# Pastebin p5bVH09H
quoting yunxing here: 
So the problem in log that you posted is that the compiler doesn't know if it should reduce UIDENT to constr_ident or mod_ext_longident
09:51:06 if you look at https://github.com/facebook/reason/issues/491
09:51:49 but if you don't ask it to reduce, it knows how to shift by itself.
09:52:37 so instead of constr_ident generalized_constructor_arguments attributes, you can write two rules like `UIDENT generalized_constructor_arguments attributes` and `UIDENT LPAREN mod_ext_longident RPAREN`
09:53:36 this way, after it reads UIDENT, it won't be confused about which one to reduce, since it doesn't need to reduce at all. It can just shift the UIDENT