need some clarification on compile-time type vs. run-time type

[Brendan Eich]

On Nov 9, 2007, at 3:20 PM, Graydon Hoare wrote:

> Types never need to be "re-evaluated" to reflect "mutation"
> in their environment. The evaluation of type expressions can (and
> should) memoize types.

And furthermore, merging type expressions and value expressions, as  
Yuh-Ruey seems to want, at the limit means an undecidable type  
system. We are not planning to approach anything like that. We want  
fixed type terms once open program units that reference them close.

/be