| The following hugs module is rejected under Hugs 1.3c.
| ...
| with the message:
|
| ERROR "Oops.hs" (line 9): Cannot build superclass instance
| *** Instance : Bar a b
| *** Context supplied : Foo a b (bad type)
| *** Required superclass : Foo a b
|
| Is this a bug, implementation restriction or user error?
It *was* a bug in the original Hugs 1.3c release, but was
fixed in March by the p1 patch. The patches were sent round
to hugs-bugs in April, but if you missed it, you can get a
copy from: http://www.cs.nott.ac.uk/~mpj/hugs13/p1
Alternatively, you might prefer to switch to the 981112
version of Hugs 1.4 that was announced last week, which
inherits all known bugfixes to Hugs 1.3c, including this
one.
All the best,
Mark
