#9590: AMP breaks `haskell2010` package -------------------------------------+------------------------------------- Reporter: hvr | Owner: ekmett Type: bug | Status: closed Priority: high | Milestone: 7.10.1 Component: Core Libraries | Version: 7.9 Resolution: fixed | Keywords: AMP, Operating System: Unknown/Multiple | report-impact Type of failure: GHC rejects | Architecture: valid program | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: Phab:D510 -------------------------------------+------------------------------------- Comment (by hvr): Even something like `{-# LANGUAGE RebindableSyntax=haskell2010:Prelude.Syntax -#}` would already be an improvement with the following semantic: - desugaring like `-XRebindableSyntax`, - *but* rather than the local scope, only what's exported by the `Prelude.Syntax` module (from the `haskell2010` package) is used for desugaring, - and `Prelude.Syntax` can be a hidden module of the `haskell2010` package (to avoid polluting the module namespace) This could allow (maybe) to write a simple shell-script wrapper `ghci2010` (or `ghc2010`) in the style of {{{#!bash #!/bin/sh ghci -XHaskell2010 \ -hide-all-packages -package haskell2010 \ -XRebindableSyntax=haskell2010:Prelude.Syntax $* }}} This is similar to the `{-# LANGUAGE Prelude=AlternatePrelude #-}` idea we were floating recently, but also takes into account desugaring. NB: this doesn't solve the issue of packages compiled against `base` and `haskell2010` to have diverging typeclass hierarchies. But I don't think we can solve that without a significant amount of complexity. I'd rather suggest to instead have packages actively support `haskell2010` (maybe as Cabal configuration option via flags, or via hs2010-compat-layer packages -- not sure yet which is best) for those few packages where there's enough demand to (like e.g. something like `containers`). My main motivation for a `haskell2010` package is to have a reference implementation for the Haskell 2010 report (which can be useful for teaching, or for being able to compile some ancient "pure" Haskell2010 code with the latest GHC), rather than having full Hackage compatibility... -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9590#comment:19 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler