Shadowing

[kjx]

what should the shadowing rules be (raised by Kim)

[kjx]

I still don't know what the shadowing rules are (see also #75, #140, #141).

There seem to be two parts:

• what declarations are forbidden from shadowing other attributes (just method arguments? method argument and locals? all names?)
• what declarations cannot be shadowed?

The most general rule is: all declarations are forbidden from shadowing, and all declarations cannot be shadowed: !findInternalDeclaringContext(name).isMissing (we do a lookup and we find a preëxisting definition). That rule, for example, forbids the following because bar.inner.x would shadow the x method in bar inherited from foo:

class foo {
    method x { "X" }
}

class bar {
    inherit foo
    class inner {
        method x { "XXXXX" }
        method y(x) { "YYYY" }
    }
}

Or (along each axis):

• should bar.inner.x only shadow a local definition in bar, not one inherited from foo?
• should bar.inner.x be permitted to shadow (almost) anything, but y's x method argument should be forbidden as it shadows the enclosing x?