1. 27 Jan, 2016 1 commit
    • niteria's avatar
      Rename "open" subst functions · 5dcae88b
      niteria authored
      This is the renaming that @simonpj requested:
      ```
      · zipOpenTCvSubst  -> zipTvSubst   (It only deals with tyvars)
      
      · zipOpenTCvSubstCoVars -> zipCvSubst   (it only deals with
      covars)
      
      · zipOpenTCvSubstBinders ->  zipTyBinderSubst  (it only deals
      with TyBinders, not covars)
      ```
      plus the `mk` variant.
      
      Test Plan: ./validate
      
      Reviewers: simonpj, goldfire, austin, bgamari
      
      Subscribers: thomie, simonpj
      
      Differential Revision: https://phabricator.haskell.org/D1853
      
      GHC Trac Issues: #11371
      5dcae88b
  2. 26 Jan, 2016 2 commits
    • niteria's avatar
      Construct in_scope set in mkTopTCvSubst · 144ddb41
      niteria authored
      The pre-condition on `mkTopTCvSubst` turned out to be wrong and
      not satisfied by any of the callers. I've fixed it, so that it
      constructs the in_scope set from the range of the substitution.
      `mkTopTCvSubst` was also unnecessarily general it is never called
      with `CoVars`, so I changed the type signature and added an assertion.
      
      Test Plan: ./validate --slow
      
      Reviewers: goldfire, simonpj, bgamari, austin
      
      Reviewed By: simonpj
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1801
      
      GHC Trac Issues: #11371
      144ddb41
    • Simon Peyton Jones's avatar
      Kill off zipTopTCvSubst in favour of zipOpenTCvSubst · 1c6d70c2
      Simon Peyton Jones authored
      As Bartosz has discovered, the invariants for substitutions were
      wrong, and in particular the "mkTop...Subst" and "zipTop..Subst"
      functions were building substitutions that didn't obey even the
      old invariants.
      
      This patch kills of the bogus zipTopTCvSubst in favour of the
      more robust zipOpenTCvSubst.
      
      I tripped over this because my upcoming patch (concerning SetLevels,
      Trac #11330) triggered an ASSERT failure in the substitution
      well-formedness assertion in TyCoRep.
      1c6d70c2
  3. 20 Jan, 2016 1 commit
    • Ben Gamari's avatar
      Rework derivation of type representations for wired-in things · 84b0ebed
      Ben Gamari authored
      Previously types defined by `GHC.Types` and `GHC.Prim` had their
      `Typeable` representations manually defined in `GHC.Typeable.Internals`.
      This was terrible, resulting in a great deal of boilerplate and a number
      of bugs due to missing or inconsistent representations (see #11120).
      
      Here we take a different tack, initially proposed by Richard Eisenberg:
      We wire-in the `Module`, `TrName`, and `TyCon` types, allowing them to
      be used in `GHC.Types`. We then allow the usual type representation
      generation logic to handle this module.
      
      `GHC.Prim`, on the other hand, is a bit tricky as it has no object code
      of its own.  To handle this we instead place the type representations
      for the types defined here in `GHC.Types`.
      
      On the whole this eliminates several special-cases as well as a fair
      amount of boilerplate from hand-written representations. Moreover, we
      get full coverage of primitive types for free.
      
      Test Plan: Validate
      
      Reviewers: goldfire, simonpj, austin, hvr
      
      Subscribers: goldfire, simonpj, thomie
      
      Differential Revision: https://phabricator.haskell.org/D1774
      
      GHC Trac Issues: #11120
      84b0ebed
  4. 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
  5. 13 Jan, 2016 1 commit
    • Ben Gamari's avatar
      Add missing type representations · ac3cf68c
      Ben Gamari authored
      Previously we were missing `Typeable` representations for several
      wired-in types (and their promoted constructors). These include,
      
       * `Nat`
       * `Symbol`
       * `':`
       * `'[]`
      
      Moreover, some constructors were incorrectly identified as being defined
      in `GHC.Types` whereas they were in fact defined in `GHC.Prim`.
      
      Ultimately this is just a temporary band-aid as there is general
      agreement that we should eliminate the manual definition of these
      representations entirely.
      
      Test Plan: Validate
      
      Reviewers: austin, hvr
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1769
      
      GHC Trac Issues: #11120
      ac3cf68c
  6. 24 Dec, 2015 1 commit
    • 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
  7. 23 Dec, 2015 1 commit
  8. 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
  9. 25 Nov, 2015 1 commit
    • Simon Peyton Jones's avatar
      Refactor default methods (Trac #11105) · 924f8517
      Simon Peyton Jones authored
      This patch does some signficant refactoring to the treatment
      of default methods in class declarations, and more generally
      to the type checking of type/class decls.
      
      Highlights:
      
      * When the class has a generic-default method, such as
           class C a where
             op :: a -> a -> Bool
             default op :: Ord a => a -> a -> a
        the ClassOpItem records the type of the generic-default,
        in this case the type (Ord a => a -> a -> a)
      
      * I killed off Class.DefMeth in favour of the very-similar
        BasicTypes.DefMethSpec.  However it turned out to be better
        to use a Maybe, thus
            Maybe (DefMethSpec Type)
        with Nothing meaning "no default method".
      
      * In TcTyClsDecls.tcTyClGroup, we used to accumulate a [TyThing],
        but I found a way to make it much simpler, accumulating only
        a [TyCon].  Much less wrapping and unwrapping.
      
      * On the way I also fixed Trac #10896 in a better way. Instead
        of killing off all ambiguity checks whenever there are any type
        errors (the fix in commit 8e8b9ed9), I instead recover in
        TcTyClsDecls.checkValidTyCl.
      
      There was a lot of associated simplification all round
      924f8517
  10. 30 Oct, 2015 1 commit
    • Ben Gamari's avatar
      Generate Typeable info at definition sites · 91c6b1f5
      Ben Gamari authored
      This is the second attempt at merging D757.
      
      This patch implements the idea floated in Trac #9858, namely that we
      should generate type-representation information at the data type
      declaration site, rather than when solving a Typeable constraint.
      
      However, this turned out quite a bit harder than I expected. I still
      think it's the right thing to do, and it's done now, but it was quite
      a struggle.
      
      See particularly
      
       * Note [Grand plan for Typeable] in TcTypeable (which is a new module)
       * Note [The overall promotion story] in DataCon (clarifies existing
      stuff)
      
      The most painful bit was that to generate Typeable instances (ie
      TyConRepName bindings) for every TyCon is tricky for types in ghc-prim
      etc:
      
       * We need to have enough data types around to *define* a TyCon
       * Many of these types are wired-in
      
      Also, to minimise the code generated for each data type, I wanted to
      generate pure data, not CAFs with unpackCString# stuff floating about.
      
      Performance
      ~~~~~~~~~~~
      Three perf/compiler tests start to allocate quite a bit more. This isn't
      surprising, because they all allocate zillions of data types, with
      practically no other code, esp. T1969
      
       * T1969:    GHC allocates 19% more
       * T4801:    GHC allocates 13% more
       * T5321FD:  GHC allocates 13% more
       * T9675:    GHC allocates 11% more
       * T783:     GHC allocates 11% more
       * T5642:    GHC allocates 10% more
      
      I'm treating this as acceptable. The payoff comes in Typeable-heavy
      code.
      
      Remaining to do
      ~~~~~~~~~~~~~~~
      
       * I think that "TyCon" and "Module" are over-generic names to use for
         the runtime type representations used in GHC.Typeable. Better might
      be
         "TrTyCon" and "TrModule". But I have not yet done this
      
       * Add more info the the "TyCon" e.g. source location where it was
         defined
      
       * Use the new "Module" type to help with Trac Trac #10068
      
       * It would be possible to generate TyConRepName (ie Typeable
         instances) selectively rather than all the time. We'd need to persist
         the information in interface files. Lacking a motivating reason I
      have
         not done this, but it would not be difficult.
      
      Refactoring
      ~~~~~~~~~~~
      As is so often the case, I ended up refactoring more than I intended.
      In particular
      
       * In TyCon, a type *family* (whether type or data) is repesented by a
         FamilyTyCon
           * a algebraic data type (including data/newtype instances) is
             represented by AlgTyCon This wasn't true before; a data family
             was represented as an AlgTyCon. There are some corresponding
             changes in IfaceSyn.
      
           * Also get rid of the (unhelpfully named) tyConParent.
      
       * In TyCon define 'Promoted', isomorphic to Maybe, used when things are
         optionally promoted; and use it elsewhere in GHC.
      
       * Cleanup handling of knownKeyNames
      
       * Each TyCon, including promoted TyCons, contains its TyConRepName, if
         it has one. This is, in effect, the name of its Typeable instance.
      
      Updates haddock submodule
      
      Test Plan: Let Harbormaster validate
      
      Reviewers: austin, hvr, goldfire
      
      Subscribers: goldfire, thomie
      
      Differential Revision: https://phabricator.haskell.org/D1404
      
      GHC Trac Issues: #9858
      91c6b1f5
  11. 29 Oct, 2015 3 commits
    • Ben Gamari's avatar
      Revert "Generate Typeable info at definition sites" · bbaf76f9
      Ben Gamari authored
      This reverts commit bef2f03e.
      
      This merge was botched
      
      Also reverts haddock submodule.
      bbaf76f9
    • Ben Gamari's avatar
      Generate Typeable info at definition sites · bef2f03e
      Ben Gamari authored
      This patch implements the idea floated in Trac #9858, namely that we
      should generate type-representation information at the data type
      declaration site, rather than when solving a Typeable constraint.
      
      However, this turned out quite a bit harder than I expected. I still
      think it's the right thing to do, and it's done now, but it was quite
      a struggle.
      
      See particularly
      
       * Note [Grand plan for Typeable] in TcTypeable (which is a new module)
       * Note [The overall promotion story] in DataCon (clarifies existing stuff)
      
      The most painful bit was that to generate Typeable instances (ie
      TyConRepName bindings) for every TyCon is tricky for types in ghc-prim
      etc:
      
       * We need to have enough data types around to *define* a TyCon
       * Many of these types are wired-in
      
      Also, to minimise the code generated for each data type, I wanted to
      generate pure data, not CAFs with unpackCString# stuff floating about.
      
      Performance
      ~~~~~~~~~~~
      Three perf/compiler tests start to allocate quite a bit more. This isn't
      surprising, because they all allocate zillions of data types, with
      practically no other code, esp. T1969
      
       * T3294:   GHC allocates 110% more (filed #11030 to track this)
       * T1969:   GHC allocates 30% more
       * T4801:   GHC allocates 14% more
       * T5321FD: GHC allocates 13% more
       * T783:    GHC allocates 12% more
       * T9675:   GHC allocates 12% more
       * T5642:   GHC allocates 10% more
       * T9961:   GHC allocates 6% more
      
       * T9203:   Program allocates 54% less
      
      I'm treating this as acceptable. The payoff comes in Typeable-heavy
      code.
      
      Remaining to do
      ~~~~~~~~~~~~~~~
      
       * I think that "TyCon" and "Module" are over-generic names to use for
         the runtime type representations used in GHC.Typeable. Better might be
         "TrTyCon" and "TrModule". But I have not yet done this
      
       * Add more info the the "TyCon" e.g. source location where it was
         defined
      
       * Use the new "Module" type to help with Trac Trac #10068
      
       * It would be possible to generate TyConRepName (ie Typeable
         instances) selectively rather than all the time. We'd need to persist
         the information in interface files. Lacking a motivating reason I have
         not done this, but it would not be difficult.
      
      Refactoring
      ~~~~~~~~~~~
      As is so often the case, I ended up refactoring more than I intended.
      In particular
      
       * In TyCon, a type *family* (whether type or data) is repesented by a
         FamilyTyCon
           * a algebraic data type (including data/newtype instances) is
             represented by AlgTyCon This wasn't true before; a data family
             was represented as an AlgTyCon. There are some corresponding
             changes in IfaceSyn.
      
           * Also get rid of the (unhelpfully named) tyConParent.
      
       * In TyCon define 'Promoted', isomorphic to Maybe, used when things are
         optionally promoted; and use it elsewhere in GHC.
      
       * Cleanup handling of knownKeyNames
      
       * Each TyCon, including promoted TyCons, contains its TyConRepName, if
         it has one. This is, in effect, the name of its Typeable instance.
      
      Requires update of the haddock submodule.
      
      Differential Revision: https://phabricator.haskell.org/D757
      bef2f03e
    • Matthew Pickering's avatar
      Record pattern synonyms · 2a74a64e
      Matthew Pickering authored
      This patch implements an extension to pattern synonyms which allows user
      to specify pattern synonyms using record syntax. Doing so generates
      appropriate selectors and update functions.
      
      === Interaction with Duplicate Record Fields ===
      
      The implementation given here isn't quite as general as it could be with
      respect to the recently-introduced `DuplicateRecordFields` extension.
      
      Consider the following module:
      
          {-# LANGUAGE DuplicateRecordFields #-}
          {-# LANGUAGE PatternSynonyms #-}
      
          module Main where
      
          pattern S{a, b} = (a, b)
          pattern T{a}    = Just a
      
          main = do
            print S{ a = "fst", b = "snd" }
            print T{ a = "a" }
      
      In principle, this ought to work, because there is no ambiguity. But at
      the moment it leads to a "multiple declarations of a" error. The problem
      is that pattern synonym record selectors don't do the same name mangling
      as normal datatypes when DuplicateRecordFields is enabled. They could,
      but this would require some work to track the field label and selector
      name separately.
      
      In particular, we currently represent datatype selectors in the third
      component of AvailTC, but pattern synonym selectors are just represented
      as Avails (because they don't have a corresponding type constructor).
      Moreover, the GlobalRdrElt for a selector currently requires it to have
      a parent tycon.
      
      (example due to Adam Gundry)
      
      === Updating Explicitly Bidirectional Pattern Synonyms ===
      
      Consider the following
      
      ```
      pattern Silly{a} <- [a] where
        Silly a = [a, a]
      
      f1 = a [5] -- 5
      
      f2 = [5] {a = 6} -- currently [6,6]
      ```
      
      === Fixing Polymorphic Updates ===
      
      They were fixed by adding these two lines in `dsExpr`. This might break
      record updates but will be easy to fix.
      
      ```
      + ; let req_wrap = mkWpTyApps (mkTyVarTys univ_tvs)
      
      - , pat_wrap = idHsWrapper }
      +, pat_wrap = req_wrap }
      ```
      
      === Mixed selectors error ===
      
      Note [Mixed Record Field Updates]
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      
      Consider the following pattern synonym.
      
          data MyRec = MyRec { foo :: Int, qux :: String }
      
          pattern HisRec{f1, f2} = MyRec{foo = f1, qux=f2}
      
      This allows updates such as the following
      
          updater :: MyRec -> MyRec
          updater a = a {f1 = 1 }
      
      It would also make sense to allow the following update (which we
      reject).
      
          updater a = a {f1 = 1, qux = "two" } ==? MyRec 1 "two"
      
      This leads to confusing behaviour when the selectors in fact refer the
      same field.
      
          updater a = a {f1 = 1, foo = 2} ==? ???
      
      For this reason, we reject a mixture of pattern synonym and normal
      record selectors in the same update block. Although of course we still
      allow the following.
      
          updater a = (a {f1 = 1}) {foo = 2}
      
          > updater (MyRec 0 "str")
          MyRec 2 "str"
      2a74a64e
  12. 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
  13. 03 Sep, 2015 1 commit
  14. 27 Aug, 2015 1 commit
  15. 10 Aug, 2015 1 commit
  16. 27 Jul, 2015 1 commit
    • Adam Sandberg Eriksson's avatar
      Implementation of StrictData language extension · f842ad6c
      Adam Sandberg Eriksson authored
      This implements the `StrictData` language extension, which lets the
      programmer default to strict data fields in datatype declarations on a
      per-module basis.
      
      Specification and motivation can be found at
      https://ghc.haskell.org/trac/ghc/wiki/StrictPragma
      
      This includes a tricky parser change due to conflicts regarding `~` in
      the type level syntax: all ~'s are parsed as strictness annotations (see
      `strict_mark` in Parser.y) and then turned into equality constraints at
      the appropriate places using `RdrHsSyn.splitTilde`.
      
      Updates haddock submodule.
      
      Test Plan: Validate through Harbormaster.
      
      Reviewers: goldfire, austin, hvr, simonpj, tibbe, bgamari
      
      Reviewed By: simonpj, tibbe, bgamari
      
      Subscribers: lelf, simonpj, alanz, goldfire, thomie, bgamari, mpickering
      
      Differential Revision: https://phabricator.haskell.org/D1033
      
      GHC Trac Issues: #8347
      f842ad6c
  17. 18 May, 2015 1 commit
    • Simon Peyton Jones's avatar
      Refactor tuple constraints · ffc21506
      Simon Peyton Jones authored
      Make tuple constraints be handled by a perfectly ordinary
      type class, with the component constraints being the
      superclasses:
          class (c1, c2) => (c2, c2)
      
      This change was provoked by
      
        #10359  inability to re-use a given tuple
                constraint as a whole
      
        #9858   confusion between term tuples
                and constraint tuples
      
      but it's generally a very nice simplification. We get rid of
       -  In Type, the TuplePred constructor of PredTree,
          and all the code that dealt with TuplePreds
       -  In TcEvidence, the constructors EvTupleMk, EvTupleSel
      
      See Note [How tuples work] in TysWiredIn.
      
      Of course, nothing is ever entirely simple. This one
      proved quite fiddly.
      
      - I did quite a bit of renaming, which makes this patch
        touch a lot of modules. In partiuclar tupleCon -> tupleDataCon.
      
      - I made constraint tuples known-key rather than wired-in.
        This is different to boxed/unboxed tuples, but it proved
        awkward to have all the superclass selectors wired-in.
        Easier just to use the standard mechanims.
      
      - While I was fiddling with known-key names, I split the TH Name
        definitions out of DsMeta into a new module THNames.  That meant
        that the known-key names can all be gathered in PrelInfo, without
        causing module loops.
      
      - I found that the parser was parsing an import item like
            T( .. )
        as a *data constructor* T, and then using setRdrNameSpace to
        fix it.  Stupid!  So I changed the parser to parse a *type
        constructor* T, which means less use of setRdrNameSpace.
      
        I also improved setRdrNameSpace to behave better on Exact Names.
        Largely on priciple; I don't think it matters a lot.
      
      - When compiling a data type declaration for a wired-in thing like
        tuples (,), or lists, we don't really need to look at the
        declaration.  We have the wired-in thing!  And not doing so avoids
        having to line up the uniques for data constructor workers etc.
        See Note [Declarations for wired-in things]
      
      - I found that FunDeps.oclose wasn't taking superclasses into
        account; easily fixed.
      
      - Some error message refactoring for invalid constraints in TcValidity
      
      - Haddock needs to absorb the change too; so there is a submodule update
      ffc21506
  18. 14 May, 2015 1 commit
    • Austin Seipp's avatar
      Revert multiple commits · 3cf8ecdc
      Austin Seipp authored
      This reverts multiple commits from Simon:
      
        - 04a484ea Test Trac #10359
        - a9ccd37a Test Trac #10403
        - c0aae6f6 Test Trac #10248
        - eb6ca851 Make the "matchable-given" check happen first
        - ca173aa3 Add a case to checkValidTyCon
        - 51cbad15 Update haddock submodule
        - 6e1174da Separate transCloVarSet from fixVarSet
        - a8493e03 Fix imports in HscMain (stage2)
        - a154944b Two wibbles to fix the build
        - 5910a1bc Change in capitalisation of error msg
        - 130e93aa Refactor tuple constraints
        - 8da785d5 Delete commented-out line
      
      These break the build by causing Haddock to fail mysteriously when
      trying to examine GHC.Prim it seems.
      3cf8ecdc
  19. 13 May, 2015 1 commit
    • Simon Peyton Jones's avatar
      Refactor tuple constraints · 130e93aa
      Simon Peyton Jones authored
      Make tuple constraints be handled by a perfectly ordinary
      type class, with the component constraints being the
      superclasses:
          class (c1, c2) => (c2, c2)
      
      This change was provoked by
      
        #10359  inability to re-use a given tuple
                constraint as a whole
      
        #9858   confusion between term tuples
                and constraint tuples
      
      but it's generally a very nice simplification. We get rid of
       -  In Type, the TuplePred constructor of PredTree,
          and all the code that dealt with TuplePreds
       -  In TcEvidence, the constructors EvTupleMk, EvTupleSel
      
      See Note [How tuples work] in TysWiredIn.
      
      Of course, nothing is ever entirely simple. This one
      proved quite fiddly.
      
      - I did quite a bit of renaming, which makes this patch
        touch a lot of modules. In partiuclar tupleCon -> tupleDataCon.
      
      - I made constraint tuples known-key rather than wired-in.
        This is different to boxed/unboxed tuples, but it proved
        awkward to have all the superclass selectors wired-in.
        Easier just to use the standard mechanims.
      
      - While I was fiddling with known-key names, I split the TH Name
        definitions out of DsMeta into a new module THNames.  That meant
        that the known-key names can all be gathered in PrelInfo, without
        causing module loops.
      
      - I found that the parser was parsing an import item like
            T( .. )
        as a *data constructor* T, and then using setRdrNameSpace to
        fix it.  Stupid!  So I changed the parser to parse a *type
        constructor* T, which means less use of setRdrNameSpace.
      
        I also improved setRdrNameSpace to behave better on Exact Names.
        Largely on priciple; I don't think it matters a lot.
      
      - When compiling a data type declaration for a wired-in thing like
        tuples (,), or lists, we don't really need to look at the
        declaration.  We have the wired-in thing!  And not doing so avoids
        having to line up the uniques for data constructor workers etc.
        See Note [Declarations for wired-in things]
      
      - I found that FunDeps.oclose wasn't taking superclasses into
        account; easily fixed.
      
      - Some error message refactoring for invalid constraints in TcValidity
      130e93aa
  20. 11 Jan, 2015 1 commit
  21. 08 Jan, 2015 1 commit
    • Simon Peyton Jones's avatar
      Improve HsBang · 9564bb8c
      Simon Peyton Jones authored
      Provoked by questions from Johan
      
       - Improve comments, fix misleading stuff
       - Add commented synonyms for HsSrcBang, HsImplBang, and use them throughout
       - Rename HsUserBang to HsSrcBang
       - Rename dataConStrictMarks to dataConSrcBangs
                dataConRepBangs    to dataConImplBangs
      
      This renaming affects Haddock in a trivial way, hence submodule update
      9564bb8c
  22. 06 Jan, 2015 1 commit
    • Simon Peyton Jones's avatar
      Major patch to add -fwarn-redundant-constraints · 32973bf3
      Simon Peyton Jones authored
      The idea was promted by Trac #9939, but it was Christmas, so I did
      some recreational programming that went much further.
      
      The idea is to warn when a constraint in a user-supplied context is
      redundant.  Everything is described in detail in
        Note [Tracking redundant constraints]
      in TcSimplify.
      
      Main changes:
      
       * The new ic_status field in an implication, of type ImplicStatus.
         It replaces ic_insol, and includes information about redundant
         constraints.
      
       * New function TcSimplify.setImplicationStatus sets the ic_status.
      
       * TcSigInfo has sig_report_redundant field to say whenther a
         redundant constraint should be reported; and similarly
         the FunSigCtxt constructor of UserTypeCtxt
      
       * EvBinds has a field eb_is_given, to record whether it is a given
         or wanted binding. Some consequential chagnes to creating an evidence
         binding (so that we record whether it is given or wanted).
      
       * AbsBinds field abs_ev_binds is now a *list* of TcEvBiinds;
         see Note [Typechecking plan for instance declarations] in
         TcInstDcls
      
       * Some significant changes to the type checking of instance
         declarations; Note [Typechecking plan for instance declarations]
         in TcInstDcls.
      
       * I found that TcErrors.relevantBindings was failing to zonk the
         origin of the constraint it was looking at, and hence failing to
         find some relevant bindings.  Easy to fix, and orthogonal to
         everything else, but hard to disentangle.
      
      Some minor refactorig:
      
       * TcMType.newSimpleWanteds moves to Inst, renamed as newWanteds
      
       * TcClassDcl and TcInstDcls now have their own code for typechecking
         a method body, rather than sharing a single function. The shared
         function (ws TcClassDcl.tcInstanceMethodBody) didn't have much code
         and the differences were growing confusing.
      
       * Add new function TcRnMonad.pushLevelAndCaptureConstraints, and
         use it
      
       * Add new function Bag.catBagMaybes, and use it in TcSimplify
      32973bf3
  23. 03 Dec, 2014 1 commit
  24. 21 Nov, 2014 1 commit
    • Simon Peyton Jones's avatar
      Rejig builders for pattern synonyms, especially unlifted ones · e8762081
      Simon Peyton Jones authored
      When a pattern synonym is for an unlifted pattern, its "builder" would
      naturally be a top-level unlifted binding, which isn't allowed.  So we
      give it an extra Void# argument.
      
      Our Plan A involved then making *two* Ids for these builders, with
      some consequential fuss in the desugarer.  This was more pain than I
      liked, so I've re-jigged it.
      
       * There is just one builder for a pattern synonym.
      
       * It may have an extra Void# arg, but this decision is signalled
         by the Bool in the psBuilder field.
      
         I did the same for the psMatcher field.
      
         Both Bools are serialised into interface files, so there is
         absolutely no doubt whether that extra Void# argument is required.
      
       * I renamed "wrapper" to "builder".  We have too may "wrappers"
      
       * In order to deal with typecchecking occurrences of P in expressions,
         I refactored the tcInferId code in TcExpr.
      
      All of this allowed me to revert 5fe872
         "Apply compulsory unfoldings during desugaring, except for `seq` which is special."
      which turned out to be a rather messy hack in DsBinds
      e8762081
  25. 20 Nov, 2014 1 commit
    • Jan Stolarek's avatar
      Split SynTyCon to SynonymTyCon and FamilyTyCon · 696fc4ba
      Jan Stolarek authored
      This patch refactors internal representation of type synonyms and type families by splitting them into two separate data constructors of TyCon data type. The main motivation is is that some fields make sense only for type synonyms and some make sense only for type families. This will be even more true with the upcoming injective type families.
      
      There is also some refactoring of names to keep the naming constistent. And thus tc_kind field has become tyConKind and tc_roles has become tcRoles. Both changes are not visible from the outside of TyCon module.
      
      Updates haddock submodule
      
      Reviewers: simonpj
      
      Differential Revision: https://phabricator.haskell.org/D508
      
      GHC Trac Issues: #9812
      696fc4ba
  26. 13 Nov, 2014 1 commit
  27. 08 Nov, 2014 1 commit
  28. 26 Sep, 2014 1 commit
  29. 07 Aug, 2014 1 commit
  30. 27 May, 2014 2 commits
  31. 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
  32. 08 May, 2014 1 commit
  33. 20 Jan, 2014 1 commit
    • cactus's avatar
      Implement pattern synonyms · 4f8369bf
      cactus 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/ImplementationReviewed-by: Simon Peyton Jones's avatarSimon Peyton Jones <simonpj@microsoft.com>
      Signed-off-by: default avatarAustin Seipp <austin@well-typed.com>
      4f8369bf
  34. 01 Oct, 2013 2 commits
  35. 18 Sep, 2013 1 commit