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* Taming the Kind Inference MonsterSimon Peyton Jones2018-11-291-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | My original goal was (Trac #15809) to move towards using level numbers as the basis for deciding which type variables to generalise, rather than searching for the free varaibles of the environment. However it has turned into a truly major refactoring of the kind inference engine. Let's deal with the level-numbers part first: * Augment quantifyTyVars to calculate the type variables to quantify using level numbers, and compare the result with the existing approach. That is; no change in behaviour, just a WARNing if the two approaches give different answers. * To do this I had to get the level number right when calling quantifyTyVars, and this entailed a bit of care, especially in the code for kind-checking type declarations. * However, on the way I was able to eliminate or simplify a number of calls to solveEqualities. This work is incomplete: I'm not /using/ level numbers yet. When I subsequently get rid of any remaining WARNings in quantifyTyVars, that the level-number answers differ from the current answers, then I can rip out the current "free vars of the environment" stuff. Anyway, this led me into deep dive into kind inference for type and class declarations, which is an increasingly soggy part of GHC. Richard already did some good work recently in commit 5e45ad10ffca1ad175b10f6ef3327e1ed8ba25f3 Date: Thu Sep 13 09:56:02 2018 +0200 Finish fix for #14880. The real change that fixes the ticket is described in Note [Naughty quantification candidates] in TcMType. but I kept turning over stones. So this patch has ended up with a pretty significant refactoring of that code too. Kind inference for types and classes ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * Major refactoring in the way we generalise the inferred kind of a TyCon, in kcTyClGroup. Indeed, I made it into a new top-level function, generaliseTcTyCon. Plus a new Note to explain it Note [Inferring kinds for type declarations]. * We decided (Trac #15592) not to treat class type variables specially when dealing with Inferred/Specified/Required for associated types. That simplifies things quite a bit. I also rewrote Note [Required, Specified, and Inferred for types] * Major refactoring of the crucial function kcLHsQTyVars: I split it into kcLHsQTyVars_Cusk and kcLHsQTyVars_NonCusk because the two are really quite different. The CUSK case is almost entirely rewritten, and is much easier because of our new decision not to treat the class variables specially * I moved all the error checks from tcTyClTyVars (which was a bizarre place for it) into generaliseTcTyCon and/or the CUSK case of kcLHsQTyVars. Now tcTyClTyVars is extremely simple. * I got rid of all the all the subtleties in tcImplicitTKBndrs. Indeed now there is no difference between tcImplicitTKBndrs and kcImplicitTKBndrs; there is now a single bindImplicitTKBndrs. Same for kc/tcExplicitTKBndrs. None of them monkey with level numbers, nor build implication constraints. scopeTyVars is gone entirely, as is kcLHsQTyVarBndrs. It's vastly simpler. I found I could get rid of kcLHsQTyVarBndrs entirely, in favour of the bnew bindExplicitTKBndrs. Quantification ~~~~~~~~~~~~~~ * I now deal with the "naughty quantification candidates" of the previous patch in candidateQTyVars, rather than in quantifyTyVars; see Note [Naughty quantification candidates] in TcMType. I also killed off closeOverKindsCQTvs in favour of the same strategy that we use for tyCoVarsOfType: namely, close over kinds at the occurrences. And candidateQTyVars no longer needs a gbl_tvs argument. * Passing the ContextKind, rather than the expected kind itself, to tc_hs_sig_type_and_gen makes it easy to allocate the expected result kind (when we are in inference mode) at the right level. Type families ~~~~~~~~~~~~~~ * I did a major rewrite of the impenetrable tcFamTyPats. The result is vastly more comprehensible. * I got rid of kcDataDefn entirely, quite a big function. * I re-did the way that checkConsistentFamInst works, so that it allows alpha-renaming of invisible arguments. * The interaction of kind signatures and family instances is tricky. Type families: see Note [Apparently-nullary families] Data families: see Note [Result kind signature for a data family instance] and Note [Eta-reduction for data families] * The consistent instantation of an associated type family is tricky. See Note [Checking consistent instantiation] and Note [Matching in the consistent-instantation check] in TcTyClsDecls. It's now checked in TcTyClsDecls because that is when we have the relevant info to hand. * I got tired of the compromises in etaExpandFamInst, so I did the job properly by adding a field cab_eta_tvs to CoAxBranch. See Coercion.etaExpandCoAxBranch. tcInferApps and friends ~~~~~~~~~~~~~~~~~~~~~~~ * I got rid of the mysterious and horrible ClsInstInfo argument to tcInferApps, checkExpectedKindX, and various checkValid functions. It was horrible! * I got rid of [Type] result of tcInferApps. This list was used only in tcFamTyPats, when checking the LHS of a type instance; and if there is a cast in the middle, the list is meaningless. So I made tcInferApps simpler, and moved the complexity (not much) to tcInferApps. Result: tcInferApps is now pretty comprehensible again. * I refactored the many function in TcMType that instantiate skolems. Smaller things * I rejigged the error message in checkValidTelescope; I think it's quite a bit better now. * checkValidType was not rejecting constraints in a kind signature forall (a :: Eq b => blah). blah2 That led to further errors when we then do an ambiguity check. So I make checkValidType reject it more aggressively. * I killed off quantifyConDecl, instead calling kindGeneralize directly. * I fixed an outright bug in tyCoVarsOfImplic, where we were not colleting the tyvar of the kind of the skolems * Renamed ClsInstInfo to AssocInstInfo, and made it into its own data type * Some fiddling around with pretty-printing of family instances which was trickier than I thought. I wanted wildcards to print as plain "_" in user messages, although they each need a unique identity in the CoAxBranch. Some other oddments * Refactoring around the trace messages from reportUnsolved. * A bit of extra tc-tracing in TcHsSyn.commitFlexi This patch fixes a raft of bugs, and includes tests for them. * #14887 * #15740 * #15764 * #15789 * #15804 * #15817 * #15870 * #15874 * #15881
* [TTG: Handling Source Locations] Foundation and PatShayan-Najd2018-11-243-502/+566
| | | | | | | | | | | | | | | | | | This patch removes the ping-pong style from HsPat (only, for now), using the plan laid out at https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow/HandlingSourceLocations (solution A). - the class `HasSrcSpan`, and its functions (e.g., `cL` and `dL`), are introduced - some instances of `HasSrcSpan` are introduced - some constructors `L` are replaced with `cL` - some patterns `L` are replaced with `dL->L` view pattern - some type annotation are necessarily updated (e.g., `Pat p` --> `Pat (GhcPass p)`) Phab diff: D5036 Trac Issues #15495 Updates haddock submodule
* Revert "'DynFlag'-free version of 'mkParserFlags'"Ben Gamari2018-11-233-83/+55
| | | | This reverts commit 5aa29231ab7603537284eff5e4caff3a73dba6d2.
* Revert "Simplify 'ExtBits' in the lexer"Ben Gamari2018-11-233-238/+306
| | | | This reverts commit d2fbc33c4ff3074126ab71654af8bbf8a46e4e11.
* Fix unused-import warningsDavid Eichmann2018-11-221-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes a fairly long-standing bug (dating back to 2015) in RdrName.bestImport, namely commit 9376249b6b78610db055a10d05f6592d6bbbea2f Author: Simon Peyton Jones <simonpj@microsoft.com> Date: Wed Oct 28 17:16:55 2015 +0000 Fix unused-import stuff in a better way In that patch got the sense of the comparison back to front, and thereby failed to implement the unused-import rules described in Note [Choosing the best import declaration] in RdrName This led to Trac #13064 and #15393 Fixing this bug revealed a bunch of unused imports in libraries; the ones in the GHC repo are part of this commit. The two important changes are * Fix the bug in bestImport * Modified the rules by adding (a) in Note [Choosing the best import declaration] in RdrName Reason: the previosu rules made Trac #5211 go bad again. And the new rule (a) makes sense to me. In unravalling this I also ended up doing a few other things * Refactor RnNames.ImportDeclUsage to use a [GlobalRdrElt] for the things that are used, rather than [AvailInfo]. This is simpler and more direct. * Rename greParentName to greParent_maybe, to follow GHC naming conventions * Delete dead code RdrName.greUsedRdrName Bumps a few submodules. Reviewers: hvr, goldfire, bgamari, simonmar, jrtc27 Subscribers: rwbarton, carter Differential Revision: https://phabricator.haskell.org/D5312
* Simplify 'ExtBits' in the lexerAlec Theriault2018-11-223-306/+238
| | | | | | | | | | | | | | | | | | The main change is to export 'ExtBits' instead of defining/exporting a bunch of boilerplate functions that test for a particular 'ExtBits'. In the process, I also * cleaned up an unneeded special case for 'ITstatic' * made 'UsePosPrags' another variant of 'ExtBits' * made the logic in 'reservedSymsFM' match that of 'reservedWordsFM' Test Plan: make test Reviewers: bgamari, alanz Subscribers: sjakobi, rwbarton, mpickering, carter Differential Revision: https://phabricator.haskell.org/D5332
* 'DynFlag'-free version of 'mkParserFlags'Alec Theriault2018-11-223-55/+83
| | | | | | | | | | | | | | | | | | | | | | | | | Obtaining a `DynFlags` is difficult, making using the lexer/parser for pure parsing/lexing unreasonably difficult, even with `mkPStatePure`. This is despite the fact that we only really need * language extension flags * warning flags * a handful of boolean options The new `mkParserFlags'` function makes is easier to directly construct a `ParserFlags`. Furthermore, since `pExtsBitmap` is just a footgun, I've gone ahead and made `ParserFlags` an abstract type. Reviewers: bgamari, alanz, sjakobi Reviewed By: bgamari, sjakobi Subscribers: mpickering, sjakobi, rwbarton, carter GHC Trac Issues: #11301 Differential Revision: https://phabricator.haskell.org/D5269
* Remove warnings-silencing flags for code generated by AlexSimon Jakobi2018-11-221-45/+9
| | | | | | | | | | | | | | | | | | Current versions of Alex don't seem to produce as many warnings any more. In order to silence a warning and to avoid overlong lines, I've taken the liberty of refactoring 'tok_num'. Test Plan: ./validate Reviewers: bgamari, simonmar Reviewed By: simonmar Subscribers: erikd, rwbarton, carter Differential Revision: https://phabricator.haskell.org/D5319
* Smarter HsType pretty-print for promoted dataconsSimon Peyton Jones2018-11-151-3/+3
| | | | | | | | | | | | | | | | | | | | | Fix Trac #15898, by being smarter about when to print a space before a promoted data constructor, in a HsType. I had to implement a mildly tiresome function HsType.lhsTypeHasLeadingPromotionQuote It has multiple cases, of course, but it's very simple. The patch improves the error-message output in a bunch of cases, and (to my surprise) actually fixes a bug in the output of T14343 (Trac #14343), thus - In the expression: _ :: Proxy '('( 'True, 'False), 'False) + In the expression: _ :: Proxy '( '( 'True, 'False), 'False) I discovered that there were two copies of the PromotionFlag type (a boolean, with helpfully named data cons), one in IfaceType and one in HsType. So I combined into one, PromotionFlag, and moved it to BasicTypes. That's why quite a few files are touched, but it's all routine.
* Lower precedence for {-# UNPACK #-}Vladislav Zavialov2018-11-011-35/+85
| | | | | | | | | | Test Plan: Validate Reviewers: goldfire, bgamari Subscribers: osa1, mpickering, rwbarton, carter Differential Revision: https://phabricator.haskell.org/D5221
* More explicit foralls (GHC Proposal 0007)Matthew Yacavone2018-10-272-63/+167
| | | | | | | | | | | | | | | | | | | | | | | | | | | Allow the user to explicitly bind type/kind variables in type and data family instances (including associated instances), closed type family equations, and RULES pragmas. Follows the specification of GHC Proposal 0007, also fixes #2600. Advised by Richard Eisenberg. This modifies the Template Haskell AST -- old code may break! Other Changes: - convert HsRule to a record - make rnHsSigWcType more general - add repMaybe to DsMeta Includes submodule update for Haddock. Test Plan: validate Reviewers: goldfire, bgamari, alanz Subscribers: simonpj, RyanGlScott, goldfire, rwbarton, thomie, mpickering, carter GHC Trac Issues: #2600, #14268 Differential Revision: https://phabricator.haskell.org/D4894
* Fix #15781 by using ktypedocs on type synonym RHSesRyan Scott2018-10-241-3/+8
| | | | | | | | | | | | | | | | | | | | | | Summary: This is a follow-up to D5173, which permitted unparenthesized kind signatures in certain places. One place that appeared to be overlooked was the right-hand sides of type synonyms, which this patch addresses by introducing a `ktypedoc` parser production (which is to `ctypdoc` as `ktype` is to `ctype`) and using it in the right place. Test Plan: make test TEST="KindSigs T15781" Reviewers: harpocrates, bgamari Reviewed By: harpocrates Subscribers: rwbarton, mpickering, carter GHC Trac Issues: #15781 Differential Revision: https://phabricator.haskell.org/D5245
* Trigger multiline mode in GHCi on '\case' (#13087)Alec Theriault2018-10-241-0/+1
| | | | | | | | | | | | | | | | | | | Summary: In ALR, 'ITlcase' should expect an opening curly. This is probably a forgotten edge case in ALR, since `maybe_layout` (which handles the non-ALR layout) already deals with the 'ITlcase' token properly. Test Plan: make TEST=T10453 && make TEST=T13087 Reviewers: bgamari, RyanGlScott Reviewed By: RyanGlScott Subscribers: RyanGlScott, rwbarton, carter GHC Trac Issues: #10453, #13087 Differential Revision: https://phabricator.haskell.org/D5236
* Surprising error message with bang patternSasa Bogicevic2018-10-151-3/+24
| | | | | | | | | | | | Reviewers: bgamari, alanz Reviewed By: bgamari Subscribers: sgraf, mpickering, rwbarton, thomie, carter GHC Trac Issues: #13600 Differential Revision: https://phabricator.haskell.org/D5040
* Include -fwarn-star-is-type in -WcompatVladislav Zavialov2018-10-121-1/+2
| | | | | | | | | | | | | | | | | According to the deprecation schedule in the accepted proposal, the first step is to include `-fwarn-star-is-type` in `-Wcompat`. Test Plan: Validate Reviewers: bgamari Reviewed By: bgamari Subscribers: rwbarton, carter GHC Trac Issues: #15476 Differential Revision: https://phabricator.haskell.org/D5044
* Set `infixr -1 ->`Alec Theriault2018-10-042-8/+18
| | | | | | | | | | | | | | | | | | | | | | | | | Summary: This simply makes explicit what is already the case. Due to special treatment in the parser, `->` has the lowest fixity. This patch propagates that information to: * GHCi, where `:info ->` now return the right fixity * TH, where `reifyFixity` returns the right fixity * the generated sources for `GHC.Prim` See #15235. Test Plan: make test Reviewers: bgamari, alanz, RyanGlScott Reviewed By: RyanGlScott Subscribers: int-index, RyanGlScott, rwbarton, mpickering, carter GHC Trac Issues: #15235 Differential Revision: https://phabricator.haskell.org/D5199
* Allow (unparenthesized) kind signaturesAlec Theriault2018-10-042-32/+52
| | | | | | | | | | | | | | | | Summary: This allows for things like `[t :: MyKind]`, `(a :: k, b)`, and so on. Test Plan: make TEST=T11622 && make TEST=T8708 Reviewers: RyanGlScott, bgamari, simonpj, goldfire, alanz Reviewed By: RyanGlScott, simonpj Subscribers: alanz, simonpj, rwbarton, mpickering, carter GHC Trac Issues: #11622, #8708 Differential Revision: https://phabricator.haskell.org/D5173
* Improve generated `GHC.Prim` docsAlec Theriault2018-10-041-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: * Extended `genprimcode` to generate Haddock-compatible deprecations, as well as displaying information about which functions are LLVM-only and which functions can fail with an unchecked exception. * Ported existing deprecations to the new format, and also added a deprecation on `par#` (see Trac #15227). * Emit an error on fixity/deprecation of builtins, unless we are processing the module in which that name is defined (see Trac #15233). That means the following is no longer accepted (outside of `GHC.Types`): ``` infixr 7 : {-# DEPRECATED (:) "cons is deprecated" #-} ``` * Generate `data (->) a b` with docs and fixity in `GHC.Prim`. This means: GHC can now parse `data (->) a b` and `infixr 0 ->` (only in `GHC.Prim`) and `genprimcode` can digest `primtype (->) a b` (See Trac #4861) as well as some misc fixes along the way. Reviewers: bgamari, RyanGlScott Reviewed By: RyanGlScott Subscribers: RyanGlScott, rwbarton, mpickering, carter GHC Trac Issues: #15227, #15233, #4861 Differential Revision: https://phabricator.haskell.org/D5167
* Parse the (!) type operator and allow type operators in existential contextVladislav Zavialov2018-10-043-227/+515
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: Improve the way `(!)`, `(~)`, and other type operators are handled in the parser, fixing two issues at once: 1. `(!)` can now be used as a type operator that respects fixity and precedence (#15457) 2. Existential context of a data constructor no longer needs parentheses (#15675) In addition to that, with this patch it is now trivial to adjust precedence of the `{-# UNPACK #-}` pragma, as suggested in https://ghc.haskell.org/trac/ghc/ticket/14761#comment:7 There was a small change to API Annotations. Before this patch, `(~)` was a strange special case that produced an annotation unlike any other type operator. After this patch, when `(~)` or `(!)` are used to specify strictness they produce AnnTilde and AnnBang annotations respectively, and when they are used as type operators, they produce no annotations. Test Plan: Validate Reviewers: simonpj, bgamari, alanz, RyanGlScott Reviewed By: RyanGlScott Subscribers: RyanGlScott, rwbarton, mpickering, carter GHC Trac Issues: #15457, #15675 Differential Revision: https://phabricator.haskell.org/D5180
* Don't show constraint tuples in errors (#14907)Alec Theriault2018-09-251-3/+19
| | | | | | | | | | | | | | | | | | | | | Summary: This means that 'GHC.Classes.(%,%)' is no longer mentioned in error messages for things like class (a,b,c) -- outside of 'GHC.Classes' class (a,Bool) Test Plan: make TEST=T14907a && make TEST=T14907b Reviewers: RyanGlScott, bgamari Reviewed By: RyanGlScott Subscribers: rwbarton, carter GHC Trac Issues: #14907 Differential Revision: https://phabricator.haskell.org/D5172
* Fix #line pragmas in nested commentsBen Sklaroff2018-08-211-44/+122
| | | | | | | | | | | | | | | | | | | | | When parsing a nested comment or nested doc comment in the lexer, if we see a line starting with '#' we attempt to parse a #line pragma. This fixes how ghc handles output of the C preproccesor (-cpp flag) when the original source has C comments or pragmas inside haskell comments. Updates haddock submodule. Test Plan: ./validate Reviewers: bgamari Reviewed By: bgamari Subscribers: rwbarton, thomie, carter GHC Trac Issues: #314 Differential Revision: https://phabricator.haskell.org/D4934
* Add a solveEqualities to tcClassDecl1Simon Peyton Jones2018-08-211-2/+1
| | | | | | | | | | | | | | Trac #15505 showed that, when we have a type error, we could have an unfilled-in coercion hole. We don't want an assertion error in that case. The underlying cause is that tcClassDecl1 should call solveEqualities to fully solve all top-level equalities (or fail in the attempt). I also refactored the ClassDecl case for tcTyClDecl1 into a new function tcClassDecl1. That makes it symmetrical with the others.
* Refactor (~) to reduce the suerpclass stackSimon Peyton Jones2018-07-272-4/+3
| | | | | | | | | | | | | | | | | | | | | | | The constraint (~) used to be (effectively): class a ~~ b => (a :: k) ~ (b :: k) but, with this patch, it is now defined uniformly with (~~) and Coercible like this: class a ~# b => (a :: k) ~ (b :: k) Result: * One less superclass selection when goinng from (~) to (~#) Better for compile time and better for debugging with -ddump-simpl * The code for (~), (~~), and Coercible looks uniform, and appears together, e.g. in TysWiredIn and ClsInst.matchGlobalInst. Previously the code for (~) was different, and unique. Not only is this simpler, but it also makes the compiler a bit faster; T12227: 9% less allocation T12545: 7% less allocation This patch fixes Trac #15421
* Do not imply NoStarIsType by TypeOperators/TypeInTypeVladislav Zavialov2018-07-162-8/+17
| | | | | | | | | | | | | | | | | | | | | | Implementation of the "Embrace TypeInType" proposal was done according to the spec, which specified that TypeOperators must imply NoStarIsType. This implication was meant to prevent breakage and to be removed in 2 releases. However, compiling head.hackage has shown that this implication only magnified the breakage, so there is no reason to have it in the first place. To remain in compliance with the three-release policy, we add a workaround to define the (*) type operator even when -XStarIsType is on. Test Plan: ./validate Reviewers: bgamari, RyanGlScott, goldfire, phadej, hvr Reviewed By: bgamari, RyanGlScott Subscribers: harpocrates, rwbarton, thomie, carter Differential Revision: https://phabricator.haskell.org/D4865
* Fix mkGadtDecl does not set con_forall correctlyAlan Zimmerman2018-06-291-1/+1
| | | | | | | | | | | | A GADT declaration surrounded in parens does not det the con_forall field correctly. e.g. data MaybeDefault v where TestParens :: (forall v . (Eq v) => MaybeDefault v) Closes #15323
* API Annotations when parsing typappAlan Zimmerman2018-06-261-2/+2
| | | | | | | Make sure the original annotations are still accessible for a promoted type. Closes #15303
* Tweak API Annotations for ConDeclGADTAlan Zimmerman2018-06-242-7/+7
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* Allow :info for (~) in GHCiRyan Scott2018-06-201-1/+3
| | | | | | | | | | | | | | | | | | | `(~)` is not an identifier according to GHC's parser, which is why GHCi's `:info` command wouldn't work on it. To rectify this, we apply the same fix that was put in place for `(->)`: add `(~)` to GHC's `identifier` parser production. Test Plan: make test TEST=T10059 Reviewers: bgamari Reviewed By: bgamari Subscribers: rwbarton, thomie, mpickering, carter GHC Trac Issues: #10059 Differential Revision: https://phabricator.haskell.org/D4877
* Fix API Annotations for GADT constructorsAlan Zimmerman2018-06-192-23/+30
| | | | | | | | | | | | | | | | | | | Summary: This patch completes the work for #14529 by making sure that all API Annotations end up attached to a SrcSpan that appears in the final ParsedSource. Updates Haddock submodule Test Plan: ./validate Reviewers: goldfire, bgamari Subscribers: rwbarton, thomie, mpickering, carter GHC Trac Issues: #14529 Differential Revision: https://phabricator.haskell.org/D4867
* No Unicode in Parser.yVladislav Zavialov2018-06-151-1/+1
| | | | | | | | | | | | | | | | | Unicode characters in Parser.y cause build failures on systems where the locale does not support Unicode. See https://mail.haskell.org/pipermail/ghc-devs/2018-June/015874.html Test Plan: ./validate Reviewers: bgamari Reviewed By: bgamari Subscribers: rwbarton, thomie, mpickering, carter Differential Revision: https://phabricator.haskell.org/D4850
* Embrace -XTypeInType, add -XStarIsTypeVladislav Zavialov2018-06-143-159/+223
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: Implement the "Embrace Type :: Type" GHC proposal, .../ghc-proposals/blob/master/proposals/0020-no-type-in-type.rst GHC 8.0 included a major change to GHC's type system: the Type :: Type axiom. Though casual users were protected from this by hiding its features behind the -XTypeInType extension, all programs written in GHC 8+ have the axiom behind the scenes. In order to preserve backward compatibility, various legacy features were left unchanged. For example, with -XDataKinds but not -XTypeInType, GADTs could not be used in types. Now these restrictions are lifted and -XTypeInType becomes a redundant flag that will be eventually deprecated. * Incorporate the features currently in -XTypeInType into the -XPolyKinds and -XDataKinds extensions. * Introduce a new extension -XStarIsType to control how to parse * in code and whether to print it in error messages. Test Plan: Validate Reviewers: goldfire, hvr, bgamari, alanz, simonpj Reviewed By: goldfire, simonpj Subscribers: rwbarton, thomie, mpickering, carter GHC Trac Issues: #15195 Differential Revision: https://phabricator.haskell.org/D4748
* Allow Haddock comments before function arguments.Iavor Diatchki2018-06-071-0/+9
| | | | | | | | | | | | | | | Currently, documentation strings on function arguments has to be written after the argument (i.e., using `{-^ -}` comments). This patch allows us to use `{-| -}` comments to put the comment string before an argument. The same works for the results of functions. Reviewers: bgamari Reviewed By: bgamari Subscribers: rwbarton, thomie, mpickering, carter Differential Revision: https://phabricator.haskell.org/D4767
* Move 'HsBangTy' out in constructor argumentsAlec Theriault2018-06-071-2/+27
| | | | | | | | | | | | | | | | | | | | When run with -haddock, a constructor argument can have both a a strictness/unpackedness annotation and a docstring. The parser binds 'HsBangTy' more tightly than 'HsDocTy', yet for constructor arguments we really need the 'HsBangTy' on the outside. This commit does this shuffling in the 'mkConDeclH98' and 'mkGadtDecl' smart constructors. Test Plan: haddockA038, haddockC038 Reviewers: bgamari, dfeuer Reviewed By: bgamari Subscribers: dfeuer, rwbarton, thomie, carter Differential Revision: https://phabricator.haskell.org/D4727
* Introduce DerivingViaRyan Scott2018-06-043-32/+60
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This implements the `DerivingVia` proposal put forth in https://github.com/ghc-proposals/ghc-proposals/pull/120. This introduces the `DerivingVia` deriving strategy. This is a generalization of `GeneralizedNewtypeDeriving` that permits the user to specify the type to `coerce` from. The major change in this patch is the introduction of the `ViaStrategy` constructor to `DerivStrategy`, which takes a type as a field. As a result, `DerivStrategy` is no longer a simple enumeration type, but rather something that must be renamed and typechecked. The process by which this is done is explained more thoroughly in section 3 of this paper ( https://www.kosmikus.org/DerivingVia/deriving-via-paper.pdf ), although I have inlined the relevant parts into Notes where possible. There are some knock-on changes as well. I took the opportunity to do some refactoring of code in `TcDeriv`, especially the `mkNewTypeEqn` function, since it was bundling all of the logic for (1) deriving instances for newtypes and (2) `GeneralizedNewtypeDeriving` into one huge broth. `DerivingVia` reuses much of part (2), so that was factored out as much as possible. Bumps the Haddock submodule. Test Plan: ./validate Reviewers: simonpj, bgamari, goldfire, alanz Subscribers: alanz, goldfire, rwbarton, thomie, mpickering, carter GHC Trac Issues: #15178 Differential Revision: https://phabricator.haskell.org/D4684
* Remove ~# from surface syntaxDavid Feuer2018-06-023-7/+1
| | | | | | | | | | | | | | | | | | | For some reason, it seems that the `ConstraintKinds` commit introduced `~#` into Haskell syntax, in a pretty broken manner. Unless and until we have an actual story for unboxed equality, it doesn't make sense to expose it. Moreover, the way it was donet was wrong enough and small enough that it will probably be easier to start over if we do that. Yank it out. Reviewers: bgamari, RyanGlScott Reviewed By: RyanGlScott Subscribers: RyanGlScott, rwbarton, thomie, mpickering, carter GHC Trac Issues: #15209 Differential Revision: https://phabricator.haskell.org/D4763
* vectorise: Put it out of its miseryBen Gamari2018-06-023-87/+9
| | | | | | | | | | | | | | | | | | | | | Poor DPH and its vectoriser have long been languishing; sadly it seems there is little chance that the effort will be rekindled. Every few years we discuss what to do with this mass of code and at least once we have agreed that it should be archived on a branch and removed from `master`. Here we do just that, eliminating heaps of dead code in the process. Here we drop the ParallelArrays extension, the vectoriser, and the `vector` and `primitive` submodules. Test Plan: Validate Reviewers: simonpj, simonmar, hvr, goldfire, alanz Reviewed By: simonmar Subscribers: goldfire, rwbarton, thomie, mpickering, carter Differential Revision: https://phabricator.haskell.org/D4761
* Make HsDocString a newtype of ByteStringSimon Jakobi2018-05-301-5/+5
| | | | | | | | | | | | | | | | | Docstrings don't profit from FastString's interning, so we switch to a different type that doesn't incur this overhead. Updates the haddock submodule. Reviewers: alexbiehl, bgamari Reviewed By: alexbiehl, bgamari Subscribers: rwbarton, thomie, mpickering, carter GHC Trac Issues: #15157 Differential Revision: https://phabricator.haskell.org/D4743
* Refactor LitStringSylvain Henry2018-05-132-22/+0
| | | | | | | | | | | | | | | | | | Refactor LitString so that the string length is computed at most once and then stored. Also remove strlen and memcmp wrappers (it seems like they were a workaround for a very old GCC when using -fvia-C). Bumps haddock submodule. Reviewers: bgamari, dfeuer, nickkuk Reviewed By: bgamari, nickkuk Subscribers: nickkuk, dfeuer, thomie, carter Differential Revision: https://phabricator.haskell.org/D4630
* Use correct source spans for EmptyCaseRyan Scott2018-05-121-2/+3
| | | | | | | | | | | | | | | | | | | Summary: The parser's calculation of source spans for `EmptyCase` expressions was a bit off, leading to some wonky-looking error messages. Easily fixed with some uses of `comb3` and `sLL`. Test Plan: make test TEST=T15139 Reviewers: bgamari, simonpj Reviewed By: simonpj Subscribers: simonpj, rwbarton, thomie, mpickering, carter GHC Trac Issues: #15139 Differential Revision: https://phabricator.haskell.org/D4685
* TTG : complete for balance of hsSyn ASTAlan Zimmerman2018-04-272-156/+181
| | | | | | | | | | | | | | | | | | 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
* Better error message for empty character literal, for Trac #13450.HE, Tao2018-04-191-10/+48
| | | | | | | | | | | | | | | | | For empty character literal, the `''`, report error message properly rather than just throw a "parser error" with wrong error location. Test Plan: make test TEST="T13450 T13450TH" Reviewers: goldfire, bgamari Reviewed By: bgamari Subscribers: thomie, mpickering, carter GHC Trac Issues: #13450 Differential Revision: https://phabricator.haskell.org/D4594
* TTG for HsBinds and Data instances Plan BAlan Zimmerman2018-04-132-27/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Revert "Fix #14838 by marking TH-spliced code as FromSource"Ben Gamari2018-04-101-5/+5
| | | | | | | | | | | | | | | | This reverts commit ffb2738f86c4e4c3f0eaacf0a95d7326fdd2e383. Due to #14987. Reviewers: goldfire, RyanGlScott Reviewed By: RyanGlScott Subscribers: RyanGlScott, thomie, carter GHC Trac Issues: #14987, #14838 Differential Revision: https://phabricator.haskell.org/D4545
* Restore Trees That Grow reverted commitsAlan Zimmerman2018-04-092-264/+266
| | | | | | | | | | | | | | | | | | The following commits were reverted prior to the release of GHC 8.4.1, because the time to derive Data instances was too long [1]. 438dd1cbba13d35f3452b4dcef3f94ce9a216905 Phab:D4147 e3ec2e7ae94524ebd111963faf34b84d942265b4 Phab:D4177 47ad6578ea460999b53eb4293c3a3b3017a56d65 Phab:D4186 The work is continuing, as the minimum bootstrap compiler is now GHC 8.2.1, and this allows Plan B[2] for instances to be used. This will land in a following commit. Updates Haddock submodule [1] https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow/Instances [2] https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow/Instances#PLANB
* Remove HasSourceText and SourceTextX classesAlan Zimmerman2018-04-071-16/+13
| | | | | | | | Updates haddock submodule to match. Test Plan : Validate Differential Revision: https://phabricator.haskell.org/D4199
* Allow PartialTypeSignatures in standalone deriving contextsRyan Scott2018-03-231-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Slighly improve infix con app pattern errorsÖmer Sinan Ağacan2018-03-141-6/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Given this program: main = do f $ do a <- return 3 c <- do return 5 GHC previously gave this error message: Main.hs:2:7: error: Parse error in pattern: do a <- return 3 c Possibly caused by a missing 'do'? | 2 | f $ do | ^^... What happened is GHC considered the whole `f $ do a <- return 3 c` as a pattern. When parsed as an expression it becomes an infix application of `($)`, and GHC checks left and right hand sides before checking if `($)` is a valid infix constructor name, and shows the first error it got. If instead we first check if the infix op is valid in pattern context, the error message becomes much clearer: Main.hs:2:3: error: Parse error in pattern: f $ do a <- return 3 c Possibly caused by a missing 'do'? | 2 | f $ do | ^^^^^^... This may not entirely fix #11188 but I think it's an improvement. Reviewers: bgamari Reviewed By: bgamari Subscribers: rwbarton, thomie, carter GHC Trac Issues: #11188 Differential Revision: https://phabricator.haskell.org/D4497
* Fix #14838 by marking TH-spliced code as FromSourceRyan Scott2018-03-021-5/+5
| | | | | | | | | | | | | | | | | | | | | | 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
* Raise parse error for `data T where`.HE, Tao2018-02-132-8/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | Empty GADTs data declarations can't be identified in type checker. This patch adds additional checks in parser and raise a parse error when encounter empty GADTs declarations but extension `GADTs` is not enabled. Only empty declarations are checked in parser to avoid affecting existing error messages related to missing GADTs extension. This patch should fix issue 8258. Signed-off-by: HE, Tao <sighingnow@gmail.com> Test Plan: make test TEST="T8258 T8258NoGADTs" Reviewers: bgamari, mpickering, alanz, RyanGlScott Reviewed By: bgamari, RyanGlScott Subscribers: adamse, RyanGlScott, rwbarton, thomie, mpickering, carter GHC Trac Issues: #8258 Differential Revision: https://phabricator.haskell.org/D4350
* UnboxedTuples can't be used as constraintsHE, Tao2018-01-311-1/+12
| | | | | | | | | | | | | | | | Fixes #14740. Test Plan: make test TEST="14740" Reviewers: bgamari, simonpj Reviewed By: simonpj Subscribers: simonpj, rwbarton, thomie, carter GHC Trac Issues: #14740 Differential Revision: https://phabricator.haskell.org/D4359
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