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* Update Trac ticket URLs to point to GitLabRyan Scott2019-03-157-20/+20
| | | | | This moves all URL references to Trac tickets to their corresponding GitLab counterparts.
* Stop inferring over-polymorphic kindsSimon Peyton Jones2019-03-091-20/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | Before this patch GHC was trying to be too clever (Trac #16344); it succeeded in kind-checking this polymorphic-recursive declaration data T ka (a::ka) b = MkT (T Type Int Bool) (T (Type -> Type) Maybe Bool) As Note [No polymorphic recursion] discusses, the "solution" was horribly fragile. So this patch deletes the key lines in TcHsType, and a wodge of supporting stuff in the renamer. There were two regressions, both the same: a closed type family decl like this (T12785b) does not have a CUSK: type family Payload (n :: Peano) (s :: HTree n x) where Payload Z (Point a) = a Payload (S n) (a `Branch` stru) = a To kind-check the equations we need a dependent kind for Payload, and we don't get that any more. Solution: make it a CUSK by giving the result kind -- probably a good thing anyway. The other case (T12442) was very similar: a close type family declaration without a CUSK.
* TH: support raw bytes literals (#14741)Sylvain Henry2019-03-081-0/+8
| | | | | | | | | | | | | | | | | | | GHC represents String literals as ByteString internally for efficiency reasons. However, until now it wasn't possible to efficiently create large string literals with TH (e.g. to embed a file in a binary, cf #14741): TH code had to unpack the bytes into a [Word8] that GHC then had to re-pack into a ByteString. This patch adds the possibility to efficiently create a "string" literal from raw bytes. We get the following compile times for different sizes of TH created literals: || Size || Before || After || Gain || || 30K || 2.307s || 2.299 || 0% || || 3M || 3.073s || 2.400s || 21% || || 30M || 8.517s || 3.390s || 60% || Ticket #14741 can be fixed if the original code uses this new TH feature.
* Be more careful when naming TyCon bindersSimon Peyton Jones2019-03-051-5/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes two rather gnarly test cases: * Trac #16342 (mutual recursion) See Note [Tricky scoping in generaliseTcTyCon] * Trac #16221 (shadowing) See Note [Unification variables need fresh Names] The main changes are: * Substantial reworking of TcTyClsDecls.generaliseTcTyCon This is the big change, and involves the rather tricky function TcHsSyn.zonkRecTyVarBndrs. See Note [Inferring kinds for type declarations] and Note [Tricky scoping in generaliseTcTyCon] for the details. * bindExplicitTKBndrs_Tv and bindImplicitTKBndrs_Tv both now allocate /freshly-named/ unification variables. Indeed, more generally, unification variables are always fresh; see Note [Unification variables need fresh Names] in TcMType * Clarify the role of tcTyConScopedTyVars. See Note [Scoped tyvars in a TcTyCon] in TyCon As usual, this dragged in some more refactoring: * Renamed TcMType.zonkTyCoVarBndr to zonkAndSkolemise * I renamed checkValidTelescope to checkTyConTelescope; it's only used on TyCons, and indeed takes a TyCon as argument. * I folded the slightly-mysterious reportFloatingKvs into checkTyConTelescope. (Previously all its calls immediately followed a call to checkTyConTelescope.) It makes much more sense there. * I inlined some called-once functions to simplify checkValidTyFamEqn. It's less spaghetti-like now. * This patch also fixes Trac #16251. I'm not quite sure why #16251 went wrong in the first place, nor how this patch fixes it, but hey, it's good, and life is short.
* Visible dependent quantificationRyan Scott2019-03-014-32/+139
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This implements GHC proposal 35 (https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0035-forall-arrow.rst) by adding the ability to write kinds with visible dependent quantification (VDQ). Most of the work for supporting VDQ was actually done _before_ this patch. That is, GHC has been able to reason about kinds with VDQ for some time, but it lacked the ability to let programmers directly write these kinds in the source syntax. This patch is primarly about exposing this ability, by: * Changing `HsForAllTy` to add an additional field of type `ForallVisFlag` to distinguish between invisible `forall`s (i.e, with dots) and visible `forall`s (i.e., with arrows) * Changing `Parser.y` accordingly The rest of the patch mostly concerns adding validity checking to ensure that VDQ is never used in the type of a term (as permitting this would require full-spectrum dependent types). This is accomplished by: * Adding a `vdqAllowed` predicate to `TcValidity`. * Introducing `splitLHsSigmaTyInvis`, a variant of `splitLHsSigmaTy` that only splits invisible `forall`s. This function is used in certain places (e.g., in instance declarations) to ensure that GHC doesn't try to split visible `forall`s (e.g., if it tried splitting `instance forall a -> Show (Blah a)`, then GHC would mistakenly allow that declaration!) This also updates Template Haskell by introducing a new `ForallVisT` constructor to `Type`. Fixes #16326. Also fixes #15658 by documenting this feature in the users' guide.
* Expression/command ambiguity resolutionVladislav Zavialov2019-02-232-50/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch removes 'HsArrApp' and 'HsArrForm' from 'HsExpr' by introducing a new ambiguity resolution system in the parser. Problem: there are places in the grammar where we do not know whether we are parsing an expression or a command: proc x -> do { (stuff) -< x } -- 'stuff' is an expression proc x -> do { (stuff) } -- 'stuff' is a command Until we encounter arrow syntax (-<) we don't know whether to parse 'stuff' as an expression or a command. The old solution was to parse as HsExpr always, and rejig later: checkCommand :: LHsExpr GhcPs -> P (LHsCmd GhcPs) This meant polluting 'HsExpr' with command-related constructors. In other words, limitations of the parser were affecting the AST, and all other code (the renamer, the typechecker) had to deal with these extra constructors by panicking. We fix this abstraction leak by parsing into an intermediate representation, 'ExpCmd': data ExpCmdG b where ExpG :: ExpCmdG HsExpr CmdG :: ExpCmdG HsCmd type ExpCmd = forall b. ExpCmdG b -> PV (Located (b GhcPs)) checkExp :: ExpCmd -> PV (LHsExpr GhcPs) checkCmd :: ExpCmd -> PV (LHsCmd GhcPs) checkExp f = f ExpG -- interpret as an expression checkCmd f = f CmdG -- interpret as a command See Note [Ambiguous syntactic categories] for details. Now the intricacies of parsing have no effect on the hsSyn AST when it comes to the expression/command ambiguity. Future work: apply the same principles to the expression/pattern ambiguity.
* Add AnonArgFlag to FunTySimon Peyton Jones2019-02-231-7/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The big payload of this patch is: Add an AnonArgFlag to the FunTy constructor of Type, so that (FunTy VisArg t1 t2) means (t1 -> t2) (FunTy InvisArg t1 t2) means (t1 => t2) The big payoff is that we have a simple, local test to make when decomposing a type, leading to many fewer calls to isPredTy. To me the code seems a lot tidier, and probably more efficient (isPredTy has to take the kind of the type). See Note [Function types] in TyCoRep. There are lots of consequences * I made FunTy into a record, so that it'll be easier when we add a linearity field, something that is coming down the road. * Lots of code gets touched in a routine way, simply because it pattern matches on FunTy. * I wanted to make a pattern synonym for (FunTy2 arg res), which picks out just the argument and result type from the record. But alas the pattern-match overlap checker has a heart attack, and either reports false positives, or takes too long. In the end I gave up on pattern synonyms. There's some commented-out code in TyCoRep that shows what I wanted to do. * Much more clarity about predicate types, constraint types and (in particular) equality constraints in kinds. See TyCoRep Note [Types for coercions, predicates, and evidence] and Note [Constraints in kinds]. This made me realise that we need an AnonArgFlag on AnonTCB in a TyConBinder, something that was really plain wrong before. See TyCon Note [AnonTCB InivsArg] * When building function types we must know whether we need VisArg (mkVisFunTy) or InvisArg (mkInvisFunTy). This turned out to be pretty easy in practice. * Pretty-printing of types, esp in IfaceType, gets tidier, because we were already recording the (->) vs (=>) distinction in an ad-hoc way. Death to IfaceFunTy. * mkLamType needs to keep track of whether it is building (t1 -> t2) or (t1 => t2). See Type Note [mkLamType: dictionary arguments] Other minor stuff * Some tidy-up in validity checking involving constraints; Trac #16263
* Make a smart mkAppTyMSimon Peyton Jones2019-02-142-12/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch finally delivers on Trac #15952. Specifically * Completely remove Note [The tcType invariant], along with its complicated consequences (IT1-IT6). * Replace Note [The well-kinded type invariant] with: Note [The Purely Kinded Type Invariant (PKTI)] * Instead, establish the (PKTI) in TcHsType.tcInferApps, by using a new function mkAppTyM when building a type application. See Note [mkAppTyM]. * As a result we can remove the delicate mkNakedXX functions entirely. Specifically, mkNakedCastTy retained lots of extremly delicate Refl coercions which just cluttered everything up, and(worse) were very vulnerable to being silently eliminated by (say) substTy. This led to a succession of bug reports. The result is noticeably simpler to explain, simpler to code, and Richard and I are much more confident that it is correct. It does not actually fix any bugs, but it brings us closer. E.g. I hoped it'd fix #15918 and #15799, but it doesn't quite do so. However, it makes it much easier to fix. I also did a raft of other minor refactorings: * Use tcTypeKind consistently in the type checker * Rename tcInstTyBinders to tcInvisibleTyBinders, and refactor it a bit * Refactor tcEqType, pickyEqType, tcEqTypeVis Simpler, probably more efficient. * Make zonkTcType zonk TcTyCons, at least if they have any free unification variables -- see zonk_tc_tycon in TcMType.zonkTcTypeMapper. Not zonking these TcTyCons was actually a bug before. * Simplify try_to_reduce_no_cache in TcFlatten (a lot) * Combine checkExpectedKind and checkExpectedKindX. And then combine the invisible-binder instantation code Much simpler now. * Fix a little bug in TcMType.skolemiseQuantifiedTyVar. I'm not sure how I came across this originally. * Fix a little bug in TyCoRep.isUnliftedRuntimeRep (the ASSERT was over-zealous). Again I'm not certain how I encountered this. * Add a missing solveLocalEqualities in TcHsType.tcHsPartialSigType. I came across this when trying to get level numbers right.
* Implement -Wredundant-record-wildcards and -Wunused-record-wildcardsMatthew Pickering2019-02-142-29/+48
| | | | | | | | | -Wredundant-record-wildcards warns when a .. pattern binds no variables. -Wunused-record-wildcards warns when none of the variables bound by a .. pattern are used. These flags are enabled by `-Wall`.
* Minor refactor of CUSK handlingSimon Peyton Jones2019-02-081-10/+19
| | | | | | | | | Previously, in getFamDeclInitialKind, we were figuring out whether the enclosing class decl had a CUSK very indirectly, via tcTyConIsPoly. This patch just makes the computation much more direct and easy to grok. No change in behaviour.
* API Annotations: parens anns discarded for `(*)` operatorAlan Zimmerman2019-02-081-1/+2
| | | | | | | | | | | | | | | The patch from https://phabricator.haskell.org/D4865 introduces go _ (HsParTy _ (dL->L l (HsStarTy _ isUni))) acc ann fix = do { warnStarBndr l ; let name = mkOccName tcClsName (if isUni then "★" else "*") ; return (cL l (Unqual name), acc, fix, ann) } which discards the parens annotations belonging to the HsParTy. Updates haddock submodule Closes #16265
* API Annotations: AnnAt disconnected for TYPEAPPAlan Zimmerman2019-02-082-13/+15
| | | | | | | | | | | | For the code type family F1 (a :: k) (f :: k -> Type) :: Type where F1 @Peano a f = T @Peano f a the API annotation for the first @ is not attached to a SourceSpan in the ParsedSource Closes #16236
* Fix #14579 by defining tyConAppNeedsKindSig, and using itRyan Scott2019-02-051-41/+46
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* Refactor splice_exp in Parser.yVladislav Zavialov2019-02-051-11/+3
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* Fix missing space in ppr_cmd for HsCmdArrFormVladislav Zavialov2019-02-031-2/+2
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* Use ByteString to represent Cmm string literals (#16198)Sylvain Henry2019-01-311-2/+1
| | | | Also used ByteString in some other relevant places
* Use sigPrec in more places in Convert and HsUtilsRyan Scott2019-01-282-39/+36
| | | | | | | | | Trac #16183 was caused by TH conversion (in `Convert`) not properly inserting parentheses around occurrences of explicit signatures where appropriate, such as in applications, function types, and type family equations. Solution: use `parenthesizeHsType sigPrec` in these places. While I was in town, I also updated `nlHsFunTy` to do the same thing.
* A few typofixesGabor Greif2019-01-231-1/+1
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* Remove TODO in HsExprMatthew Pickering2019-01-201-1/+0
| | | | It is correct to be `GhcTc` as the data type is for expressions which are inside splices so they can be delayed until desugaring.
* Run typed splices in the zonkerMatthew Pickering2019-01-111-0/+20
| | | | | | | | | | | | | | | | | Summary: This fixes #15471 In the typechecker we check that the splice has the right type but we crucially don't zonk the generated expression. This is because we might end up unifying type variables from outer scopes later on. Reviewers: simonpj, goldfire, bgamari Subscribers: rwbarton, carter GHC Trac Issues: #15471 Differential Revision: https://phabricator.haskell.org/D5286
* Visible kind applicationmynguyen2019-01-037-147/+252
| | | | | | | | | | | | | | | | | | | | | | | Summary: This patch implements visible kind application (GHC Proposal 15/#12045), as well as #15360 and #15362. It also refactors unnamed wildcard handling, and requires that type equations in type families in Template Haskell be written with full type on lhs. PartialTypeSignatures are on and warnings are off automatically with visible kind application, just like in term-level. There are a few remaining issues with this patch, as documented in ticket #16082. Includes a submodule update for Haddock. Test Plan: Tests T12045a/b/c/TH1/TH2, T15362, T15592a Reviewers: simonpj, goldfire, bgamari, alanz, RyanGlScott, Iceland_jack Subscribers: ningning, Iceland_jack, RyanGlScott, int-index, rwbarton, mpickering, carter GHC Trac Issues: `#12045`, `#15362`, `#15592`, `#15788`, `#15793`, `#15795`, `#15797`, `#15799`, `#15801`, `#15807`, `#15816` Differential Revision: https://phabricator.haskell.org/D5229
* Use unicode arrows with -fprint-unicode-syntaxKrzysztof Gogolewski2018-12-191-1/+1
| | | | | | | | | | | | | | | | | | Summary: See #8959, this is one more place where we can pretty-print Unicode syntax. Test Plan: validate Reviewers: nomeata, bgamari Reviewed By: bgamari Subscribers: rwbarton, carter GHC Trac Issues: #8959 Differential Revision: https://phabricator.haskell.org/D5439
* Enable rebindable fail with overloaded stringsShayne Fletcher2018-12-112-4/+9
| | | | | | | | | | | | | | Summary: enable rebindable fail with overloaded strings Reviewers: bgamari, simonpj Reviewed By: bgamari, simonpj Subscribers: simonpj, ndmitchell, rwbarton, carter GHC Trac Issues: #15645 Differential Revision: https://phabricator.haskell.org/D5251
* Taming the Kind Inference MonsterSimon Peyton Jones2018-11-292-69/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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-Najd2018-11-245-236/+317
| | | | | | | | | | | | | | | | | | 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
* Fix unused-import warningsDavid Eichmann2018-11-225-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Smarter HsType pretty-print for promoted dataconsSimon Peyton Jones2018-11-152-28/+59
| | | | | | | | | | | | | | | | | | | | | 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.
* Fix #15815 by parenthesizing the arguments to infix ~Ryan Scott2018-10-291-1/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | An unfortunate consequence of commit b9483981d128f55d8dae3f434f49fa6b5b30c779 (`Remove HsEqTy and XEqTy`) is infix uses of `~` in TH quotes now desugar differently than before. In particular, we have that: ```haskell a ~ (Int -> Int) ``` Now desugars to: ```haskell HsOpTy a (~) (HsOpTy Int (->) Int) ``` Which GHC interprets as being: ```haskell a ~ Int -> Int ``` Or, equivalently: ```haskell (a ~ Int) -> Int ``` Which is different than what was intended! This is the cause of #15815. All of this has revealed that we likely need to renovate the way we desugar infix type operators to be more consistent with the treatment for infix expressions (see https://ghc.haskell.org/trac/ghc/ticket/15815#comment:5 for more on this.) Doing so would constitute a breaking change, however, so we will likely want to wait until another major GHC release to do this. In the meantime, this patch offers a non-invasive change to the way that infix uses of `~` are desugared. This makes the program in #15815 compile again by inserting extra `HsParTy`s around the arguments to `~` if they are lacking them. Test Plan: make test TEST=T15815 Reviewers: int-index, goldfire, bgamari Reviewed By: int-index Subscribers: int-e, rwbarton, carter GHC Trac Issues: #15815 Differential Revision: https://phabricator.haskell.org/D5274
* More explicit foralls (GHC Proposal 0007)Matthew Yacavone2018-10-277-108/+150
| | | | | | | | | | | | | | | | | | | | | | | | | | | 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 #15761 by adding parensRichard Eisenberg2018-10-171-7/+9
| | | | | | This was just a pretty-printer infelicity. Fixed now. Test case: printer/T15761
* Fix #15738 by defining (and using) parenthesizeHsContextRyan Scott2018-10-152-2/+15
| | | | | | | | | | | | | | | | | | | | | With `QuantifiedConstraints`, `forall`s can appear in more nested positions than they could before, but `Convert` and the TH pretty-printer were failing to take this into account. On the `Convert` side, this is fixed by using a `parenthesizeHsContext` to parenthesize singleton quantified constraints that appear to the left of a `=>`. (A similar fix is applied to the TH pretty-printer.) Test Plan: make test TEST=T15738 Reviewers: goldfire, bgamari Reviewed By: bgamari Subscribers: rwbarton, carter GHC Trac Issues: #15738 Differential Revision: https://phabricator.haskell.org/D5222
* Minor documentation markup fix in HsExpr.hsJosh Price2018-10-141-1/+1
| | | | PR: https://github.com/ghc/ghc/pull/202/
* Don't drop arguments in TH type argumentsAlec Theriault2018-10-041-9/+13
| | | | | | | | | | | | | | | | | | | Summary: When converting from TH AST back to HsType, we were occasionally dropping type arguments. This resulted in incorrectly accepted programs as well as incorrectly rejected programs. Test Plan: make TEST=T15360a && make TEST=T15360b Reviewers: goldfire, bgamari, tdammers Reviewed By: bgamari, tdammers Subscribers: RyanGlScott, rwbarton, carter GHC Trac Issues: #15360 Differential Revision: https://phabricator.haskell.org/D5188
* Allow (unparenthesized) kind signaturesAlec Theriault2018-10-045-6/+6
| | | | | | | | | | | | | | | | 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
* Don't look up unnecessary return in LastStmtSimon Peyton Jones2018-09-231-17/+20
| | | | | | This fixes Trac #15607. The general pattern is well established (e.g. see the guard_op binding in rnStmt of BodyStme), but we weren't using it for LastStmt.
* Buglet in reporting out of scope errors in rulesSimon Peyton Jones2018-09-231-2/+9
| | | | | | | | Most out of scope errors get reported by the type checker these days, but not all. Example, the function on the LHS of a RULE. Trace #15659 pointed out that this less-heavily-used code path produce a "wacky" error message. Indeed so. Easily fixed.
* Add support for ImplicitParams and RecursiveDo in THMichael Sloan2018-09-141-8/+41
| | | | | | | | | | | | | | | | | | | | | | | | Summary: This adds TH support for the ImplicitParams and RecursiveDo extensions. I'm submitting this as one review because I cannot cleanly make the two commits independent. Initially, my goal was just to add ImplicitParams support, and I found that reasonably straightforward, so figured I might as well use my newfound knowledge to address some other TH omissions. Test Plan: Validate Reviewers: goldfire, austin, bgamari, RyanGlScott Reviewed By: RyanGlScott Subscribers: carter, RyanGlScott, thomie GHC Trac Issues: #1262 Differential Revision: https://phabricator.haskell.org/D1979
* Rename kind vars in left-to-right order in bindHsQTyVarsRyan Scott2018-08-281-2/+15
| | | | | | | | | | | | | | | | | | | | Summary: When renaming kind variables in an `LHsQTyVars`, we were erroneously putting all of the kind variables in the binders //after// the kind variables in the body, resulting in #15568. The fix is simple: just swap the order of these two around. Test Plan: make test TEST=T15568 Reviewers: simonpj, bgamari, goldfire Reviewed By: goldfire Subscribers: goldfire, rwbarton, carter GHC Trac Issues: #15568 Differential Revision: https://phabricator.haskell.org/D5108
* Fix #15572 by checking for promoted names in ConTRyan Scott2018-08-281-1/+8
| | | | | | | | | | | | | | | | | | | | | | Summary: When converting `ConT`s to `HsTyVar`s in `Convert`, we were failing to account for the possibility of promoted data constructor names appearing in a `ConT`, which could result in improper pretty-printing results (as observed in #15572). The fix is straightforward: use `Promoted` instead of `NotPromoted` when the name of a `ConT` is a data constructor name. Test Plan: make test TEST=T15572 Reviewers: goldfire, bgamari, simonpj, monoidal Reviewed By: goldfire, simonpj Subscribers: monoidal, rwbarton, carter GHC Trac Issues: #15572 Differential Revision: https://phabricator.haskell.org/D5112
* Fix #15550 by quoting RULE names during TH conversionRyan Scott2018-08-271-2/+2
| | | | | | | | | | | | | | | | | | | Summary: When converting a `RuleP` to a GHC source `RuleD` during TH conversion, we were stupidly not double-quoting the name of the rule. Easily fixed. Test Plan: make test TEST=T15550 Reviewers: goldfire, bgamari, simonpj Reviewed By: simonpj Subscribers: simonpj, rwbarton, carter GHC Trac Issues: #15550 Differential Revision: https://phabricator.haskell.org/D5090
* Replace most occurences of foldl with foldl'.klebinger.andreas@gmx.at2018-08-212-8/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds foldl' to GhcPrelude and changes must occurences of foldl to foldl'. This leads to better performance especially for quick builds where GHC does not perform strictness analysis. It does change strictness behaviour when we use foldl' to turn a argument list into function applications. But this is only a drawback if code looks ONLY at the last argument but not at the first. And as the benchmarks show leads to fewer allocations in practice at O2. Compiler performance for Nofib: O2 Allocations: -1 s.d. ----- -0.0% +1 s.d. ----- -0.0% Average ----- -0.0% O2 Compile Time: -1 s.d. ----- -2.8% +1 s.d. ----- +1.3% Average ----- -0.8% O0 Allocations: -1 s.d. ----- -0.2% +1 s.d. ----- -0.1% Average ----- -0.2% Test Plan: ci Reviewers: goldfire, bgamari, simonmar, tdammers, monoidal Reviewed By: bgamari, monoidal Subscribers: tdammers, rwbarton, thomie, carter Differential Revision: https://phabricator.haskell.org/D4929
* Fix redundant imports of ClassBen Gamari2018-08-211-1/+0
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* Add a solveEqualities to tcClassDecl1Simon Peyton Jones2018-08-212-4/+5
| | | | | | | | | | | | | | 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.
* Fix #15527 by pretty-printing an RdrName prefixlyRyan Scott2018-08-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | Summary: When `(.) @Int` is used without enabling `TypeApplications`, the resulting error message will pretty-print the (symbolic) `RdrName` `(.)`. However, it does so without parenthesizing it, which causes the pretty-printed expression to appear as `.@Int`. Yuck. Since the expression in a type application will always be prefix, we can fix this issue by using `pprPrefixOcc` instead of plain ol' `ppr`. Test Plan: make test TEST=T15527 Reviewers: bgamari, monoidal, simonpj Reviewed By: monoidal, simonpj Subscribers: rwbarton, carter GHC Trac Issues: #15527 Differential Revision: https://phabricator.haskell.org/D5071
* Properly designate LambdaCase alts as CaseAlt in THRyan Scott2018-08-141-1/+1
| | | | | | | | | | | | | | | | | | | | | | Summary: When `\case` expressions are parsed normally, their alternatives are marked as `CaseAlt` (which means that they are pretty-printed without a `\` character in front of them, unlike for lambda expressions). However, `\case` expressions created by way of Template Haskell (in `Convert`) inconsistently designated the case alternatives as `LambdaExpr`, causing them to be pretty-printed poorly (as shown in #15518). The fix is simple: use `CaseAlt` consistently. Test Plan: make test TEST=T15518 Reviewers: goldfire, bgamari Subscribers: rwbarton, carter GHC Trac Issues: #15518 Differential Revision: https://phabricator.haskell.org/D5069
* Remove decideKindGeneralisationPlanRichard Eisenberg2018-08-021-19/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | TypeInType came with a new function: decideKindGeneralisationPlan. This type-level counterpart to the term-level decideGeneralisationPlan chose whether or not a kind should be generalized. The thinking was that if `let` should not be generalized, then kinds shouldn't either (under the same circumstances around -XMonoLocalBinds). However, this is too conservative -- the situation described in the motivation for "let should be be generalized" does not occur in types. This commit thus removes decideKindGeneralisationPlan, always generalizing. One consequence is that tc_hs_sig_type_and_gen no longer calls solveEqualities, which reports all unsolved constraints, instead relying on the solveLocalEqualities in tcImplicitTKBndrs. An effect of this is that reporing kind errors gets delayed more frequently. This seems to be a net benefit in error reporting; often, alongside a kind error, the type error is now reported (and users might find type errors easier to understand). Some of these errors ended up at the top level, where it was discovered that the GlobalRdrEnv containing the definitions in the local module was not in the TcGblEnv, and thus errors were reported with qualified names unnecessarily. This commit rejiggers some of the logic around captureTopConstraints accordingly. One error message (typecheck/should_fail/T1633) is a regression, mentioning the name of a default method. However, that problem is already reported as #10087, its solution is far from clear, and so I'm not addressing it here. This commit fixes #15141. As it's an internal refactor, there is no concrete test case for it. Along the way, we no longer need the hsib_closed field of HsImplicitBndrs (it was used only in decideKindGeneralisationPlan) and so it's been removed, simplifying the datatype structure. Along the way, I removed code in the validity checker that looks at coercions. This isn't related to this patch, really (though it was, at one point), but it's an improvement, so I kept it. This updates the haddock submodule.
* Fix #15385 by using addDictsDs in matchGuardsRyan Scott2018-07-301-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: When coverage checking pattern-matches, we rely on the call sites in the desugarer to populate the local dictionaries and term evidence in scope using `addDictsDs` and `addTmCsDs`. But it turns out that only the call site for desugaring `case` expressions was actually doing this properly. In another part of the desugarer, `matchGuards` (which handles pattern guards), it did not update the local dictionaries in scope at all, leading to #15385. Fixing this is relatively straightforward: just augment the `BindStmt` case of `matchGuards` to use `addDictsDs` and `addTmCsDs`. Accomplishing this took a little bit of import/export tweaking: * We now need to export `collectEvVarsPat` from `HsPat.hs`. * To avoid an import cycle with `Check.hs`, I moved `isTrueLHsExpr` from `DsGRHSs.hs` to `DsUtils.hs`, which resides lower on the import chain. Test Plan: make test TEST=T15385 Reviewers: simonpj, bgamari Reviewed By: simonpj Subscribers: rwbarton, thomie, carter GHC Trac Issues: #15385 Differential Revision: https://phabricator.haskell.org/D4968
* Fix pretty-printing of data declarations in splicesKrzysztof Gogolewski2018-07-221-2/+2
| | | | | | | | | | | | | | Test Plan: validate Reviewers: RyanGlScott, bgamari Reviewed By: RyanGlScott Subscribers: rwbarton, thomie, carter GHC Trac Issues: #15365 Differential Revision: https://phabricator.haskell.org/D4998
* Fix the GHCi debugger with ApplicativeDoSimon Marlow2018-07-221-1/+5
| | | | | | | | | | | | | | | | | | | | | Summary: `collectLStmtsBinders` was returning nothing for `ApplicativeStmts`, which caused the debugger to not track free variables in many cases when using `ApplicativeDo`. Test Plan: * new test case * validate Reviewers: bgamari, erikd Reviewed By: bgamari Subscribers: rwbarton, thomie, carter GHC Trac Issues: #15422 Differential Revision: https://phabricator.haskell.org/D4991
* Fix #15423 by using pprAStmtContextRyan Scott2018-07-201-1/+1
| | | | | | | | | | | | | | | | | Summary: Previously, we were using `pprStmtContext` instead, which led to error messages missing indefinite articles where they were required. Test Plan: make test TEST="T13242a T7786 Typeable1" Reviewers: bgamari Subscribers: rwbarton, thomie, carter GHC Trac Issues: #15423 Differential Revision: https://phabricator.haskell.org/D4992
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