ComponentCounter

@component struct TestComponent0
{
    int a, b;
}

@component class TestComponent1 // component cannot be a class
{
    string str;
}

@component union TestComponent2
{
    float f;
    uint  u;
}

static assert(!isComponent!int);
static assert(isComponent!TestComponent0);
static assert(!isComponent!TestComponent1);
static assert(isComponent!TestComponent2);