type (!'a, !'result, !'ty, 'nullable) t = 'a
constraint
'a =
< graphql_arg : ( unit -> 'ty Schema.Arg.arg_typ ) Core_kernel.ref
; map : ( 'ty -> 'result ) Core_kernel.ref
; nullable_graphql_arg :
( unit -> 'nullable Schema.Arg.arg_typ ) Core_kernel.ref
; skip : bool Core_kernel.ref.. >