integer is not treated as integer: The union type LENGTHTO field must contain only integer, bitstring or octetstring fields

Summary

the type integer INT1 is not identified as integer

Steps and/or TTCN-3 code to reproduce

module proba {

type union my_attribute_length {
  INT1         short_length,
  LIN2_BO_LAST extended_length
}

type record my_attribute {
  my_attribute_length      attribute_length,
  octetstring  attribute_value
} with {
  variant (attribute_length) "LENGTHTO(attribute_value)"
}

type integer INT1 (0..255) with { variant "FIELDLENGTH(8)" };
type integer LIN2_BO_LAST (0..65535) with { variant "FIELDLENGTH(16), COMP(nosign), BYTEORDER(last)" };


} with {
  encode "RAW"
}

What is the current bug behavior?

proba.ttcn:8.6-11.1: error: The union type LENGTHTO field must contain only integer, bitstring or octetstring fields proba.ttcn:8.6-11.1: error: The union type LENGTHTO field must contain only integer, bitstring or octetstring fields

What is the expected correct behavior?

no error

Relevant logs and/or screenshots

The

type union my_attribute_length {
  integer         short_length,
  integer         extended_length
} with {
  variant (short_length) "FIELDLENGTH(8)"
  variant (extended_length) "FIELDLENGTH(16), COMP(nosign), BYTEORDER(last)"
}

compiled correctly

/cc @aknappqwt @mmagyari