BLD: Drop typing extension as an (optional) runtime dependency

It might return in the future, but as of the moment we don't need it anymore

4 files changed, 1 insertions, 46 deletions

diff --git a/environment.yml b/environment.yml
index 5fb7d292d..188e29a4f 100644
--- a/environment.yml
+++ b/environment.yml
@@ -17,9 +17,8 @@ dependencies:
   - pytest-cov
   - pytest-xdist
   - hypothesis
-  # For type annotations 
+  # For type annotations
   - mypy=0.902
-  - typing_extensions
   # For building docs
   - sphinx=4.1.1
   - numpydoc=1.1.0
diff --git a/numpy/typing/__init__.py b/numpy/typing/__init__.py
index bfa7982c0..d60ddb5bb 100644
--- a/numpy/typing/__init__.py
+++ b/numpy/typing/__init__.py
@@ -5,13 +5,6 @@ Typing (:mod:`numpy.typing`)
 
 .. versionadded:: 1.20
 
-.. warning::
-
-  Some of the types in this module rely on features only present in
-  the standard library in Python 3.8 and greater. If you want to use
-  these types in earlier versions of Python, you should install the
-  typing-extensions_ package.
-
 Large parts of the NumPy API have PEP-484-style type annotations. In
 addition a number of type aliases are available to users, most prominently
 the two below:
diff --git a/numpy/typing/tests/test_typing_extensions.py b/numpy/typing/tests/test_typing_extensions.py
deleted file mode 100644
index f59f222fb..000000000
--- a/numpy/typing/tests/test_typing_extensions.py
+++ /dev/null
@@ -1,35 +0,0 @@
-"""Tests for the optional typing-extensions dependency."""
-
-import sys
-import textwrap
-import subprocess
-
-CODE = textwrap.dedent(r"""
-    import sys
-    import importlib
-
-    assert "typing_extensions" not in sys.modules
-    assert "numpy.typing" not in sys.modules
-
-    # Importing `typing_extensions` will now raise an `ImportError`
-    sys.modules["typing_extensions"] = None
-    assert importlib.import_module("numpy.typing")
-""")
-
-
-def test_no_typing_extensions() -> None:
-    """Import `numpy.typing` in the absence of typing-extensions.
-
-    Notes
-    -----
-    Ideally, we'd just run the normal typing tests in an environment where
-    typing-extensions is not installed, but unfortunatelly this is currently
-    impossible as it is an indirect hard dependency of pytest.
-
-    """
-    p = subprocess.run([sys.executable, '-c', CODE], capture_output=True)
-    if p.returncode:
-        raise AssertionError(
-            f"Non-zero return code: {p.returncode!r}\n\n{p.stderr.decode()}"
-        )
-
diff --git a/test_requirements.txt b/test_requirements.txt
index e2dcdaed3..ee47af8f0 100644
--- a/test_requirements.txt
+++ b/test_requirements.txt
@@ -10,6 +10,4 @@ pickle5; python_version == '3.7' and platform_python_implementation != 'PyPy'
 cffi
 # For testing types. Notes on the restrictions:
 # - Mypy relies on C API features not present in PyPy
-# - There is no point in installing typing_extensions without mypy
 mypy==0.910; platform_python_implementation != "PyPy"
-typing_extensions==3.10.0.0; platform_python_implementation != "PyPy"