1. 27 Jul, 2017 1 commit
    • Richard Eisenberg's avatar
      Fix #13819 by refactoring TypeEqOrigin.uo_thing · c2417b87
      Richard Eisenberg authored
      The uo_thing field of TypeEqOrigin is used to track the
      "thing" (either term or type) that has the type (kind) stored
      in the TypeEqOrigin fields. Previously, this was sometimes a
      proper Core Type, which needed zonking and tidying. Now, it
      is only HsSyn: much simpler, and the error messages now use
      the user-written syntax.
      
      But this aspect of uo_thing didn't cause #13819; it was the
      sibling field uo_arity that did. uo_arity stored the number
      of arguments of uo_thing, useful when reporting something
      like "should have written 2 fewer arguments". We wouldn't want
      to say that if the thing didn't have two arguments. However,
      in practice, GHC was getting this wrong, and this message
      didn't seem all that helpful. Furthermore, the calculation
      of the number of arguments is what caused #13819 to fall over.
      This patch just removes uo_arity. In my opinion, the change
      to error messages is a nudge in the right direction.
      
      Test case: typecheck/should_fail/T13819
      c2417b87
  2. 11 Jul, 2017 1 commit
    • Ömer Sinan Ağacan's avatar
      Mention which -Werror promoted a warning to an error · 4befb415
      Ömer Sinan Ağacan authored
      Previously -Werror or -Werror=flag printed warnings as usual and then
      printed
      these two lines:
      
          <no location info>: error:
          Failing due to -Werror.
      
      This is not ideal: first, it's not clear which flag made one of the
      warnings an
      error. Second, warning messages are not modified in any way, so there's
      no way
      to know which warnings caused this error.
      
      With this patch we (1) promote warning messages to error messages if a
      relevant
      -Werror is enabled (2) mention which -Werror is used during this
      promotion.
      
      Previously:
      
          [1 of 1] Compiling Main             ( test.hs, test.o )
      
          test.hs:9:10: warning: [-Wincomplete-patterns]
              Pattern match(es) are non-exhaustive
              In a case alternative: Patterns not matched: (C2 _)
            |
          9 | sInt s = case s of
            |          ^^^^^^^^^...
      
          test.hs:12:14: warning: [-Wmissing-fields]
              • Fields of ‘Rec’ not initialised: f2
              • In the first argument of ‘print’, namely ‘Rec {f1 =
      1}’
                In the expression: print Rec {f1 = 1}
                In an equation for ‘main’: main = print Rec {f1 = 1}
             |
          12 | main = print Rec{ f1 = 1 }
             |              ^^^^^^^^^^^^^
      
          <no location info>: error:
          Failing due to -Werror.
      
      Now:
      
          [1 of 1] Compiling Main             ( test.hs, test.o )
      
          test.hs:9:10: error: [-Wincomplete-patterns,
      -Werror=incomplete-patterns]
              Pattern match(es) are non-exhaustive
              In a case alternative: Patterns not matched: (C2 _)
            |
          9 | sInt s = case s of
            |          ^^^^^^^^^...
      
          test.hs:12:14: error: [-Wmissing-fields, -Werror=missing-fields]
              • Fields of ‘Rec’ not initialised: f2
              • In the first argument of ‘print’, namely ‘Rec {f1 =
      1}’
                In the expression: print Rec {f1 = 1}
                In an equation for ‘main’: main = print Rec {f1 = 1}
             |
          12 | main = print Rec{ f1 = 1 }
             |              ^^^^^^^^^^^^^
      
      Test Plan: - Update old tests, add new tests if there aren't any
      relevant tests
      
      Reviewers: austin, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: rwbarton, thomie
      
      Differential Revision: https://phabricator.haskell.org/D3709
      4befb415
  3. 03 Jul, 2017 1 commit
  4. 29 Jun, 2017 1 commit
  5. 05 Jun, 2017 1 commit
    • Alan Zimmerman's avatar
      Udate hsSyn AST to use Trees that Grow · 8e6ec0fa
      Alan Zimmerman authored
      Summary:
      See https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow
      
      This commit prepares the ground for a full extensible AST, by replacing the type
      parameter for the hsSyn data types with a set of indices into type families,
      
          data GhcPs -- ^ Index for GHC parser output
          data GhcRn -- ^ Index for GHC renamer output
          data GhcTc -- ^ Index for GHC typechecker output
      
      These are now used instead of `RdrName`, `Name` and `Id`/`TcId`/`Var`
      
      Where the original name type is required in a polymorphic context, this is
      accessible via the IdP type family, defined as
      
          type family IdP p
          type instance IdP GhcPs = RdrName
          type instance IdP GhcRn = Name
          type instance IdP GhcTc = Id
      
      These types are declared in the new 'hsSyn/HsExtension.hs' module.
      
      To gain a better understanding of the extension mechanism, it has been applied
      to `HsLit` only, also replacing the `SourceText` fields in them with extension
      types.
      
      To preserve extension generality, a type class is introduced to capture the
      `SourceText` interface, which must be honoured by all of the extension points
      which originally had a `SourceText`.  The class is defined as
      
          class HasSourceText a where
            -- Provide setters to mimic existing constructors
            noSourceText  :: a
            sourceText    :: String -> a
      
            setSourceText :: SourceText -> a
            getSourceText :: a -> SourceText
      
      And the constraint is captured in `SourceTextX`, which is a constraint type
      listing all the extension points that make use of the class.
      
      Updating Haddock submodule to match.
      
      Test Plan: ./validate
      
      Reviewers: simonpj, shayan-najd, goldfire, austin, bgamari
      
      Subscribers: rwbarton, thomie, mpickering
      
      Differential Revision: https://phabricator.haskell.org/D3609
      8e6ec0fa
  6. 08 May, 2017 1 commit
  7. 10 Mar, 2017 1 commit
    • Simon Peyton Jones's avatar
      Improve error messages for skolems · 48d1866e
      Simon Peyton Jones authored
      In error messages like this
          • Couldn't match type ‘c’ with ‘f0 (a -> b)’
            ‘c’ is a rigid type variable bound by
              the type signature for:
                f :: ((a -> b) -> b) -> forall c. c -> a
      
      we need to take case both to actually show that 'forall c',
      and to make sure that its name lines with the 'c' in the
      error message.
      
      This has been shaky for some time, and this commit puts it on solid
      ground.  See TcRnTypes: Note [SigSkol SkolemInfo]
      
      The main changes are
      
      * SigSkol gets an extra field that records the way in which the
        type signature was skolemised.
      
      * The type in SigSkol is now the /un/-skolemised version
      
      * pprSkolemInfo uses the info to make the tidy type line up
        nicely
      
      Lots of error message wibbles!
      48d1866e
  8. 30 Jan, 2017 1 commit
    • Ryan Scott's avatar
      Check that a default type signature aligns with the non-default signature · 7363d538
      Ryan Scott authored
      Before, GHC was extremely permissive about the form a default type
      signature could take on in a class declaration. Notably, it would accept
      garbage like this:
      
        class Monad m => MonadSupply m where
          fresh :: m Integer
          default fresh :: MonadTrans t => t m Integer
          fresh = lift fresh
      
      And then give an extremely confusing error message when you actually
      tried to declare an empty instance of MonadSupply. We now do extra
      validity checking of default type signatures to ensure that they align
      with their non-default type signature counterparts. That is, a default
      type signature is allowed to differ from the non-default one only in its
      context - they must otherwise be alpha-equivalent.
      
      Fixes #12918.
      
      Test Plan: ./validate
      
      Reviewers: goldfire, simonpj, austin, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: mpickering, dfeuer, thomie
      
      Differential Revision: https://phabricator.haskell.org/D2983
      
      GHC Trac Issues: #12918
      7363d538
  9. 07 Dec, 2016 1 commit
    • Alan Zimmerman's avatar
      Add HsSyn prettyprinter tests · 499e4382
      Alan Zimmerman authored
      Summary:
      Add prettyprinter tests, which take a file, parse it, pretty print it,
      re-parse the pretty printed version and then compare the original and
      new ASTs (ignoring locations)
      
      Updates haddock submodule to match the AST changes.
      
      There are three issues outstanding
      
      1. Extra parens around a context are not reproduced. This will require an
         AST change and will be done in a separate patch.
      
      2. Currently if an `HsTickPragma` is found, this is not pretty-printed,
         to prevent noise in the output.
      
         I am not sure what the desired behaviour in this case is, so have left
         it as before. Test Ppr047 is marked as expected fail for this.
      
      3. Apart from in a context, the ParsedSource AST keeps all the parens from
         the original source.  Something is happening in the renamer to remove the
         parens around visible type application, causing T12530 to fail, as the
         dumped splice decl is after the renamer.
      
         This needs to be fixed by keeping the parens, but I do not know where they
         are being removed.  I have amended the test to pass, by removing the parens
         in the expected output.
      
      Test Plan: ./validate
      
      Reviewers: goldfire, mpickering, simonpj, bgamari, austin
      
      Reviewed By: simonpj, bgamari
      
      Subscribers: simonpj, goldfire, thomie, mpickering
      
      Differential Revision: https://phabricator.haskell.org/D2752
      
      GHC Trac Issues: #3384
      499e4382
  10. 02 Dec, 2016 1 commit
  11. 02 Nov, 2016 1 commit
    • Simon Peyton Jones's avatar
      Get rid of TcTyVars more assiduously · 99689492
      Simon Peyton Jones authored
      * I found a bug in 'generalize' in TcTyClsDecls.kcTyClGroup, where
        the kind variables weren't being turned into proper TyVars, so
        we got (skolem) TcTyVars in TyCons, which shouldn't happen.  Fix
        was easy.
      
      * Similarly TcHsType.kindGeneralizeType wasn't turning the forall'd
        TcTyVars into TyVars.  To achieve this I defined TcHsTyn.zonkSigType.
      
      * All this allowed me to remove awkward and ill-explained bit of
        footwork on DFunIds in Inst.newClsInst
      
      This is just refactoring, but it does make the printout from
      -ddump-deriv make a bit more sense by not grautuitiously cloning
      type variables.  In the display I was seeing
      
         instance C [a_df4] where
            f x = ...a_dx5...
      
      where actually the d_df4 and a_dx5 were the same.
      99689492
  12. 21 Oct, 2016 1 commit
    • Simon Peyton Jones's avatar
      A collection of type-inference refactorings. · 3f5673f3
      Simon Peyton Jones authored
      This patch does a raft of useful tidy-ups in the type checker.
      I've been meaning to do this for some time, and finally made
      time to do it en route to ICFP.
      
      1. Modify TcType.ExpType to make a distinct data type,
         InferResult for the Infer case, and consequential
         refactoring.
      
      2. Define a new function TcUnify.fillInferResult, to fill in
         an InferResult. It uses TcMType.promoteTcType to promote
         the type to the level of the InferResult.
         See TcMType Note [Promoting a type]
         This refactoring is in preparation for an improvement
         to typechecking pattern bindings, coming next.
      
         I flirted with an elaborate scheme to give better
         higher rank inference, but it was just too complicated.
         See TcMType Note [Promotion and higher rank types]
      
      3. Add to InferResult a new field ir_inst :: Bool to say
         whether or not the type used to fill in the
         InferResult should be deeply instantiated.  See
         TcUnify Note [Deep instantiation of InferResult].
      
      4. Add a TcLevel to SkolemTvs. This will be useful generally
      
          - it's a fast way to see if the type
            variable escapes when floating (not used yet)
      
          - it provides a good consistency check when updating a
            unification variable (TcMType.writeMetaTyVarRef, the
            level_check_ok check)
      
         I originally had another reason (related to the flirting
         in (2), but I left it in because it seems like a step in
         the right direction.
      
      5. Reduce and simplify the plethora of uExpType,
         tcSubType and related functions in TcUnify.  It was
         such an opaque mess and it's still not great, but it's
         better.
      
      6. Simplify the uo_expected field of TypeEqOrigin.  Richard
         had generatlised it to a ExpType, but it was almost always
         a Check type.  Now it's back to being a plain TcType which
         is much, much easier.
      
      7. Improve error messages by refraining from skolemisation when
         it's clear that there's an error: see
         TcUnify Note [Don't skolemise unnecessarily]
      
      8. Type.isPiTy and isForAllTy seem to be missing a coreView check,
         so I added it
      
      9. Kill off tcs_used_tcvs.  Its purpose is to track the
         givens used by wanted constraints.  For dictionaries etc
         we do that via the free vars of the /bindings/ in the
         implication constraint ic_binds.  But for coercions we
         just do update-in-place in the type, rather than
         generating a binding.  So we need something analogous to
         bindings, to track what coercions we have added.
      
         That was the purpose of tcs_used_tcvs.  But it only
         worked for a /single/ iteration, whereas we may have
         multiple iterations of solving an implication.  Look
         at (the old) 'setImplicationStatus'.  If the constraint
         is unsolved, it just drops the used_tvs on the floor.
         If it becomes solved next time round, we'll pick up
         coercions used in that round, but ignore ones used in
         the first round.
      
         There was an outright bug.  Result = (potentialy) bogus
         unused-constraint errors.  Constructing a case where this
         actually happens seems quite trick so I did not do so.
      
         Solution: expand EvBindsVar to include the (free vars of
         the) coercions, so that the coercions are tracked in
         essentially the same way as the bindings.
      
         This turned out to be much simpler.  Less code, more
         correct.
      
      10. Make the ic_binds field in an implication have type
            ic_binds :: EvBindsVar
          instead of (as previously)
             ic_binds :: Maybe EvBindsVar
          This is notably simpler, and faster to use -- less
          testing of the Maybe.  But in the occaional situation
          where we don't have anywhere to put the bindings, the
          belt-and-braces error check is lost.  So I put it back
          as an ASSERT in 'setImplicationStatus' (see the use of
          'termEvidenceAllowed')
      
      All these changes led to quite bit of error message wibbling
      3f5673f3
  13. 08 Oct, 2016 1 commit
  14. 25 Jun, 2016 2 commits
    • eir@cis.upenn.edu's avatar
      Refactor tcInferArgs and add comments. · 4cc5a39e
      eir@cis.upenn.edu authored
      This removes an unnecessary loop looking for invisible binders
      and tries to clarify what the very closely-related functions
      tcInferArgs, tc_infer_args, tcInferApps all do.
      4cc5a39e
    • eir@cis.upenn.edu's avatar
      s/Invisible/Inferred/g s/Visible/Required/g · 5fdb854c
      eir@cis.upenn.edu authored
      This renames VisibilityFlag from
      
      > data VisibilityFlag = Visible | Specified | Invisible
      
      to
      
      > data ArgFlag = Required | Specified | Inferred
      
      The old name was quite confusing, because both Specified
      and Invisible were invisible! The new names are hopefully clearer.
      5fdb854c
  15. 15 Jun, 2016 2 commits
    • Simon Peyton Jones's avatar
      Major patch to introduce TyConBinder · e368f326
      Simon Peyton Jones authored
      Before this patch, following the TypeInType innovations,
      each TyCon had two lists:
        - tyConBinders :: [TyBinder]
        - tyConTyVars  :: [TyVar]
      
      They were in 1-1 correspondence and contained
      overlapping information.  More broadly, there were many
      places where we had to pass around this pair of lists,
      instead of a single list.
      
      This commit tidies all that up, by having just one list of
      binders in a TyCon:
      
        - tyConBinders :: [TyConBinder]
      
      The new data types look like this:
      
        Var.hs:
           data TyVarBndr tyvar vis = TvBndr tyvar vis
           data VisibilityFlag = Visible | Specified | Invisible
           type TyVarBinder = TyVarBndr TyVar VisibilityFlag
      
        TyCon.hs:
           type TyConBinder = TyVarBndr TyVar TyConBndrVis
      
           data TyConBndrVis
             = NamedTCB VisibilityFlag
             | AnonTCB
      
        TyCoRep.hs:
           data TyBinder
             = Named TyVarBinder
             | Anon Type
      
      Note that Var.TyVarBdr has moved from TyCoRep and has been
      made polymorphic in the tyvar and visiblity fields:
      
           type TyVarBinder = TyVarBndr TyVar VisibilityFlag
              -- Used in ForAllTy
           type TyConBinder = TyVarBndr TyVar TyConBndrVis
              -- Used in TyCon
      
           type IfaceForAllBndr  = TyVarBndr IfaceTvBndr VisibilityFlag
           type IfaceTyConBinder = TyVarBndr IfaceTvBndr TyConBndrVis
               -- Ditto, in interface files
      
      There are a zillion knock-on changes, but everything
      arises from these types.  It was a bit fiddly to get the
      module loops to work out right!
      
      Some smaller points
      ~~~~~~~~~~~~~~~~~~~
      * Nice new functions
          TysPrim.mkTemplateKiTyVars
          TysPrim.mkTemplateTyConBinders
        which help you make the tyvar binders for dependently-typed
        TyCons.  See comments with their definition.
      
      * The change showed up a bug in TcGenGenerics.tc_mkRepTy, where the code
        was making an assumption about the order of the kind variables in the
        kind of GHC.Generics.(:.:).  I fixed this; see TcGenGenerics.mkComp.
      e368f326
    • Simon Peyton Jones's avatar
      Re-add FunTy (big patch) · 77bb0927
      Simon Peyton Jones authored
      With TypeInType Richard combined ForAllTy and FunTy, but that was often
      awkward, and yielded little benefit becuase in practice the two were
      always treated separately.  This patch re-introduces FunTy.  Specfically
      
      * New type
          data TyVarBinder = TvBndr TyVar VisibilityFlag
        This /always/ has a TyVar it.  In many places that's just what
        what we want, so there are /lots/ of TyBinder -> TyVarBinder changes
      
      * TyBinder still exists:
          data TyBinder = Named TyVarBinder | Anon Type
      
      * data Type = ForAllTy TyVarBinder Type
                  | FunTy Type Type
                  |  ....
      
      There are a LOT of knock-on changes, but they are all routine.
      
      The Haddock submodule needs to be updated too
      77bb0927
  16. 13 Jun, 2016 1 commit
  17. 22 Apr, 2016 1 commit
    • Simon Peyton Jones's avatar
      Improve the behaviour of warnIf · f02af79e
      Simon Peyton Jones authored
      Now that warnIf takes a "reason", we can test the reason
      in warnIf rather than in the caller.  Less code, and less
      risk of getting the test and the reason out of sync.
      f02af79e
  18. 29 Mar, 2016 1 commit
    • niteria's avatar
      Build correct substitution in instDFunType · a49228e3
      niteria authored
      We will use `ty` in the range of the substitution, hence
      the substitution needs `ty`'s free vars in-scope.
      They don't seem easily available by other means, so we
      just compute them.
      
      Test Plan: ./validate
      
      Reviewers: austin, goldfire, bgamari, simonpj
      
      Reviewed By: simonpj
      
      Subscribers: thomie, simonmar
      
      Differential Revision: https://phabricator.haskell.org/D2043
      
      GHC Trac Issues: #11371
      a49228e3
  19. 25 Feb, 2016 1 commit
    • barrucadu's avatar
      Print which warning-flag controls an emitted warning · bb5afd3c
      barrucadu authored
      Both gcc and clang tell which warning flag a reported warning can be
      controlled with, this patch makes ghc do the same. More generally, this
      allows for annotated compiler output, where an optional annotation is
      displayed in brackets after the severity.
      
      This also adds a new flag `-f(no-)show-warning-groups` to control
      whether to show which warning-group (such as `-Wall` or `-Wcompat`)
      a warning belongs to. This flag is on by default.
      
      This implements #10752
      
      Reviewed By: quchen, bgamari, hvr
      
      Differential Revision: https://phabricator.haskell.org/D1943
      bb5afd3c
  20. 24 Feb, 2016 1 commit
    • eir@cis.upenn.edu's avatar
      Address #11471 by putting RuntimeRep in kinds. · d8c64e86
      eir@cis.upenn.edu authored
      See Note [TYPE] in TysPrim. There are still some outstanding
      pieces in #11471 though, so this doesn't actually nail the bug.
      
      This commit also contains a few performance improvements:
      
      * Short-cut equality checking of nullary type syns
      
      * Compare types before kinds in eqType
      
      * INLINE coreViewOneStarKind
      
      * Store tycon binders separately from kinds.
      
      This resulted in a ~10% performance improvement in compiling
      the Cabal package. No change in functionality other than
      performance. (This affects the interface file format, though.)
      
      This commit updates the haddock submodule.
      d8c64e86
  21. 18 Feb, 2016 1 commit
    • Simon Peyton Jones's avatar
      (Another) minor refactoring of substitutions · b5292557
      Simon Peyton Jones authored
      No change in functionality here, but greater clarity:
      
      * In FamInstEnv.FlattenEnv, kill off the fi_in_scope field
        We are already maintaining an in-scope set in the fe_subst field,
        so it's silly do to it twice.
      
        (This isn't strictly connected to the rest of this patch, but
        the nomenclature changes below affect the same code, so I put
        them together.)
      
      * TyCoRep.extendTCVSubst used to take a TyVar or a CoVar and work
        out what to do, but in fact we almost always know which of the
        two we are doing.  So:
          - define extendTvSubst, extendCvSubst
          - and use them
      
      * Similar renamings in TyCoRep:
         - extendTCvSubstList        -->   extendTvSubstList
         - extendTCvSubstBinder      -->   extendTvSubstBinder
         - extendTCvSubstAndInScope  --> extendTvSubstAndInScope
      
      * Add Type.extendTvSubstWithClone, extendCvSubstWithClone
      
      * Similar nomenclature changes in Subst, SimplEnv, Specialise
      
      * Kill off TyCoRep.substTelescope (never used)
      b5292557
  22. 30 Jan, 2016 1 commit
    • niteria's avatar
      Add asserts to other substitution functions · bb956eb8
      niteria authored
      This adds asserts to `substTys`, `substCo` and `substCos` in
      the same spirit as already existing asserts on `substTy`, protecting
      every possible entry point to `subst_ty` and `subst_co`.
      
      I've replaced the violators with unchecked versions.
      
      Test Plan: ./validate --slow
      
      Reviewers: simonpj, goldfire, austin, bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1862
      
      GHC Trac Issues: #11371
      bb956eb8
  23. 27 Jan, 2016 1 commit
    • eir@cis.upenn.edu's avatar
      Refactor the typechecker to use ExpTypes. · 00cbbab3
      eir@cis.upenn.edu authored
      The idea here is described in [wiki:Typechecker]. Briefly,
      this refactor keeps solid track of "synthesis" mode vs
      "checking" in GHC's bidirectional type-checking algorithm.
      When in synthesis mode, the expected type is just an IORef
      to write to.
      
      In addition, this patch does a significant reworking of
      RebindableSyntax, allowing much more freedom in the types
      of the rebindable operators. For example, we can now have
      `negate :: Int -> Bool` and
      `(>>=) :: m a -> (forall x. a x -> m b) -> m b`. The magic
      is in tcSyntaxOp.
      
      This addresses tickets #11397, #11452, and #11458.
      
      Tests:
        typecheck/should_compile/{RebindHR,RebindNegate,T11397,T11458}
        th/T11452
      00cbbab3
  24. 19 Jan, 2016 1 commit
    • niteria's avatar
      Check InScopeSet in substTy and provide substTyUnchecked · 9d33adb6
      niteria authored
      This adds sanity checks to `substTy` that implement:
      
      > when calling substTy subst ty it should be the case that the in-scope
      > set in the substitution is a superset of
      > * The free vars of the range of the substitution
      > * The free vars of ty minus the domain of the substitution
      
      and replaces violators with unchecked version. The violators were found
      by running the GHC test suite.
      
      This ensures that I can work on this incrementally and that what I fix won't
      be undone by some other change.
      
      It also includes a couple of fixes that I've already done.
      
      Test Plan: ./validate
      
      Reviewers: simonmar, goldfire, simonpj, austin, bgamari
      
      Reviewed By: simonpj, bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1792
      
      GHC Trac Issues: #11371
      9d33adb6
  25. 18 Jan, 2016 1 commit
    • Jan Stolarek's avatar
      Replace calls to `ptext . sLit` with `text` · b8abd852
      Jan Stolarek authored
      Summary:
      In the past the canonical way for constructing an SDoc string literal was the
      composition `ptext . sLit`.  But for some time now we have function `text` that
      does the same.  Plus it has some rules that optimize its runtime behaviour.
      This patch takes all uses of `ptext . sLit` in the compiler and replaces them
      with calls to `text`.  The main benefits of this patch are clener (shorter) code
      and less dependencies between module, because many modules now do not need to
      import `FastString`.  I don't expect any performance benefits - we mostly use
      SDocs to report errors and it seems there is little to be gained here.
      
      Test Plan: ./validate
      
      Reviewers: bgamari, austin, goldfire, hvr, alanz
      
      Subscribers: goldfire, thomie, mpickering
      
      Differential Revision: https://phabricator.haskell.org/D1784
      b8abd852
  26. 24 Dec, 2015 2 commits
    • eir@cis.upenn.edu's avatar
      Visible type application · 2db18b81
      eir@cis.upenn.edu authored
      This re-working of the typechecker algorithm is based on
      the paper "Visible type application", by Richard Eisenberg,
      Stephanie Weirich, and Hamidhasan Ahmed, to be published at
      ESOP'16.
      
      This patch introduces -XTypeApplications, which allows users
      to say, for example `id @Int`, which has type `Int -> Int`. See
      the changes to the user manual for details.
      
      This patch addresses tickets #10619, #5296, #10589.
      2db18b81
    • Simon Peyton Jones's avatar
      Refactoring only · 1af0d36b
      Simon Peyton Jones authored
      This moves code around to more sensible places.
      
      - Construction for CoAxiom is localised in FamInstEnv
      
      - orphNamesOfxx moves to CoreFVs
      
      - roughMatchTcs, instanceCantMatch moves to Unify
      
      - mkNewTypeCo moves from Coercion to FamInstEnv, and is
        renamed mkNewTypeCoAxiom, which makes more sense
      1af0d36b
  27. 22 Dec, 2015 1 commit
    • Simon Peyton Jones's avatar
      Fix typechecking for pattern synonym signatures · f40e122b
      Simon Peyton Jones authored
      Various tickets have revealed bad shortcomings in the typechecking of
      pattern type synonyms.  Discussed a lot in (the latter part of)
      Trac #11224.
      
      This patch fixes the most complex issues:
      
      - Both parser and renamer now treat pattern synonyms as an
        ordinary LHsSigType.  Nothing special.  Hooray.
      
      - tcPatSynSig (now in TcPatSyn) typechecks the signature, and
        decomposes it into its pieces.
        See Note [Pattern synonym signatures]
      
      - tcCheckPatSyn has had a lot of refactoring.
        See Note [Checking against a pattern signature]
      
      The result is a lot tidier and more comprehensible.
      Plus, it actually works!
      
      NB: this patch doesn't actually address the precise
          target of #11224, namely "inlining pattern synonym
          does not preserve semantics".  That's an unrelated
          bug, with a separate patch.
      
      ToDo: better documentation in the user manual
      
      Test Plan: Validate
      
      Reviewers: austin, hvr, goldfire
      
      Subscribers: goldfire, mpickering, thomie, simonpj
      
      Differential Revision: https://phabricator.haskell.org/D1685
      
      GHC Trac Issues: #11224
      f40e122b
  28. 15 Dec, 2015 1 commit
    • Ben Gamari's avatar
      Expose enabled language extensions to TH · c1e25536
      Ben Gamari authored
      This exposes `template-haskell` functions for querying the language
      extensions which are enabled when compiling a module,
      
      - an `isExtEnabled` function to check whether an extension is enabled
      - an `extsEnabled` function to obtain a full list of enabled extensions
      
      To avoid code duplication this adds a `GHC.LanguageExtensions` module to
      `ghc-boot` and moves `DynFlags.ExtensionFlag` into it. A happy
      consequence of this is that the ungainly `DynFlags` lost around 500
      lines. Moreover, flags corresponding to language extensions are now
      clearly distinguished from other flags due to the `LangExt.*` prefix.
      
      Updates haddock submodule.
      
      This fixes #10820.
      
      Test Plan: validate
      
      Reviewers: austin, spinda, hvr, goldfire, alanz
      
      Reviewed By: goldfire
      
      Subscribers: mpickering, RyanGlScott, hvr, simonpj, thomie
      
      Differential Revision: https://phabricator.haskell.org/D1200
      
      GHC Trac Issues: #10820
      c1e25536
  29. 12 Dec, 2015 1 commit
  30. 11 Dec, 2015 1 commit
    • eir@cis.upenn.edu's avatar
      Add kind equalities to GHC. · 67465497
      eir@cis.upenn.edu authored
      This implements the ideas originally put forward in
      "System FC with Explicit Kind Equality" (ICFP'13).
      
      There are several noteworthy changes with this patch:
       * We now have casts in types. These change the kind
         of a type. See new constructor `CastTy`.
      
       * All types and all constructors can be promoted.
         This includes GADT constructors. GADT pattern matches
         take place in type family equations. In Core,
         types can now be applied to coercions via the
         `CoercionTy` constructor.
      
       * Coercions can now be heterogeneous, relating types
         of different kinds. A coercion proving `t1 :: k1 ~ t2 :: k2`
         proves both that `t1` and `t2` are the same and also that
         `k1` and `k2` are the same.
      
       * The `Coercion` type has been significantly enhanced.
         The documentation in `docs/core-spec/core-spec.pdf` reflects
         the new reality.
      
       * The type of `*` is now `*`. No more `BOX`.
      
       * Users can write explicit kind variables in their code,
         anywhere they can write type variables. For backward compatibility,
         automatic inference of kind-variable binding is still permitted.
      
       * The new extension `TypeInType` turns on the new user-facing
         features.
      
       * Type families and synonyms are now promoted to kinds. This causes
         trouble with parsing `*`, leading to the somewhat awkward new
         `HsAppsTy` constructor for `HsType`. This is dispatched with in
         the renamer, where the kind `*` can be told apart from a
         type-level multiplication operator. Without `-XTypeInType` the
         old behavior persists. With `-XTypeInType`, you need to import
         `Data.Kind` to get `*`, also known as `Type`.
      
       * The kind-checking algorithms in TcHsType have been significantly
         rewritten to allow for enhanced kinds.
      
       * The new features are still quite experimental and may be in flux.
      
       * TODO: Several open tickets: #11195, #11196, #11197, #11198, #11203.
      
       * TODO: Update user manual.
      
      Tickets addressed: #9017, #9173, #7961, #10524, #8566, #11142.
      Updates Haddock submodule.
      67465497
  31. 02 Dec, 2015 1 commit
  32. 22 Nov, 2015 1 commit
    • Alan Zimmerman's avatar
      ApiAnnotations: Make all RdrName occurences Located · 3df9563e
      Alan Zimmerman authored
      At the moment the API Annotations can only be used on the ParsedSource,
      as there are changes made to the RenamedSource that prevent it from
      being used to round trip source code.
      
      It is possible to build a map from every Located Name in the
      RenamedSource from its location to the Name, which can then be used when
      resolved names are required when changing the ParsedSource.
      
      However, there are instances where the identifier is not located,
      specifically
      
        (GHC.VarPat name)
        (GHC.HsVar name)
        (GHC.UserTyVar name)
        (GHC.HsTyVar name)
      
      Replace each of the name types above with (Located name)
      
      Updates the haddock submodule.
      
      Test Plan: ./validate
      
      Reviewers: austin, goldfire, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: goldfire, thomie, mpickering
      
      Differential Revision: https://phabricator.haskell.org/D1512
      
      GHC Trac Issues: #11019
      3df9563e
  33. 16 Oct, 2015 1 commit
    • Adam Gundry's avatar
      Implement DuplicateRecordFields · b1884b0e
      Adam Gundry authored
      This implements DuplicateRecordFields, the first part of the
      OverloadedRecordFields extension, as described at
      https://ghc.haskell.org/trac/ghc/wiki/Records/OverloadedRecordFields/DuplicateRecordFields
      
      This includes fairly wide-ranging changes in order to allow multiple
      records within the same module to use the same field names.  Note that
      it does *not* allow record selector functions to be used if they are
      ambiguous, and it does not have any form of type-based disambiguation
      for selectors (but it does for updates). Subsequent parts will make
      overloading selectors possible using orthogonal extensions, as
      described on the wiki pages.  This part touches quite a lot of the
      codebase, and requires changes to several GHC API datatypes in order
      to distinguish between field labels (which may be overloaded) and
      selector function names (which are always unique).
      
      The Haddock submodule has been adapted to compile with the GHC API
      changes, but it will need further work to properly support modules
      that use the DuplicateRecordFields extension.
      
      Test Plan: New tests added in testsuite/tests/overloadedrecflds; these
      will be extended once the other parts are implemented.
      
      Reviewers: goldfire, bgamari, simonpj, austin
      
      Subscribers: sjcjoosten, haggholm, mpickering, bgamari, tibbe, thomie,
      goldfire
      
      Differential Revision: https://phabricator.haskell.org/D761
      b1884b0e
  34. 08 Oct, 2015 1 commit
  35. 06 Oct, 2015 1 commit
  36. 24 Jul, 2015 1 commit
    • Simon Peyton Jones's avatar
      Refactoring around FunDeps · d53d8089
      Simon Peyton Jones authored
      This refactoring was triggered by Trac #10675.
      
      We were using 'improveClsFD' (previously called 'checkClsFD') for
      both
        * Improvement: improving a constraint against top-level instances
        * Consistency: checking when two top-level instances are
          consistent
      
      Using the same code for both seemed attractive at the time, but
      it's just too complicated.  So I've split it:
       * Improvement: improveClsFD
       * Consistency: checkFunDeps
      
      Much clearer now!
      d53d8089
  37. 18 Jun, 2015 1 commit
    • Simon Peyton Jones's avatar
      Remove some horrible munging of origins for Coercible · 02bac025
      Simon Peyton Jones authored
      I just didn't think it was buying enough for all the cruft it caused.
      We can put some back if people start complaining about poor error
      messages. I forget quite how I tripped over this but I got sucked in.
      
      * Lots of tidying up in TcErrors
      
      * Rename pprArisingAt to pprCtLoc, by analogy with pprCtOrigin
      
      * Remove CoercibleOrigin data constructor from CtOrigin
      
      * Make relevantBindings return a Ct with a zonked
        and tidied CtOrigin
      
      * Add to TcRnTypes
            ctOrigin   :: Ct -> CtOrigin
            ctEvOrigin :: CtEvidence -> CtOrigin
            setCtLoc   :: Ct -> CtLoc -> Ct
      02bac025