1. 23 Jun, 2016 1 commit
    • Simon Peyton Jones's avatar
      Give lookupGRE_Name a better API · 3e0af469
      Simon Peyton Jones authored
      lookupGRE_Name should return either zero or one GREs, never
      several. This is a consequence of INVARIANT 1 on GlobalRdrEnv.
      
      So it's better if it returns a Maybe; the panic on multiple results
      is put in one place, instead of being scattered or ignored.
      
      Just refactoring, no change in behaviour
      3e0af469
  2. 15 Jun, 2016 1 commit
    • Simon Peyton Jones's avatar
      Re-add FunTy (big patch) · 77bb0927
      Simon Peyton Jones authored
      With TypeInType Richard combined ForAllTy and FunTy, but that was often
      awkward, and yielded little benefit becuase in practice the two were
      always treated separately.  This patch re-introduces FunTy.  Specfically
      
      * New type
          data TyVarBinder = TvBndr TyVar VisibilityFlag
        This /always/ has a TyVar it.  In many places that's just what
        what we want, so there are /lots/ of TyBinder -> TyVarBinder changes
      
      * TyBinder still exists:
          data TyBinder = Named TyVarBinder | Anon Type
      
      * data Type = ForAllTy TyVarBinder Type
                  | FunTy Type Type
                  |  ....
      
      There are a LOT of knock-on changes, but they are all routine.
      
      The Haddock submodule needs to be updated too
      77bb0927
  3. 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
  4. 18 May, 2016 1 commit
    • niteria's avatar
      Kill varSetElems in tidyFreeTyCoVars · 6282bc31
      niteria authored
      I haven't observed this to have an effect on nondeterminism,
      but tidyOccName appears to modify the TidyOccEnv in a
      way dependent on the order of inputs.
      It's easy enough to change it to be deterministic to be on the
      safe side.
      
      Test Plan: ./validate
      
      Reviewers: simonmar, austin, bgamari, simonpj
      
      Reviewed By: simonpj
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2238
      
      GHC Trac Issues: #4012
      6282bc31
  5. 15 May, 2016 1 commit
    • Ömer Sinan Ağacan's avatar
      Fix a performance issue with -fprint-expanded-synonyms · e4834edf
      Ömer Sinan Ağacan authored
      The type synonym expander was doing redundant work by looking at same
      types again and again. This patch fixes the loop code when both of the
      types can be expanded, to do `O(min(n, m))` comparisons and `O(n + m)`
      expansions, where `n` is expansions of the first type and `m` is
      expansions of the second type.
      
      Reported by sjcjoosten in T10547.
      
      Test Plan:
      Added a regression test that was taking several minutes to type check
      before this patch.
      
      Reviewers: bgamari, simonpj, austin, ezyang
      
      Reviewed By: bgamari, simonpj, austin, ezyang
      
      Subscribers: simonpj, thomie
      
      Differential Revision: https://phabricator.haskell.org/D2198
      
      GHC Trac Issues: #10547
      e4834edf
  6. 12 May, 2016 1 commit
  7. 10 May, 2016 1 commit
    • niteria's avatar
      Kill unnecessary cmpType in lhs_cmp_type · 4ac0e815
      niteria authored
      This is the only call site of `lhs_cmp_type` and we only
      care about equality.
      `cmpType` is nondeterministic (because `TyCon`s are compared
      with Uniques in `cmpTc`), so if we don't have to use it, it's
      better not to.
      
      Test Plan: ./validate
      
      Reviewers: simonmar, goldfire, bgamari, austin, simonpj
      
      Reviewed By: simonpj
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2172
      
      GHC Trac Issues: #4012
      4ac0e815
  8. 28 Apr, 2016 2 commits
  9. 26 Apr, 2016 1 commit
    • niteria's avatar
      Kill varSetElems in TcErrors · 2dc5b92e
      niteria authored
      The uses of varSetElems in these places are unnecessary and while it
      doesn't intruduce non-determinism in the ABI the plan is to get
      rid of all varSetElems to get some compile time guarantees.
      
      Test Plan: ./validate
      
      Reviewers: austin, simonmar, bgamari, goldfire, simonpj
      
      Reviewed By: simonpj
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2141
      
      GHC Trac Issues: #4012
      2dc5b92e
  10. 19 Apr, 2016 1 commit
  11. 15 Apr, 2016 1 commit
    • niteria's avatar
      Kill some unnecessary varSetElems · 928d7473
      niteria authored
      When you do `varSetElems (tyCoVarsOfType x)` it's equivalent to
      `tyCoVarsOfTypeList x`.
      
      Why? If you look at the implementation:
      ```
      tyCoVarsOfTypeList ty = runFVList $ tyCoVarsOfTypeAcc ty
      tyCoVarsOfType ty = runFVSet $ tyCoVarsOfTypeAcc ty
      ```
      they use the same helper function. The helper function returns a
      deterministically ordered list and a set. The only difference
      between the two is which part of the result they take. It is redundant
      to take the set and then immediately convert it to a list.
      
      This helps with determinism and we eventually want to replace the uses
      of `varSetElems` with functions that don't leak the values of uniques.
      This change gets rid of some instances that are easy to kill.
      
      I chose not to annotate every place where I got rid of `varSetElems`
      with a comment about non-determinism, because once we get rid of
      `varSetElems` it will not be possible to do the wrong thing.
      
      Test Plan: ./validate
      
      Reviewers: goldfire, austin, simonmar, bgamari, simonpj
      
      Reviewed By: simonpj
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2115
      
      GHC Trac Issues: #4012
      928d7473
  12. 10 Apr, 2016 1 commit
    • Jason Eisenberg's avatar
      Fix suggestions for unbound variables (#11680) · 470d4d5b
      Jason Eisenberg authored
      When the typechecker generates the error message for an out-of-scope
      variable, it now uses the GlobalRdrEnv with respect to which the
      variable is unbound, not the GlobalRdrEnv which is available at the time
      the error is reported.  Doing so ensures we do not provide suggestions
      which themselves are out-of-scope (because they are bound in a later
      inter-splice group).
      
      Nonetheless, we do note in the error message if an unambiguous, exact
      match to the out-of-scope variable is found in a later inter-splice
      group, and we specify where that match is not in scope.
      
      Test Plan: ./validate
      
      Reviewers: goldfire, austin, bgamari
      
      Reviewed By: goldfire
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D2000
      
      GHC Trac Issues: #11680
      470d4d5b
  13. 31 Mar, 2016 1 commit
  14. 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
  15. 16 Mar, 2016 1 commit
    • eir@cis.upenn.edu's avatar
      Clean up some pretty-printing in errors. · 5d98b8bf
      eir@cis.upenn.edu authored
      It turns out that there were some pretty egregious mistakes
      in the code that suggested -fprint-explicit-kinds, which are
      fixed. This commit also reorders a bunch of error messages,
      which I think is an improvement.
      
      This also adds the test case for #11471, which is what
      triggered the cleanup in TcErrors. Now that #11473 is done,
      there is nothing more outstanding for #11471.
      
      test case: dependent/should_fail/T11471
      5d98b8bf
  16. 15 Mar, 2016 1 commit
    • eir@cis.upenn.edu's avatar
      Fix #11407. · e9bf7bb5
      eir@cis.upenn.edu authored
      This removes the `defer_me` check that was in checkTauTvUpdate
      and uses only a type family check instead. The old defer_me check
      repeated work done by fast_check in occurCheckExpand.
      
      There is also some error message improvement, necessitated by
      the terrible error message that the test case produced, even when
      it didn't consume all of memory.
      
      test case: dependent/should_fail/T11407
      
      [skip ci]
      e9bf7bb5
  17. 27 Feb, 2016 2 commits
  18. 26 Feb, 2016 2 commits
    • Simon Peyton Jones's avatar
      Comments and white space only · 253ccdf0
      Simon Peyton Jones authored
      253ccdf0
    • Simon Peyton Jones's avatar
      Exclude TyVars from the constraint solver · 7496be5c
      Simon Peyton Jones authored
      There is a general invariant that the constraint solver doesn't see
      TyVars, only TcTyVars.  But when checking the generic-default
      signature of a class, we called checkValidType on the generic-default
      type, which had the class TyVar free. That in turn meant that it wasn't
      considered during flattening, which led to the error reported in
      Trac #11608.
      
      The fix is simple: call checkValidType on the /closed/ type. Easy.
      
      While I was at it, I added a bunch of ASSERTs about the TcTyVar
      invariant.
      7496be5c
  19. 25 Feb, 2016 2 commits
    • barrucadu's avatar
      Print which warning-flag controls an emitted warning · bb5afd3c
      barrucadu authored
      Both gcc and clang tell which warning flag a reported warning can be
      controlled with, this patch makes ghc do the same. More generally, this
      allows for annotated compiler output, where an optional annotation is
      displayed in brackets after the severity.
      
      This also adds a new flag `-f(no-)show-warning-groups` to control
      whether to show which warning-group (such as `-Wall` or `-Wcompat`)
      a warning belongs to. This flag is on by default.
      
      This implements #10752
      
      Reviewed By: quchen, bgamari, hvr
      
      Differential Revision: https://phabricator.haskell.org/D1943
      bb5afd3c
    • Rik Steenkamp's avatar
      Improve pattern synonym error messages (add `PatSynOrigin`) · 116528c8
      Rik Steenkamp authored
      Adds a new data constructor `PatSynOrigin Bool Name` to the `CtOrigin`
      data type. This allows for better error messages when the origin of a
      wanted constraint is a pattern synonym declaration.
      
      Fixes T10873.
      
      Reviewers: mpickering, simonpj, austin, thomie, bgamari
      
      Reviewed By: simonpj, thomie, bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1866
      
      GHC Trac Issues: #10873
      116528c8
  20. 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
  21. 17 Feb, 2016 1 commit
  22. 16 Feb, 2016 3 commits
    • Yuras's avatar
      Suggest candidate instances in error message · 5fc06b97
      Yuras authored
      See Trac #9611. In "No instance..." error message we suggest instances
      for other types with the same occ name. It is usefull e.g. when we have
      two different versions of the same package installed.
      
      Test Plan: typecheck/should_fail/tcfail224
      
      Reviewers: austin, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1919
      
      GHC Trac Issues: #9611
      5fc06b97
    • Rik Steenkamp's avatar
      Fix typos · 49c5cb40
      Rik Steenkamp authored
      Reviewers: bgamari, austin
      
      Reviewed By: austin
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1915
      49c5cb40
    • Rik Steenkamp's avatar
      Fix two wrong uses of "data constructor" in error msgs · af5a0e50
      Rik Steenkamp authored
      Replace `NoDataKinds :: PromotionErr` by `NoDataKindsTC` and
      `NoDataKindsDC` (just like there is `NoTypeInTypeTC` and
      `NoTypeInTypeDC`). This allows for a correct error message when a kind
      signature contains a type constructor and `-XDataKinds` is not
      specified.
      
      Apply a small fix to `TcError.hs` where instead of "data constructor" we
      should say "pattern synonym".
      
      Reviewers: austin, goldfire, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: goldfire, thomie
      
      Differential Revision: https://phabricator.haskell.org/D1909
      af5a0e50
  23. 15 Feb, 2016 2 commits
    • Simon Peyton Jones's avatar
      Comments only · bb7f2308
      Simon Peyton Jones authored
      bb7f2308
    • Simon Peyton Jones's avatar
      Improve error message suppression · 18cd7124
      Simon Peyton Jones authored
      TcErrors has a system for suppressing some type errors if a more
      serious one occurs.  But there was a crucial missing case, which
      sometimes resulted in a cascade of irrelevant errors overwhelming
      the actual cause. This was Trac #11541.
      
      The fix is simple.  Worth merging to 8.0
      18cd7124
  24. 09 Feb, 2016 1 commit
    • Ben Gamari's avatar
      TcErrors: Fix plural form of "instance" error · c8702e30
      Ben Gamari authored
      Previously "types" was inappropriately made plural instead of
      "instance",
      
          instance Eq Ordering -- Defined in ‘GHC.Classes’
          ...plus 24 others
          ...plus 13 instance involving out-of-scope typess
      c8702e30
  25. 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
  26. 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
      Simplify API to tcMatchTys · 5a62b6ac
      Simon Peyton Jones authored
      Previously tcMatchTys took a set of "template type variables" to
      bind.  But all the calls are top-level, and we always want to
      bind all variables in the template.  So I simplified the API
      by omitting that argument.
      
      There should be no change in behaviour.
      
      Feel free to merge to 8.0 if it helps in merging other patches
      5a62b6ac
  27. 07 Jan, 2016 1 commit
    • Simon Peyton Jones's avatar
      Tidy up tidySkolemInfo · 290a553e
      Simon Peyton Jones authored
      Previously tidySkolemInfo used tidyOpenType, and returned a new
      TidyEnv.  But that's not needed any more, because all the skolems
      should be in scope in the constraint tree.
      
      I also removed a (now-unnecessary) field of UnifyForAllSkol
      290a553e
  28. 31 Dec, 2015 1 commit
  29. 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
  30. 17 Dec, 2015 1 commit
  31. 16 Dec, 2015 1 commit
    • quchen's avatar
      Add `-W(no-)xxx` aliases for `-f(no-)warn-xxx` flags · 2206fa8c
      quchen authored
      This also updates the user's guide to refer to the `-W`-based warning
      flags by default.
      
      Quoting the release note entry:
      
      | Warnings can now be controlled with `-W(no-)...` flags in addition to
      | the old `-f(no-)warn...` ones. This was done as the first part of a
      | rewrite of the warning system to provide better control over warnings,
      | better warning messages, and more common syntax compared to other
      | compilers. The old `-fwarn...`-based warning flags will remain
      | functional for the forseeable future.
      
      This is part of
      https://ghc.haskell.org/wiki/Design/Warnings
      and addresses #11218
      
      Reviewed By: hvr, bgamari
      
      Differential Revision: https://phabricator.haskell.org/D1613
      2206fa8c
  32. 15 Dec, 2015 1 commit
    • Ben Gamari's avatar
      Expose enabled language extensions to TH · c1e25536
      Ben Gamari authored
      This exposes `template-haskell` functions for querying the language
      extensions which are enabled when compiling a module,
      
      - an `isExtEnabled` function to check whether an extension is enabled
      - an `extsEnabled` function to obtain a full list of enabled extensions
      
      To avoid code duplication this adds a `GHC.LanguageExtensions` module to
      `ghc-boot` and moves `DynFlags.ExtensionFlag` into it. A happy
      consequence of this is that the ungainly `DynFlags` lost around 500
      lines. Moreover, flags corresponding to language extensions are now
      clearly distinguished from other flags due to the `LangExt.*` prefix.
      
      Updates haddock submodule.
      
      This fixes #10820.
      
      Test Plan: validate
      
      Reviewers: austin, spinda, hvr, goldfire, alanz
      
      Reviewed By: goldfire
      
      Subscribers: mpickering, RyanGlScott, hvr, simonpj, thomie
      
      Differential Revision: https://phabricator.haskell.org/D1200
      
      GHC Trac Issues: #10820
      c1e25536