Extention function position types are not generated for nested sequences

[joukewitteveen]

If save-position is applied to a grandchild in a sequence, the *_extention_function_positions type is not generated, but the encoding/decoding code does rely on it.

The following reproducer is adapted from the CRC example and tested for the C code generated.

-- ASN.1

MYMODULE DEFINITIONS ::= BEGIN

PacketHeader ::= SEQUENCE
{
    version    INTEGER(1..100),
    release    INTEGER(1..100)
}

PacketPayload ::= CHOICE
{
    aReal               REAL,
    anInteger           INTEGER (0 .. 65535),
    anotherSizeArray    SEQUENCE (SIZE (1..100)) OF INTEGER (1..200)
}

Packet ::= SEQUENCE {
    p-header PacketHeader,
    p-body   SEQUENCE {
        p-payload PacketPayload
    }
}

END

-- ACN

MYMODULE DEFINITIONS ::= BEGIN

Packet [post-encoding-function my-encoding-patcher, post-decoding-validator crc-validator]
{
    p-header [],
    p-body   [] {
        p-payload [],
        packet-crc32 NULL [pattern '00000000'H, save-position] -- 32 bits
    }
}

END

The following errors from the gcc output show how the correct encoding function is generated, but the type definition is missing:

a.c: In function ‘Packet_ACN_Encode’:
a.c:428:9: error: unknown type name ‘Packet_extension_function_positions’
  428 |         Packet_extension_function_positions bitStreamPositions_1;
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.c:443:45: error: request for member ‘Packet_p_body_packet_crc32’ in something not a structure or union
  443 |                         bitStreamPositions_1.Packet_p_body_packet_crc32 = *pBitStrm; //save position of the bit stream
      |                                             ^

It would be very nice if the type were generated (instead of deciding this is not supported).