Implicitly capturing this in a closure fails in the C++ compiler

[weltschildkroete]

The following code

struct Foo {
    public message: String

    public function print_message(this) {
        let captures_this = function() {
            println(this.message)
        }

        captures_this()
    }
}

gives a error: 'this' cannot be implicitly captured in this context in the C++ compiler, when it should probably just fail in the jakt compiler.

[awesomekling]

Indeed, it looks like we don't validate captures at all right now.
Definitely an area that needs improvement :)