LWG3788 jthread::operator=(jthread&&) postconditions are unimplementable under self-assignment

Author: burblebee

source/threads.tex

@@ -1756,19 +1756,18 @@
 \begin{itemdescr}
 \pnum
 \effects
-If \tcode{joinable()} is \tcode{true},
-calls \tcode{request_stop()} and then \tcode{join()}.
-Assigns the state of \tcode{x} to \tcode{*this}
+If \tcode{\&x == this} is \tcode{true}, there are no effects.
+Otherwise, if \tcode{joinable()} is \tcode{true},
+calls \tcode{request_stop()} and then \tcode{join()},
+then assigns the state of \tcode{x} to \tcode{*this}
 and sets \tcode{x} to a default constructed state.
 
 \pnum
 \ensures
-\tcode{x.get_id() == id()}
-and \tcode{get_id()} returns the value of \tcode{x.get_id()}
+\tcode{get_id()} returns the value of \tcode{x.get_id()}
 prior to the assignment.
 \tcode{ssource} has the value of \tcode{x.ssource}
-prior to the assignment
-and \tcode{x.ssource.stop_possible()} is \tcode{false}.
+prior to the assignment.
 
 \pnum
 \returns