Incorrect SMT2 generation when using C structs

[david-k]

The following program is correctly verified by CBMC but fails with Z3 (outputs sat) using the generated SMT2 file:

typedef struct
{
	char val;
} Struct;

int main()
{
	char a;
	Struct r;
	r.val = a;

	__CPROVER_assert(r.val == a, "equal");
}

On the other hand, if you directly initialize r (Struct r = {a};) then Z3 outputs the correct result. The SMT2 file is a bit above my head so I couldn't really figure out what's wrong.

[kroening]

I get UNSAT with either minisat or Z3; can you confirm that you are using the latest version of CBMC, please?

[david-k]

I can confirm this for CBMC 5.6 and for master from a couple of days ago. Also, it's only SMT2 that seems to be wrong, DIMACS works fine.

Here is the incorrect SMT2 file:
smt2.txt

[tautschnig]

This works fine with today's version of CBMC, and perhaps any version since 5.7.