diff --git a/xml/issue4172.xml b/xml/issue4172.xml
index 68ebbacf82..b9dcf670d9 100644
--- a/xml/issue4172.xml
+++ b/xml/issue4172.xml
@@ -3,7 +3,7 @@
Also, the move assignment operator doesn't specify what it returns.
+`shared_lock` has the same problems, and can be fixed in the same way.
+
+Modify
++++shared_lock& operator=(shared_lock&& sl) noexcept; ++-17- Effects: +
+If `owns` calls `pm->unlock_shared()`.+Equivalent to: `shared_lock{std::move(sl)}.swap(*this)`. ++-?- Returns: `*this`. +
++
+-18- Postconditions: +`pm == sl_p.pm` and `owns == sl_p.owns` +(where `sl_p` is the state of `sl` just prior to this assignment), +`sl.pm == nullptr` and `sl.owns == false`. ++