Internal error for forward reference

[Charles]

The following code causes an internal error:

class A

    var _foo = B.bar


class B

    def bar as String is shared
        return ''

Note that the equivalent C# works fine:

class A {

	protected string _foo = B.Bar();
	
}

class B {

	public static string Bar() {
		return "";
	}

}

Though C# has no "var" at the member var level, nor "from var" for declaring properties.

[Charles]

Note that the error happens during "bind interface" on A and then _foo which causes a "bind implementation" for "B.bar", but B.bar is "not ready" because B has not yet had a "bind interface". This directly happens due to BoxMember.isUsed being set, but I haven't checked if it would happen further in the execution if .isUsed didn't trigger it.

It's kind of surprising that we don't run into this more often.

[Charles]

First reported by kobi7 at  http://cobra-language.com/forums/viewtopic.php?f=4&t=17245

[Charles]

Fixed in changeset:3093

The line is still not accepted, but it is now caught as an error and the error message gives 3 possible changes:

error: Cannot compile initialization expression at this point. Add an
explicit type to the `var` ("as <type>") or move to a `cue init` or change
the expression.

[Charles]

In the description, I said "The equivalent C#" but in fact there is no equivalent C# because there is no var type inference at the class member level. The C# code explicitly types the _foo member. I should have said "The closest C#..."