Escape analysis

[pcwalton]

We could use some escape analysis. This will be useful both to ensure that aliases don't escape and to enable optimizations (heap allocation to stack frame for closure environments, etc.)

This should be a separate pass that operates independently (or, someday, in parallel with) the typechecker.

[brson]

What precisely is this about? Have we already implemented any of the things you had in mind in the year since this was opened?

[pcwalton]

Obsolete.