1. 24 Mar, 2016 1 commit
  2. 15 Mar, 2016 1 commit
    • eir@cis.upenn.edu's avatar
      Refactor visible type application. · 972730cc
      eir@cis.upenn.edu authored
      This replaces the old HsType and HsTypeOut constructors
      with HsAppType and HsAppTypeOut, leading to some simplification.
      (This refactoring addresses #11329.)
      
      This also fixes #11456, which stumbled over HsType (which is
      not an expression).
      
      test case: ghci/scripts/T11456
      
      [skip ci]
      972730cc
  3. 12 Feb, 2016 1 commit
    • Simon Peyton Jones's avatar
      Improve pretty-printing of HsWrappers · d0846243
      Simon Peyton Jones authored
      Reduces un-neede parens.
      
      Also -fprint-typechecker-elaboration now makes type applications
      and casts in expressions also appear.  (Previously those were
      confusingly controlled by -fprint-explicit-coercions.)
      d0846243
  4. 27 Jan, 2016 1 commit
    • eir@cis.upenn.edu's avatar
      Refactor the typechecker to use ExpTypes. · 00cbbab3
      eir@cis.upenn.edu authored
      The idea here is described in [wiki:Typechecker]. Briefly,
      this refactor keeps solid track of "synthesis" mode vs
      "checking" in GHC's bidirectional type-checking algorithm.
      When in synthesis mode, the expected type is just an IORef
      to write to.
      
      In addition, this patch does a significant reworking of
      RebindableSyntax, allowing much more freedom in the types
      of the rebindable operators. For example, we can now have
      `negate :: Int -> Bool` and
      `(>>=) :: m a -> (forall x. a x -> m b) -> m b`. The magic
      is in tcSyntaxOp.
      
      This addresses tickets #11397, #11452, and #11458.
      
      Tests:
        typecheck/should_compile/{RebindHR,RebindNegate,T11397,T11458}
        th/T11452
      00cbbab3
  5. 18 Jan, 2016 1 commit
    • Jan Stolarek's avatar
      Replace calls to `ptext . sLit` with `text` · b8abd852
      Jan Stolarek authored
      Summary:
      In the past the canonical way for constructing an SDoc string literal was the
      composition `ptext . sLit`.  But for some time now we have function `text` that
      does the same.  Plus it has some rules that optimize its runtime behaviour.
      This patch takes all uses of `ptext . sLit` in the compiler and replaces them
      with calls to `text`.  The main benefits of this patch are clener (shorter) code
      and less dependencies between module, because many modules now do not need to
      import `FastString`.  I don't expect any performance benefits - we mostly use
      SDocs to report errors and it seems there is little to be gained here.
      
      Test Plan: ./validate
      
      Reviewers: bgamari, austin, goldfire, hvr, alanz
      
      Subscribers: goldfire, thomie, mpickering
      
      Differential Revision: https://phabricator.haskell.org/D1784
      b8abd852
  6. 16 Jan, 2016 1 commit
    • Alan Zimmerman's avatar
      Work SourceText in for all integer literals · 3a1babd6
      Alan Zimmerman authored
      Summary:
      Certain syntactic elements have integers in them, such as fixity
      specifications, SPECIALISE pragmas and so on.
      
      The lexer will accept mult-radix literals, with arbitrary leading zeros
      in these.
      
      Bring in a SourceText field to each affected AST element to capture the
      original literal text for use with API Annotations.
      
      Affected hsSyn elements are
      
      ```
           -- See note [Pragma source text]
           data Activation = NeverActive
                           | AlwaysActive
                           | ActiveBefore SourceText PhaseNum
                                -- Active only *strictly before* this phase
                           | ActiveAfter SourceText PhaseNum
                                 -- Active in this phase and later
                           deriving( Eq, Data, Typeable )
                                     -- Eq used in comparing rules in HsDecls
      
           data Fixity = Fixity SourceText Int FixityDirection
             -- Note [Pragma source text]
             deriving (Data, Typeable)
       ```
      
      and
      
      ```
            | HsTickPragma         -- A pragma introduced tick
               SourceText           -- Note [Pragma source text] in BasicTypes
               (StringLiteral,(Int,Int),(Int,Int))
                                                -- external span for this tick
               ((SourceText,SourceText),(SourceText,SourceText))
                  -- Source text for the four integers used in the span.
                  -- See note [Pragma source text] in BasicTypes
               (LHsExpr id)
      ```
      
      Updates haddock submodule
      
      Test Plan: ./validate
      
      Reviewers: goldfire, bgamari, austin
      
      Reviewed By: bgamari
      
      Subscribers: thomie, mpickering
      
      Differential Revision: https://phabricator.haskell.org/D1781
      
      GHC Trac Issues: #11430
      3a1babd6
  7. 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
  8. 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
    • Adam Gundry's avatar
      Fix infix record field fixity (#11167 and #11173). · 6e56ac58
      Adam Gundry authored
      This extends D1585 with proper support for infix duplicate record
      fields.  In particular, it is now possible to declare record fields as
      infix in a module for which `DuplicateRecordFields` is enabled, fixity
      is looked up correctly and a readable (although unpleasant) error
      message is generated if multiple fields with different fixities are in
      scope.
      
      As a bonus, `DEPRECATED` and `WARNING` pragmas now work for
      duplicate record fields. The pragma applies to all fields with the
      given label.
      
      In addition, a couple of minor `DuplicateRecordFields` bugs, which were
      pinpointed by the `T11167_ambig` test case, are fixed by this patch:
      
        - Ambiguous infix fields can now be disambiguated by putting a type
          signature on the first argument
      
        - Polymorphic type constructor signatures (such as `ContT () IO a` in
          `T11167_ambig`) now work for disambiguation
      
      Parts of this patch are from D1585 authored by @KaneTW.
      
      Test Plan: New tests added.
      
      Reviewers: KaneTW, bgamari, austin
      
      Reviewed By: bgamari
      
      Subscribers: thomie, hvr
      
      Differential Revision: https://phabricator.haskell.org/D1600
      
      GHC Trac Issues: #11167, #11173
      6e56ac58
  9. 09 Dec, 2015 1 commit
  10. 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
  11. 23 Nov, 2015 1 commit
  12. 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
  13. 18 Nov, 2015 2 commits
    • msosn's avatar
      Fix inconsistent pretty-printing of type families · c61759d5
      msosn authored
      After the changes, the three functions used to print type families
      were identical, so they are refactored into one.
      
      Original RHSs of data instance declarations are recreated and
      printed in user error messages.
      
      RHSs containing representation TyCons are printed in the
      Coercion Axioms section in a typechecker dump.
      
      Add vbar to the list of SDocs exported by Outputable.
      Replace all text "|" docs with it.
      
      Fixes #10839
      
      Reviewers: goldfire, jstolarek, austin, bgamari
      
      Reviewed By: jstolarek
      
      Subscribers: jstolarek, thomie
      
      Differential Revision: https://phabricator.haskell.org/D1441
      
      GHC Trac Issues: #10839
      c61759d5
    • Simon Peyton Jones's avatar
      Refactor HsExpr.RecordCon, RecordUpd · 07eb258d
      Simon Peyton Jones authored
      This follows Matthew's patch making pattern synoyms work
      with records.
      
      This patch
       - replaces the (PostTc id [FieldLabel]) field of
         RecordCon with (PostTc id ConLike)
      
       - record-ises both RecordCon and RecordUpd, which
         both have quite a lot of fields.
      
      No change in behaviour
      07eb258d
  14. 17 Nov, 2015 2 commits
  15. 13 Nov, 2015 1 commit
    • Alan Zimmerman's avatar
      APIAnnotations:add Locations in hsSyn for layout · 2290c8bd
      Alan Zimmerman authored
      Summary:
      At the moment ghc-exactprint, which uses the GHC API Annotations to
      provide a framework for roundtripping Haskell source code with optional
      AST edits, has to implement a horrible workaround to manage the points
      where layout needs to be captured.
      
      These are
      
          MatchGroup
          HsDo
          HsCmdDo
          HsLet
          LetStmt
          HsCmdLet
          GRHSs
      
      To provide a more natural representation, the contents subject to layout
      rules need to be wrapped in a SrcSpan.
      
      This commit does this.
      
      Trac ticket #10250
      
      Test Plan: ./validate
      
      Reviewers: hvr, goldfire, bgamari, austin, mpickering
      
      Reviewed By: mpickering
      
      Subscribers: thomie, mpickering
      
      Differential Revision: https://phabricator.haskell.org/D1370
      
      GHC Trac Issues: #10250
      2290c8bd
  16. 11 Nov, 2015 1 commit
    • Alan Zimmerman's avatar
      Remove fun_infix from Funbind, as it is now in Match · f0f9365f
      Alan Zimmerman authored
      One of the changes D538 introduced is to add `m_fun_id_infix` to `Match`
      
      ```lang=hs
      data Match id body
        = Match {
              m_fun_id_infix :: (Maybe (Located id,Bool)),
                -- fun_id and fun_infix for functions with multiple equations
                -- only present for a RdrName. See note [fun_id in Match]
              m_pats :: [LPat id], -- The patterns
              m_type :: (Maybe (LHsType id)),
                                       -- A type signature for the result of the match
                                       -- Nothing after typechecking
              m_grhss :: (GRHSs id body)
        } deriving (Typeable)
      ```
      
      This was done to track the individual locations and fixity of the
      `fun_id` for each of the defining equations for a function when there
      are more than one.
      
      For example, the function `(&&&)` is defined with some prefix and some
      infix equations below.
      
      ```lang=hs
          (&&&  ) [] [] =  []
          xs    &&&   [] =  xs
          (  &&&  ) [] ys =  ys
      ```
      
      This means that the fun_infix is now superfluous in the `FunBind`. This
      has not been removed as a potentially risky change just before 7.10 RC2,
      and so must be done after.
      
      This ticket captures that task, which includes processing these fields
      through the renamer and beyond.
      
      Ticket #9988 introduced these fields into `Match` through renaming, this
      ticket it to continue through type checking and then remove it from
      `FunBind` completely.
      
      The split happened so that #9988 could land in 7.10
      
      Trac ticket : #10061
      
      Test Plan: ./validate
      
      Reviewers: goldfire, austin, simonpj, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: simonpj, thomie, mpickering
      
      Differential Revision: https://phabricator.haskell.org/D1285
      
      GHC Trac Issues: #10061
      f0f9365f
  17. 07 Nov, 2015 1 commit
  18. 30 Oct, 2015 1 commit
    • Adam Gundry's avatar
      Disambiguate record selectors by type signature · 0a163741
      Adam Gundry authored
      This makes DuplicateRecordFields more liberal in when it will
      accept ambiguous record selectors, making use of type information in a
      similar way to updates. See Note [Disambiguating record fields] for more
      details. I've also refactored how record updates are disambiguated.
      
      Test Plan: New and amended tests in overloadedrecflds
      
      Reviewers: simonpj, goldfire, bgamari, austin
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1391
      0a163741
  19. 29 Oct, 2015 1 commit
    • 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
  20. 16 Oct, 2015 2 commits
    • Jan Stolarek's avatar
      Add typed holes support in Template Haskell. · 75492e74
      Jan Stolarek authored
      Fixes #10267. Typed holes in typed Template Haskell currently don't work.
      See #10945 and #10946.
      75492e74
    • 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
  21. 20 Sep, 2015 1 commit
  22. 17 Sep, 2015 1 commit
  23. 21 Aug, 2015 1 commit
    • thomie's avatar
      Refactor: delete most of the module FastTypes · 2f29ebbb
      thomie authored
      This reverses some of the work done in #1405, and goes back to the
      assumption that the bootstrap compiler understands GHC-haskell.
      
      In particular:
        * use MagicHash instead of _ILIT and _CLIT
        * pattern matching on I# if possible, instead of using iUnbox
          unnecessarily
        * use Int#/Char#/Addr# instead of the following type synonyms:
          - type FastInt   = Int#
          - type FastChar  = Char#
          - type FastPtr a = Addr#
        * inline the following functions:
          - iBox           = I#
          - cBox           = C#
          - fastChr        = chr#
          - fastOrd        = ord#
          - eqFastChar     = eqChar#
          - shiftLFastInt  = uncheckedIShiftL#
          - shiftR_FastInt = uncheckedIShiftRL#
          - shiftRLFastInt = uncheckedIShiftRL#
        * delete the following unused functions:
          - minFastInt
          - maxFastInt
          - uncheckedIShiftRA#
          - castFastPtr
          - panicDocFastInt and pprPanicFastInt
        * rename panicFastInt back to panic#
      
      These functions remain, since they actually do something:
        * iUnbox
        * bitAndFastInt
        * bitOrFastInt
      
      Test Plan: validate
      
      Reviewers: austin, bgamari
      
      Subscribers: rwbarton
      
      Differential Revision: https://phabricator.haskell.org/D1141
      
      GHC Trac Issues: #1405
      2f29ebbb
  24. 02 Aug, 2015 1 commit
    • Alan Zimmerman's avatar
      Replace (SourceText,FastString) with StringLiteral data type · 15dd7007
      Alan Zimmerman authored
      Summary:
      Phab:D907 introduced SourceText for a number of data types, by replacing
      FastString with (SourceText,FastString). Since this has an Outputable
      instance, no warnings are generated when ppr is called on it, but
      unexpected output is generated. See Phab:D1096 for an example of this.
      
      Replace the (SourceText,FastString) tuples with a new data type,
      ```lang=hs
      data StringLiteral = StringLiteral SourceText FastString
      ```
      
      Update haddock submodule accordingly
      
      Test Plan: ./validate
      
      Reviewers: hvr, austin, rwbarton, trofi, bgamari
      
      Reviewed By: trofi, bgamari
      
      Subscribers: thomie, trofi, rwbarton, mpickering
      
      Differential Revision: https://phabricator.haskell.org/D1101
      
      GHC Trac Issues: #10692
      15dd7007
  25. 30 Jul, 2015 1 commit
  26. 26 Jun, 2015 1 commit
    • Simon Peyton Jones's avatar
      Treat out-of-scope variables as holes · fb7b6922
      Simon Peyton Jones authored
      This patch implements the idea in Trac #10569.
      
      * An out-of-scope variable is treated as a typed expression
        hole.
      
      * That is, we don't report it in the type checker, not the
        renamer, and we when we do report it, we give its type.
      
      * Moreover, we can defer the error to runtime with
        -fdefer-typed-holes
      
      In implementation terms:
      
      * The renamer turns an unbound variable into a HsUnboundVar
      
      * The type checker emits a Hole constraint for a
        HsUnboundVar, and turns it back into a HsVar
      
      It was a bit painful to implement because a whole raft of
      error messages change slightly.  But there was absolutely
      nothing hard in principle.
      
      Holes are reported with a bunch of possibly-useful context,
      notably the "relevant bindings".  I found that this was
      distracting clutter in the very common case of a mis-typed
      variable that is only accidentally not in scope, so I've
      arranged to print the context information only for true holes,
      that is ones starting with an underscore.
      
      Unbound data constructors use in patterns, like
        f (D x) = x
      are still reportd by the renamer, and abort compilation
      before type checking.
      fb7b6922
  27. 01 Jun, 2015 1 commit
    • Alan Zimmerman's avatar
      ApiAnnotations : strings in warnings do not return SourceText · e6191d1c
      Alan Zimmerman authored
      Summary:
      The strings used in a WARNING pragma are captured via
      
          strings :: { Located ([AddAnn],[Located FastString]) }
              : STRING { sL1 $1 ([],[L (gl $1) (getSTRING $1)]) }
          ..
      
      The STRING token has a method getSTRINGs that returns the original
      source text for a string.
      
      A warning of the form
      
          {-# WARNING Logic
                    , mkSolver
                    , mkSimpleSolver
                    , mkSolverForLogic
                    , solverSetParams
                    , solverPush
                    , solverPop
                    , solverReset
                    , solverGetNumScopes
                    , solverAssertCnstr
                    , solverAssertAndTrack
                    , solverCheck
                    , solverCheckAndGetModel
                    , solverGetReasonUnknown
                    "New Z3 API support is still incomplete and fragile: \
                    \you may experience segmentation faults!"
            #-}
      
      returns the concatenated warning string rather than the original source.
      
      This patch now deals with all remaining instances of getSTRING to bring
      in a SourceText for each.
      
      This updates the haddock submodule as well, for the AST change.
      
      Test Plan: ./validate
      
      Reviewers: hvr, austin, goldfire
      
      Reviewed By: austin
      
      Subscribers: bgamari, thomie, mpickering
      
      Differential Revision: https://phabricator.haskell.org/D907
      
      GHC Trac Issues: #10313
      e6191d1c
  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. 06 May, 2015 2 commits
  32. 03 Apr, 2015 1 commit
  33. 02 Mar, 2015 1 commit
  34. 10 Feb, 2015 1 commit
    • Simon Peyton Jones's avatar
      Refactor the handling of quasi-quotes · f46360ed
      Simon Peyton Jones authored
      As Trac #10047 points out, a quasi-quotation [n|...blah...|] is supposed
      to behave exactly like $(n "...blah...").  But it doesn't!  This was outright
      wrong: quasiquotes were being run even inside brackets.
      
      Now that TH supports both typed and untyped splices, a quasi-quote is properly
      regarded as a particular syntax for an untyped splice. But apart from that
      they should be treated the same.  So this patch refactors the handling of
      quasiquotes to do just that.
      
      The changes touch quite a lot of files, but mostly in a routine way.
      The biggest changes by far are in RnSplice, and more minor changes in
      TcSplice.  These are the places where there was real work to be done.
      Everything else is routine knock-on changes.
      
      * No more QuasiQuote forms in declarations, expressions, types, etc.
        So we get rid of these data constructors
          * HsBinds.QuasiQuoteD
          * HsExpr.HsSpliceE
          * HsPat.QuasiQuotePat
          * HsType.HsQuasiQuoteTy
      
      * We get rid of the HsQuasiQuote type altogether
      
      * Instead, we augment the HsExpr.HsSplice type to have three
        consructors, for the three types of splice:
          * HsTypedSplice
          * HsUntypedSplice
          * HsQuasiQuote
        There are some related changes in the data types in HsExpr near HsSplice.
        Specifically: PendingRnSplice, PendingTcSplice, UntypedSpliceFlavour.
      
      * In Hooks, we combine rnQuasiQuoteHook and rnRnSpliceHook into one.
        A smaller, clearer interface.
      
      * We have to update the Haddock submodule, to accommodate the hsSyn changes
      f46360ed
  35. 19 Jan, 2015 1 commit
    • Alan Zimmerman's avatar
      API Annotations documentation update, parsing issue, add example test · 851ed721
      Alan Zimmerman authored
      Summary:
      Add a reference note to each AnnKeywordId haddock comment so GHC
      developers will have an idea why they are there.
      
      Add a new test to ghc-api/annotations to serve as a template for other
      GHC developers when they need to update the parser. It provides output
      which checks that each SrcSpan that an annotation is attached to
      actually appears in the `ParsedSource`, and lists the individual
      annotations. The idea is that a developer writes a version of this
      which parses a sample file using whatever syntax is changed in
      Parser.y, and can then check that all the annotations come through.
      
      Depends on D538
      
      Test Plan: ./validate
      
      Reviewers: simonpj, hvr, austin
      
      Reviewed By: austin
      
      Subscribers: thomie, jstolarek
      
      Differential Revision: https://phabricator.haskell.org/D620
      851ed721