Why does this compile when I make the class a template?

Question

I am purposely using the dot and arrow operator incorrectly, but I'm confused why it compiles when I decide to make the class a template.

Compiles:

template <class B> 
struct Boss {

  bool operator==( Boss & other ) {

    return this.x == other -> x;

  }

};

int main() {

}

Does not compile:

struct Boss {

  bool operator==( Boss & other ) {

    return this.x == other -> x;

  }

};

int main() {

}

Answer 1

Templates are not fully checked for correctness if they are not instantiated. They are only checked for syntax. this.x, while not semantically correct (because this is not, and cannot be a type that supports that operation), is still syntactically correct.

Answer 2

It compiles because templates are not checked until you use it. If you try to do something useful in your main(), it will give you a compile error.