fileset: flatten arguments list

Just prepares for flattening 'or' nodes. This change would have no impact on
performance.

mercurial/fileset.py

@@ -103,7 +103,7 b' def parse(expr):'
     tree, pos = p.parse(tokenize(expr))
     if pos != len(expr):
         raise error.ParseError(_("invalid token"), pos)
-    return tree
+    return parser.simplifyinfixops(tree, {'list'})
 
 def getsymbol(x):
     if x and x[0] == 'symbol':
@@ -131,7 +131,7 b' def getlist(x):'
     if not x:
         return []
     if x[0] == 'list':
-        return getlist(x[1]) + [x[2]]
+        return list(x[1:])
     return [x]
 
 def getargs(x, min, max, err):
@@ -174,7 +174,7 b' def minusmatch(mctx, x, y):'
 def negatematch(mctx, x):
     raise error.ParseError(_("can't use negate operator in this context"))
 
-def listmatch(mctx, x, y):
+def listmatch(mctx, *xs):
     raise error.ParseError(_("can't use a list in this context"),
                            hint=_('see hg help "filesets.x or y"'))
 

tests/test-fileset.t

@@ -111,6 +111,15 b' Test invalid syntax'
       None))
   hg: parse error: can't use negate operator in this context
   [255]
+  $ fileset -p parsed 'a, b, c'
+  * parsed:
+  (list
+    (symbol 'a')
+    (symbol 'b')
+    (symbol 'c'))
+  hg: parse error: can't use a list in this context
+  (see hg help "filesets.x or y")
+  [255]
 
   $ fileset '"path":.'
   hg: parse error: not a symbol