`sig
type missing_feature =
Pexp_letexception
| Ppat_open
| Pexp_unreachable
| PSig
| Pcstr_record
| Pconst_integer
| Pconst_float
| Pcl_open
| Pcty_open
| Oinherit
| Pwith_typesubst_longident
| Pwith_modsubst_longident
exception Migration_error of Migrate_parsetree_def.missing_feature *
Location.t
val missing_feature_description :
Migrate_parsetree_def.missing_feature -> string
val missing_feature_minimal_version :
Migrate_parsetree_def.missing_feature -> string
val migration_error_message :
Migrate_parsetree_def.missing_feature -> string
end`