Fix version brackets in CHOICE

[johvik]

Quote from Rec. ITU-T X.691 (02/2021) end of section 23: "NOTE – Version brackets in the definition of choice extension additions have no effect on how "ExtensionAdditionAlternatives" are encoded."

In other words elements inside version brackets should not be grouped together for CHOICE (as opposed to how its done for SEQUENCE).

[mouse07410]

First, apologies for delayed response.

Could you give an example or two of what the current situation is, and how it would look after your PR is merged?

[johvik]

I will use the test I added (tests/tests-asn1c-compiler/165-choice-extended-group-OK.asn1) as an example.

Before this change it produced this struct:

typedef struct Choice {
	Choice_PR present;
	union Choice_u {
		long	 a;
		/*
		 * This type is extensible,
		 * possible extensions are below.
		 */
		long	 b;
		struct ext1 {
			long	 c;
			
			/* Context for parsing across buffer boundaries */
			asn_struct_ctx_t _asn_ctx;
		} *ext1;
		struct ext2 {
			long	 d;
			long	 e;
			
			/* Context for parsing across buffer boundaries */
			asn_struct_ctx_t _asn_ctx;
		} *ext2;
		struct ext3 {
			long	 f;
			long	 g;
			
			/* Context for parsing across buffer boundaries */
			asn_struct_ctx_t _asn_ctx;
		} *ext3;
	} choice;
	
	/* Context for parsing across buffer boundaries */
	asn_struct_ctx_t _asn_ctx;
} Choice_t;

After this change it produces this struct:

typedef struct Choice {
	Choice_PR present;
	union Choice_u {
		long	 a;
		/*
		 * This type is extensible,
		 * possible extensions are below.
		 */
		long	 b;
		long	 c;
		long	 d;
		long	 e;
		long	 f;
		long	 g;
	} choice;
	
	/* Context for parsing across buffer boundaries */
	asn_struct_ctx_t _asn_ctx;
} Choice_t;