Programs compile if commands are declared but not defined about sink HOT 6 CLOSED

More than just that... any of these partial labels can be left dangling around:

def test
    goto foo
end
test

def test
    declare test2
    test2
end
test

do
    declare test
    test
end

etc

from sink.

This is exposing some more weird behavior:

for: range 2
    test:
    say 'hi'
end
goto test

Technically valid, but feels like it shouldn't be. It jumps back into the loop, then falls out because the hidden variable is over the range. What happens if this hidden variable is reassigned?

from sink.

And we also have this beauty:

for: range 2
    goto skip
    var a
    skip:
    say a
    a = 1
end

outputs:

nil
1

from sink.

And this

goto into
for: range 5
    into:
    say 1
end

from sink.

Okay, so rewinding this discussion a bit...

I'm talking about two broad issues:

1. Incomplete labels can currently exist, and cause weird issues -- this needs to be fixed
2. Goto over variable boundaries can happen -- this I'm just accepting as an acceptable cost for using goto in the first place, user beware

from sink.

b3c2d26 fixes

from sink.