1. 13 Jun, 2016 1 commit
    • Simon Peyton Jones's avatar
      Improve typechecking of let-bindings · 15b9bf4b
      Simon Peyton Jones authored
      This major commit was initially triggered by #11339, but it spiraled
      into a major review of the way in which type signatures for bindings
      are handled, especially partial type signatures.  On the way I fixed a
      number of other bugs, namely
         #12069
         #12033
         #11700
         #11339
         #11670
      
      The main change is that I completely reorganised the way in which type
      signatures in bindings are handled. The new story is in TcSigs
      Note [Overview of type signatures].  Some specific:
      
      * Changes in the data types for signatures in TcRnTypes:
        TcIdSigInfo and new TcIdSigInst
      
      * New module TcSigs deals with typechecking type signatures
        and pragmas. It contains code mostly moved from TcBinds,
        which is already too big
      
      * HsTypes: I swapped the nesting of HsWildCardBndrs
        and HsImplicitBndsrs, so that the wildcards are on the
        oustide not the insidde in a LHsSigWcType.  This is just
        a matter of convenient, nothing deep.
      
      There are a host of other changes as knock-on effects, and
      it all took FAR longer than I anticipated :-).  But it is
      a significant improvement, I think.
      
      Lots of error messages changed slightly, some just variants but
      some modest improvements.
      
      New tests
      
      * typecheck/should_compile
          * SigTyVars: a scoped-tyvar test
          * ExPat, ExPatFail: existential pattern bindings
          * T12069
          * T11700
          * T11339
      
      * partial-sigs/should_compile
          * T12033
          * T11339a
          * T11670
      
      One thing to check:
      
      * Small change to output from ghc-api/landmines.
        Need to check with Alan Zimmerman
      15b9bf4b
  2. 06 Jun, 2016 1 commit
    • Alan Zimmerman's avatar
      Merge MatchFixity and HsMatchContext · a13cb279
      Alan Zimmerman authored
      Summary:
      MatchFixity was introduced to facilitate use of API Annotations.
      
      HsMatchContext does the same thing with more detail, but is chased
      through all over the place to provide context when processing a Match.
      
      Since we already have MatchFixity in the Match, it may as well provide
      the full context.
      
      updates submodule haddock
      
      Test Plan: ./validate
      
      Reviewers: austin, goldfire, bgamari
      
      Subscribers: thomie, mpickering
      
      Differential Revision: https://phabricator.haskell.org/D2271
      
      GHC Trac Issues: #12105
      
      (cherry picked from commit 306ecad5)
      a13cb279
  3. 24 May, 2016 1 commit
    • Simon Peyton Jones's avatar
      Don't split the arg types in a PatSyn signature · 03d89603
      Simon Peyton Jones authored
      This patch fixes Trac #11977, and #12108, rather satisfactorily
      maily by deleting code!
      
        pattern P :: Eq a => a -> a -> Int
      
      The idea is simply /not/ to split the bit after the '=>' into the
      pattern argument types, but to keep the (a->a->Int) part
      un-decomposed, in the patsig_body_ty field of a TcPatSynInfo.
      
      There is one awkward wrinkle, which is that we can't split the
      implicitly-bound type variables into existential and universal until
      we know which types are arguments and which are part of the result.
      So we postpone the decision until we have the declaration in hand.
      See TcPatSyn Note [The pattern-synonym signature splitting rule]
      03d89603
  4. 23 May, 2016 2 commits
  5. 16 May, 2016 1 commit
    • niteria's avatar
      Kill varSetElems in tcInferPatSynDecl · 21fe4ffd
      niteria authored
      varSetElems introduces unnecessary non-determinism and while
      I didn't estabilish experimentally that this matters here
      I'm convinced that it will, because I expect pattern synonyms
      to end up in interface files.
      
      Test Plan: ./validate
      
      Reviewers: austin, simonmar, bgamari, mpickering, simonpj
      
      Reviewed By: simonpj
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2206
      
      GHC Trac Issues: #4012
      21fe4ffd
  6. 28 Apr, 2016 2 commits
    • Simon Peyton Jones's avatar
      Refactor RecordPatSynField, FieldLabel · 3dce4f2d
      Simon Peyton Jones authored
      This patch uses the named fields of
       * FieldLabel
       * RecordPatSynField
      in construction and pattern matching. The fields
      existed before, but we were often using positional notation.
      
      Also a minor refactor of the API of mkPatSynRecSelBinds
      
      No change in functionality
      3dce4f2d
    • Simon Peyton Jones's avatar
      Comments only · 1e86cab4
      Simon Peyton Jones authored
      1e86cab4
  7. 22 Apr, 2016 1 commit
    • Simon Peyton Jones's avatar
      Simplify defaultKindVar and friends · 970ff585
      Simon Peyton Jones authored
      I found zonkQuantifiedTyVar rather complicated, especially the two
      places where we defaulted RuntimeRep variables. This simplifies and
      modularises the story.
      
      Refactoring only.
      970ff585
  8. 20 Apr, 2016 1 commit
  9. 19 Apr, 2016 1 commit
    • Simon Peyton Jones's avatar
      Refactor computing dependent type vars · 17eb2419
      Simon Peyton Jones authored
      There should be no change in behaviour here
      
      * Move splitDepVarsOfType(s) from Type to TcType
      
      * Define data type TcType.TcDepVars, document what it means,
        and use it where appropriate, notably in splitDepVarsOfType(s)
      
      * Use it in TcMType.quantifyTyVars and friends
      17eb2419
  10. 02 Apr, 2016 1 commit
    • Rik Steenkamp's avatar
      Improve printing of pattern synonym types · 72bd7f7b
      Rik Steenkamp authored
      Add the function `pprPatSynType :: PatSyn -> SDoc` for printing pattern
      synonym types, and remove the ambiguous `patSynType` function. Also,
      the types in a `PatSyn` are now tidy.
      
      Haddock submodule updated to reflect the removal of `patSynType` by
      mpickering.
      
      Fixes: #11213.
      
      Reviewers: goldfire, simonpj, austin, mpickering, bgamari
      
      Reviewed By: simonpj, mpickering
      
      Subscribers: bollmann, simonpj, thomie
      
      Differential Revision: https://phabricator.haskell.org/D1896
      
      GHC Trac Issues: #11213
      72bd7f7b
  11. 31 Mar, 2016 1 commit
  12. 24 Mar, 2016 1 commit
    • Rik Steenkamp's avatar
      Add `PatSynSigSkol` and modify `PatSynCtxt` · 997312b0
      Rik Steenkamp authored
      As the type of a pattern synonym cannot in general be represented by a
      value of type Type, we cannot use a value `SigSkol (PatSynCtxt n) (Check
      ty)` to represent the signature of a pattern synonym (this causes
      incorrect signatures to be printed in error messages). Therefore we now
      represent it by a value `PatSynSigSkol n` (instead of incorrect
      signatures we simply print no explicit signature).
      
      Furthermore, we rename `PatSynCtxt` to `PatSynBuilderCtxt`, and use
      `SigSkol (PatSynBuilderCtxt n) (Check ty)` to represent the type of a
      bidirectional pattern synonym when used in an expression context.
      Before, this type was represented by a value `SigSkol (PatSynCtxt n)
      (Check ty)`, which caused incorrect error messages.
      
      Also, in `mk_dict_err` of `typecheck\TcErrors.hs` we now distinguish
      between all enclosing implications and "useful" enclosing implications,
      for better error messages concerning pattern synonyms. See `Note [Useful
      implications]`.
      
      See the Phabricator page for examples.
      
      Reviewers: mpickering, goldfire, simonpj, austin, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1967
      
      GHC Trac Issues: #11667
      997312b0
  13. 21 Mar, 2016 2 commits
    • eir@cis.upenn.edu's avatar
      Zonk before calling splitDepVarsOfType. · 5c0c751a
      eir@cis.upenn.edu authored
      It was Utterly Wrong before.
      
      Note to self: Never, ever take the free vars of an unzonked type.
      5c0c751a
    • eir@cis.upenn.edu's avatar
      Track specified/invisible more carefully. · 35e93797
      eir@cis.upenn.edu authored
      In particular, this allows correct tracking of specified/invisible
      for variables in Haskell98 data constructors and in pattern synonyms.
      GADT-syntax constructors are harder, and are left until #11721.
      
      This was all inspired by Simon's comments to my fix for #11512,
      which this subsumes.
      
      Test case: ghci/scripts/TypeAppData
      
      [skip ci]  (The test case fails because of an unrelated problem
      fixed in the next commit.)
      35e93797
  14. 09 Mar, 2016 1 commit
  15. 26 Feb, 2016 1 commit
  16. 25 Feb, 2016 2 commits
  17. 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
  18. 16 Feb, 2016 1 commit
  19. 09 Feb, 2016 1 commit
  20. 02 Feb, 2016 1 commit
    • niteria's avatar
      Use a correct substitution in tcCheckPatSynDecl · 07ed2413
      niteria authored
      The `substTheta` call didn't have the free variables of the
      `prov_theta` in the `in_scope` set. It should be enough to add
      `univ_tvs`, as all the `ex_tvs` are already in the domain of
      the substitution.
      
      Test Plan: added a testcase
      
      Reviewers: simonpj, bgamari, goldfire, austin
      
      Reviewed By: simonpj, bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1879
      
      GHC Trac Issues: #11524
      07ed2413
  21. 27 Jan, 2016 2 commits
    • 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
    • Ömer Sinan Ağacan's avatar
      s/unLifted/unlifted for consistency · 4faa1a63
      Ömer Sinan Ağacan authored
      This was causing trouble as we had to remember when to use "unLifted"
      and when to use "unlifted".
      
      "unlifted" is used instead of "unLifted" as it's a single word.
      
      Reviewers: austin, hvr, goldfire, bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1852
      4faa1a63
  22. 21 Jan, 2016 1 commit
    • Simon Peyton Jones's avatar
      Re-add missing kind generalisation · c572430c
      Simon Peyton Jones authored
      When splitting H98/GADT syntax in ConDecl we lost a key
      kind-generalisation step.
      
      I also renamed tcHsTyVarBndrs to tcExplicitTKBnders, by analogy
      with tcImplicitTkBndrs.
      
      This fixes Trac #11459.
      
      Merge to 8.0.
      c572430c
  23. 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
  24. 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
    • Simon Peyton Jones's avatar
      Implement scoped type variables in pattern synonyms · e2c7b7ee
      Simon Peyton Jones authored
      This fixes Trac #11351.   The implementation is pretty
      simple, happily.
      
      I took the opportunity to re-order the prov/req context
      in builder-ids, which was confusingly backwards.
      e2c7b7ee
  25. 07 Jan, 2016 1 commit
    • Simon Peyton Jones's avatar
      Use an Implication in 'deriving' error · 02c1c573
      Simon Peyton Jones authored
      Trac #11437 showed that erroneous constraints from a 'deriving'
      clause need to be wrapped in an Implication to properly scope
      their skolems.
      
      The main change is in TcDeriv.simplifyDeriv; the call to
      buildImplicationFor is new.
      02c1c573
  26. 31 Dec, 2015 1 commit
  27. 24 Dec, 2015 1 commit
    • 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
  28. 23 Dec, 2015 1 commit
  29. 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
  30. 20 Dec, 2015 1 commit
  31. 11 Dec, 2015 2 commits
    • 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
    • Matthew Pickering's avatar
      Make sure PatSyns only get added once to tcg_patsyns · 41ef8f70
      Matthew Pickering authored
      Summary: Before, `PatSyn`s were getting added twice to `tcg_patsyns` so
      when inspecting afterwards there were duplicates in the list.
      This makes sure that only they only get added once.
      
      Reviewers: austin, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1597
      41ef8f70
  32. 01 Dec, 2015 1 commit
    • Simon Peyton Jones's avatar
      Refactor treatment of wildcards · 1e041b73
      Simon Peyton Jones authored
      This patch began as a modest refactoring of HsType and friends, to
      clarify and tidy up exactly where quantification takes place in types.
      Although initially driven by making the implementation of wildcards more
      tidy (and fixing a number of bugs), I gradually got drawn into a pretty
      big process, which I've been doing on and off for quite a long time.
      
      There is one compiler performance regression as a result of all
      this, in perf/compiler/T3064.  I still need to look into that.
      
      * The principal driving change is described in Note [HsType binders]
        in HsType.  Well worth reading!
      
      * Those data type changes drive almost everything else.  In particular
        we now statically know where
      
             (a) implicit quantification only (LHsSigType),
                 e.g. in instance declaratios and SPECIALISE signatures
      
             (b) implicit quantification and wildcards (LHsSigWcType)
                 can appear, e.g. in function type signatures
      
      * As part of this change, HsForAllTy is (a) simplified (no wildcards)
        and (b) split into HsForAllTy and HsQualTy.  The two contructors
        appear when and only when the correponding user-level construct
        appears.  Again see Note [HsType binders].
      
        HsExplicitFlag disappears altogether.
      
      * Other simplifications
      
           - ExprWithTySig no longer needs an ExprWithTySigOut variant
      
           - TypeSig no longer needs a PostRn name [name] field
             for wildcards
      
           - PatSynSig records a LHsSigType rather than the decomposed
             pieces
      
           - The mysterious 'GenericSig' is now 'ClassOpSig'
      
      * Renamed LHsTyVarBndrs to LHsQTyVars
      
      * There are some uninteresting knock-on changes in Haddock,
        because of the HsSyn changes
      
      I also did a bunch of loosely-related changes:
      
      * We already had type synonyms CoercionN/CoercionR for nominal and
        representational coercions.  I've added similar treatment for
      
            TcCoercionN/TcCoercionR
      
            mkWpCastN/mkWpCastN
      
        All just type synonyms but jolly useful.
      
      * I record-ised ForeignImport and ForeignExport
      
      * I improved the (poor) fix to Trac #10896, by making
        TcTyClsDecls.checkValidTyCl recover from errors, but adding a
        harmless, abstract TyCon to the envt if so.
      
      * I did some significant refactoring in RnEnv.lookupSubBndrOcc,
        for reasons that I have (embarrassingly) now totally forgotten.
        It had to do with something to do with import and export
      
      Updates haddock submodule.
      1e041b73
  33. 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