Can't get conjunction type resolution to work about bosquelanguage

[mrkmarron]

Thanks for the very useful bug report. There were a couple of things going on here. One of them was fixed in PR #371 and there is a parser issues I opened bug #372.

The expected result of your example is the type error since you have 2 possible resolutions of the static call -- Foo::ala and Bar::ala. We check that there is only 1 unique resolution of the call. So, the following would be ok:

concept Foo {
    static ala(a: Int): Int {
        _debug("Called Foo::ala");
        return a;
    }
}

concept Bar {
}

entrypoint function main(): Int {
   return Foo&Bar::ala(1);
}

In this case there is only 1 possible resolution -- namely Foo::ala.

This isn't too useful when dealing with explicit types since you could just write Foo::ala instead. However, it can be very convenient when dealing with template instantiation:

function baz<T>(a: Int): Int {
   return T::ala(a);
}

In this case we want to be able to call baz<Foo&Bar>(3) instead of having to ensure that each template type that may be used in a static resolution is unique. Similarly we should also allow cases like:

entity E provides Foo {
}

entrypoint function main(): Int {
   return E::ala(1);
}

In this case we resolve the correct static member from the derived type instead of requiring the developer to use the exact concept type that specifies the static member.

I am merging PR #371 which should get this working but please repoen if there are other issues or questions.