forked from GitHub/gf-core
It was used only in cases where a lock field needed to be added to a
run-time variable, like e.g. in examples/phrasebook/SentencesTha.gf:
lin
PGreetingMale g = mkText (lin Text g) (lin Text (ss "ครับ")) | g ;
PGreetingFemale g = mkText (lin Text g) (lin Text (ss "ค่ะ")) | g ;
But lock fields are only meaningful during type checking and can safely be
ignored in later passes.