Fixes issue I've been having running pipenv as an editable install on windows. (#5770)

pipenv/__init__.py

@@ -1,9 +1,26 @@
+import importlib.util
 import os
+import sys
 import warnings
 
+
+def _ensure_modules():
+    spec = importlib.util.spec_from_file_location(
+        "typing_extensions",
+        location=os.path.join(
+            os.path.dirname(__file__), "patched", "pip", "_vendor", "typing_extensions.py"
+        ),
+    )
+    typing_extensions = importlib.util.module_from_spec(spec)
+    sys.modules["typing_extensions"] = typing_extensions
+    spec.loader.exec_module(typing_extensions)
+
+
+_ensure_modules()
+
 from pipenv.__version__ import __version__  # noqa
-from pipenv.cli import cli
+from pipenv.cli import cli  # noqa
-from pipenv.patched.pip._vendor.urllib3.exceptions import DependencyWarning
+from pipenv.patched.pip._vendor.urllib3.exceptions import DependencyWarning  # noqa
 
 warnings.filterwarnings("ignore", category=DependencyWarning)
 warnings.filterwarnings("ignore", category=ResourceWarning)

pipenv/resolver.py

@@ -8,6 +8,15 @@ os.environ["PIP_PYTHON_PATH"] = str(sys.executable)
 
 
 def _ensure_modules():
+    spec = importlib.util.spec_from_file_location(
+        "typing_extensions",
+        location=os.path.join(
+            os.path.dirname(__file__), "patched", "pip", "_vendor", "typing_extensions.py"
+        ),
+    )
+    typing_extensions = importlib.util.module_from_spec(spec)
+    sys.modules["typing_extensions"] = typing_extensions
+    spec.loader.exec_module(typing_extensions)
     spec = importlib.util.spec_from_file_location(
         "pipenv", location=os.path.join(os.path.dirname(__file__), "__init__.py")
     )