ChaiScript handling of transitive inheritance

[nickmertin]

• Compiler Used: clang 8.0.0
• Operating System: Linux
• Architecture (ARM/x86/32bit/64bit/etc): x86_64

Expected Behavior

Transitive inheritance implied by known inheritance relationships should be automatically respected.

Actual Behavior

Transitive inheritance relationships bust be explicitly added.

Minimal Example to Reproduce Behavior

#include <iostream>

#include <chaiscript/chaiscript.hpp>

class A {};
class B : public A {};
class C : public B {};

int main() {
    chaiscript::ChaiScript chai;

    chai.add(chaiscript::user_type<A>(), "A");
    chai.add(chaiscript::user_type<B>(), "B");
    chai.add(chaiscript::user_type<C>(), "C");

    chai.add(chaiscript::base_class<A, B>());
    chai.add(chaiscript::base_class<B, C>());
    // chai.add(chaiscript::base_class<A, C>());

    chai.add(chaiscript::fun([] (A) {}), "foo");
    chai.add_global(chaiscript::Boxed_Value{C{}}, "value");

    try {
        chai.eval("foo(value)");
    } catch (chaiscript::exception::eval_error &e) {
        std::cerr << e.pretty_print();
    }
    return 0;
}

Error:

Error: "Error calling function 'foo'" With parameters: (C) during evaluation at (__EVAL__ 1, 1)
                                                           
  Expected: (A)                                            
                                                                                                                       
  __EVAL__ (1, 1) 'foo value  '                                                                                        

The error is fixed by uncommenting the third base_class line; however, this relationship should be presumed based on the previous two.