[GHC] #10868: Make GHC generics capable of handling unboxed types
#10868: Make GHC generics capable of handling unboxed types -------------------------------------+------------------------------------- Reporter: | Owner: RyanGlScott RyanGlScott | Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #8468 Differential Revisions: | -------------------------------------+------------------------------------- Currently, GHC generics will not accept any unboxed constructor arguments: {{{ $ ghci GHCi, version 7.10.2: http://www.haskell.org/ghc/ :? for help λ> :set -XMagicHash -XDeriveGeneric λ> :m + GHC.Generics GHC.Exts λ> data IntHash = IntHash Int# deriving Generic <interactive>:4:38: Can't make a derived instance of ‘Generic IntHash’: IntHash must not have unlifted or polymorphic arguments In the data declaration for ‘IntHash’ }}} This makes GHC generics strictly less powerful than `deriving` clauses in some scenarios, as typeclasses like `Eq`, `Ord`, and `Show` are capable of special-casing certain unboxed types: {{{ λ> :set -ddump-deriv λ> data IntHash = IntHash Int# deriving Show ==================== Derived instances ==================== Derived instances: instance GHC.Show.Show Ghci1.IntHash where GHC.Show.showsPrec a_a1OJ (Ghci1.IntHash b1_a1OK) = GHC.Show.showParen ((a_a1OJ GHC.Classes.>= 11)) ((GHC.Base..) (GHC.Show.showString "IntHash ") (GHC.Show.showsPrec 11 (GHC.Types.I# b1_a1OK))) GHC.Show.showList = GHC.Show.showList__ (GHC.Show.showsPrec 0) }}} As discussed on the GHC devs mailing list [https://mail.haskell.org/pipermail/ghc-devs/2015-September/009895.html previously], Andres suggested adding new generic representation types to mark where `Int#`, `Char#`, etc. are used (suggesting the name `UInt` to represent `Int#`). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10868> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler
#10868: Make GHC generics capable of handling unboxed types -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: | RyanGlScott Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #8468 | Differential Revisions: Phab:D1239 -------------------------------------+------------------------------------- Changes (by RyanGlScott): * differential: => Phab:D1239 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10868#comment:1> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler
#10868: Make GHC generics capable of handling unboxed types -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: RyanGlScott Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #8468 | Differential Rev(s): Phab:D1239 -------------------------------------+------------------------------------- Comment (by Ben Gamari <ben@…>): In [changeset:"6cde981a8788b225819be28659caddc35b77972d/ghc" 6cde981/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="6cde981a8788b225819be28659caddc35b77972d" Make GHC generics capable of handling unboxed types This adds a data family (`URec`) and six data family instances (`UAddr`, `UChar`, `UDouble`, `UFloat`, `UInt`, and `UWord`) which a `deriving Generic(1)` clause will generate if it sees `Addr#`, `Char#`, `Double#`, `Float#`, `Int#`, or `Word#`, respectively. The programmer can then provide instances for these data family instances to provide custom implementations for unboxed types, similar to how derived `Eq`, `Ord`, and `Show` instances currently special-case unboxed types. Fixes #10868. Test Plan: ./validate Reviewers: goldfire, dreixel, bgamari, austin, hvr, kosmikus Reviewed By: dreixel, kosmikus Subscribers: simonpj, thomie Differential Revision: https://phabricator.haskell.org/D1239 GHC Trac Issues: #10868 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10868#comment:2> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler
#10868: Make GHC generics capable of handling unboxed types -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: RyanGlScott Type: feature request | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #8468 | Differential Rev(s): Phab:D1239 -------------------------------------+------------------------------------- Changes (by bgamari): * status: new => closed * resolution: => fixed -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10868#comment:3> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler
#10868: Make GHC generics capable of handling unboxed types -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: RyanGlScott Type: feature request | Status: closed Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: 7.10.2 Resolution: fixed | Keywords: Generics Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #8468 | Differential Rev(s): Phab:D1239 Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * keywords: => Generics -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10868#comment:5> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler
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