Revert and use typing_extensions.deprecated instead

Author: CoolCat467

pyproject.toml

@@ -50,6 +50,8 @@ dependencies = [
     # cffi is required on Windows, except on PyPy where it is built-in
     "cffi>=1.14; os_name == 'nt' and implementation_name != 'pypy'",
     "exceptiongroup; python_version < '3.11'",
+    # using typing_extensions.depreciated in _sync.py
+    "typing_extensions >= 4.15.0",
 ]
 dynamic = ["version"]
 

src/trio/_sync.py

@@ -4,6 +4,7 @@
 from typing import TYPE_CHECKING, Literal, Protocol
 
 import attrs
+from typing_extensions import deprecated
 
 import trio
 
@@ -113,17 +114,16 @@ def statistics(self) -> EventStatistics:
         """
         return EventStatistics(tasks_waiting=len(self._tasks))
 
-    if not TYPE_CHECKING:
-
-        def __bool__(self) -> Literal[True]:
-            """Return True and raise warning."""
-            warn_deprecated(
-                self.__bool__,
-                "0.31.0",
-                issue=3238,
-                instead=self.is_set,
-            )
-            return True
+    @deprecated
+    def __bool__(self) -> Literal[True]:
+        """Return True and raise warning."""
+        warn_deprecated(
+            self.__bool__,
+            "0.31.0",
+            issue=3238,
+            instead=self.is_set,
+        )
+        return True
 
 
 class _HasAcquireRelease(Protocol):