1. 28 Mar, 2017 1 commit
  2. 27 Mar, 2017 1 commit
    • Richard Eisenberg's avatar
      Fix #13458 · cea71418
      Richard Eisenberg authored
      Core Lint shouldn't check representations of types that don't
      have representations.
      
      test case: typecheck/should_compile/T13458
      cea71418
  3. 17 Mar, 2017 1 commit
  4. 14 Mar, 2017 1 commit
    • Richard Eisenberg's avatar
      Fix #13337. · e0c433c8
      Richard Eisenberg authored and Ben Gamari's avatar Ben Gamari committed
      The big change is the introduction of solveSomeEqualities. This
      is just like solveEqualities, but it doesn't fail if there are unsolved
      equalities when it's all done. Anything unsolved is re-emitted. This
      is appropriate if we are not kind-generalizing, so this new form
      is used when decideKindGeneralizationPlan says not to.
      
      We initially thought that any use of solveEqualities would be tied
      to kind generalization, but this isn't true. For example, we need
      to solveEqualities a bunch in the "tc" pass in TcTyClsDecls (which
      is really desugaring). These equalities are all surely going to be
      soluble (if they weren't the "kc" pass would fail), but we still
      need to solve them again. Perhaps if the "kc" pass produced type-
      checked output that is then desugared, solveEqualities really would
      be tied only to kind generalization.
      
      Updates haddock submodule.
      
      Test Plan: ./validate, typecheck/should_compile/T13337
      
      Reviewers: simonpj, bgamari, austin
      
      Reviewed By: simonpj
      
      Subscribers: RyanGlScott, rwbarton, thomie
      
      Differential Revision: https://phabricator.haskell.org/D3315
      e0c433c8
  5. 10 Mar, 2017 1 commit
    • Simon Peyton Jones's avatar
      Fix constraint simplification in rules · af6ed4a6
      Simon Peyton Jones authored
      Trac #13381 showed that we were losing track of a wanted constraint
      when simplifying the LHS constraints for a RULE.
      
      This patch fixes it, makes the code a bit simpler, and better
      documented.
      af6ed4a6
  6. 02 Mar, 2017 1 commit
    • Edward Z. Yang's avatar
      Properly represent abstract classes in Class and IfaceDecl · fb5cd9d6
      Edward Z. Yang authored
      
      
      Summary:
      Previously, abstract classes looked very much like normal
      classes, except that they happened to have no methods,
      superclasses or ATs, and they came from boot files.  This
      patch gives abstract classes a proper representation in
      Class and IfaceDecl, by moving the things which are never
      defined for abstract classes into ClassBody/IfaceClassBody.
      
      Because Class is abstract, this change had ~no disruption
      to any of the code in GHC; if you ask about the methods of
      an abstract class, we'll just give you an empty list.
      
      This also fixes a bug where abstract type classes were incorrectly
      treated as representationally injective (they're not!)
      
      Fixes #13347, and a TODO in the code.
      Signed-off-by: default avatarEdward Z. Yang <ezyang@cs.stanford.edu>
      
      Test Plan: validate
      
      Reviewers: simonpj, bgamari, austin
      
      Subscribers: goldfire, thomie
      
      Differential Revision: https://phabricator.haskell.org/D3236
      fb5cd9d6
  7. 26 Feb, 2017 1 commit
    • rwbarton's avatar
      tests: remove extra_files.py (#12223) · 3415bcaa
      rwbarton authored and Ben Gamari's avatar Ben Gamari committed
      The script I used is included as testsuite/driver/kill_extra_files.py,
      though at this point it is for mostly historical interest.
      
      Some of the tests in libraries/hpc relied on extra_files.py, so this
      commit includes an update to that submodule.
      
      One test in libraries/process also relies on extra_files.py, but we
      cannot update that submodule so easily, so for now we special-case it
      in the test driver.
      3415bcaa
  8. 18 Feb, 2017 1 commit
    • Ben Gamari's avatar
      Generalize kind of the (->) tycon · b207b536
      Ben Gamari authored
      This is generalizes the kind of `(->)`, as discussed in #11714.
      
      This involves a few things,
      
       * Generalizing the kind of `funTyCon`, adding two new `RuntimeRep`
      binders,
        ```lang=haskell
      (->) :: forall (r1 :: RuntimeRep) (r2 :: RuntimeRep)
                     (a :: TYPE r1) (b :: TYPE r2).
              a -> b -> *
        ```
      
       * Unsaturated applications of `(->)` are expressed as explicit
      `TyConApp`s
      
       * Saturated applications of `(->)` are expressed as `FunTy` as they are
      currently
      
       * Saturated applications of `(->)` are expressed by a new `FunCo`
      constructor in coercions
      
       * `splitTyConApp` needs to ensure that `FunTy`s are split to a
      `TyConApp`
         of `(->)` with the appropriate `RuntimeRep` arguments
      
       * Teach CoreLint to check that all saturated applications of `(->)` are
      represented with `FunTy`
      
      At the moment I assume that `Constraint ~ *`, which is an annoying
      source of complexity. This will
      be simplified once D3023 is resolved.
      
      Also, this introduces two known regressions,
      
      `tcfail181`, `T10403`
      =====================
      Only shows the instance,
      
          instance Monad ((->) r) -- Defined in ‘GHC.Base’
      
      in its error message when -fprint-potential-instances is used. This is
      because its instance head now mentions 'LiftedRep which is not in scope.
      I'm not entirely sure of the right way to fix this so I'm just accepting
      the new output for now.
      
      T5963 (Typeable)
      ================
      
      T5963 is now broken since Data.Typeable.Internals.mkFunTy computes its
      fingerprint without the RuntimeRep variables that (->) expects. This
      will be fixed with the merge of D2010.
      
      Haddock performance
      ===================
      
      The `haddock.base` and `haddock.Cabal` tests regress in allocations by
      about 20%. This certainly hurts, but it's also not entirely unexpected:
      the size of every function type grows with this patch and Haddock has a
      lot of functions in its heap.
      b207b536
  9. 14 Feb, 2017 1 commit
    • vivid-synth's avatar
      Allow type defaulting for multi-param type classes with ExtendedDefaultRules · c3bbd1af
      vivid-synth authored and Ben Gamari's avatar Ben Gamari committed
      Expressions like the following will now typecheck:
      
      ```
          data A x = A deriving Show
      
          class ToA a x where
             toA :: a -> A x
      
          instance ToA Integer x where
             toA _ = A
      
          main = print (toA 5 :: A Bool)
      ```
      
      The new defaulting rules are
      
      Find all the unsolved constraints. Then:
      
      * Find those that have exactly one free type variable, and partition
        that subset into groups that share a common type variable `a`.
      * Now default `a` (to one of the types in the default list) if at least
        one of the classes `Ci` is an interactive class
      
      Reviewers: goldfire, bgamari, austin, mpickering, simonpj
      
      Reviewed By: bgamari, simonpj
      
      Subscribers: mpickering, simonpj, goldfire, thomie
      
      Differential Revision: https://phabricator.haskell.org/D2822
      c3bbd1af
  10. 12 Feb, 2017 1 commit
  11. 09 Feb, 2017 1 commit
  12. 22 Jan, 2017 2 commits
  13. 20 Jan, 2017 1 commit
  14. 19 Jan, 2017 1 commit
    • Richard Eisenberg's avatar
      Update levity polymorphism · e7985ed2
      Richard Eisenberg authored
      This commit implements the proposal in
      https://github.com/ghc-proposals/ghc-proposals/pull/29 and
      https://github.com/ghc-proposals/ghc-proposals/pull/35.
      
      Here are some of the pieces of that proposal:
      
      * Some of RuntimeRep's constructors have been shortened.
      
      * TupleRep and SumRep are now parameterized over a list of RuntimeReps.
      * This
      means that two types with the same kind surely have the same
      representation.
      Previously, all unboxed tuples had the same kind, and thus the fact
      above was
      false.
      
      * RepType.typePrimRep and friends now return a *list* of PrimReps. These
      functions can now work successfully on unboxed tuples. This change is
      necessary because we allow abstraction over unboxed tuple types and so
      cannot
      always handle unboxed tuples specially as we did before.
      
      * We sometimes have to create an Id from a PrimRep. I thus split PtrRep
      * into
      LiftedRep and UnliftedRep, so that the created Ids have the right
      strictness.
      
      * The RepType.RepType type was removed, as it didn't seem to help with
      * much.
      
      * The RepType.repType function is also removed, in favor of typePrimRep.
      
      * I have waffled a good deal on whether or not to keep VoidRep in
      TyCon.PrimRep. In the end, I decided to keep it there. PrimRep is *not*
      represented in RuntimeRep, and typePrimRep will never return a list
      including
      VoidRep. But it's handy to have in, e.g., ByteCodeGen and friends. I can
      imagine another design choice where we have a PrimRepV type that is
      PrimRep
      with an extra constructor. That seemed to be a heavier design, though,
      and I'm
      not sure what the benefit would be.
      
      * The last, unused vestiges of # (unliftedTypeKind) have been removed.
      
      * There were several pretty-printing bugs that this change exposed;
      * these are fixed.
      
      * We previously checked for levity polymorphism in the types of binders.
      * But we
      also must exclude levity polymorphism in function arguments. This is
      hard to check
      for, requiring a good deal of care in the desugarer. See Note [Levity
      polymorphism
      checking] in DsMonad.
      
      * In order to efficiently check for levity polymorphism in functions, it
      * was necessary
      to add a new bit of IdInfo. See Note [Levity info] in IdInfo.
      
      * It is now safe for unlifted types to be unsaturated in Core. Core Lint
      * is updated
      accordingly.
      
      * We can only know strictness after zonking, so several checks around
      * strictness
      in the type-checker (checkStrictBinds, the check for unlifted variables
      under a ~
      pattern) have been moved to the desugarer.
      
      * Along the way, I improved the treatment of unlifted vs. banged
      * bindings. See
      Note [Strict binds checks] in DsBinds and #13075.
      
      * Now that we print type-checked source, we must be careful to print
      * ConLikes correctly.
      This is facilitated by a new HsConLikeOut constructor to HsExpr.
      Particularly troublesome
      are unlifted pattern synonyms that get an extra void# argument.
      
      * Includes a submodule update for haddock, getting rid of #.
      
      * New testcases:
        typecheck/should_fail/StrictBinds
        typecheck/should_fail/T12973
        typecheck/should_run/StrictPats
        typecheck/should_run/T12809
        typecheck/should_fail/T13105
        patsyn/should_fail/UnliftedPSBind
        typecheck/should_fail/LevPolyBounded
        typecheck/should_compile/T12987
        typecheck/should_compile/T11736
      
      * Fixed tickets:
        #12809
        #12973
        #11736
        #13075
        #12987
      
      * This also adds a test case for #13105. This test case is
      * "compile_fail" and
      succeeds, because I want the testsuite to monitor the error message.
      When #13105 is fixed, the test case will compile cleanly.
      e7985ed2
  15. 09 Jan, 2017 1 commit
  16. 08 Jan, 2017 1 commit
    • Ömer Sinan Ağacan's avatar
      Parse holes as infix operators · 6c869f90
      Ömer Sinan Ağacan authored
      Reported as #13050. Since holes are expressions but not identifiers,
      holes were not allowed in infix operator position. This patch introduces
      a new production in infix operator parser to allow this.
      
      Reviewers: simonpj, austin, bgamari
      
      Reviewed By: simonpj
      
      Subscribers: simonpj, RyanGlScott, thomie, mpickering
      
      Differential Revision: https://phabricator.haskell.org/D2910
      
      GHC Trac Issues: #13050
      6c869f90
  17. 18 Dec, 2016 1 commit
  18. 17 Dec, 2016 1 commit
    • eir@cis.upenn.edu's avatar
      Reshuffle levity polymorphism checks. · 8906e7b7
      eir@cis.upenn.edu authored and Ben Gamari's avatar Ben Gamari committed
      Previously, GHC checked for bad levity polymorphism to the left of all
      arrows in data constructors. This was wrong, as reported in #12911
      (where an example is also shown). The solution is to check each
      individual argument for bad levity polymorphism.  Thus the check has
      been moved from TcValidity to TcTyClsDecls.
      
      A similar situation exists with pattern synonyms, also fixed here.
      
      This patch also nabs #12819 while I was in town.
      
      Test cases: typecheck/should_compile/T12911, patsyn/should_fail/T12819
      
      Test Plan: ./validate
      
      Reviewers: simonpj, austin, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2783
      
      GHC Trac Issues: #12819, #12911
      8906e7b7
  19. 15 Dec, 2016 1 commit
  20. 12 Dec, 2016 1 commit
  21. 06 Dec, 2016 1 commit
  22. 05 Dec, 2016 2 commits
    • Simon Peyton Jones's avatar
      Test Trac #12925 · 3e3f7c21
      Simon Peyton Jones authored
      3e3f7c21
    • Simon Peyton Jones's avatar
      Fix an asymptotic bug in the occurrence analyser · 517d03e4
      Simon Peyton Jones authored
      Trac #12425 and #12234 showed up a major and long-standing
      bug in the occurrence analyser, whereby it could generate
      explonentially large program!
      
      There's a lot of commentary on #12425; and it's all described
      in Note [Loop breakers, node scoring, and stability]
      
      I did quite a lot of refactoring to make the code comprehensibe
      again (its structure had bit-rotted rather), so the patch
      looks bigger than it really is.
      
      Hurrah!
      
      I did a nofib run to check that I hadn't inadertently ruined
      anything:
      
      --------------------------------------------------------------------------------
              Program           Size    Allocs   Runtime   Elapsed  TotalMem
      --------------------------------------------------------------------------------
                fluid          -0.3%     -1.5%      0.01      0.01     +0.0%
               parser          -0.9%     +0.6%      0.04      0.04     +0.0%
               prolog          -0.1%     +1.2%      0.00      0.00     +0.0%
      
      --------------------------------------------------------------------------------
                  Min          -0.9%     -1.5%     -8.6%     -8.7%     +0.0%
                  Max          +0.1%     +1.2%     +7.7%     +7.8%     +2.4%
       Geometric Mean          -0.2%     -0.0%     -0.2%     -0.3%     +0.0%
      
      I checked what happened in 'prolog'.  It seems that we have a
      recursive data structure something like this
      
         f :: [blah]
         f x = build (\cn.  ...g...  )
      
         g :: [blah2]
         g y = ....(foldr k z (f y))....
      
      If we inline 'f' into 'g' we get better fusion than the other
      way round, but we don't have any way to spot that at the moment.
      (I wonder if we could do worker/wrapper for functions returning
      a 'build'?)  It was happening before by a fluke.
      
      Anyway I decided to accept this; it's relatively rare I think.
      517d03e4
  23. 17 Nov, 2016 1 commit
    • Edward Z. Yang's avatar
      Test for type synonym loops on TyCon. · 31398fbc
      Edward Z. Yang authored
      
      
      Summary:
      Previously, we tested for type synonym loops by doing
      a syntactic test on the literal type synonym declarations.
      However, in some cases, loops could go through hs-boot
      files, leading to an infinite loop (#12042); a similar
      situation can occur when signature merging.
      
      This commit replaces the syntactic test with a test on
      TyCon, simply by walking down all type synonyms until
      we bottom out, or find we've looped back.  It's a lot
      simpler.
      Signed-off-by: default avatarEdward Z. Yang <ezyang@cs.stanford.edu>
      
      Test Plan: validate
      
      Reviewers: simonpj, austin, bgamari
      
      Subscribers: goldfire, thomie
      
      Differential Revision: https://phabricator.haskell.org/D2656
      
      GHC Trac Issues: #12042
      31398fbc
  24. 02 Nov, 2016 1 commit
  25. 26 Oct, 2016 1 commit
    • Simon Peyton Jones's avatar
      Fundeps work even for unary type classes · 801c2637
      Simon Peyton Jones authored
      The functional-dependency improvement functions,
         improveFromAnother
         improveFromInstEnv
      had a side-condition that said the type class has to have at
      least two arguments.  But not so, as Trac #12763 shows:
      
         class C a | -> a where ...
      
      is perfectly legal, albeit a bit of a corner case.
      801c2637
  26. 24 Oct, 2016 1 commit
    • Simon Peyton Jones's avatar
      Prioritise class-level equality costraints · 1c4a39d3
      Simon Peyton Jones authored
      This patch fixes Trac #12734 by prioritising the class-level
      variants of equality constraints, namely (a~b) and (a~~b).
      
      See comment:10 of Trac #12734 for a description of what
      went wrong, and Note [Prioritise class equalities] in TcSMonad.
      
      The fix is still not great, but it's a definite step forward, and
      cures the particular problem.
      
      Worth merging to 8.0.
      1c4a39d3
  27. 21 Oct, 2016 2 commits
    • Simon Peyton Jones's avatar
      Test Trac #12507 · cdbc73ae
      Simon Peyton Jones authored
      This is now working apparently.  It relates to when a
      polymorphic function gets instantiated, under some
      implicit paramter bindings.
      cdbc73ae
    • Simon Peyton Jones's avatar
      Refactor typechecking of pattern bindings · 45bfd1a6
      Simon Peyton Jones authored
      This patch fixes a regression introduced, post 8.0.1, by
      this major commit:
      
           commit 15b9bf4b
           Author: Simon Peyton Jones <simonpj@microsoft.com>
           Date:   Sat Jun 11 23:49:27 2016 +0100
      
               Improve typechecking of let-bindings
      
               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.
      
      I didn't get the typechecking of pattern bindings right, leading
      to Trac #12427.
      
      In fixing this I found that this program doesn't work:
      
        data T where
          T :: a -> ((forall b. [b]->[b]) -> Int) -> T
      
        h1 y = case y of T _ v -> v
      
      Works in 7.10, but not in 8.0.1.
      
      There's a happy ending. I found a way to fix this, and improve
      pattern bindings too.  Not only does this fix #12427, but it also
      allows
      
      In particular,we now can accept
      
        data T where MkT :: a -> Int -> T
      
        ... let { MkT _ q = t } in ...
      
      Previously this elicited "my head exploded" but it's really
      fine since q::Int.
      
      The approach is described in detail in TcBinds
         Note [Typechecking pattern bindings]
      Super cool.  And not even a big patch!
      45bfd1a6
  28. 17 Oct, 2016 1 commit
  29. 08 Oct, 2016 2 commits
  30. 30 Sep, 2016 1 commit
    • Simon Peyton Jones's avatar
      Fix impredicativity (again) · b612da66
      Simon Peyton Jones authored
      This patch fixes Trac #12616.
      
      Dignosis.  In TcUnify.tc_sub_type_ds we were going to some trouble to
      support co- and contra-variance even for impredicative types.  With
      -XImpredicativeTYpes, this allowed a unification variable to be
      unified with a polytype (probably wrongly) and that caused later
      trouble in the constraint solver, where -XImpredicativeTypes was /not/
      on.  In effect, -XImpredicativeTypes can't be switched on locally.
      
      Why did we want ImpredicativeTypes locally?  Because the program
      generated by GND for a higher-rank method involved impredicative
      instantation of 'coerce':
            op = coerce op   -- where op has a higher rank type
      See Note [Newtype-deriving instances] in TcGenDeriv.
      
      Cure.
      
      1.  It is ghastly to rely on ImpredicativeTypes (a 100% flaky
          feature) to instantiate coerce polymorphically.  Happily we
          now have Visible Type Application, so I've used that instead
          which should be solid and reliable.
      
      2.  I deleted the code in tc_sub_type_ds that allows the constraint
          solver to "look through" a unification variable to find a
          polytype.  That used to be essential in the days of ReturnTv,
          but it's utterly unreliable and should be consigned to the dustbin
          of history.  (We have ExpType now for the essential uses.)
      
      Tests involving ImpredicativeTypes are affected, but I'm not worried
      about them... it's advertised as a feature you can't rely on, and
      I want to reform it outright.
      b612da66
  31. 12 Sep, 2016 1 commit
    • Simon Peyton Jones's avatar
      Be less picky about reporing inaccessible code · 03541cba
      Simon Peyton Jones authored
      Triggered by the discussion on Trac #12466, this patch
      makes GHC less aggressive about reporting an error when
      there are insoluble Givens.
      
      Being so agressive was making some libraries fail to
      compile, and is arguably wrong in at least some cases.
      See the discussion on the ticket.
      
      Several test now pass when they failed before; see
      the files-modified list for this patch.
      03541cba
  32. 31 Aug, 2016 2 commits
  33. 21 Aug, 2016 1 commit
    • Edward Z. Yang's avatar
      Axe initIfaceTc, tie the knot through HPT (or if_rec_types). · e907e1f1
      Edward Z. Yang authored
      
      
      Summary:
      initIfaceTc was originally used to make sure when we typecheck
      an interface, it can find the TyThings for things it itself
      defined.  However, in the case of retypecheckLoop, this wasn't
      necessary because we ALREADY tied the knot through the HPT.
      
      This commit removes initIfaceTc, instead relying on the HPT
      to tie the knot.  genModDetails' caller needed to be modified
      to tie the knot, but there are not that many call-sites of
      typecheckIface so the change is quite reasonable.
      
      We also introduce a new 'initIfaceLoad', which does
      NOT set up 'if_rec_types'.  It's used when we're
      typechecking old, up-to-date interfaces in, since we're
      never going to update the type environment.
      
      The full details are in Note [Knot-tying typecheckIface].
      Displeasingly, we need a special case to handle DFuns in
      the case of tcHiBootIface, see
      Note [DFun knot-tying special case] for the gory details.
      
      I also added another test which tickles a bug in a buggy
      version of this patch (see "Why the seq?")
      Signed-off-by: default avatarEdward Z. Yang <ezyang@cs.stanford.edu>
      
      Test Plan: validate
      
      Reviewers: simonpj, austin, bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2349
      e907e1f1
  34. 20 Jul, 2016 2 commits