What is a type error?

[Marshall]

Joachim Durchholz wrote:
> Darren New schrieb:
> > As far as I understand it, Eiffel compilers don't even make use of
> > postconditions to optimize code or eliminate run-time checks (like null
> > pointer testing).
>
> That's correct.
>
> I think a large part of the reasons why this isn't done is that Eiffel's
> semantics is (a) too complicated (it's an imperative language after
> all), and (b) not formalized, which makes it difficult to assess what
> optimizations are safe and what aren't.

I can see the lack of a formal model being an issue, but is the
imperative bit really all that much of an obstacle? How hard
is it really to deal with assignment? Or does the issue have
more to do with pointers, aliasing, etc.?


Marshall