If topicalization

[Luke Palmer]

I vaguely recall that we went over this already, but I forgot the
conclusion if we did.

In Damian and Larry's talk here at OSCON, I saw the example:

    if foo() -> $foo {
        # use $foo
    }

How can that possibly work?  If a bare closure { } is equivalent to ->
?$_ is rw { }, then the normal:

    if foo() {...}

Turns into:

    if foo() -> ?$_ is rw { }

And every if topicalizes! I'm sure we don't want that.

Luke