--- a/mercurial/templatefuncs.py	Sat Mar 31 23:34:15 2018 -0700
+++ b/mercurial/templatefuncs.py	Sun Apr 01 11:06:29 2018 +0900
@@ -175,7 +175,7 @@
     if len(args) != 1:
         raise error.ParseError(_("mailmap expects one argument"))
 
-    author = evalfuncarg(context, mapping, args[0])
+    author = evalstring(context, mapping, args[0])
 
     cache = context.resource(mapping, 'cache')
     repo = context.resource(mapping, 'repo')