mercurial/minifileset.py

--- a/mercurial/minifileset.py	Thu Jan 04 14:20:58 2018 +0900
+++ b/mercurial/minifileset.py	Sat Jan 13 15:07:37 2018 +0900
@@ -56,9 +56,8 @@
             'size': lambda n, s: fileset.sizematcher(tree[2])(s),
         }
 
-        x = tree[1]
-        name = x[1]
-        if x[0] == 'symbol' and name in symbols:
+        name = fileset.getsymbol(tree[1])
+        if name in symbols:
             return symbols[name]
 
         raise error.UnknownIdentifier(name, symbols.keys())