rnfail018.hs:12:37: Not in scope: type variable ‛a’

rnfail018.hs:12:42: Not in scope: type variable ‛m’

rnfail018.hs:12:47: Not in scope: type variable ‛m’

rnfail018.hs:12:49: Not in scope: type variable ‛a’