On 02/15/2013 03:52 AM, Simon Peyton-Jones wrote:
| Does this mean that if OverloadedLists is on and more than one fromList | or toList is in scope (even if one of them is GHC.Exts.fromList/toList), | then list literals and patterns (resp.) will not compile?
No... the documentation is poor on that point:
* Normally, it'll use GHC.Exts.fromList (etc) regardless of whether GHC.Exts is imported, or what other fromList's are in scope.
* If you also use -XRebindableSyntax, it'll use whatever fromList is in scope. Then if you imported Data.Map and GHC.Exts it'd be ambiguous.
This is precisely the behaviour of, say integer literals. Normally they desugar to a call of the Prelude's fromInteger, but with RebindableSyntax it becomes whatever fromInteger is in scope.
I'll fix the documentation.
Simon
Ah, that's what I'd expect. Thanks! -Isaac