cparser can't handle some usage of (probably invalid) weird struct initializations

[GabrielRavier]

typedef struct
{
    int a;
} s1;

struct s2
{
    s1;
    int s1;
};

void f(struct s2* p)
{
}

cparser outputs this :

cparser: ./src/ast/type_t.h:266: is_type_compound: Assertion `!is_typeref(type)' failed.
Aborted (core dumped)