1. 14 May, 2018 1 commit
    • Ryan Scott's avatar
      Fix #14875 by introducing PprPrec, and using it · 21e1a00c
      Ryan Scott authored
      Trying to determine when to insert parentheses during TH
      conversion is a bit of a mess. There is an assortment of functions
      that try to detect this, such as:
      
      * `hsExprNeedsParens`
      * `isCompoundHsType`
      * `hsPatNeedsParens`
      * `isCompoundPat`
      * etc.
      
      To make things worse, each of them have slightly different semantics.
      Plus, they don't work well in the presence of explicit type
      signatures, as #14875 demonstrates.
      
      All of these problems can be alleviated with the use of an explicit
      precedence argument (much like what `showsPrec` currently does). To
      accomplish this, I introduce a new `PprPrec` data type, and define
      standard predences for things like function application, infix
      operators, function arrows, and explicit type signatures (that last
      one is new). I then added `PprPrec` arguments to the various
      `-NeedsParens` functions, and use them to make smarter decisions
      about when things need to be parenthesized.
      
      A nice side effect is that functions like `isCompoundHsType` are
      now completely unneeded, since they're simply aliases for
      `hsTypeNeedsParens appPrec`. As a result, I did a bit of refactoring
      to remove these sorts of functions. I also did a pass over various
      utility functions in GHC for constructing AST forms and used more
      appropriate precedences where convenient.
      
      Along the way, I also ripped out the existing `TyPrec`
      data type (which was tailor-made for pretty-printing `Type`s) and
      replaced it with `PprPrec` for consistency.
      
      Test Plan: make test TEST=T14875
      
      Reviewers: alanz, goldfire, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: rwbarton, thomie, carter
      
      GHC Trac Issues: #14875
      
      Differential Revision: https://phabricator.haskell.org/D4688
      21e1a00c
  2. 27 Apr, 2018 1 commit
    • Alan Zimmerman's avatar
      TTG : complete for balance of hsSyn AST · c3823cba
      Alan Zimmerman authored
      Summary:
      - remove PostRn/PostTc fields
      - remove the HsVect In/Out distinction for Type, Class and Instance
      - remove PlaceHolder in favour of NoExt
      - Simplify OutputableX constraint
      
      Updates haddock submodule
      
      Test Plan: ./validate
      
      Reviewers: goldfire, bgamari
      
      Subscribers: goldfire, thomie, mpickering, carter
      
      Differential Revision: https://phabricator.haskell.org/D4625
      c3823cba
  3. 13 Apr, 2018 1 commit
    • Alan Zimmerman's avatar
      TTG for HsBinds and Data instances Plan B · b1386942
      Alan Zimmerman authored
      Summary:
      - Add the balance of the TTG extensions for hsSyn/HsBinds
      
      - Move all the (now orphan) data instances into hsSyn/HsInstances and
      use TTG Data instances Plan B
      https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow/Instances#PLANB
      
      Updates haddock submodule.
      
      Illustrative numbers
      
      Compiling HsInstances before using Plan B.
      
      Max residency ~ 5G
      <<ghc: 629,864,691,176 bytes, 5300 GCs,
             321075437/1087762592 avg/max bytes residency (23 samples),
             2953M in use, 0.000 INIT (0.000 elapsed),
             383.511 MUT (384.986 elapsed), 37.426 GC (37.444 elapsed) :ghc>>
      
      Using Plan B
      
      Max residency 1.1G
      
      <<ghc: 78,832,782,968 bytes, 2884 GCs,
             222140352/386470152 avg/max bytes residency (34 samples),
             1062M in use, 0.001 INIT (0.001 elapsed),
             56.612 MUT (62.917 elapsed), 32.974 GC (32.923 elapsed) :ghc>>
      
      Test Plan: ./validate
      
      Reviewers: shayan-najd, goldfire, bgamari
      
      Subscribers: goldfire, thomie, mpickering, carter
      
      Differential Revision: https://phabricator.haskell.org/D4581
      b1386942
  4. 10 Apr, 2018 1 commit
  5. 09 Apr, 2018 1 commit
  6. 07 Apr, 2018 1 commit
  7. 01 Apr, 2018 1 commit
    • Richard Eisenberg's avatar
      Track type variable scope more carefully. · faec8d35
      Richard Eisenberg authored
      The main job of this commit is to track more accurately the scope
      of tyvars introduced by user-written foralls. For example, it would
      be to have something like this:
      
        forall a. Int -> (forall k (b :: k). Proxy '[a, b]) -> Bool
      
      In that type, a's kind must be k, but k isn't in scope. We had a
      terrible way of doing this before (not worth repeating or describing
      here, but see the old tcImplicitTKBndrs and friends), but now
      we have a principled approach: make an Implication when kind-checking
      a forall. Doing so then hooks into the existing machinery for
      preventing skolem-escape, performing floating, etc. This also means
      that we bump the TcLevel whenever going into a forall.
      
      The new behavior is done in TcHsType.scopeTyVars, but see also
      TcHsType.tc{Im,Ex}plicitTKBndrs, which have undergone significant
      rewriting. There are several Notes near there to guide you. Of
      particular interest there is that Implication constraints can now
      have skolems that are out of order; this situation is reported in
      TcErrors.
      
      A major consequence of this is a slightly tweaked process for type-
      checking type declarations. The new Note [Use SigTvs in kind-checking
      pass] in TcTyClsDecls lays it out.
      
      The error message for dependent/should_fail/TypeSkolEscape has become
      noticeably worse. However, this is because the code in TcErrors goes to
      some length to preserve pre-8.0 error messages for kind errors. It's time
      to rip off that plaster and get rid of much of the kind-error-specific
      error messages. I tried this, and doing so led to a lovely error message
      for TypeSkolEscape. So: I'm accepting the error message quality regression
      for now, but will open up a new ticket to fix it, along with a larger
      error-message improvement I've been pondering. This applies also to
      dependent/should_fail/{BadTelescope2,T14066,T14066e}, polykinds/T11142.
      
      Other minor changes:
       - isUnliftedTypeKind didn't look for tuples and sums. It does now.
      
       - check_type used check_arg_type on both sides of an AppTy. But the left
         side of an AppTy isn't an arg, and this was causing a bad error message.
         I've changed it to use check_type on the left-hand side.
      
       - Some refactoring around when we print (TYPE blah) in error messages.
         The changes decrease the times when we do so, to good effect.
         Of course, this is still all controlled by
         -fprint-explicit-runtime-reps
      
      Fixes #14066 #14749
      
      Test cases: dependent/should_compile/{T14066a,T14749},
                  dependent/should_fail/T14066{,c,d,e,f,g,h}
      faec8d35
  8. 23 Mar, 2018 1 commit
    • Ryan Scott's avatar
      Allow PartialTypeSignatures in standalone deriving contexts · affdea82
      Ryan Scott authored
      Summary:
      At its core, this patch is a simple tweak that allows a user
      to write:
      
      ```lang=haskell
      deriving instance _ => Eq (Foo a)
      ```
      
      Which is functionally equivalent to:
      
      ```lang=haskell
      data Foo a = ...
        deriving Eq
      ```
      
      But with the added flexibility that `StandaloneDeriving` gives you
      (namely, the ability to use it anywhere, not just in the same module
      that `Foo` was declared in). This fixes #13324, and should hopefully
      address a use case brought up in #10607.
      
      Currently, only the use of a single, extra-constraints wildcard is
      permitted in a standalone deriving declaration. Any other wildcard
      is rejected, so things like
      `deriving instance (Eq a, _) => Eq (Foo a)` are currently forbidden.
      
      There are quite a few knock-on changes brought on by this change:
      
      * The `HsSyn` type used to represent standalone-derived instances
        was previously `LHsSigType`, which isn't sufficient to hold
        wildcard types. This needed to be changed to `LHsSigWcType` as a
        result.
      
      * Previously, `DerivContext` was a simple type synonym for
        `Maybe ThetaType`, under the assumption that you'd only ever be in
        the `Nothing` case if you were in a `deriving` clause. After this
        patch, that assumption no longer holds true, as you can also be
        in this situation with standalone deriving when an
        extra-constraints wildcard is used.
      
        As a result, I changed `DerivContext` to be a proper datatype that
        reflects the new wrinkle that this patch adds, and plumbed this
        through the relevant parts of `TcDeriv` and friends.
      
      * Relatedly, the error-reporting machinery in `TcErrors` also assumed
        that if you have any unsolved constraints in a derived instance,
        then you should be able to fix it by switching over to standalone
        deriving. This was always sound advice before, but with this new
        feature, it's possible to have unsolved constraints even when
        you're standalone-deriving something!
      
        To rectify this, I tweaked some constructors of `CtOrigin` a bit
        to reflect this new subtlety.
      
      This requires updating the Haddock submodule. See my fork at
      https://github.com/RyanGlScott/haddock/commit/067d52fd4be15a1842cbb05f42d9d482de0ad3a7
      
      Test Plan: ./validate
      
      Reviewers: simonpj, goldfire, bgamari
      
      Reviewed By: simonpj
      
      Subscribers: goldfire, rwbarton, thomie, mpickering, carter
      
      GHC Trac Issues: #13324
      
      Differential Revision: https://phabricator.haskell.org/D4383
      affdea82
  9. 19 Mar, 2018 1 commit
  10. 13 Mar, 2018 1 commit
    • Ryan Scott's avatar
      Drop GHC 8.0 compatibility · 152055a1
      Ryan Scott authored
      GHC 8.4.1 is out, so now GHC's support window only extends
      back to GHC 8.2. This means we can delete gobs of code that were
      only used for GHC 8.0 support. Hooray!
      
      Test Plan: ./validate
      
      Reviewers: bgamari, erikd, dfeuer
      
      Reviewed By: bgamari, dfeuer
      
      Subscribers: alexbiehl, dfeuer, rwbarton, thomie, carter
      
      Differential Revision: https://phabricator.haskell.org/D4492
      152055a1
  11. 02 Mar, 2018 4 commits
    • Ryan Scott's avatar
      Fix #14838 by marking TH-spliced code as FromSource · ffb2738f
      Ryan Scott authored
      Previously, any Template Haskell code that was spliced would
      be marked as `Generated`, which would completely suppress pattern-
      match coverage warnings for it, which several folks found confusing.
      Indeed, Template Haskell-spliced code is "source" code in some sense,
      as users specifically request that it be put into their program, so
      changing its designation to `FromSource` makes sense from that
      perspective.
      
      Test Plan: make test TEST=T14838
      
      Reviewers: goldfire, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: rwbarton, thomie, carter
      
      GHC Trac Issues: #14838
      
      Differential Revision: https://phabricator.haskell.org/D4440
      ffb2738f
    • Ryan Scott's avatar
      Permit conversion of partially applied PromotedTupleTs · 68357020
      Ryan Scott authored
      Summary:
      We were simply missing a case in `Convert` for when have a
      `PromotedTupleT` that wasn't fully saturated. Easily fixed.
      
      Test Plan: make test TEST=T14843
      
      Reviewers: goldfire, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: rwbarton, thomie, carter
      
      GHC Trac Issues: #14843
      
      Differential Revision: https://phabricator.haskell.org/D4442
      68357020
    • Ryan Scott's avatar
      Fix #14817 by not double-printing data family instance kind signatures · aef2b429
      Ryan Scott authored
      Within `pprDataFamInstDecl`, we were invoking `pprFamInstLHS` to
      pretty-print a data family instance header, and we were passing `Just` a
      kind signature to `pprFamInstLHS` to make it pretty-print the kind
      signature alongside it (this is a consequence of commit
      d1ef223c). But this is silly, because
      then invoke `pp_data_defn`, which //also// pretty-prints the kind
      signature, resulting in the kind signature being printed twice by
      mistake.
      
      This fix is simple—pass `Nothing` to `pprFamInstLHS` instead.
      
      Test Plan: make test TEST=T14817
      
      Reviewers: alanz, bgamari, mpickering
      
      Reviewed By: mpickering
      
      Subscribers: mpickering, rwbarton, thomie, carter
      
      GHC Trac Issues: #14817
      
      Differential Revision: https://phabricator.haskell.org/D4418
      aef2b429
    • Tao He's avatar
      Improve exhaustive checking for guards in pattern bindings and MultiIf. · e8e9f6a7
      Tao He authored
      Previously we didn't do exhaustive checking on MultiIf expressions
      and guards in pattern bindings.
      
      We can construct the `LMatch` directly from GRHSs or [LHsExpr]
      (MultiIf's alts) then feed it to checkMatches, without construct the
      MatchGroup and using function `matchWrapper`.
      Signed-off-by: Tao He's avatarHE, Tao <sighingnow@gmail.com>
      
      Test Plan: make test TEST="T14773a T14773b"
      
      Reviewers: bgamari, RyanGlScott, simonpj
      
      Reviewed By: bgamari, simonpj
      
      Subscribers: rwbarton, thomie, carter
      
      GHC Trac Issues: #14773
      
      Differential Revision: https://phabricator.haskell.org/D4400
      e8e9f6a7
  12. 18 Jan, 2018 1 commit
    • Ryan Scott's avatar
      Fix #14681 and #14682 with precision-aimed parentheses · 575c009d
      Ryan Scott authored
      It turns out that `Convert` was recklessly leaving off
      parentheses in two places:
      
      * Negative numeric literals
      * Patterns in lambda position
      
      This patch fixes it by adding three new functions, `isCompoundHsLit`,
      `isCompoundHsOverLit`, and `isCompoundPat`, and using them in the
      right places in `Convert`. While I was in town, I also sprinkled
      `isCompoundPat` among some `Pat`-constructing functions in `HsUtils`
      to help avoid the likelihood of this problem happening in other
      places. One of these places is in `TcGenDeriv`, and sprinkling
      `isCompountPat` there fixes #14682
      
      Test Plan: make test TEST="T14681 T14682"
      
      Reviewers: alanz, goldfire, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: rwbarton, thomie, carter
      
      GHC Trac Issues: #14681, #14682
      
      Differential Revision: https://phabricator.haskell.org/D4323
      575c009d
  13. 15 Jan, 2018 1 commit
  14. 04 Jan, 2018 1 commit
    • Ryan Scott's avatar
      Make typeToLHsType produce kind signatures for tycon applications · 649e7772
      Ryan Scott authored
      Summary:
      `GeneralizedNewtypeDeriving` generates calls to `coerce`
      which take visible type arguments. These types must be produced by
      way of `typeToLHsType`, which converts a `Type` to an `LHsType`.
      However, `typeToLHsType` was leaving off important kind information
      when a `Type` contained a poly-kinded tycon application, leading to
      incorrectly generated code in #14579.
      
      This fixes the issue by tweaking `typeToLHsType` to generate
      explicit kind signatures for tycon applications. This makes the
      generated code noisier, but at least the program from #14579 now
      works correctly.
      
      Test Plan: make test TEST=T14579
      
      Reviewers: simonpj, bgamari
      
      Reviewed By: simonpj
      
      Subscribers: rwbarton, thomie, carter
      
      GHC Trac Issues: #14579
      
      Differential Revision: https://phabricator.haskell.org/D4264
      649e7772
  15. 21 Dec, 2017 3 commits
    • Simon Peyton Jones's avatar
      Simplify HsPatSynDetails · 584cbd4a
      Simon Peyton Jones authored
      This is a pure refactoring.  Use HsConDetails to implement
      HsPatSynDetails, instead of defining a whole new data type.
      Less code, fewer types, all good.
      584cbd4a
    • Ryan Scott's avatar
      Improve treatment of sectioned holes · 4d41e921
      Ryan Scott authored
      Summary:
      Previously, GHC was pretty-printing left-section holes
      incorrectly and not parsing right-sectioned holes at all. This patch
      fixes both problems.
      
      Test Plan: make test TEST=T14590
      
      Reviewers: bgamari, simonpj
      
      Reviewed By: simonpj
      
      Subscribers: simonpj, rwbarton, thomie, mpickering, carter
      
      GHC Trac Issues: #14590
      
      Differential Revision: https://phabricator.haskell.org/D4273
      4d41e921
    • Ryan Scott's avatar
      Fix #14578 by checking isCompoundHsType in more places · 1bd91a7a
      Ryan Scott authored
      Summary:
      The `HsType` pretty-printer does not automatically insert
      parentheses where necessary for type applications, so a function
      `isCompoundHsType` was created in D4056 towards this purpose.
      However, it was not used in as many places as it ought to be,
      resulting in #14578.
      
      Test Plan: make test TEST=T14578
      
      Reviewers: alanz, bgamari, simonpj
      
      Reviewed By: alanz, simonpj
      
      Subscribers: simonpj, rwbarton, thomie, carter
      
      GHC Trac Issues: #14578
      
      Differential Revision: https://phabricator.haskell.org/D4266
      1bd91a7a
  16. 19 Dec, 2017 1 commit
  17. 18 Dec, 2017 1 commit
  18. 07 Dec, 2017 1 commit
    • Simon Peyton Jones's avatar
      Refactor ConDecl: Trac #14529 · fa29df02
      Simon Peyton Jones authored
      This patch refactors HsDecls.ConDecl.  Specifically
      
      * ConDeclGADT was horrible, with all the information hidden
        inside con_res_ty.  Now it's kept separate, as it should be.
      
      * ConDeclH98: use [LHsTyVarBndr] instead of LHsQTyVars for the
        existentials. There is no implicit binding here.
      
      * Add a field con_forall to both ConDeclGADT and ConDeclH98
        which says if there is an explicit user-written forall.
      
      * Field renamings in ConDecl
           con_cxt     to con_mb_cxt
           con_details to con_args
      
      There is an accompanying submodule update to Haddock.
      
      Also the following change turned out to remove a lot of clutter:
      
      * add a smart constructor for HsAppsTy, namely mkHsAppsTy,
        and use it consistently. This avoids a lot of painful pattern
        matching for the common singleton case.
      
      Two api-annotation tests (T10278, and T10399) are broken, hence marking
      them as expect_broken(14529).  Alan is going to fix them, probably by
      changing the con_forall field to
         con_forall :: Maybe SrcSpan
      instead of Bool
      fa29df02
  19. 21 Nov, 2017 1 commit
    • Ben Gamari's avatar
      Revert "trees that grow" work · 314bc314
      Ben Gamari authored
      As documented in #14490, the Data instances currently blow up
      compilation time by too much to stomach. Alan will continue working on
      this in a branch and we will perhaps merge to 8.2 before 8.2.1 to avoid
      having to perform painful cherry-picks in 8.2 minor releases.
      
      Reverts haddock submodule.
      
      This reverts commit 47ad6578.
      This reverts commit e3ec2e7a.
      This reverts commit 438dd1cb.
      This reverts commit 0ff152c9.
      314bc314
  20. 14 Nov, 2017 1 commit
  21. 11 Nov, 2017 1 commit
  22. 08 Nov, 2017 1 commit
  23. 07 Nov, 2017 2 commits
  24. 27 Oct, 2017 1 commit
  25. 11 Oct, 2017 1 commit
  26. 07 Oct, 2017 2 commits
    • Ryan Scott's avatar
      Simply Data instance context for AmbiguousFieldOcc · f337a208
      Ryan Scott authored
      The current, verbose instance context can be compacted into
      `DataId pass`. Indeed, that's what most of the `Data` instances
      in this module already do, so this just makes things consistent.
      f337a208
    • Ryan Scott's avatar
      Fix #14320 by looking through HsParTy in more places · f1d2db68
      Ryan Scott authored
      Summary:
      GHC was needlessly rejecting GADT constructors' type
      signatures that were surrounded in parentheses due to the fact that
      `splitLHsForAllTy` and `splitLHsQualTy` (which are used to check as
      part of checking if GADT constructor return types are correct)
      weren't looking through parentheses (i.e., `HsParTy`). This is
      easily fixed, though.
      
      Test Plan: make test TEST=T14320
      
      Reviewers: austin, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: rwbarton, thomie
      
      GHC Trac Issues: #14320
      
      Differential Revision: https://phabricator.haskell.org/D4072
      f1d2db68
  27. 05 Oct, 2017 1 commit
  28. 02 Oct, 2017 1 commit
  29. 26 Sep, 2017 1 commit
  30. 19 Sep, 2017 1 commit
    • Herbert Valerio Riedel's avatar
      compiler: introduce custom "GhcPrelude" Prelude · f63bc730
      Herbert Valerio Riedel authored
      This switches the compiler/ component to get compiled with
      -XNoImplicitPrelude and a `import GhcPrelude` is inserted in all
      modules.
      
      This is motivated by the upcoming "Prelude" re-export of
      `Semigroup((<>))` which would cause lots of name clashes in every
      modulewhich imports also `Outputable`
      
      Reviewers: austin, goldfire, bgamari, alanz, simonmar
      
      Reviewed By: bgamari
      
      Subscribers: goldfire, rwbarton, thomie, mpickering, bgamari
      
      Differential Revision: https://phabricator.haskell.org/D3989
      f63bc730
  31. 15 Sep, 2017 1 commit
    • Ryan Scott's avatar
      Fix #14228 by marking SumPats as non-irrefutable · f4d50a0e
      Ryan Scott authored
      `isIrrefutableHsPat` should always return `False` for unboxed sum
      patterns (`SumPat`s), since they always have at least one other
      corresponding pattern of the same arity (since the minimum arity for a
      `SumPat` is 2). Failure to do so causes incorrect code to be generated
      for pattern synonyms that use unboxed sums, as shown in #14228.
      
      Test Plan: make test TEST=T14228
      
      Reviewers: austin, bgamari, simonpj
      
      Reviewed By: simonpj
      
      Subscribers: simonpj, rwbarton, thomie
      
      GHC Trac Issues: #14228
      
      Differential Revision: https://phabricator.haskell.org/D3951
      f4d50a0e
  32. 12 Sep, 2017 1 commit
  33. 31 Aug, 2017 1 commit
    • Simon Peyton Jones's avatar
      Add debugPprType · 805b29bb
      Simon Peyton Jones authored
      We pretty-print a type by converting it to an IfaceType and
      pretty-printing that.  But
       (a) that's a bit indirect, and
       (b) delibrately loses information about (e.g.) the kind
            on the /occurrences/ of a type variable
      
      So this patch implements debugPprType, which pretty prints
      the type directly, with no fancy formatting.  It's just used
      for debugging.
      
      I took the opportunity to refactor the debug-pretty-printing
      machinery a little.  In particular, define these functions
      and use them:
      
        ifPprDeubug :: SDoc -> SDOc -> SDoc
          -- Says what to do with and without -dppr-debug
        whenPprDebug :: SDoc -> SDoc
          -- Says what to do with  -dppr-debug; without is empty
        getPprDebug :: (Bool -> SDoc) -> SDoc
      
      getPprDebug used to be called sdocPprDebugWith
      whenPprDebug used to be called ifPprDebug
      
      So a lot of files get touched in a very mechanical way
      805b29bb