Typechecker goes nuts

Something really weird is happening when typechecking the following trivial program:

int id (int x) { return x; }
int main () { return id ((1, (1, 1))); }

sac2c dies at:

**  6: Running type inference system ...
  **** Enforcing Specializations ...
  **** Running type inference system ...


OOOOOOOPS, your program crashed the compiler 8-((

Backtrace suggests that:

0x00007ffff7af9325 in TYisProd (type=0x0)
    at /tmp/sac2c/src/libsac2c/typecheck/new_types.c:3480
3480	     DBUG_RETURN (NTYPE_CON (type) == TC_prod);
(gdb) backtrace 
#0  0x00007ffff7af9325 in TYisProd (type=0x0)
    at /tmp/sac2c/src/libsac2c/typecheck/new_types.c:3480
#1  0x00007ffff7afafc4 in TYeliminateAlpha (t1=0x0)
    at /tmp/sac2c/src/libsac2c/typecheck/new_types.c:4153

Could it be that (1, (1, 1)) is treated as a tuple by some reason?