From d599a535b2739f9a441c33e95ec8bb521516d18b Mon Sep 17 00:00:00 2001
From: Bas van Beek <43369155+BvB93@users.noreply.github.com>
Date: Sat, 4 Sep 2021 18:16:53 +0200
Subject: [PATCH] Allow `math.trunc` to only accept `__trunc__`-supporting
 objects (#6003)

Add SupportsTrunc protocol
---
 stdlib/_typeshed/__init__.pyi | 3 +++
 stdlib/math.pyi               | 3 ++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/stdlib/_typeshed/__init__.pyi b/stdlib/_typeshed/__init__.pyi
index cf67751f8..493c4d088 100644
--- a/stdlib/_typeshed/__init__.pyi
+++ b/stdlib/_typeshed/__init__.pyi
@@ -41,6 +41,9 @@ class SupportsLenAndGetItem(Protocol[_T_co]):
     def __len__(self) -> int: ...
     def __getitem__(self, __k: int) -> _T_co: ...
 
+class SupportsTrunc(Protocol):
+    def __trunc__(self) -> int: ...
+
 # Mapping-like protocols
 
 # stable
diff --git a/stdlib/math.pyi b/stdlib/math.pyi
index 5a1e71a1c..1046676be 100644
--- a/stdlib/math.pyi
+++ b/stdlib/math.pyi
@@ -1,4 +1,5 @@
 import sys
+from _typeshed import SupportsTrunc
 from typing import Iterable, SupportsFloat, SupportsInt, Tuple, overload
 
 e: float
@@ -94,7 +95,7 @@ def sinh(__x: SupportsFloat) -> float: ...
 def sqrt(__x: SupportsFloat) -> float: ...
 def tan(__x: SupportsFloat) -> float: ...
 def tanh(__x: SupportsFloat) -> float: ...
-def trunc(__x: SupportsFloat) -> int: ...
+def trunc(__x: SupportsTrunc) -> int: ...
 
 if sys.version_info >= (3, 9):
     def ulp(__x: SupportsFloat) -> float: ...