#4069: aSet.remove(otherSet) would always report the empty frozenset([]) as the missing key.
Now it correctly refers to the initial otherset.
Reviewed by Raymond. Will backport to 2.6.
diff --git a/Misc/NEWS b/Misc/NEWS
index c32bd68..50494f4 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,11 @@
Core and Builtins
-----------------
+- Issue #4069: When set.remove(element) is used with a set element, the element
+ is temporarily replaced with an equivalent frozenset. But the eventual
+ KeyError would always report the empty frozenset([]) as the missing key. Now
+ it correctly refers to the initial element.
+
Library
-------