diff -r 50a6c3c55db1 -r 9452112c8eb0 mercurial/templater.py
--- a/mercurial/templater.py	Fri Jun 12 14:43:59 2015 -0700
+++ b/mercurial/templater.py	Sat Jun 13 20:14:22 2015 +0900
@@ -248,7 +248,7 @@
 
     def getpatterns(i):
         if i < len(args):
-            s = args[i][1].strip()
+            s = stringify(args[i][0](context, mapping, args[i][1])).strip()
             if s:
                 return [s]
         return []