1. 17 Feb, 2016 1 commit
  2. 15 Feb, 2016 1 commit
  3. 12 Feb, 2016 1 commit
  4. 11 Feb, 2016 1 commit
  5. 08 Feb, 2016 1 commit
    • Simon Peyton Jones's avatar
      Allow foralls in instance decls · 2cf3cac6
      Simon Peyton Jones authored
      This patch finally makes it possible to have explicit
      foralls in an instance decl
         instance forall (a :: *). Eq a => Eq [a] where ...
      
      This is useful to allow kind signatures or indeed
      explicicit kind for-alls; see Trac #11519
      
      I thought it would be really easy, because an instance
      declaration already contains an actual HsSigType, so all
      the syntactic baggage is there.  But in fact it turned
      out that instance declarations were kind-checked a
      little differently, because the body kind of the forall
      is 'Constraint' rather than '*'.
      
      So I fixed that.  There a slight kludge
      (see Note [Body kind of a HsQualTy], but it's still a
      significant improvement.
      
      I also did the usual other round of refactoring,
      improved a few error messages, tidied up comments etc.
      The only significant aspect of all that was
      
        * Kill mkNakedSpecSigmaTy, mkNakedPhiTy, mkNakedFunTy
          These function names suggest that they do something
          complicated, but acutally they do nothing. So I
          killed them.
      
        * Swap the arg order of mkNamedBinder, just so that it is
          convenient to say 'map (mkNamedBinder Invisible) tvs'
      
        * I had to improve isPredTy, to deal with (illegal)
          types like
             (Eq a => Eq [a]) => blah
          See Note [isPeredTy complications] in Type.hs
      
      Still to come: user manual documentation for the
      instance-decl change.
      2cf3cac6
  6. 02 Feb, 2016 1 commit
  7. 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
  8. 27 Jan, 2016 4 commits
  9. 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
  10. 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
  11. 18 Jan, 2016 2 commits
    • 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
    • Eric Seidel's avatar
      un-wire-in error, undefined, CallStack, and IP · a7b751db
      Eric Seidel authored
      I missed a crucial step in the wiring-in process of `CallStack` in D861,
      the bit where you actually wire-in the Name... This led to a nasty bug
      where GHC thought `CallStack` was not wired-in and tried to fingerprint
      it, which failed because the defining module was not loaded.
      
      But we don't need `CallStack` to be wired-in anymore since `error` and
      `undefined` no longer need to be wired-in. So we just remove them all.
      
      Updates haddock submodule.
      
      Test Plan: `./validate` and `make slowtest TEST=tc198`
      
      Reviewers: simonpj, goldfire, austin, hvr, bgamari
      
      Reviewed By: simonpj, bgamari
      
      Subscribers: goldfire, thomie
      
      Projects: #ghc
      
      Differential Revision: https://phabricator.haskell.org/D1739
      
      GHC Trac Issues: #11331
      a7b751db
  12. 15 Jan, 2016 1 commit
    • Ryan Scott's avatar
      Expand type/kind synonyms in TyVars before deriving-related typechecking · 165ae440
      Ryan Scott authored
      Before, it was possible to have a datatypes such as
      
      ```
      type ConstantT a b = a
      newtype T (f :: * -> *) (a :: ConstantT * f) = T (f a) deriving Functor
      
      data family TFam (f :: * -> *) (a :: *)
      newtype instance TFam f (ConstantT a f) = TFam (f a) deriving Functor
      ```
      
      fail to eta-reduce because either (1) a TyVar had a kind synonym that
      mentioned another TyVar, or (2) an instantiated type was itself a type
      synonym that mentioned another TyVar. A little bit of tweaking to
      `expandTypeSynonyms` and applying it before the eta-reduction check in
      the `deriving` machinery is sufficient to fix this.
      
      Fixes #11416.
      
      Test Plan: ./validate
      
      Reviewers: goldfire, simonpj, austin, bgamari
      
      Reviewed By: simonpj
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1772
      
      GHC Trac Issues: #11416
      165ae440
  13. 13 Jan, 2016 1 commit
  14. 31 Dec, 2015 2 commits
  15. 26 Dec, 2015 1 commit
  16. 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
  17. 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
  18. 09 Dec, 2015 1 commit
  19. 07 Dec, 2015 1 commit
  20. 04 Dec, 2015 1 commit
  21. 03 Dec, 2015 1 commit
    • Georgios Karachalias's avatar
      Major Overhaul of Pattern Match Checking (Fixes #595) · 8a506104
      Georgios Karachalias authored
      This patch adresses several problems concerned with exhaustiveness and
      redundancy checking of pattern matching. The list of improvements includes:
      
      * Making the check type-aware (handles GADTs, Type Families, DataKinds, etc.).
        This fixes #4139, #3927, #8970 and other related tickets.
      
      * Making the check laziness-aware. Cases that are overlapped but affect
        evaluation are issued now with "Patterns have inaccessible right hand side".
        Additionally, "Patterns are overlapped" is now replaced by "Patterns are
        redundant".
      
      * Improved messages for literals. This addresses tickets #5724, #2204, etc.
      
      * Improved reasoning concerning cases where simple and overloaded
        patterns are matched (See #322).
      
      * Substantially improved reasoning for pattern guards. Addresses #3078.
      
      * OverloadedLists extension does not break exhaustiveness checking anymore
        (addresses #9951). Note that in general this cannot be handled but if we know
        that an argument has type '[a]', we treat it as a list since, the instance of
        'IsList' gives the identity for both 'fromList' and 'toList'. If the type is
        not clear or is not the list type, then the check cannot do much still. I am
        a bit concerned about OverlappingInstances though, since one may override the
        '[a]' instance with e.g. an '[Int]' instance that is not the identity.
      
      * Improved reasoning for nested pattern matching (partial solution). Now we
        propagate type and (some) term constraints deeper when checking, so we can
        detect more inconsistencies. For example, this is needed for #4139.
      
      I am still not satisfied with several things but I would like to address at
      least the following before the next release:
          Term constraints are too many and not printed for non-exhaustive matches
      (with the exception of literals). This sometimes results in two identical (in
      appearance) uncovered warnings. Unless we actually show their difference, I
      would like to have a single warning.
      8a506104
  22. 16 Nov, 2015 1 commit
  23. 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
  24. 29 Oct, 2015 2 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
  25. 02 Sep, 2015 1 commit
    • Eric Seidel's avatar
      Use IP based CallStack in error and undefined · 6740d70d
      Eric Seidel authored
      This patch modifies `error`, `undefined`, and `assertError` to use
      implicit call-stacks to provide better error messages to users.
      
      There are a few knock-on effects:
      
      - `GHC.Classes.IP` is now wired-in so it can be used in the wired-in
        types for `error` and `undefined`.
      
      - `TysPrim.tyVarList` has been replaced with a new function
        `TysPrim.mkTemplateTyVars`. `tyVarList` made it easy to introduce
        subtle bugs when you need tyvars of different kinds. The naive
      
        ```
        tv1 = head $ tyVarList kind1
        tv2 = head $ tyVarList kind2
        ```
      
        would result in `tv1` and `tv2` sharing a `Unique`, thus substitutions
        would be applied incorrectly, treating `tv1` and `tv2` as the same
        tyvar. `mkTemplateTyVars` avoids this pitfall by taking a list of kinds
        and producing a single tyvar of each kind.
      
      - The types `GHC.SrcLoc.SrcLoc` and `GHC.Stack.CallStack` now live in
        ghc-prim.
      
      - The type `GHC.Exception.ErrorCall` has a new constructor
        `ErrorCallWithLocation` that takes two `String`s instead of one, the
        2nd one being arbitrary metadata about the error (but usually the
        call-stack). A bi-directional pattern synonym `ErrorCall` continues to
        provide the old API.
      
      Updates Cabal, array, and haddock submodules.
      
      Reviewers: nh2, goldfire, simonpj, hvr, rwbarton, austin, bgamari
      
      Reviewed By: simonpj
      
      Subscribers: rwbarton, rodlogic, goldfire, maoe, simonmar, carter,
      liyang, bgamari, thomie
      
      Differential Revision: https://phabricator.haskell.org/D861
      
      GHC Trac Issues: #5273
      6740d70d
  26. 05 Aug, 2015 1 commit
    • Simon Peyton Jones's avatar
      Tidy up and refactor wildcard handling · 95364812
      Simon Peyton Jones authored
      When examining #10615, I found the wildcard handling hard
      to understand.  This patch refactors quite a bit, but with
      no real change in behaviour.
      
       * Split out TcIdSigInfo from TcSigInfo, as a separate type,
         like TcPatSynInfo.
      
       * Make TcIdSigInfo express more invariants by pushing the
         wildard info into TcIdSigBndr
      
       * Remove all special treatment of unification variables that arise
         from wildcards; so the TauTv of TcType.MetaInfo loses its Bool
         argument.
      
      A ton of konck on changes.  The result is significantly simpler, I think.
      95364812
  27. 16 Jun, 2015 1 commit
    • eir@cis.upenn.edu's avatar
      Refactor handling of decomposition. · 7eceffb3
      eir@cis.upenn.edu authored
      This adds the significant Note [Decomposing equalities] to
      TcCanonical, trying to sort out the various cases involved.
      
      The only functional change this commit should make is a different
      treatment of data families, which were wrong before (they could
      be decomposed at role R, which is wrong).
      7eceffb3
  28. 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
  29. 14 May, 2015 1 commit
  30. 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
  31. 22 Apr, 2015 1 commit
    • Simon Peyton Jones's avatar
      Do not decompose => (Trac #9858) · c0b5adbd
      Simon Peyton Jones authored
      We really don't want to unify (a b) with (Eq a => ty).
      The ever-ingenious Oerjan discovered this problem;
      see comment:101 in Trac #9858.
      
      See Note [Decomposing fat arrow c=>t] in Type.hs
      c0b5adbd
  32. 02 Mar, 2015 1 commit