1. 23 May, 2014 2 commits
  2. 15 May, 2014 1 commit
    • Herbert Valerio Riedel's avatar
      Add LANGUAGE pragmas to compiler/ source files · 23892440
      Herbert Valerio Riedel authored
      In some cases, the layout of the LANGUAGE/OPTIONS_GHC lines has been
      reorganized, while following the convention, to
      - place `{-# LANGUAGE #-}` pragmas at the top of the source file, before
        any `{-# OPTIONS_GHC #-}`-lines.
      - Moreover, if the list of language extensions fit into a single
        `{-# LANGUAGE ... -#}`-line (shorter than 80 characters), keep it on one
        line. Otherwise split into `{-# LANGUAGE ... -#}`-lines for each
        individual language extension. In both cases, try to keep the
        enumeration alphabetically ordered.
        (The latter layout is preferable as it's more diff-friendly)
      While at it, this also replaces obsolete `{-# OPTIONS ... #-}` pragma
      occurences by `{-# OPTIONS_GHC ... #-}` pragmas.
  3. 06 May, 2014 1 commit
    • Simon Peyton Jones's avatar
      Modularise pretty-printing for foralls · 3c3ce829
      Simon Peyton Jones authored
      See TypeRep.pprUserForAll.  This just makes forall-printing a bit more
      consistent.  In particular, I wasn't seeing the kind foralls when
      displaying a CoAxiom or CoAxBranch
      The output on T7939 is just possible a bit too verbose now, but even if so
      that's an error in the right direction.
  4. 17 Mar, 2014 1 commit
  5. 01 Feb, 2014 1 commit
  6. 27 Nov, 2013 2 commits
    • Joachim Breitner's avatar
      Get rid of EvCoercible · 808ded9c
      Joachim Breitner authored
      and use EvCoercion to describe the evidence for Coercible instances.
    • Joachim Breitner's avatar
      Roleify TcCoercion · 9d643cf6
      Joachim Breitner authored
      Previously, TcCoercion were only used to represent boxed Nominal
      coercions. In order to also talk about boxed Representational coercions
      in the type checker, we add Roles to TcCoercion. Again, we closely
      mirror Coercion.
      The roles are verified by a few assertions, and at the latest after
      conversion to Coercion. I have put my trust in the comprehensiveness of
      the testsuite here, but any role error after desugaring popping up now
      might be caused by this refactoring.
  7. 22 Nov, 2013 2 commits
    • Simon Peyton Jones's avatar
      Replace (State# RealWorld) with Void# where we just want a 0-bit value · f4384647
      Simon Peyton Jones authored
      We were re-using the super-magical "state token" type (which has
      VoidRep and is zero bits wide) for situations in which we simply want
      to lambda-abstract over a zero-bit argument. For example, join points:
         case (case x of { True -> e1; False -> e2 }) of
            Red  -> f1
            Blue -> True
        let $j1 = \voidArg::Void# -> f1
        case x of
          True -> case e1 of
                    Red -> $j1 void
                    Blue -> True
          False -> case e2 of
                    Red -> $j1 void
                    Blue -> True
      This patch introduces
         * The new primitive type GHC.Prim.Void#, with PrimRep = VoidRep
         * A new global Id GHC.Prim.voidPrimId :: Void#.
           This has no binding because the code generator drops it,
           but is used as an argument (eg in the call of $j1)
         * A new local Id, MkId.voidArgId, which can be lambda-bound
           when you need to lambda-abstract over it.
      and uses them throughout.
      Now the State# thing is used only when we need state!
    • Simon Peyton Jones's avatar
      Fix type-equality in the type checker (fixes Trac #8553) · 985663ea
      Simon Peyton Jones authored
      For horrible reasons (Note [Comparison with OpenTypeKind] in Type), the
      function Type.eqType currently equates OOpenKind with *.  This may or may
      not be a good idea (it's certainly a revolting one) but it DOES NOT WORK
      in the type checker, which *does* need to distinguish OpenKind and *.
      Rather than solve the underlying problem (I have some ideas) I just
      introduced a new, and very short, simple, straightforward function
      TcType.tcEqType to do the job.
  8. 20 Nov, 2013 1 commit
  9. 12 Oct, 2013 1 commit
  10. 01 Oct, 2013 1 commit
  11. 20 Sep, 2013 1 commit
  12. 13 Sep, 2013 1 commit
  13. 08 Sep, 2013 1 commit
  14. 02 Sep, 2013 1 commit
    • Simon Peyton Jones's avatar
      Make Specialise close over kind variables (fixes Trac #8196) · 8d7dd547
      Simon Peyton Jones authored
      This is a lingering bug from the introduction of polymorphic kinds.
      In the specialiser we were specialising over a type, but failing
      to specialise over the kinds it mentions.
      The fix is simple: add a call to closeOverKinds.
      Most of the patch is to add closeOverKinds, and to use it in a few
      other places where we are doing essentially the same thing.
  15. 02 Aug, 2013 1 commit
  16. 11 Jun, 2013 1 commit
  17. 10 Jun, 2013 1 commit
    • Simon Peyton Jones's avatar
      Fix egregious typo in cmpTypeX · 0239d783
      Simon Peyton Jones authored
      Reported in Trac #7272.  "tv1" should be "tv2"!
      However, things weren't as simple as they sound, because
      treating (x:Open) as different from (x:*) gave rise to
      new failures; see Note [Comparison with OpenTypeKind] in Type.
      My hacky solution is to treat OpenKind as equal to * and #,
      at least in Core etc.  Hence the faff in Type.cmpTc.
      I do not like this.  But it seems like another messy consequence
      of including sub-kinding.  Sigh.
  18. 06 Jun, 2013 1 commit
    • Simon Peyton Jones's avatar
      Add TyCon.checkRecTc, and use in in typeArity · a1a67b58
      Simon Peyton Jones authored
      This just formalises an abstraction we've been using anyway,
      namely to expand "recursive" TyCons until we see them twice.
      We weren't doing this in typeArity, and that inconsistency
      was leading to a subsequent ASSERT failure, when compiling
      Stream.hs, which has a newtype like this
         newtype Stream m a b = Stream (m (Either b (a, Stream m a b)))
  19. 30 May, 2013 1 commit
  20. 03 May, 2013 1 commit
    • Simon Peyton Jones's avatar
      Make isPredTy not use typeKind · f3472f55
      Simon Peyton Jones authored
      The pretty-printer uses isPredTy to decide whether to use "=>" or "->",
      and typeKind crashes on ill-kinded types. But it's really unhelpful for
      the pretty-printer to crash on an ill-kinded type, because then you can't
      see it!
  21. 06 Apr, 2013 1 commit
  22. 15 Feb, 2013 1 commit
  23. 28 Jan, 2013 1 commit
    • Simon Peyton Jones's avatar
      Pure refactoring · f1fa6eb2
      Simon Peyton Jones authored
      * Move tidyType and friends from TcType to TypeRep
        (It was always wrong to have it in TcType.)
      * Move mkCoAxBranch and friends from FamInst to Coercion
      * Move pprCoAxBranch and friends from FamInstEnv to Coercion
      No change in functionality, though there might be a little
      wibble in error message output, because I combined two different
      functions both called pprCoAxBranch!
  24. 25 Jan, 2013 1 commit
  25. 24 Jan, 2013 1 commit
    • Simon Peyton Jones's avatar
      Introduce CPR for sum types (Trac #5075) · d3b8991b
      Simon Peyton Jones authored
      The main payload of this patch is to extend CPR so that it
      detects when a function always returns a result constructed
      with the *same* constructor, even if the constructor comes from
      a sum type.  This doesn't matter very often, but it does improve
      some things (results below).
      Binary sizes increase a little bit, I think because there are more
      wrappers.  This with -split-objs.  Without split-ojbs binary sizes
      increased by 6% even for HelloWorld.hs.  It's hard to see exactly why,
      but I think it was because System.Posix.Types.o got included in the
      linked binary, whereas it didn't before.
              Program           Size    Allocs   Runtime   Elapsed  TotalMem
                fluid          +1.8%     -0.3%      0.01      0.01     +0.0%
                  tak          +2.2%     -0.2%      0.02      0.02     +0.0%
                 ansi          +1.7%     -0.3%      0.00      0.00     +0.0%
            cacheprof          +1.6%     -0.3%     +0.6%     +0.5%     +1.4%
              parstof          +1.4%     -4.4%      0.00      0.00     +0.0%
              reptile          +2.0%     +0.3%      0.02      0.02     +0.0%
                  Min          +1.1%     -4.4%     -4.7%     -4.7%    -15.0%
                  Max          +2.3%     +0.3%     +8.3%     +9.4%    +50.0%
       Geometric Mean          +1.9%     -0.1%     +0.6%     +0.7%     +0.3%
      Other things in this commit
      * Got rid of the Lattice class in Demand
      * Refactored the way that products and newtypes are
        decomposed (no change in functionality)
  26. 22 Dec, 2012 1 commit
    • eir@cis.upenn.edu's avatar
      Implement overlapping type family instances. · 8366792e
      eir@cis.upenn.edu authored
      An ordered, overlapping type family instance is introduced by 'type
      where', followed by equations. See the new section in the user manual
      ( for details. The canonical example is Boolean equality at the
      type family Equals (a :: k) (b :: k) :: Bool
      type instance where
        Equals a a = True
        Equals a b = False
      A branched family instance, such as this one, checks its equations in
      and applies only the first the matches. As explained in the note
      checking within groups] in FamInstEnv.lhs, we must be careful not to
      say, (Equals Int b) to False, because b might later unify with Int.
      This commit includes all of the commits on the overlapping-tyfams
      branch. SPJ
      requested that I combine all my commits over the past several months
      into one
      monolithic commit. The following GHC repos are affected: ghc, testsuite,
      utils/haddock, libraries/template-haskell, and libraries/dph.
      Here are some details for the interested:
      - The definition of CoAxiom has been moved from TyCon.lhs to a
        new file CoAxiom.lhs. I made this decision because of the
        number of definitions necessary to support BranchList.
      - BranchList is a GADT whose type tracks whether it is a
        singleton list or not-necessarily-a-singleton-list. The reason
        I introduced this type is to increase static checking of places
        where GHC code assumes that a FamInst or CoAxiom is indeed a
        singleton. This assumption takes place roughly 10 times
        throughout the code. I was worried that a future change to GHC
        would invalidate the assumption, and GHC might subtly fail to
        do the right thing. By explicitly labeling CoAxioms and
        FamInsts as being Unbranched (singleton) or
        Branched (not-necessarily-singleton), we make this assumption
        explicit and checkable. Furthermore, to enforce the accuracy of
        this label, the list of branches of a CoAxiom or FamInst is
        stored using a BranchList, whose constructors constrain its
        type index appropriately.
      I think that the decision to use BranchList is probably the most
      controversial decision I made from a code design point of view.
      Although I provide conversions to/from ordinary lists, it is more
      efficient to use the brList... functions provided in CoAxiom than
      always to convert. The use of these functions does not wander far
      from the core CoAxiom/FamInst logic.
      BranchLists are motivated and explained in the note [Branched axioms] in
      - The CoAxiom type has changed significantly. You can see the new
        type in CoAxiom.lhs. It uses a CoAxBranch type to track
        branches of the CoAxiom. Correspondingly various functions
        producing and consuming CoAxioms had to change, including the
        binary layout of interface files.
      - To get branched axioms to work correctly, it is important to have a
        of type "apartness": two types are apart if they cannot unify, and no
        substitution of variables can ever get them to unify, even after type
        simplification. (This is different than the normal failure to unify
        of the type family bit.) This notion in encoded in tcApartTys, in
        Because apartness is finer-grained than unification, the tcUnifyTys
        calls tcApartTys.
      - CoreLinting axioms has been updated, both to reflect the new
        form of CoAxiom and to enforce the apartness rules of branch
        application. The formalization of the new rules is in
      - The FamInst type (in types/FamInstEnv.lhs) has changed
        significantly, paralleling the changes to CoAxiom. Of course,
        this forced minor changes in many files.
      - There are several new Notes in FamInstEnv.lhs, including one
        discussing confluent overlap and why we're not doing it.
      - lookupFamInstEnv, lookupFamInstEnvConflicts, and
        lookup_fam_inst_env' (the function that actually does the work)
        have all been more-or-less completely rewritten. There is a
        Note [lookup_fam_inst_env' implementation] describing the
        implementation. One of the changes that affects other files is
        to change the type of matches from a pair of (FamInst, [Type])
        to a new datatype (which now includes the index of the matching
        branch). This seemed a better design.
      - The TySynInstD constructor in Template Haskell was updated to
        use the new datatype TySynEqn. I also bumped the TH version
        number, requiring changes to DPH cabal files. (That's why the
        DPH repo has an overlapping-tyfams branch.)
      - As SPJ requested, I refactored some of the code in HsDecls:
       * splitting up TyDecl into SynDecl and DataDecl, correspondingly
         changing HsTyDefn to HsDataDefn (with only one constructor)
       * splitting FamInstD into TyFamInstD and DataFamInstD and
         splitting FamInstDecl into DataFamInstDecl and TyFamInstDecl
       * making the ClsInstD take a ClsInstDecl, for parallelism with
         InstDecl's other constructors
       * changing constructor TyFamily into FamDecl
       * creating a FamilyDecl type that stores the details for a family
         declaration; this is useful because FamilyDecls can appear in classes
         other decls cannot
       * restricting the associated types and associated type defaults for a
       * class
         to be the new, more restrictive types
       * splitting cid_fam_insts into cid_tyfam_insts and cid_datafam_insts,
         according to the new types
       * perhaps one or two more that I'm overlooking
      None of these changes has far-reaching implications.
      - The user manual, section, is updated to describe the new type
  27. 19 Dec, 2012 2 commits
  28. 01 Dec, 2012 2 commits
    • Simon Peyton Jones's avatar
      Remove dead code predTreePredType · b5ce9deb
      Simon Peyton Jones authored
    • eir@cis.upenn.edu's avatar
      Added GHC formalism to the GHC source tree. · 81b7e587
      eir@cis.upenn.edu authored
      As per a request from Simon PJ, I wrote up a formalism of the core
      language in GHC, System FC. The writeup lives in docs/core-spec.
      I also added comments to a number of files dealing with the core
      language reminding authors to update the formalism when updating the
      code. In the next commit will be a README file in docs/core-spec
      with more details of how to do this.
  29. 26 Nov, 2012 1 commit
  30. 02 Oct, 2012 1 commit
  31. 17 Sep, 2012 1 commit
    • Simon Peyton Jones's avatar
      Add type "holes", enabled by -XTypeHoles, Trac #5910 · 8a9a7a8c
      Simon Peyton Jones authored
      This single commit combines a lot of work done by
      Thijs Alkemade <thijsalkemade@gmail.com>, plus a slew
      of subsequent refactoring by Simon PJ.
      The basic idea is
      * Add a new expression form "_", a hole, standing for a not-yet-written expression
      * Give a useful error message that
         (a) gives the type of the hole
         (b) gives the types of some enclosing value bindings that
             mention the hole
      Driven by this goal I did a LOT of refactoring in TcErrors, which in turn
      allows us to report enclosing value bindings for other errors, not just
      holes.  (Thijs rightly did not attempt this!)
      The major data type change is a new form of constraint
        data Ct = ...
          	  | CHoleCan {
          	      cc_ev       :: CtEvidence,
          	      cc_hole_ty  :: TcTauType,
          	      cc_depth    :: SubGoalDepth }
      I'm still in two minds about whether this is the best plan. Another
      possibility would be to have a predicate type for holes, somthing like
         class Hole a where
           holeValue :: a
      It works the way it is, but there are some annoying special cases for
      CHoleCan (just grep for "CHoleCan").
  32. 15 Sep, 2012 1 commit
    • Simon Peyton Jones's avatar
      Fix Trac #7237; mixup with empty tuples · 84bb8541
      Simon Peyton Jones authored
      When converting from Core to STG, we swith pattern matching on
      on a *nullary* unboxed tuple into matching using a PrimAlt on RealWorld#
         case e (RealWorld#) of { DEFAULT -> ... }
      This semms messy to me, but it works.  There was a bug in that we were
      changing to PrimAlt, but not using a DEFAULT AltCon.
  33. 29 Aug, 2012 1 commit
  34. 20 Jul, 2012 1 commit
  35. 15 Jul, 2012 1 commit