fileset: move copy constructor of matchctx near __init__

mercurial/fileset.py

@@ -462,6 +462,9 b' class matchctx(object):'
         self._badfn = badfn
         self._status = None
 
+    def switch(self, basectx, ctx):
+        return matchctx(basectx, ctx, self._badfn)
+
     def withstatus(self, keys):
         """Create matchctx which has precomputed status specified by the keys"""
         mctx = matchctx(self._basectx, self.ctx, self._badfn)
@@ -528,9 +531,6 b' class matchctx(object):'
         return matchmod.nevermatcher(repo.root, repo.getcwd(),
                                      badfn=self._badfn)
 
-    def switch(self, basectx, ctx):
-        return matchctx(basectx, ctx, self._badfn)
-
 def match(ctx, expr, badfn=None):
     """Create a matcher for a single fileset expression"""
     tree = filesetlang.parse(expr)