1. 07 Jun, 2014 1 commit
  2. 03 Jun, 2014 2 commits
    • Simon Peyton Jones's avatar
      Use IfLclName instead of OccName in IfaceEqSpec · 6e8861c9
      Simon Peyton Jones authored
      The type variables in the IfaceEqSpec of a data constructor are really
      ordinarly *occurrences*, so they should be IfLclNames just like any
      other type variable occurence.
      6e8861c9
    • Simon Peyton Jones's avatar
      Do pretty-printing of TyThings via IfaceDecl (Trac #7730) · b4856f9f
      Simon Peyton Jones authored
      All the initial work on this was done fy 'archblob' (fcsernik@gmail.com);
      thank you!
      
      I reviewed the patch, started some tidying, up and then ended up in a huge
      swamp of changes, not all of which I can remember now.  But:
      
      * To suppress kind arguments when we have -fno-print-explicit-kinds,
          - IfaceTyConApp argument types are in a tagged list IfaceTcArgs
      
      * To allow overloaded types to be printed with =>, add IfaceDFunTy to IfaceType.
      
      * When printing data/type family instances for the user, I've made them
        print out an informative RHS, which is a new feature. Thus
              ghci> info T
              data family T a
              data instance T Int = T1 Int Int
              data instance T Bool = T2
      
      * In implementation terms, pprIfaceDecl has just one "context" argument,
        of type IfaceSyn.ShowSub, which says
             - How to print the binders of the decl
               see note [Printing IfaceDecl binders] in IfaceSyn
             - Which sub-comoponents (eg constructors) to print
      
      * Moved FastStringEnv from RnEnv to OccName
      
      It all took a ridiculously long time to do.  But it's done!
      b4856f9f
  3. 27 May, 2014 1 commit
  4. 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.
      23892440
  5. 08 May, 2014 1 commit
  6. 03 May, 2014 1 commit
  7. 22 Mar, 2014 1 commit
    • eir@cis.upenn.edu's avatar
      Remove redundant compatibility check. · b0bcbc04
      eir@cis.upenn.edu authored
      Previously, the closed type family compatibility check was
      done even when type-checking an interface file. But interface
      files now store compatibility info, so this check was redundant.
      b0bcbc04
  8. 20 Jan, 2014 1 commit
    • Gergő Érdi's avatar
      Implement pattern synonyms · 4f8369bf
      Gergő Érdi authored
      This patch implements Pattern Synonyms (enabled by -XPatternSynonyms),
      allowing y ou to assign names to a pattern and abstract over it.
      
      The rundown is this:
      
        * Named patterns are introduced by the new 'pattern' keyword, and can
          be either *unidirectional* or *bidirectional*. A unidirectional
          pattern is, in the simplest sense, simply an 'alias' for a pattern,
          where the LHS may mention variables to occur in the RHS. A
          bidirectional pattern synonym occurs when a pattern may also be used
          in expression context.
      
        * Unidirectional patterns are declared like thus:
      
              pattern P x <- x:_
      
          The synonym 'P' may only occur in a pattern context:
      
              foo :: [Int] -> Maybe Int
              foo (P x) = Just x
              foo _     = Nothing
      
        * Bidirectional patterns are declared like thus:
      
              pattern P x y = [x, y]
      
          Here, P may not only occur as a pattern, but also as an expression
          when given values for 'x' and 'y', i.e.
      
              bar :: Int -> [Int]
              bar x = P x 10
      
        * Patterns can't yet have their own type signatures; signatures are inferred.
      
        * Pattern synonyms may not be recursive, c.f. type synonyms.
      
        * Pattern synonyms are also exported/imported using the 'pattern'
          keyword in an import/export decl, i.e.
      
              module Foo (pattern Bar) where ...
      
          Note that pattern synonyms share the namespace of constructors, so
          this disambiguation is required as a there may also be a 'Bar'
          type in scope as well as the 'Bar' pattern.
      
        * The semantics of a pattern synonym differ slightly from a typical
          pattern: when using a synonym, the pattern itself is matched,
          followed by all the arguments. This means that the strictness
          differs slightly:
      
              pattern P x y <- [x, y]
      
              f (P True True) = True
              f _             = False
      
              g [True, True] = True
              g _            = False
      
          In the example, while `g (False:undefined)` evaluates to False,
          `f (False:undefined)` results in undefined as both `x` and `y`
          arguments are matched to `True`.
      
      For more information, see the wiki:
      
          https://ghc.haskell.org/trac/ghc/wiki/PatternSynonyms
          https://ghc.haskell.org/trac/ghc/wiki/PatternSynonyms/Implementation
      
      Reviewed-by: Simon Peyton Jones's avatarSimon Peyton Jones <simonpj@microsoft.com>
      Signed-off-by: default avatarAustin Seipp <austin@well-typed.com>
      4f8369bf
  9. 05 Nov, 2013 1 commit
  10. 18 Oct, 2013 2 commits
  11. 20 Sep, 2013 1 commit
    • Simon Peyton Jones's avatar
      Refactor AMP warnings a bit · e17072d1
      Simon Peyton Jones authored
      There was a bit of clutter (tryTc stuff) caused by the
      fact that tcLookupImported didn't return a MaybeErr.
      Now it does.  That finishes up Trac #8004.
      e17072d1
  12. 18 Sep, 2013 1 commit
  13. 13 Sep, 2013 1 commit
    • Iavor S. Diatchki's avatar
      Add support for evaluation of type-level natural numbers. · 1f77a534
      Iavor S. Diatchki authored
      This patch implements some simple evaluation of type-level expressions
      featuring natural numbers.  We can evaluate *concrete* expressions that
      use the built-in type families (+), (*), (^), and (<=?), declared in
      GHC.TypeLits.   We can also do some type inference involving these
      functions.  For example, if we encounter a constraint such as `(2 + x) ~ 5`
      we can infer that `x` must be 3.  Note, however, this is used only to
      resolve unification variables (i.e., as a form of a constraint improvement)
      and not to generate new facts.  This is similar to how functional
      dependencies work in GHC.
      
      The patch adds a new form of coercion, `AxiomRuleCo`, which makes use
      of a new form of axiom called `CoAxiomRule`.  This is the form of evidence
      generate when we solve a constraint, such as `(1 + 2) ~ 3`.
      
      The patch also adds support for built-in type-families, by adding a new
      form of TyCon rhs: `BuiltInSynFamTyCon`.  such built-in type-family
      constructors contain a record with functions that are used by the
      constraint solver to simplify and improve constraints involving the
      built-in function (see `TcInteract`).  The record in defined in `FamInst`.
      
      The type constructors and rules for evaluating the type-level functions
      are in a new module called `TcTypeNats`.
      1f77a534
  14. 04 Sep, 2013 1 commit
  15. 02 Sep, 2013 1 commit
    • Simon Peyton Jones's avatar
      Remove the final vestiges of InlineWrappers · e4a1d2d0
      Simon Peyton Jones authored
      Part of Nick Frisby's patch (c080f727)
      for late demand-analysis removed the over-zealous short-cut whereby
      strictness wrappers were not spelled out in detail in interface files.
      
      This patch completes the process by
       * removing InlineWrapper from UnfoldingSource
       * removing IfWrapper from IfaceUnfolding
      
      There was a tiny bit of special ad-hocery for wrappers, in OccurAnal,
      but fortunately that too turns out to be rendered irrelevant by
      the more uniform treatment, and after that there was no need
      to remember which functions are wrappers.
      e4a1d2d0
  16. 29 Aug, 2013 1 commit
  17. 05 Aug, 2013 1 commit
  18. 02 Aug, 2013 1 commit
  19. 24 Jun, 2013 1 commit
  20. 21 Jun, 2013 1 commit
    • eir@cis.upenn.edu's avatar
      Revise implementation of overlapping type family instances. · 569b2652
      eir@cis.upenn.edu authored
      This commit changes the syntax and story around overlapping type
      family instances. Before, we had "unbranched" instances and
      "branched" instances. Now, we have closed type families and
      open ones.
      
      The behavior of open families is completely unchanged. In particular,
      coincident overlap of open type family instances still works, despite
      emails to the contrary.
      
      A closed type family is declared like this:
      > type family F a where
      >   F Int = Bool
      >   F a   = Char
      The equations are tried in order, from top to bottom, subject to
      certain constraints, as described in the user manual. It is not
      allowed to declare an instance of a closed family.
      569b2652
  21. 30 May, 2013 2 commits
    • Simon Peyton Jones's avatar
      Fix a trailing case in making FamInstTyCon, · d0ecba6d
      Simon Peyton Jones authored
      where the invariant didn't hold, leading to
      subsequent chaos. Happily an ASSERT caught it.
      d0ecba6d
    • Simon Peyton Jones's avatar
      Make 'SPECIALISE instance' work again · 1ed04090
      Simon Peyton Jones authored
      This is a long-standing regression (Trac #7797), which meant that in
      particular the Eq [Char] instance does not get specialised.
      (The *methods* do, but the dictionary itself doesn't.)  So when you
      call a function
           f :: Eq a => blah
      on a string type (ie a=[Char]), 7.6 passes a dictionary of un-specialised
      methods.
      
      This only matters when calling an overloaded function from a
      specialised context, but that does matter in some programs.  I
      remember (though I cannot find the details) that Nick Frisby discovered
      this to be the source of some pretty solid performanc regresisons.
      
      Anyway it works now. The key change is that a DFunUnfolding now takes
      a form that is both simpler than before (the DFunArg type is eliminated)
      and more general:
      
      data Unfolding
        = ...
        | DFunUnfolding {     -- The Unfolding of a DFunId
          			-- See Note [DFun unfoldings]
            		  	--     df = /\a1..am. \d1..dn. MkD t1 .. tk
                              --                                 (op1 a1..am d1..dn)
           		      	--     	    	      	       	   (op2 a1..am d1..dn)
              df_bndrs :: [Var],      -- The bound variables [a1..m],[d1..dn]
              df_con   :: DataCon,    -- The dictionary data constructor (never a newtype datacon)
              df_args  :: [CoreExpr]  -- Args of the data con: types, superclasses and methods,
          }                           -- in positional order
      
      That in turn allowed me to re-enable the DFunUnfolding specialisation in
      DsBinds.  Lots of details here in TcInstDcls:
      	  Note [SPECIALISE instance pragmas]
      
      I also did some refactoring, in particular to pass the InScopeSet to
      exprIsConApp_maybe (which in turn means it has to go to a RuleFun).
      
      NB: Interface file format has changed!
      1ed04090
  22. 25 Apr, 2013 1 commit
  23. 15 Feb, 2013 1 commit
  24. 13 Feb, 2013 1 commit
  25. 28 Jan, 2013 1 commit
    • Simon Peyton Jones's avatar
      More refactoring of FamInst/FamInstEnv; finally fixes Trac #7524 · a98e51ec
      Simon Peyton Jones authored
      Quite a bit of tidying up here; the fix to #7524 is actually
      only a small part.
      
      * Be fully clear that the cab_tvs in a CoAxBranch are not
        fresh.  See Note [CoAxBranch type variables] in CoAxiom.
      
      * Use CoAxBranch to replace the ATDfeault type in Class.
        CoAxBranch is perfect here.  This change allowed me to
        delete quite a bit of boilerplate code, including the
        corresponding IfaceSynType.
      
      * Tidy up the construction of CoAxBranches, and when FamIntBranch is
        freshened.  The latter onw happens only in FamInst.newFamInst.
      
      * Tidy the tyvars of a CoAxBranch when we build them, done in
        FamInst.mkCoAxBranch.  See Note [Tidy axioms when we build them]
        in that module.  This is what fixes #7524.
      
      Much niceer now.
      a98e51ec
  26. 25 Jan, 2013 1 commit
    • Simon Peyton Jones's avatar
      Refactor and improve the promotion inference · 09ff0e0d
      Simon Peyton Jones authored
      It should be the case that either an entire mutually recursive
      group of data type declarations can be promoted, or none of them.
      It's really odd to promote some data constructors of a type but
      not others. Eg
        data T a = T1 a | T2 Int
      Here T1 is sort-of-promotable but T2 isn't (becuase Int isn't
      promotable).
      
      This patch makes it all-or-nothing. At the same time I've made
      the TyCon point to its promoted cousin (via the tcPromoted field
      of an AlgTyCon), as well as vice versa (via the ty_con field of
      PromotedTyCon).
      
      The inference for the group is done in TcTyDecls, the same place
      that infers which data types are recursive, another global question.
      09ff0e0d
  27. 17 Jan, 2013 1 commit
    • Simon Peyton Jones's avatar
      Major patch to implement the new Demand Analyser · 0831a12e
      Simon Peyton Jones authored
      This patch is the result of Ilya Sergey's internship at MSR.  It
      constitutes a thorough overhaul and simplification of the demand
      analyser.  It makes a solid foundation on which we can now build.
      Main changes are
      
      * Instead of having one combined type for Demand, a Demand is
         now a pair (JointDmd) of
            - a StrDmd and
            - an AbsDmd.
         This allows strictness and absence to be though about quite
         orthogonally, and greatly reduces brain melt-down.
      
      * Similarly in the DmdResult type, it's a pair of
           - a PureResult (indicating only divergence/non-divergence)
           - a CPRResult (which deals only with the CPR property
      
      * In IdInfo, the
          strictnessInfo field contains a StrictSig, not a Maybe StrictSig
          demandInfo     field contains a Demand, not a Maybe Demand
        We don't need Nothing (to indicate no strictness/demand info)
        any more; topSig/topDmd will do.
      
      * Remove "boxity" analysis entirely.  This was an attempt to
        avoid "reboxing", but it added complexity, is extremely
        ad-hoc, and makes very little difference in practice.
      
      * Remove the "unboxing strategy" computation. This was an an
        attempt to ensure that a worker didn't get zillions of
        arguments by unboxing big tuples.  But in fact removing it
        DRAMATICALLY reduces allocation in an inner loop of the
        I/O library (where the threshold argument-count had been
        set just too low).  It's exceptional to have a zillion arguments
        and I don't think it's worth the complexity, especially since
        it turned out to have a serious performance hit.
      
      * Remove quite a bit of ad-hoc cruft
      
      * Move worthSplittingFun, worthSplittingThunk from WorkWrap to
        Demand. This allows JointDmd to be fully abstract, examined
        only inside Demand.
      
      Everything else really follows from these changes.
      
      All of this is really just refactoring, so we don't expect
      big performance changes, but acutally the numbers look quite
      good.  Here is a full nofib run with some highlights identified:
      
              Program           Size    Allocs   Runtime   Elapsed  TotalMem
      --------------------------------------------------------------------------------
               expert          -2.6%    -15.5%      0.00      0.00     +0.0%
                fluid          -2.4%     -7.1%      0.01      0.01     +0.0%
                   gg          -2.5%    -28.9%      0.02      0.02    -33.3%
            integrate          -2.6%     +3.2%     +2.6%     +2.6%     +0.0%
              mandel2          -2.6%     +4.2%      0.01      0.01     +0.0%
             nucleic2          -2.0%    -16.3%      0.11      0.11     +0.0%
                 para          -2.6%    -20.0%    -11.8%    -11.7%     +0.0%
               parser          -2.5%    -17.9%      0.05      0.05     +0.0%
               prolog          -2.6%    -13.0%      0.00      0.00     +0.0%
               puzzle          -2.6%     +2.2%     +0.8%     +0.8%     +0.0%
              sorting          -2.6%    -35.9%      0.00      0.00     +0.0%
             treejoin          -2.6%    -52.2%     -9.8%     -9.9%     +0.0%
      --------------------------------------------------------------------------------
                  Min          -2.7%    -52.2%    -11.8%    -11.7%    -33.3%
                  Max          -1.8%     +4.2%    +10.5%    +10.5%     +7.7%
       Geometric Mean          -2.5%     -2.8%     -0.4%     -0.5%     -0.4%
      
      Things to note
      
      * Binary sizes are smaller. I don't know why, but it's good.
      
      * Allocation is sometiemes a *lot* smaller. I believe that all the big numbers
        (I checked treejoin, gg, sorting) arise from one place, namely a function
        GHC.IO.Encoding.UTF8.utf8_decode, which is strict in two Buffers both of
        which have several arugments.  Not w/w'ing both arguments (which is what
        we did before) has a big effect.  So the big win in actually somewhat
        accidental, gained by removing the "unboxing strategy" code.
      
      * A couple of benchmarks allocate slightly more.  This turns out
        to be due to reboxing (integrate).  But the biggest increase is
        mandel2, and *that* turned out also to be a somewhat accidental
        loss of CSE, and pointed the way to doing better CSE: see Trac
        #7596.
      
      * Runtimes are never very reliable, but seem to improve very slightly.
      
      All in all, a good piece of work.  Thank you Ilya!
      0831a12e
  28. 05 Jan, 2013 1 commit
    • eir@cis.upenn.edu's avatar
      Refactor invariants for FamInsts. · 5765248b
      eir@cis.upenn.edu authored
      This commit mirrors work done in the commit for ClsInsts, 5efe9b...
      
      Specifically:
      - All FamInsts have *fresh* type variables. So, no more freshness work
      in addLocalFamInst
      
      Also:
      - Some pretty-printing code around FamInsts was cleaned up a bit
      This caused location information to be added to CoAxioms and index
      information to be added to FamInstBranches.
      5765248b
  29. 01 Jan, 2013 1 commit
  30. 23 Dec, 2012 1 commit
    • Simon Peyton Jones's avatar
      Make {-# UNPACK #-} work for type/data family invocations · 1ee1cd41
      Simon Peyton Jones authored
      This fixes most of Trac #3990.  Consider
        data family D a
        data instance D Double = CD Int Int
        data T = T {-# UNPACK #-} !(D Double)
      Then we want the (D Double unpacked).
      
      To do this we need to construct a suitable coercion, and it's much
      safer to record that coercion in the interface file, lest the in-scope
      instances differ somehow.  That in turn means elaborating the HsBang
      type to include a coercion.
      
      To do that I moved HsBang from BasicTypes to DataCon, which caused
      quite a few minor knock-on changes.
      
      Interface-file format has changed!
      
      Still to do: need to do knot-tying to allow instances to take effect
      within the same module.
      1ee1cd41
  31. 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
      instance
      where', followed by equations. See the new section in the user manual
      (7.7.2.2) for details. The canonical example is Boolean equality at the
      type
      level:
      
      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
      order
      and applies only the first the matches. As explained in the note
      [Instance
      checking within groups] in FamInstEnv.lhs, we must be careful not to
      simplify,
      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
      CoAxiom.lhs.
      
      - 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
        notion
        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
      family
        simplification. (This is different than the normal failure to unify
      because
        of the type family bit.) This notion in encoded in tcApartTys, in
      Unify.lhs.
        Because apartness is finer-grained than unification, the tcUnifyTys
      now
        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
        docs/core-spec/core-spec.pdf.
      
      - 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
      but
         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 7.7.2.2, is updated to describe the new type
        family
        instances.
      8366792e
  32. 05 Dec, 2012 1 commit
  33. 19 Oct, 2012 1 commit
  34. 16 Oct, 2012 1 commit
    • ian@well-typed.com's avatar
      Some alpha renaming · cd33eefd
      ian@well-typed.com authored
      Mostly d -> g (matching DynFlag -> GeneralFlag).
      Also renamed if* to when*, matching the Haskell if/when names
      cd33eefd
  35. 12 Oct, 2012 1 commit
    • Simon Peyton Jones's avatar
      Be lazier when typechecking data type contexts (Trac #7321) · beb2f743
      Simon Peyton Jones authored
      We should be lazy when type-checking the equality-contraint
      part of a data constructor's type, to make the knot-tying
      work out right.  The fact that it's always worked before
      is a fluke: no one else wrote a GADT whose type index mentions
      itself
        data T a wher
          MkT :: T (T Int)
      beb2f743
  36. 09 Oct, 2012 1 commit
    • ian@well-typed.com's avatar
      Make the opt_UF_* static flags dynamic · 0a768bcb
      ian@well-typed.com authored
      I also removed the default values from the "Discounts and thresholds"
      note: most of them were no longer up-to-date.
      
      Along the way I added FloatSuffix to the argument parser, analogous to
      IntSuffix.
      0a768bcb
  37. 18 Sep, 2012 1 commit
    • Simon Peyton Jones's avatar
      Make a start towards eta-rules and injective families · 58470fb7
      Simon Peyton Jones authored
      * Make Any into a type family (which it should always have been)
        This is to support the future introduction of eta rules for
        product types (see email on ghc-users title "PolyKind issue"
        early Sept 2012)
      
      * Add the *internal* data type support for
          (a) closed type families [so that you can't give
              type instance for 'Any']
          (b) injective type families [because Any is really
              injective]
        This amounts to two boolean flags on the SynFamilyTyCon
        constructor of TyCon.SynTyConRhs.
      
      There is some knock-on effect, but all of a routine nature.
      
      It remains to offer source syntax for either closed or
      injective families.
      58470fb7