Python from Wise Guy's Viewpoint

[prunesquallor at comcast.net]

Ed Avis <ed at membled.com> writes:

> prunesquallor at comcast.net writes:
>
>>But let us suppose that someone improved the type system of Haskell
>>such that some useful complicated constructs that did not pass the
>>type checker were now able to be verified as correct.
>
> Wouldn't you need to define the semantics for these constructs too?
> And perhaps extend the compiler to generate code for them?
>
> My original point was that the type-checker won't reject programs
> which are valid Haskell, so it makes no sense to talk about the
> checker being too strict or not allowing enough flexibility.  

So any program that currently runs on Haskell will run on the very
first version of Haskell?  No?  But Haskell won't reject programs that
are valid Haskell, so is the later version wrong?