1. 01 Oct, 2012 1 commit
    • Simon Peyton Jones's avatar
      Use System Names for evidence variables · 2b523dc3
      Simon Peyton Jones authored
      These variables all have uniformative names like "cobox" or "d".
      Make them System Names tells the pretty printer to show their
      uniques even without -dppr-debug.  That in turn makes the
      less-voluminous debug traces *much* more informative.
  2. 19 Sep, 2012 1 commit
  3. 17 Sep, 2012 2 commits
    • Simon Peyton Jones's avatar
      Another refactoring of constraints · d30b9cf4
      Simon Peyton Jones authored
      1. Rejig CtLoc
         * CtLoc is now *not* parameterised (much simpler)
         * CtLoc includes the "depth" of the constraint
         * CtLoc includes the TcLclEnv at the birthplace
           That gives (a) the SrcSpan, (b) the [ErrCtxt]
           (c) the [TcIdBinder]
         * The CtLoc of a constraint is no longer in its CtEvidence
         * Where we passed 'depth' before, now we pass CtLoc
      2. Some significant refactoring in TcErrors
         * Get rid of cec_extra
         * Traverse every constraint, so that we can be
           sure to generate bindings where necessary.
           (This was really a lurking bug before.)
      3. Merge zonking into TcCanonical.  This turned out to be
         almost trivial; just a small change to TcCanonical.flattenTyVar.
         The nice consequence is that we don't need to zonk a constraint
         before solving it; instead it gets zonked "on the fly" as it were.
    • 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").
  4. 03 Sep, 2012 1 commit
  5. 28 Aug, 2012 1 commit
  6. 15 Jul, 2012 1 commit
  7. 14 Jul, 2012 1 commit
    • Simon Peyton Jones's avatar
      Do not discard insoluble constraints in simplifyInfer · c1f01e35
      Simon Peyton Jones authored
      Before -fdefer-type-errors there we no insolubles
      (because we'd have failed before then), but with -fdefer-type-errors
      there can be.  The code is acutally a bit simpler: we just call
      emitConstraints, and eliminate the bogus-looking emitWC from TcRnMonad.
      There's a bit more tidying up to do, concerning the places we use
      keepWanted, but I need to talk to Dimitrios about that.
      Meanwhile this fixes Trac #7023
  8. 25 Jun, 2012 1 commit
  9. 18 Jun, 2012 1 commit
  10. 14 Jun, 2012 1 commit
  11. 12 Jun, 2012 1 commit
  12. 11 Jun, 2012 1 commit
    • Ian Lynagh's avatar
      Pass DynFlags to the LogAction · 5716a2f8
      Ian Lynagh authored
      A side-effect is that we can no longer use the LogAction in
      defaultErrorHandler, as we don't have DynFlags at that point.
      But all that defaultErrorHandler did is to print Strings as
      SevFatal, so now it takes a 'FatalMessager' instead.
  13. 08 Jun, 2012 1 commit
    • dimitris's avatar
      Significant refactoring of TcSimplify, in particular simplifyInfer and · 3891a056
      dimitris authored
      simplifyTop, code beautification etc. Important things:
      (a) New top-level defaulting plan, gotten rid of the SimplContext field.
          See Note [Top-level Defaulting Plan]
      (b) Serious bug fix in the floatEqualities mechanism
          See Note [Extra TcS Untouchables],[Float Equalities out of Implications]
      The changes are mostly confined in TcSimplify but there is a
      simplification wave affecting other modules as well.
  14. 06 Jun, 2012 1 commit
  15. 29 May, 2012 1 commit
  16. 28 May, 2012 1 commit
  17. 24 Apr, 2012 1 commit
  18. 13 Apr, 2012 2 commits
    • Simon Peyton Jones's avatar
      Revert "Added ':runmonad' command to GHCi" · e0e99f99
      Simon Peyton Jones authored
      Two problems, for now at any rate
        a) Breaks the build with lots of errors like
              No instance for (Show (IO ())) arising from a use of `print'
        b) Discussion of the approache hasn't converged yet
           (Simon M had a number of suggestions)
      This reverts commit eecd7c98.
    • dterei's avatar
      Added ':runmonad' command to GHCi · eecd7c98
      dterei authored
      This command allows you to lift user stmts in GHCi into an IO monad
      that implements the GHC.GHCi.GHCiSandboxIO type class. This allows for
      easy sandboxing of GHCi using :runmonad and Safe Haskell.
      Longer term it would be nice to allow a more general model for the Monad
      than GHCiSandboxIO but delaying this for the moment.
  19. 04 Apr, 2012 1 commit
  20. 02 Mar, 2012 1 commit
    • Simon Peyton Jones's avatar
      Hurrah! This major commit adds support for scoped kind variables, · 3bf54e78
      Simon Peyton Jones authored
      which (finally) fills out the functionality of polymorphic kinds.
      It also fixes numerous bugs.
      Main changes are:
      Renaming stuff
      * New type in HsTypes:
           data HsBndrSig sig = HsBSig sig [Name]
        which is used for type signatures in patterns, and kind signatures
        in types.  So when you say
             f (x :: [a]) = x ++ x
             data T (f :: k -> *) (x :: *) = MkT (f x)
        the signatures in both cases are a HsBndrSig.
      * The [Name] in HsBndrSig records the variables bound by the
        pattern, that is 'a' in the first example, 'k' in the second,
        and nothing in the third.  The renamer initialises the field.
      * As a result I was able to get rid of
           RnHsSyn.extractHsTyNames :: LHsType Name -> NameSet
        and its friends altogether.  Deleted the entire module!
        This led to some knock-on refactoring; in particular the
        type renamer now returns the free variables just like the
        term renamer.
      Kind-checking types: mainly TcHsType
      A major change is that instead of kind-checking types in two
      passes, we now do one. Under the old scheme, the first pass did
      kind-checking and (hackily) annotated the HsType with the
      inferred kinds; and the second pass desugared the HsType to a
      Type.  But now that we have kind variables inside types, the
      first pass (TcHsType.tc_hs_type) can go straight to Type, and
      zonking will squeeze out any kind unification variables later.
      This is much nicer, but it was much more fiddly than I had expected.
      The nastiest corner is this: it's very important that tc_hs_type
      uses lazy constructors to build the returned type. See
      Note [Zonking inside the knot] in TcHsType.
      Type-checking type and class declarations: mainly TcTyClsDecls
      I did tons of refactoring in TcTyClsDecls.  Simpler and nicer now.
      Typechecking bindings: mainly TcBinds
      I rejigged (yet again) the handling of type signatures in TcBinds.
      It's a bit simpler now.  The main change is that tcTySigs goes
      right through to a TcSigInfo in one step; previously it was split
      into two, part here and part later.
      Unsafe coercions
      Usually equality coercions have exactly the same kind on both
      sides.  But we do allow an *unsafe* coercion between Int# and Bool,
      say, used in
          case error Bool "flah" of { True -> 3#; False -> 0# }
          (error Bool "flah") |> unsafeCoerce Bool Int#
      So what is the instantiation of (~#) here?
         unsafeCoerce Bool Int# :: (~#) ??? Bool Int#
      I'm using OpenKind here for now, but it's un-satisfying that
      the lhs and rhs of the ~ don't have precisely the same kind.
      More minor
      * HsDecl.TySynonym has its free variables attached, which makes
        the cycle computation in TcTyDecls.mkSynEdges easier.
      * Fixed a nasty reversed-comparison bug in FamInstEnv:
        @@ -490,7 +490,7 @@ lookup_fam_inst_env' match_fun one_sided ie fam tys
           n_tys = length tys
           extra_tys = drop arity tys
           (match_tys, add_extra_tys)
      -       | arity > n_tys = (take arity tys, \res_tys -> res_tys ++ extra_tys)
      +       | arity < n_tys = (take arity tys, \res_tys -> res_tys ++ extra_tys)
              | otherwise     = (tys,            \res_tys -> res_tys)
  21. 16 Feb, 2012 1 commit
  22. 19 Jan, 2012 1 commit
  23. 12 Jan, 2012 1 commit
    • Simon Peyton Jones's avatar
      Implememt -fdefer-type-errors (Trac #5624) · 5508ada4
      Simon Peyton Jones authored
      This patch implements the idea of deferring (most) type errors to
      runtime, instead emitting only a warning at compile time.  The
      basic idea is very simple:
       * The on-the-fly unifier in TcUnify never fails; instead if it
         gets stuck it emits a constraint.
       * The constraint solver tries to solve the constraints (and is
         entirely unchanged, hooray).
       * The remaining, unsolved constraints (if any) are passed to
         TcErrors.reportUnsolved.  With -fdefer-type-errors, instead of
         emitting an error message, TcErrors emits a warning, AND emits
         a binding for the constraint witness, binding it
         to (error "the error message"), via the new form of evidence
         TcEvidence.EvDelayedError.  So, when the program is run,
         when (and only when) that witness is needed, the program will
         crash with the exact same error message that would have been
         given at compile time.
      Simple really.  But, needless to say, the exercise forced me
      into some major refactoring.
       * TcErrors is almost entirely rewritten
       * EvVarX and WantedEvVar have gone away entirely
       * ErrUtils is changed a bit:
           * New Severity field in ErrMsg
           * Renamed the type Message to MsgDoc (this change
             touches a lot of files trivially)
       * One minor change is that in the constraint solver we try
         NOT to combine insoluble constraints, like Int~Bool, else
         all such type errors get combined together and result in
         only one error message!
       * I moved some definitions from TcSMonad to TcRnTypes,
         where they seem to belong more
  24. 22 Dec, 2011 1 commit
  25. 05 Dec, 2011 1 commit
    • Simon Peyton Jones's avatar
      Allow full constraint solving under a for-all (Trac #5595) · 2e6dcdf7
      Simon Peyton Jones authored
      The main idea is that when we unify
          forall a. t1  ~  forall a. t2
      we get constraints from unifying t1~t2 that mention a.
      We are producing a coercion witnessing the equivalence of
      the for-alls, and inside *that* coercion we need bindings
      for the solved constraints arising from t1~t2.
      We didn't have way to do this before.  The big change is
      that here's a new type TcEvidence.TcCoercion, which is
      much like Coercion.Coercion except that there's a slot
      for TcEvBinds in it.
      This has a wave of follow-on changes. Not deep but broad.
      * New module TcEvidence, which now contains the HsWrapper
        TcEvBinds, EvTerm etc types that used to be in HsBinds
      * The typechecker works exclusively in terms of TcCoercion.
      * The desugarer converts TcCoercion to Coercion
      * The main payload is in TcUnify.unifySigmaTy. This is the
        function that had a gross hack before, but is now beautiful.
      * LCoercion is gone!  Hooray.
      Many many fiddly changes in conssequence.  But it's nice.
  26. 29 Nov, 2011 1 commit
    • Simon Peyton Jones's avatar
      Refactor (again) the treatment of record-selector bindings · ac11b1f1
      Simon Peyton Jones authored
      We were generating them from the tcg_tcs field of the TcGblEnv,
      but that goes badly wrong when there are top-level Template
      Haskell splices, because the tcg_tcs field grows successively.
      If we generate record-selector binds for all the TyCons in the
      accumulated list, we generate them multiple times for TyCons
      earlier in the program.  This what was happening in Trac #5665:
        data T = T { x :: Int }
        $(f 4)  -- Top level splice
        ..more code..
      Here the record selector bindings for T were being generated
      Better instead to generate the record-selector bindings in
      TcTyClsDecls, right where the new TyCons are being declared (as indeed
      they were some time ago).  This pushed me into doing some refactoring:
      instead of returning the record bindings, tcTyAndClassDecls adds them
      to the tcg_binds field of the TcGblEnv.  I think the result is a bit
      nicer, and it has the additional merit of working.
  27. 28 Nov, 2011 1 commit
    • dimitris's avatar
      This patch includes: · f3183d9a
      dimitris authored
      0) Typo in panic message.
      1) prioritization of equalities over family equalities in the worklists.
      2) rewriting of inert substitutions and solveds on-the-spot instead of
         kicking them out in the inerts. This required a monadic map over
         substitutions hence the modifications in UniqFM.
      3) Just comments and removing stale commented code.
      4) Useful SCC for simplifyInfer.
      5) Making CoreStats outputable.
  28. 18 Nov, 2011 1 commit
    • Simon Marlow's avatar
      Track #included files for recompilation checking (#4900, #3589) · 3f34e091
      Simon Marlow authored
      This was pretty straightforward: collect the filenames in the lexer,
      and add them in to the tcg_dependent_files list that the typechecker
      Note that we still don't get #included files in the ghc -M output.
      Since we don't normally lex the whole file in ghc -M, this same
      mechanism can't be used directly.
  29. 16 Nov, 2011 1 commit
  30. 11 Nov, 2011 1 commit
    • dreixel's avatar
      New kind-polymorphic core · 09015be8
      dreixel authored
      This big patch implements a kind-polymorphic core for GHC. The current
      implementation focuses on making sure that all kind-monomorphic programs still
      work in the new core; it is not yet guaranteed that kind-polymorphic programs
      (using the new -XPolyKinds flag) will work.
      For more information, see http://haskell.org/haskellwiki/GHC/Kinds
  31. 05 Nov, 2011 1 commit
    • GregWeber's avatar
      addDependentFile #4900 · b994313a
      GregWeber authored
      Let GHC know about an external dependency that Template Haskell uses
      so that GHC can recompile when the dependency changes.
      No support for ghc -M
      There is a corresponding addition to the template-haskell library
  32. 01 Nov, 2011 1 commit
  33. 26 Oct, 2011 1 commit
  34. 25 Oct, 2011 1 commit
  35. 29 Sep, 2011 1 commit
  36. 21 Sep, 2011 1 commit
    • Simon Marlow's avatar
      Add support for all top-level declarations to GHCi · 3db75724
      Simon Marlow authored
        This is work mostly done by Daniel Winograd-Cort during his
        internship at MSR Cambridge, with some further refactoring by me.
      This commit adds support to GHCi for most top-level declarations that
      can be used in Haskell source files.  Class, data, newtype, type,
      instance are all supported, as are Type Family-related declarations.
      The current set of declarations are shown by :show bindings.  As with
      variable bindings, entities bound by newer declarations shadow earlier
      Tests are in testsuite/tests/ghci/scripts/ghci039--ghci054.
      Documentation to follow.
  37. 06 Sep, 2011 1 commit
    • batterseapower's avatar
      Implement -XConstraintKind · 9729fe7c
      batterseapower authored
      Basically as documented in http://hackage.haskell.org/trac/ghc/wiki/KindFact,
      this patch adds a new kind Constraint such that:
        Show :: * -> Constraint
        (?x::Int) :: Constraint
        (Int ~ a) :: Constraint
      And you can write *any* type with kind Constraint to the left of (=>):
      even if that type is a type synonym, type variable, indexed type or so on.
      The following (somewhat related) changes are also made:
       1. We now box equality evidence. This is required because we want
          to give (Int ~ a) the *lifted* kind Constraint
       2. For similar reasons, implicit parameters can now only be of
          a lifted kind. (?x::Int#) => ty is now ruled out
       3. Implicit parameter constraints are now allowed in superclasses
          and instance contexts (this just falls out as OK with the new
          constraint solver)
      Internally the following major changes were made:
       1. There is now no PredTy in the Type data type. Instead
          GHC checks the kind of a type to figure out if it is a predicate
       2. There is now no AClass TyThing: we represent classes as TyThings
          just as a ATyCon (classes had TyCons anyway)
       3. What used to be (~) is now pretty-printed as (~#). The box
          constructor EqBox :: (a ~# b) -> (a ~ b)
       4. The type LCoercion is used internally in the constraint solver
          and type checker to represent coercions with free variables
          of type (a ~ b) rather than (a ~# b)
  38. 16 Aug, 2011 1 commit
    • Simon Peyton Jones's avatar
      Major improvement to pattern bindings · 49dbe605
      Simon Peyton Jones authored
      This patch makes a number of related improvements
      a) Implements the Haskell Prime semantics for pattern bindings
         (Trac #2357).  That is, a pattern binding p = e is typed
         just as if it had been written
              t = e
              f = case t of p -> f
              g = case t of p -> g
              ... etc ...
         where f,g are the variables bound by p. In paricular it's
         ok to say
            (f,g) = (\x -> x, \y -> True)
         and f and g will get propertly inferred types
            f :: a -> a
            g :: a -> Int
      b) Eliminates the MonoPatBinds flag altogether.  (For the moment
         it is deprecated and has no effect.)  Pattern bindings are now
         generalised as per (a).  Fixes Trac #2187 and #4940, in the
         way the users wanted!
      c) Improves the OutsideIn algorithm generalisation decision.
         Given a definition without a type signature (implying "infer
         the type"), the published algorithm rule is this:
            - generalise *top-level* functions, and
            - do not generalise *nested* functions
         The new rule is
            - generalise a binding whose free variables have
              Guaranteed Closed Types
            - do not generalise other bindings
         Generally, a top-level let-bound function has a Guaranteed
         Closed Type, and so does a nested function whose free vaiables
         are top-level functions, and so on. (However a top-level
         function that is bitten by the Monomorphism Restriction does
         not have a GCT.)
           f x = let { foo y = y } in ...
         Here 'foo' has no free variables, so it is generalised despite
         being nested.
      d) When inferring a type f :: ty for a definition f = e, check that
         the compiler would accept f :: ty as a type signature for that
         same definition.  The type is rejected precisely when the type
         is ambiguous.
            class Wob a b where
              to :: a -> b
              from :: b -> a
            foo x = [x, to (from x)]
         GHC 7.0 would infer the ambiguous type
            foo :: forall a b. Wob a b => b -> [b]
         but that type would give an error whenever it is called; and
         GHC 7.0 would reject that signature if given by the
         programmer.  The new type checker rejects it up front.
         Similarly, with the advent of type families, ambiguous types are
         easy to write by mistake.  See Trac #1897 and linked tickets for
         many examples.  Eg
            type family F a :: *
            f ::: F a -> Int
            f x = 3
         This is rejected because (F a ~ F b) does not imply a~b.  Previously
         GHC would *infer* the above type for f, but was unable to check it.
         Now even the inferred type is rejected -- correctly.
      The main implemenation mechanism is to generalise the abe_wrap
      field of ABExport (in HsBinds), from [TyVar] to HsWrapper. This
      beautiful generalisation turned out to make everything work nicely
      with minimal programming effort.  All the work was fiddling around
      the edges; the core change was easy!