GSOC | Extending Common Lisp support

[Per Bothner]

On 04/26/2012 03:18 PM, Charles Turner wrote:
> (define (test)
>    (let ((x :: integer 10.5))
>      (* x x)))
> /dev/stdin:2:23: warning - type DFloNum is incompatible with required
> type integer
> /dev/stdin:3:5: warning - cannot convert literal (of type
> gnu.math.DFloNum) to Type integer
>
> So far, as expected. But when you type (test), you get:
>
> Value '110.25' has wrong type (DFloNum) (expected: integer)

This looks like a bug in constant folding.
We're multiplying 10.5 and 10.5 - and eliminating the cast/conversion
of 10.5 to integer.  In this case we know the cast always
fails, so we shouldn't do the constant-folding.  But even if the
cast succeeds, we need to used the converted value.  I recently fixed
a bug to do that, so it is possible it works for the non-fail case.

This issue seems related to the unreachable-code issue.  I.e. the
type x really should be "unreachable" or Type.neverReturnsType.
I am looking at improvements in the area of unreachable code,
which I intend to check in soon (i.e. before the 1.12 release).

Perhaps you could record this as case as a Savannah bug so we
don't forget this?
-- 
	--Per Bothner
per@bothner.com   http://per.bothner.com/