
+    d = eval_typing(GetArg[d, list, Literal[0]])
     assert d == int | list[IntTree]
     d = eval_typing(FromUnion[d])
     assert _is_generic_permutation(d, tuple[int, list[IntTree]])
@@ -290,9 +290,9 @@ def test_type_from_union_04():
     d = eval_typing(FromUnion[GenericTree[str]])
     assert _is_generic_permutation(d, tuple[str, list[GenericTree[str]]])
 
-    d = eval_typing(GetArg[d, tuple, 1])
+    d = eval_typing(GetArg[d, tuple, Literal[1]])
     assert d == list[GenericTree[str]]
-    d = eval_typing(GetArg[d, list, 0])
+    d = eval_typing(GetArg[d, list, Literal[0]])
     assert d == str | list[GenericTree[str]]
     d = eval_typing(FromUnion[d])
     assert _is_generic_permutation(d, tuple[str, list[GenericTree[str]]])
@@ -305,40 +305,40 @@ def test_type_from_union_05():
         tuple[XNode[int, str], YNode[int, str]],
     )
 
-    x = eval_typing(GetArg[d, tuple, 0])
+    x = eval_typing(GetArg[d, tuple, Literal[0]])
     assert x == int | list[str | list[XNode[int, str]]]
 
     x = eval_typing(FromUnion[x])
     assert _is_generic_permutation(
         x, tuple[int, list[str | list[XNode[int, str]]]]
     )
-    x = eval_typing(GetArg[x, tuple, 1])
+    x = eval_typing(GetArg[x, tuple, Literal[1]])
     assert x == list[str | list[XNode[int, str]]]
-    x = eval_typing(GetArg[x, list, 0])
+    x = eval_typing(GetArg[x, list, Literal[0]])
     assert x == str | list[XNode[int, str]]
     x = eval_typing(FromUnion[x])
     assert _is_generic_permutation(x, tuple[str, list[XNode[int, str]]])
-    x = eval_typing(GetArg[x, tuple, 1])
+    x = eval_typing(GetArg[x, tuple, Literal[1]])
     assert x == list[XNode[int, str]]
-    x = eval_typing(GetArg[x, list, 0])
+    x = eval_typing(GetArg[x, list, Literal[0]])
     assert x == int | list[str | list[XNode[int, str]]]
 
-    y = eval_typing(GetArg[d, tuple, 1])
+    y = eval_typing(GetArg[d, tuple, Literal[1]])
     assert y == str | list[int | list[YNode[int, str]]]
 
     y = eval_typing(FromUnion[y])
     assert _is_generic_permutation(
         y, tuple[str, list[int | list[YNode[int, str]]]]
     )
-    y = eval_typing(GetArg[y, tuple, 1])
+    y = eval_typing(GetArg[y, tuple, Literal[1]])
     assert y == list[int | list[YNode[int, str]]]
-    y = eval_typing(GetArg[y, list, 0])
+    y = eval_typing(GetArg[y, list, Literal[0]])
     assert y == int | list[YNode[int, str]]
     y = eval_typing(FromUnion[y])
     assert _is_generic_permutation(y, tuple[int, list[YNode[int, str]]])
-    y = eval_typing(GetArg[y, tuple, 1])
+    y = eval_typing(GetArg[y, tuple, Literal[1]])
     assert y == list[YNode[int, str]]
-    y = eval_typing(GetArg[y, list, 0])
+    y = eval_typing(GetArg[y, list, Literal[0]])
     assert y == str | list[int | list[YNode[int, str]]]
 
 
@@ -349,31 +349,35 @@ def test_type_from_union_06():
         tuple[str, list[NestedTree], list[IntTree]],
     )
 
-    n = eval_typing(GetArg[d, tuple, 1])
+    n = eval_typing(GetArg[d, tuple, Literal[1]])
     assert n == list[NestedTree]
-    n = eval_typing(GetArg[n, list, 0])
+    n = eval_typing(GetArg[n, list, Literal[0]])
     assert n == str | list[NestedTree] | list[IntTree]
     n = eval_typing(FromUnion[n])
     assert _is_generic_permutation(
         n, tuple[str, list[NestedTree], list[IntTree]]
     )
 
-    n = eval_typing(FromUnion[GetArg[GetArg[n, tuple, 1], list, 0]])
+    n = eval_typing(
+        FromUnion[GetArg[GetArg[n, tuple, Literal[1]], list, Literal[0]]]
+    )
     assert _is_generic_permutation(
         n, tuple[str, list[NestedTree], list[IntTree]]
     )
 
-    i = eval_typing(GetArg[d, tuple, 2])
+    i = eval_typing(GetArg[d, tuple, Literal[2]])
     assert i == list[IntTree]
-    i = eval_typing(GetArg[i, list, 0])
+    i = eval_typing(GetArg[i, list, Literal[0]])
     assert i == int | list[IntTree]
 
-    n = eval_typing(FromUnion[GetArg[GetArg[d, tuple, 2], list, 0]])
+    n = eval_typing(
+        FromUnion[GetArg[GetArg[d, tuple, Literal[2]], list, Literal[0]]]
+    )
     assert _is_generic_permutation(n, tuple[int, list[IntTree]])
 
 
 def test_getarg_never():
-    d = eval_typing(GetArg[Never, object, 0])
+    d = eval_typing(GetArg[Never, object, Literal[0]])
     assert d is Never
 
 
@@ -418,7 +422,7 @@ def test_eval_getarg_callable_old():
 
 def test_eval_getarg_callable_01():
     t = Callable[[int, str], str]
-    args = eval_typing(GetArg[t, Callable, 0])
+    args = eval_typing(GetArg[t, Callable, Literal[0]])
     assert (
         args
         == tuple[
@@ -427,24 +431,24 @@ def test_eval_getarg_callable_01():
     )
 
     t = Callable[int, str]
-    args = eval_typing(GetArg[t, Callable, 0])
+    args = eval_typing(GetArg[t, Callable, Literal[0]])
     assert args == tuple[Param[Literal[None], int, Never]]
 
     t = Callable[[], str]
-    args = eval_typing(GetArg[t, Callable, 0])
+    args = eval_typing(GetArg[t, Callable, Literal[0]])
     assert args == tuple[()]
 
     # XXX: Is this what we want? Or should it be *args, **kwargs
     t = Callable[..., str]
-    args = eval_typing(GetArg[t, Callable, 0])
+    args = eval_typing(GetArg[t, Callable, Literal[0]])
     assert args == SpecialFormEllipsis
 
     t = Callable
-    args = eval_typing(GetArg[t, Callable, 0])
+    args = eval_typing(GetArg[t, Callable, Literal[0]])
     assert args == SpecialFormEllipsis
 
     t = Callable
-    args = eval_typing(GetArg[t, Callable, 1])
+    args = eval_typing(GetArg[t, Callable, Literal[1]])
     assert args == Any
 
 
@@ -463,7 +467,7 @@ def test_eval_getarg_callable_01():
         ],
     ],
     tuple,
-    0,
+    Literal[0],
 ]
 
 
@@ -472,7 +476,7 @@ class C:
         def f(self, x: int, /, y: int, *, z: int) -> int: ...
 
     f = eval_typing(GetMethodLike[C, Literal["f"]])
-    t = eval_typing(GetArg[f, Callable, 0])
+    t = eval_typing(GetArg[f, Callable, Literal[0]])
     assert (
         t
         == tuple[
@@ -482,7 +486,7 @@ def f(self, x: int, /, y: int, *, z: int) -> int: ...
             Param[Literal["z"], int, Literal["keyword"]],
         ]
     )
-    t = eval_typing(GetArg[f, Callable, 1])
+    t = eval_typing(GetArg[f, Callable, Literal[1]])
     assert t is int
 
 
@@ -491,7 +495,7 @@ class C:
         def f(self, x: int, /, y: int, *, z: int) -> int: ...
 
     f = eval_typing(GetMethodLike[IndirectProtocol[C], Literal["f"]])
-    t = eval_typing(GetArg[f, Callable, 0])
+    t = eval_typing(GetArg[f, Callable, Literal[0]])
     assert (
         t
         == tuple[
@@ -501,7 +505,7 @@ def f(self, x: int, /, y: int, *, z: int) -> int: ...
             Param[Literal["z"], int, Literal["keyword"]],
         ]
     )
-    t = eval_typing(GetArg[f, Callable, 1])
+    t = eval_typing(GetArg[f, Callable, Literal[1]])
     assert t is int
 
 
@@ -511,9 +515,9 @@ class C:
         def f(cls, x: int, /, y: int, *, z: int) -> int: ...
 
     f = eval_typing(GetMethodLike[C, Literal["f"]])
-    t = eval_typing(GetArg[f, classmethod, 0])
+    t = eval_typing(GetArg[f, classmethod, Literal[0]])
     assert t == C
-    t = eval_typing(GetArg[f, classmethod, 1])
+    t = eval_typing(GetArg[f, classmethod, Literal[1]])
     assert (
         t
         == tuple[
@@ -522,7 +526,7 @@ def f(cls, x: int, /, y: int, *, z: int) -> int: ...
             Param[Literal["z"], int, Literal["keyword"]],
         ]
     )
-    t = eval_typing(GetArg[f, classmethod, 2])
+    t = eval_typing(GetArg[f, classmethod, Literal[2]])
     assert t is int
 
 
@@ -532,7 +536,7 @@ class C:
         def f(cls, x: int, /, y: int, *, z: int) -> int: ...
 
     f = eval_typing(GetMethodLike[IndirectProtocol[C], Literal["f"]])
-    t = eval_typing(GetArg[f, Callable, 0])
+    t = eval_typing(GetArg[f, Callable, Literal[0]])
     assert (
         t
         == tuple[
@@ -542,7 +546,7 @@ def f(cls, x: int, /, y: int, *, z: int) -> int: ...
             Param[Literal["z"], int, Literal["keyword"]],
         ]
     )
-    t = eval_typing(GetArg[f, Callable, 1])
+    t = eval_typing(GetArg[f, Callable, Literal[1]])
     assert t is int
 
 
@@ -552,7 +556,7 @@ class C:
         def f(x: int, /, y: int, *, z: int) -> int: ...
 
     f = eval_typing(GetMethodLike[C, Literal["f"]])
-    t = eval_typing(GetArg[f, staticmethod, 0])
+    t = eval_typing(GetArg[f, staticmethod, Literal[0]])
     assert (
         t
         == tuple[
@@ -561,7 +565,7 @@ def f(x: int, /, y: int, *, z: int) -> int: ...
             Param[Literal["z"], int, Literal["keyword"]],
         ]
     )
-    t = eval_typing(GetArg[f, staticmethod, 1])
+    t = eval_typing(GetArg[f, staticmethod, Literal[1]])
     assert t is int
 
 
@@ -571,7 +575,7 @@ class C:
         def f(x: int, /, y: int, *, z: int) -> int: ...
 
     f = eval_typing(GetMethodLike[IndirectProtocol[C], Literal["f"]])
-    t = eval_typing(GetArg[f, Callable, 0])
+    t = eval_typing(GetArg[f, Callable, Literal[0]])
     assert (
         t
         == tuple[
@@ -580,7 +584,7 @@ def f(x: int, /, y: int, *, z: int) -> int: ...
             Param[Literal["z"], int, Literal["keyword"]],
         ]
     )
-    t = eval_typing(GetArg[f, Callable, 1])
+    t = eval_typing(GetArg[f, Callable, Literal[1]])
     assert t is int
 
 
@@ -589,134 +593,134 @@ class C:
         f: Callable[[int], int]
 
     f = eval_typing(GetMethodLike[IndirectProtocol[C], Literal["f"]])
-    t = eval_typing(GetArg[f, Callable, 0])
+    t = eval_typing(GetArg[f, Callable, Literal[0]])
     assert t == tuple[Param[Literal[None], int, Never],]
-    t = eval_typing(GetArg[f, Callable, 1])
+    t = eval_typing(GetArg[f, Callable, Literal[1]])
     assert t is int
 
 
 def test_eval_getarg_tuple():
     t = tuple[int, ...]
-    args = eval_typing(GetArg[t, tuple, 1])
+    args = eval_typing(GetArg[t, tuple, Literal[1]])
     assert args == SpecialFormEllipsis
 
     t = tuple
-    args = eval_typing(GetArg[t, tuple, 0])
+    args = eval_typing(GetArg[t, tuple, Literal[0]])
     assert args == Any
 
-    args = eval_typing(GetArg[t, tuple, 1])
+    args = eval_typing(GetArg[t, tuple, Literal[1]])
     assert args == SpecialFormEllipsis
 
 
 def test_eval_getarg_list():
     t = list[int]
-    arg = eval_typing(GetArg[t, list, 0])
+    arg = eval_typing(GetArg[t, list, Literal[0]])
     assert arg is int
 
     t = List[int]
-    arg = eval_typing(GetArg[t, list, 0])
+    arg = eval_typing(GetArg[t, list, Literal[0]])
     assert arg is int
 
     t = list
-    arg = eval_typing(GetArg[t, list, 0])
+    arg = eval_typing(GetArg[t, list, Literal[0]])
     assert arg == Any
 
     t = List
-    arg = eval_typing(GetArg[t, list, 0])
+    arg = eval_typing(GetArg[t, list, Literal[0]])
     assert arg == Any
 
     t = list[int]
-    arg = eval_typing(GetArg[t, List, 0])
+    arg = eval_typing(GetArg[t, List, Literal[0]])
     assert arg is int
 
     t = List[int]
-    arg = eval_typing(GetArg[t, List, 0])
+    arg = eval_typing(GetArg[t, List, Literal[0]])
     assert arg is int
 
     t = list
-    arg = eval_typing(GetArg[t, List, 0])
+    arg = eval_typing(GetArg[t, List, Literal[0]])
     assert arg == Any
 
     t = List
-    arg = eval_typing(GetArg[t, List, 0])
+    arg = eval_typing(GetArg[t, List, Literal[0]])
     assert arg == Any
 
     # indexing with -1 equivalent to 0
     t = list[int]
-    arg = eval_typing(GetArg[t, list, -1])
+    arg = eval_typing(GetArg[t, list, Literal[-1]])
     assert arg is int
 
     t = List[int]
-    arg = eval_typing(GetArg[t, list, -1])
+    arg = eval_typing(GetArg[t, list, Literal[-1]])
     assert arg is int
 
     t = list
-    arg = eval_typing(GetArg[t, list, -1])
+    arg = eval_typing(GetArg[t, list, Literal[-1]])
     assert arg == Any
 
     t = List
-    arg = eval_typing(GetArg[t, list, -1])
+    arg = eval_typing(GetArg[t, list, Literal[-1]])
     assert arg == Any
 
     t = list[int]
-    arg = eval_typing(GetArg[t, List, -1])
+    arg = eval_typing(GetArg[t, List, Literal[-1]])
     assert arg is int
 
     t = List[int]
-    arg = eval_typing(GetArg[t, List, -1])
+    arg = eval_typing(GetArg[t, List, Literal[-1]])
     assert arg is int
 
     t = list
-    arg = eval_typing(GetArg[t, List, -1])
+    arg = eval_typing(GetArg[t, List, Literal[-1]])
     assert arg == Any
 
     t = List
-    arg = eval_typing(GetArg[t, List, -1])
+    arg = eval_typing(GetArg[t, List, Literal[-1]])
     assert arg == Any
 
     # indexing with 1 always fails
     t = list[int]
-    arg = eval_typing(GetArg[t, list, 1])
+    arg = eval_typing(GetArg[t, list, Literal[1]])
     assert arg == Never
 
     t = List[int]
-    arg = eval_typing(GetArg[t, list, 1])
+    arg = eval_typing(GetArg[t, list, Literal[1]])
     assert arg == Never
 
     t = list
-    arg = eval_typing(GetArg[t, list, 1])
+    arg = eval_typing(GetArg[t, list, Literal[1]])
     assert arg == Never
 
     t = List
-    arg = eval_typing(GetArg[t, list, 1])
+    arg = eval_typing(GetArg[t, list, Literal[1]])
     assert arg == Never
 
     t = list[int]
-    arg = eval_typing(GetArg[t, List, 1])
+    arg = eval_typing(GetArg[t, List, Literal[1]])
     assert arg == Never
 
     t = List[int]
-    arg = eval_typing(GetArg[t, List, 1])
+    arg = eval_typing(GetArg[t, List, Literal[1]])
     assert arg == Never
 
     t = list
-    arg = eval_typing(GetArg[t, List, 1])
+    arg = eval_typing(GetArg[t, List, Literal[1]])
     assert arg == Never
 
     t = List
-    arg = eval_typing(GetArg[t, List, 1])
+    arg = eval_typing(GetArg[t, List, Literal[1]])
     assert arg == Never
 
 
 @pytest.mark.xfail(reason="Should this work?")
 def test_eval_getarg_union_01():
-    arg = eval_typing(GetArg[int | str, Union, 0])
+    arg = eval_typing(GetArg[int | str, Union, Literal[0]])
     assert arg is int
 
 
 @pytest.mark.xfail(reason="Should this work?")
 def test_eval_getarg_union_02():
-    arg = eval_typing(GetArg[GenericTree[int], GenericTree, 0])
+    arg = eval_typing(GetArg[GenericTree[int], GenericTree, Literal[0]])
     assert arg is int
 
 
@@ -725,14 +729,14 @@ class A[T]:
         pass
 
     t = A[int]
-    assert eval_typing(GetArg[t, A, 0]) is int
-    assert eval_typing(GetArg[t, A, -1]) is int
-    assert eval_typing(GetArg[t, A, 1]) == Never
+    assert eval_typing(GetArg[t, A, Literal[0]]) is int
+    assert eval_typing(GetArg[t, A, Literal[-1]]) is int
+    assert eval_typing(GetArg[t, A, Literal[1]]) == Never
 
     t = A
-    assert eval_typing(GetArg[t, A, 0]) == Any
-    assert eval_typing(GetArg[t, A, -1]) == Any
-    assert eval_typing(GetArg[t, A, 1]) == Never
+    assert eval_typing(GetArg[t, A, Literal[0]]) == Any
+    assert eval_typing(GetArg[t, A, Literal[-1]]) == Any
+    assert eval_typing(GetArg[t, A, Literal[1]]) == Never
 
 
 def test_eval_getarg_custom_02():
@@ -742,14 +746,14 @@ class A(Generic[T]):
         pass
 
     t = A[int]
-    assert eval_typing(GetArg[t, A, 0]) is int
-    assert eval_typing(GetArg[t, A, -1]) is int
-    assert eval_typing(GetArg[t, A, 1]) == Never
+    assert eval_typing(GetArg[t, A, Literal[0]]) is int
+    assert eval_typing(GetArg[t, A, Literal[-1]]) is int
+    assert eval_typing(GetArg[t, A, Literal[1]]) == Never
 
     t = A
-    assert eval_typing(GetArg[t, A, 0]) == Any
-    assert eval_typing(GetArg[t, A, -1]) == Any
-    assert eval_typing(GetArg[t, A, 1]) == Never
+    assert eval_typing(GetArg[t, A, Literal[0]]) == Any
+    assert eval_typing(GetArg[t, A, Literal[-1]]) == Any
+    assert eval_typing(GetArg[t, A, Literal[1]]) == Never
 
 
 def test_eval_getarg_custom_03():
@@ -757,14 +761,14 @@ class A[T = str]:
         pass
 
     t = A[int]
-    assert eval_typing(GetArg[t, A, 0]) is int
-    assert eval_typing(GetArg[t, A, -1]) is int
-    assert eval_typing(GetArg[t, A, 1]) == Never
+    assert eval_typing(GetArg[t, A, Literal[0]]) is int
+    assert eval_typing(GetArg[t, A, Literal[-1]]) is int
+    assert eval_typing(GetArg[t, A, Literal[1]]) == Never
 
     t = A
-    assert eval_typing(GetArg[t, A, 0]) is str
-    assert eval_typing(GetArg[t, A, -1]) is str
-    assert eval_typing(GetArg[t, A, 1]) == Never
+    assert eval_typing(GetArg[t, A, Literal[0]]) is str
+    assert eval_typing(GetArg[t, A, Literal[-1]]) is str
+    assert eval_typing(GetArg[t, A, Literal[1]]) == Never
 
 
 def test_eval_getarg_custom_04():
@@ -774,14 +778,14 @@ class A(Generic[T]):
         pass
 
     t = A[int]
-    assert eval_typing(GetArg[t, A, 0]) is int
-    assert eval_typing(GetArg[t, A, -1]) is int
-    assert eval_typing(GetArg[t, A, 1]) == Never
+    assert eval_typing(GetArg[t, A, Literal[0]]) is int
+    assert eval_typing(GetArg[t, A, Literal[-1]]) is int
+    assert eval_typing(GetArg[t, A, Literal[1]]) == Never
 
     t = A
-    assert eval_typing(GetArg[t, A, 0]) is str
-    assert eval_typing(GetArg[t, A, -1]) is str
-    assert eval_typing(GetArg[t, A, 1]) == Never
+    assert eval_typing(GetArg[t, A, Literal[0]]) is str
+    assert eval_typing(GetArg[t, A, Literal[-1]]) is str
+    assert eval_typing(GetArg[t, A, Literal[1]]) == Never
 
 
 TestTypeVar = TypeVar("TestTypeVar")
@@ -793,14 +797,14 @@ class ATree(Generic[TestTypeVar]):
         val: list[ATree[TestTypeVar]]
 
     t = ATree[int]
-    assert eval_typing(GetArg[t, ATree, 0]) is int
-    assert eval_typing(GetArg[t, ATree, -1]) is int
-    assert eval_typing(GetArg[t, ATree, 1]) == Never
+    assert eval_typing(GetArg[t, ATree, Literal[0]]) is int
+    assert eval_typing(GetArg[t, ATree, Literal[-1]]) is int
+    assert eval_typing(GetArg[t, ATree, Literal[1]]) == Never
 
     t = ATree
-    assert eval_typing(GetArg[t, ATree, 0]) is Any
-    assert eval_typing(GetArg[t, ATree, -1]) is Any
-    assert eval_typing(GetArg[t, ATree, 1]) == Never
+    assert eval_typing(GetArg[t, ATree, Literal[0]]) is Any
+    assert eval_typing(GetArg[t, ATree, Literal[-1]]) is Any
+    assert eval_typing(GetArg[t, ATree, Literal[1]]) == Never
 
 
 def test_eval_getarg_custom_06():
@@ -811,14 +815,14 @@ class ATree(Generic[A]):
         val: A | list[ATree[A]]
 
     t = ATree[int]
-    assert eval_typing(GetArg[t, ATree, 0]) is int
-    assert eval_typing(GetArg[t, ATree, -1]) is int
-    assert eval_typing(GetArg[t, ATree, 1]) == Never
+    assert eval_typing(GetArg[t, ATree, Literal[0]]) is int
+    assert eval_typing(GetArg[t, ATree, Literal[-1]]) is int
+    assert eval_typing(GetArg[t, ATree, Literal[1]]) == Never
 
     t = ATree
-    assert eval_typing(GetArg[t, ATree, 0]) is Any
-    assert eval_typing(GetArg[t, ATree, -1]) is Any
-    assert eval_typing(GetArg[t, ATree, 1]) == Never
+    assert eval_typing(GetArg[t, ATree, Literal[0]]) is Any
+    assert eval_typing(GetArg[t, ATree, Literal[-1]]) is Any
+    assert eval_typing(GetArg[t, ATree, Literal[1]]) == Never
 
 
 def test_eval_getarg_custom_07():
@@ -836,14 +840,14 @@ class ABTree(Generic[A, B]):
         root: ANode[A, B] | BNode[A, B]
 
     t = ABTree[int, str]
-    assert eval_typing(GetArg[t, ABTree, 0]) is int
-    assert eval_typing(GetArg[t, ABTree, 1]) is str
-    assert eval_typing(GetArg[t, ABTree, 2]) == Never
+    assert eval_typing(GetArg[t, ABTree, Literal[0]]) is int
+    assert eval_typing(GetArg[t, ABTree, Literal[1]]) is str
+    assert eval_typing(GetArg[t, ABTree, Literal[2]]) == Never
 
     t = ABTree
-    assert eval_typing(GetArg[t, ABTree, 0]) is Any
-    assert eval_typing(GetArg[t, ABTree, 1]) is Any
-    assert eval_typing(GetArg[t, ABTree, 2]) == Never
+    assert eval_typing(GetArg[t, ABTree, Literal[0]]) is Any
+    assert eval_typing(GetArg[t, ABTree, Literal[1]]) is Any
+    assert eval_typing(GetArg[t, ABTree, Literal[2]]) == Never
 
 
 def test_eval_getarg_custom_08():
@@ -860,14 +864,14 @@ def convert[T](self, func: Callable[[int], T]) -> Container2[T]: ...
     class Container2[T]: ...
 
     t = Container[int]
-    assert eval_typing(GetArg[t, Container, 0]) is int
-    assert eval_typing(GetArg[t, Container, -1]) is int
-    assert eval_typing(GetArg[t, Container, 1]) == Never
+    assert eval_typing(GetArg[t, Container, Literal[0]]) is int
+    assert eval_typing(GetArg[t, Container, Literal[-1]]) is int
+    assert eval_typing(GetArg[t, Container, Literal[1]]) == Never
 
     t = Container
-    assert eval_typing(GetArg[t, Container, 0]) is Any
-    assert eval_typing(GetArg[t, Container, -1]) is Any
-    assert eval_typing(GetArg[t, Container, 1]) == Never
+    assert eval_typing(GetArg[t, Container, Literal[0]]) is Any
+    assert eval_typing(GetArg[t, Container, Literal[-1]]) is Any
+    assert eval_typing(GetArg[t, Container, Literal[1]]) == Never
 
 
 type _Works[Ts, I] = Literal[True]
@@ -1286,7 +1290,7 @@ def func[T](x: C[T]) -> T: ...
         ]
     ],
     tuple,
-    0,
+    Literal[0],
 ]
 
 
diff --git a/typemap/type_eval/_eval_operators.py b/typemap/type_eval/_eval_operators.py
index 3489846..3842b2d 100644
--- a/typemap/type_eval/_eval_operators.py
+++ b/typemap/type_eval/_eval_operators.py
@@ -48,9 +48,7 @@ def _from_literal(val):
         return val.__args__[0]
     elif val is type(None):
         return None
-    else:
-        # TODO: check it is some literal
-        return val
+    raise AssertionError(f'expected a literal type, got {val!r}')
 
 
 def _eval_literal(val, ctx):