12 files changed, 62 insertions, 11 deletions
diff --git a/numpy/__init__.pyi b/numpy/__init__.pyi
index 992ed908a..d9b50b7b4 100644
--- a/numpy/__init__.pyi
+++ b/numpy/__init__.pyi
@@ -36,6 +36,8 @@ from numpy._typing import (
     _ArrayLikeObject_co,
     _ArrayLikeStr_co,
     _ArrayLikeBytes_co,
+    _ArrayLikeUnknown,
+    _UnknownType,
 
     # DTypes
     DTypeLike,
@@ -1549,6 +1551,12 @@ class ndarray(_ArrayOrScalarCommon, Generic[_ShapeType, _DType_co]):
     ) -> ndarray[_ShapeType2, _DType]: ...
 
     @overload
+    def __getitem__(self, key: (
+        NDArray[integer[Any]]
+        | NDArray[bool_]
+        | tuple[NDArray[integer[Any]] | NDArray[bool_], ...]
+    )) -> ndarray[Any, _DType_co]: ...
+    @overload
     def __getitem__(self, key: SupportsIndex | tuple[SupportsIndex, ...]) -> Any: ...
     @overload
     def __getitem__(self, key: (
@@ -2051,6 +2059,8 @@ class ndarray(_ArrayOrScalarCommon, Generic[_ShapeType, _DType_co]):
     def __radd__(self: NDArray[Any], other: _ArrayLikeObject_co) -> Any: ...
 
     @overload
+    def __sub__(self: NDArray[_UnknownType], other: _ArrayLikeUnknown) -> NDArray[Any]: ...
+    @overload
     def __sub__(self: NDArray[bool_], other: _ArrayLikeBool_co) -> NoReturn: ...
     @overload
     def __sub__(self: _ArrayUInt_co, other: _ArrayLikeUInt_co) -> NDArray[unsignedinteger[Any]]: ...  # type: ignore[misc]
@@ -2074,6 +2084,8 @@ class ndarray(_ArrayOrScalarCommon, Generic[_ShapeType, _DType_co]):
     def __sub__(self: NDArray[Any], other: _ArrayLikeObject_co) -> Any: ...
 
     @overload
+    def __rsub__(self: NDArray[_UnknownType], other: _ArrayLikeUnknown) -> NDArray[Any]: ...
+    @overload
     def __rsub__(self: NDArray[bool_], other: _ArrayLikeBool_co) -> NoReturn: ...
     @overload
     def __rsub__(self: _ArrayUInt_co, other: _ArrayLikeUInt_co) -> NDArray[unsignedinteger[Any]]: ...  # type: ignore[misc]
diff --git a/numpy/_typing/__init__.py b/numpy/_typing/__init__.py
index 76b806c7f..b800c54b6 100644
--- a/numpy/_typing/__init__.py
+++ b/numpy/_typing/__init__.py
@@ -199,6 +199,7 @@ from ._array_like import (
     _ArrayLikeStr_co as _ArrayLikeStr_co,
     _ArrayLikeBytes_co as _ArrayLikeBytes_co,
     _ArrayLikeUnknown as _ArrayLikeUnknown,
+    _UnknownType as _UnknownType,
 )
 from ._generic_alias import (
     NDArray as NDArray,
diff --git a/numpy/_typing/_array_like.py b/numpy/_typing/_array_like.py
index 2e5684b0b..67d67ce19 100644
--- a/numpy/_typing/_array_like.py
+++ b/numpy/_typing/_array_like.py
@@ -3,7 +3,7 @@ from __future__ import annotations
 # NOTE: Import `Sequence` from `typing` as we it is needed for a type-alias,
 # not an annotation
 from collections.abc import Collection, Callable
-from typing import Any, Sequence, Protocol, Union, TypeVar
+from typing import Any, Sequence, Protocol, Union, TypeVar, runtime_checkable
 from numpy import (
     ndarray,
     dtype,
@@ -33,10 +33,12 @@ _DType_co = TypeVar("_DType_co", covariant=True, bound="dtype[Any]")
 # array.
 # Concrete implementations of the protocol are responsible for adding
 # any and all remaining overloads
+@runtime_checkable
 class _SupportsArray(Protocol[_DType_co]):
     def __array__(self) -> ndarray[Any, _DType_co]: ...
 
 
+@runtime_checkable
 class _SupportsArrayFunc(Protocol):
     """A protocol class representing `~class.__array_function__`."""
     def __array_function__(
@@ -146,7 +148,7 @@ _ArrayLikeInt = _DualArrayLike[
 # Used as the first overload, should only match NDArray[Any],
 # not any actual types.
 # https://github.com/numpy/numpy/pull/22193
-class _UnknownType: 
+class _UnknownType:
     ...
 
 
diff --git a/numpy/_typing/_dtype_like.py b/numpy/_typing/_dtype_like.py
index b705d82fd..e92e17dd2 100644
--- a/numpy/_typing/_dtype_like.py
+++ b/numpy/_typing/_dtype_like.py
@@ -8,6 +8,7 @@ from typing import (
     TypeVar,
     Protocol,
     TypedDict,
+    runtime_checkable,
 )
 
 import numpy as np
@@ -80,6 +81,7 @@ class _DTypeDict(_DTypeDictBase, total=False):
 
 
 # A protocol for anything with the dtype attribute
+@runtime_checkable
 class _SupportsDType(Protocol[_DType_co]):
     @property
     def dtype(self) -> _DType_co: ...
diff --git a/numpy/_typing/_nested_sequence.py b/numpy/_typing/_nested_sequence.py
index 360c0f1b2..789bf3844 100644
--- a/numpy/_typing/_nested_sequence.py
+++ b/numpy/_typing/_nested_sequence.py
@@ -8,6 +8,7 @@ from typing import (
     overload,
     TypeVar,
     Protocol,
+    runtime_checkable,
 )
 
 __all__ = ["_NestedSequence"]
@@ -15,6 +16,7 @@ __all__ = ["_NestedSequence"]
 _T_co = TypeVar("_T_co", covariant=True)
 
 
+@runtime_checkable
 class _NestedSequence(Protocol[_T_co]):
     """A protocol for representing nested sequences.
 
diff --git a/numpy/array_api/__init__.py b/numpy/array_api/__init__.py
index bbe2fdce2..5e58ee0a8 100644
--- a/numpy/array_api/__init__.py
+++ b/numpy/array_api/__init__.py
@@ -121,7 +121,9 @@ warnings.warn(
     "The numpy.array_api submodule is still experimental. See NEP 47.", stacklevel=2
 )
 
-__all__ = []
+__array_api_version__ = "2021.12"
+
+__all__ = ["__array_api_version__"]
 
 from ._constants import e, inf, nan, pi
 
diff --git a/numpy/polynomial/chebyshev.py b/numpy/polynomial/chebyshev.py
index 5c595bcf6..c663ffab0 100644
--- a/numpy/polynomial/chebyshev.py
+++ b/numpy/polynomial/chebyshev.py
@@ -1959,7 +1959,8 @@ def chebpts2(npts):
     Chebyshev points of the second kind.
 
     The Chebyshev points of the second kind are the points ``cos(x)``,
-    where ``x = [pi*k/(npts - 1) for k in range(npts)]``.
+    where ``x = [pi*k/(npts - 1) for k in range(npts)]`` sorted in ascending
+    order.
 
     Parameters
     ----------
diff --git a/numpy/typing/tests/data/fail/scalars.pyi b/numpy/typing/tests/data/fail/scalars.pyi
index 964470538..c24f9e479 100644
--- a/numpy/typing/tests/data/fail/scalars.pyi
+++ b/numpy/typing/tests/data/fail/scalars.pyi
@@ -70,8 +70,6 @@ np.timedelta64(value=0)  # E: Unexpected keyword argument
 np.bytes_(b"hello", encoding='utf-8')  # E: No overload variant
 np.str_("hello", encoding='utf-8')  # E: No overload variant
 
-complex(np.bytes_("1"))  # E: No overload variant
-
 f8.item(1)  # E: incompatible type
 f8.item((0, 1))  # E: incompatible type
 f8.squeeze(axis=1)  # E: incompatible type
diff --git a/numpy/typing/tests/data/reveal/ctypeslib.pyi b/numpy/typing/tests/data/reveal/ctypeslib.pyi
index ccbdfe36e..2d30de3d1 100644
--- a/numpy/typing/tests/data/reveal/ctypeslib.pyi
+++ b/numpy/typing/tests/data/reveal/ctypeslib.pyi
@@ -20,7 +20,7 @@ AR_double: npt.NDArray[np.double]
 AR_longdouble: npt.NDArray[np.longdouble]
 AR_void: npt.NDArray[np.void]
 
-pointer: ctypes.pointer[Any]
+pointer: ctypes._Pointer[Any]
 
 reveal_type(np.ctypeslib.c_intp())  # E: {c_intp}
 
diff --git a/numpy/typing/tests/data/reveal/flatiter.pyi b/numpy/typing/tests/data/reveal/flatiter.pyi
index 0f0758175..8d3e80632 100644
--- a/numpy/typing/tests/data/reveal/flatiter.pyi
+++ b/numpy/typing/tests/data/reveal/flatiter.pyi
@@ -7,7 +7,7 @@ reveal_type(a.base)  # E: ndarray[Any, dtype[str_]]
 reveal_type(a.copy())  # E: ndarray[Any, dtype[str_]]
 reveal_type(a.coords)  # E: tuple[builtins.int, ...]
 reveal_type(a.index)  # E: int
-reveal_type(iter(a))  # E: flatiter[ndarray[Any, dtype[str_]]]
+reveal_type(iter(a))  # E: Any
 reveal_type(next(a))  # E: str_
 reveal_type(a[0])  # E: str_
 reveal_type(a[[0, 1, 2]])  # E: ndarray[Any, dtype[str_]]
diff --git a/numpy/typing/tests/data/reveal/ndarray_misc.pyi b/numpy/typing/tests/data/reveal/ndarray_misc.pyi
index 779d0909b..03fea72dc 100644
--- a/numpy/typing/tests/data/reveal/ndarray_misc.pyi
+++ b/numpy/typing/tests/data/reveal/ndarray_misc.pyi
@@ -200,8 +200,8 @@ reveal_type(AR_f8.__array_wrap__(B))  # E: ndarray[Any, dtype[object_]]
 
 reveal_type(AR_V[0])  # E: Any
 reveal_type(AR_V[0, 0])  # E: Any
-reveal_type(AR_V[AR_i8])  # E: Any
-reveal_type(AR_V[AR_i8, AR_i8])  # E: Any
+reveal_type(AR_V[AR_i8])  # E: ndarray[Any, dtype[void]]
+reveal_type(AR_V[AR_i8, AR_i8])  # E: ndarray[Any, dtype[void]]
 reveal_type(AR_V[AR_i8, None])  # E: ndarray[Any, dtype[void]]
 reveal_type(AR_V[0, ...])  # E: ndarray[Any, dtype[void]]
 reveal_type(AR_V[[0]])  # E: ndarray[Any, dtype[void]]
diff --git a/numpy/typing/tests/test_runtime.py b/numpy/typing/tests/test_runtime.py
index 5b5df49dc..44d069006 100644
--- a/numpy/typing/tests/test_runtime.py
+++ b/numpy/typing/tests/test_runtime.py
@@ -3,11 +3,19 @@
 from __future__ import annotations
 
 import sys
-from typing import get_type_hints, Union, NamedTuple, get_args, get_origin
+from typing import (
+    get_type_hints,
+    Union,
+    NamedTuple,
+    get_args,
+    get_origin,
+    Any,
+)
 
 import pytest
 import numpy as np
 import numpy.typing as npt
+import numpy._typing as _npt
 
 
 class TypeTup(NamedTuple):
@@ -80,3 +88,26 @@ def test_keys() -> None:
     keys = TYPES.keys()
     ref = set(npt.__all__)
     assert keys == ref
+
+
+PROTOCOLS: dict[str, tuple[type[Any], object]] = {
+    "_SupportsDType": (_npt._SupportsDType, np.int64(1)),
+    "_SupportsArray": (_npt._SupportsArray, np.arange(10)),
+    "_SupportsArrayFunc": (_npt._SupportsArrayFunc, np.arange(10)),
+    "_NestedSequence": (_npt._NestedSequence, [1]),
+}
+
+
+@pytest.mark.parametrize("cls,obj", PROTOCOLS.values(), ids=PROTOCOLS.keys())
+class TestRuntimeProtocol:
+    def test_isinstance(self, cls: type[Any], obj: object) -> None:
+        assert isinstance(obj, cls)
+        assert not isinstance(None, cls)
+
+    def test_issubclass(self, cls: type[Any], obj: object) -> None:
+        if cls is _npt._SupportsDType:
+            pytest.xfail(
+                "Protocols with non-method members don't support issubclass()"
+            )
+        assert issubclass(type(obj), cls)
+        assert not issubclass(type(None), cls)