run S06-operator-overloading/semicolon.t, ivanoff++
Merge pull request #190 from timo/require_is_dynamic

Require "is dynamic"
add a typed exception

for accessing stuff through CALLER that is not dynamic
refactor find_lexical.
first draft on p6store -> unchecked.

this fails at the moment because if a variable gets
a new container bound to it, the assumptions no longer
hold and we need to ignore that val.

we need a knowledge base of "poisoning actions" for this.
refactor find_lexpad_entry.
binds and usages of pseudopackages are now lava.
we can't just throw away post constraints at compile time.
maybe remove type checks for literal assignments
try to not double-check return values of subs
more safety and return typecheck elim for inlined subs.
any mention of eval from the setting and we bail.
less chance to explode at optimize-time.
depth was off-by-one.
WIP on trying to forbid SubsetHOW on the LHS

This can cause code to be run in the optimizer's context
when there's a "where" on a subset. This is bad.

The code given here doesn't actually work. I've tried hundreds
of combinations of things, none seemed to work.
WIP on turning lexicals into locals