diff --git a/src/_pytest/python.py b/src/_pytest/python.py
index 30853de94..2ce2f3f3a 100644
--- a/src/_pytest/python.py
+++ b/src/_pytest/python.py
@@ -914,7 +914,6 @@ class Metafunc:
         self.cls = cls
 
         self._calls = []
-        self._ids = set()
         self._arg2fixturedefs = fixtureinfo.name2fixturedefs
 
     @property