On Wednesday, March 5, 2003, at 05:00 PM, Mark Tullsen wrote:

Here's a (serious) bug in the type-inferencer of the November 2002 Hugs (tested using hugs98-Nov2002-rh7.3-1.i386.rpm):

data T a b = T {f1 :: a, f2 :: b} updateF1 x t = t{f1 = x}

the type inferred for updateF1: observed behavior: updateF1 :: a -> T b c -> T a d expected behavior: updateF1 :: a -> T b c -> T a c

FYI, this bug didn't exist in the Dec 2001 version.

Mark: Slurp in a fresh version from CVS. I suspect that's the bug I introduced, and was kindly spotted and fixed by Ross Patterson. --Jeff