rsg: improve yacc parsing
rsg: improve yacc parsing

Fixes #12710

glycerine/cockroach,paperstreet/cockroach,glycerine/cockroach,paperstreet/cockroach,maxlang/cockroach,vaibhavarora/cockroach,glycerine/cockroach,paperstreet/cockroach,glycerine/cockroach,glycerine/cockroach,vaibhavarora/cockroach,vaibhavarora/cockroach,paperstreet/cockroach,maxlang/cockroach,glycerine/cockroach,maxlang/cockroach,paperstreet/cockroach,maxlang/cockroach,glycerine/cockroach,maxlang/cockroach,vaibhavarora/cockroach,paperstreet/cockroach,vaibhavarora/cockroach,vaibhavarora/cockroach,maxlang/cockroach,vaibhavarora/cockroach,vaibhavarora/cockroach,paperstreet/cockroach,paperstreet/cockroach,maxlang/cockroach,glycerine/cockroach,maxlang/cockroach