The Traversable instance for Array looks unlikely to be good
Currently,
instance Ix i => Traversable (Array i) where
traverse f arr = listArray (bounds arr) `fmap` traverse f (elems arr)Since traverse is (inherently) not a good producer for list fusion, this looks suspicious. I think we almost certainly want to walk the array by hand instead.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.11 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Core Libraries |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | core-libraries-committee@haskell.org |
| Operating system | |
| Architecture |