diff -u --label /usr/local/share/emacs/26.0.50/lisp/gnus/gnus-search.el.gz --label /usr/local/share/emacs/26.0.50/lisp/gnus/gnus-search-new.el /tmp/jka-com7573izb /usr/local/share/emacs/26.0.50/lisp/gnus/gnus-search-new.el
--- /usr/local/share/emacs/26.0.50/lisp/gnus/gnus-search.el.gz
+++ /usr/local/share/emacs/26.0.50/lisp/gnus/gnus-search-new.el
@@ -1750,7 +1750,7 @@
     (with-slots (switches config-file) engine
       `(,(format "--config=%s" config-file)
 	"search"
-	(if thread
+	,(if thread
 	    "--output=threads"
 	  "--output=files")
 	"--duplicate=1" ; I have found this necessary, I don't know why.

Diff finished.  Mon Aug 14 21:31:31 2017