chibicc accepts invalid code

Hi. I've been working on a fork of chibicc to implement my own ideas. I noticed that chibicc accepts invalid code in many cases.

For example this code:

struct A
{
    struct { char b; } aa;
};

struct A
{
    float ff;
};

int foo(int i)
{
    return i;
}

int main()
{
    struct A a = 50;
    char *a = 100;
    return foo(a);
}

Something that should have been rejected:

• redefinition of struct
• assigning a struct variable with the wrong type
• assigning a char* variable with the wrong type
• re-declaring local variable with same name.
• calling a foo with char* when it takes int

I can try to make PRs for some of these, but I'm worried this project is abandoned and doesn't accept PRs anymore.