local refs

[Stephen Weeks]

> > I'm rerunning self-compiles to factor in these other global checks (and
> > also to get dominator timing in commonSubexp); 
> 
> That was definitely the cuplrit:
>             localRef starting
>                multi starting
>                multi finished in 0.70 + 1.90 (73% GC)
>                restore totals 3.03 + 3.26 (52% GC)
>                   checkGlobalsViolations totals 1.38 + 2.05 (60% GC)
>                   checkViolations totals 0.11 + 0.0 (0.0% GC)
>                   dominatorTree totals 0.82 + 1.21 (60% GC)
>                   computeDF totals 0.36 + 0.0 (0.0% GC)
>                   computeLive totals 0.02 + 0.0 (0.0% GC)
>                   computePhi totals 0.09 + 0.0 (0.0% GC)
>                   rewrite totals 0.21 + 0.0 (0.0% GC)
>                shrink totals 0.41 + 0.0 (0.0% GC)
>             localRef finished in 5.47 + 6.54 (54% GC)
> 
> Opinions on whether this check is worth keeping in there?

I'd say not.  Either of your other two solutions was fine.  I'd vote
for dropping it entirely, since the type checker catches it.