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* Remove dead codeKrzysztof Gogolewski2020-02-262-3/+0
| | | | | | * FailablePattern can no longer be created since ab51bee40c82 Therefore, Opt_WarnMissingMonadFailInstances has no effect anymore. * XWrap is no longer used, it was moved to an extension field
* Comments, small refactorKrzysztof Gogolewski2020-02-241-24/+0
| | | | | | | | | | | | * Remove outdated Note [HsForAllTy tyvar binders] and [Context quantification]. Since the wildcard refactor 1e041b7382, HsForAllTy no longer has an flag controlling explicity. The field `hsq_implicit` is gone too. The current situation is covered by Note [HsType binders] which is already linked from LHsQTyVars. * Small refactor in CoreLint, extracting common code to a function * Remove "not so sure about WpFun" in TcEvidence, per Richard's comment https://gitlab.haskell.org/ghc/ghc/merge_requests/852#note_223226 * Use mkIfThenElse in Foreign/Call, as it does exactly what we need.
* Remove Ord SrcLoc, Ord SrcSpanVladislav Zavialov2020-02-242-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before this patch, GHC relied on Ord SrcSpan to identify source elements, by using SrcSpan as Map keys: blackList :: Map SrcSpan () -- compiler/GHC/HsToCore/Coverage.hs instanceMap :: Map SrcSpan Name -- compiler/GHC/HsToCore/Docs.hs Firstly, this design is not valid in presence of UnhelpfulSpan, as it distinguishes between UnhelpfulSpan "X" and UnhelpfulSpan "Y", but those strings are messages for the user, unfit to serve as identifiers for source elements. Secondly, this design made it hard to extend SrcSpan with additional data. Recall that the definition of SrcSpan is: data SrcSpan = RealSrcSpan !RealSrcSpan | UnhelpfulSpan !FastString Say we want to extend the RealSrcSpan constructor with additional information: data SrcSpan = RealSrcSpan !RealSrcSpan !AdditionalInformation | UnhelpfulSpan !FastString getAdditionalInformation :: SrcSpan -> AdditionalInformation getAdditionalInformation (RealSrcSpan _ a) = a Now, in order for Map SrcSpan to keep working correctly, we must *ignore* additional information when comparing SrcSpan values: instance Ord SrcSpan where compare (RealSrcSpan r1 _) (RealSrcSpan r2 _) = compare r1 r2 ... However, this would violate an important law: a == b therefore f a == f b Ignoring AdditionalInformation in comparisons would mean that with f=getAdditionalInformation, the law above does not hold. A more robust design is to avoid Ord SrcSpan altogether, which is what this patch implements. The mappings are changed to use RealSrcSpan instead: blackList :: Set RealSrcSpan -- compiler/GHC/HsToCore/Coverage.hs instanceMap :: Map RealSrcSpan Name -- compiler/GHC/HsToCore/Docs.hs All SrcSpan comparisons are now done with explicit comparison strategies: SrcLoc.leftmost_smallest SrcLoc.leftmost_largest SrcLoc.rightmost_smallest These strategies are not subject to the law mentioned above and can easily discard both the string stored in UnhelpfulSpan and AdditionalInformation. Updates haddock submodule.
* Use Type instead of * in GHCBen Gamari2020-02-203-8/+11
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* GHC.Hs.Extension: Use Type instead of *Ben Gamari2020-02-201-1/+1
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* Use TTG for HsSplicedT constructorKrzysztof Gogolewski2020-02-201-6/+11
| | | | | The constructor HsSplicedT occurs only in the GhcTc pass. This enforces this fact statically via TTG.
* Disentangle DynFlags and SDocSylvain Henry2020-02-203-33/+30
| | | | | | | | | | | | | Remove several uses of `sdocWithDynFlags`. The remaining ones are mostly CodeGen related (e.g. depend on target platform constants) and will be fixed separately. Metric Decrease: T12425 T9961 WWRec T1969 T14683
* Module hierarchy: HsToCore (cf #13009)Sylvain Henry2020-02-146-16/+16
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* Always display inferred variables using bracesKrzysztof Gogolewski2020-02-121-1/+2
| | | | | | | | | | | | | We now always show "forall {a}. T" for inferred variables, previously this was controlled by -fprint-explicit-foralls. This implements part 1 of https://github.com/ghc-proposals/ghc-proposals/pull/179. Part of GHC ticket #16320. Furthermore, when printing a levity restriction error, we now display the HsWrap of the expression. This lets users see the full elaboration with -fprint-typechecker-elaboration (see also #17670)
* Introduce IsPass; refactor wrappers.Richard Eisenberg2020-02-0813-891/+480
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are two main payloads of this patch: 1. This introduces IsPass, which allows e.g. printing code to ask what pass it is running in (Renamed vs Typechecked) and thus print extension fields. See Note [IsPass] in Hs.Extension 2. This moves the HsWrap constructor into an extension field, where it rightly belongs. This is done for HsExpr and HsCmd, but not for HsPat, which is left as an exercise for the reader. There is also some refactoring around SyntaxExprs, but this is really just incidental. This patch subsumes !1721 (sorry @chreekat). Along the way, there is a bit of refactoring in GHC.Hs.Extension, including the removal of NameOrRdrName in favor of NoGhcTc. This meant that we had no real need for GHC.Hs.PlaceHolder, so I got rid of it. Updates haddock submodule. ------------------------- Metric Decrease: haddock.compiler -------------------------
* Remove unnecessary parenthesesRichard Eisenberg2020-02-081-14/+14
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* slightly better named cost-centres for simple pattern bindings #17006Adam Sandberg Eriksson2020-02-081-0/+19
| | | | | | | | | | | | | | | ``` main = do print $ g [1..100] a where g xs x = map (`mod` x) xs a :: Int = 324 ``` The above program previously attributed the cost of computing 324 to a cost centre named `(...)`, with this change the cost is attributed to `a` instead. This change only affects simple pattern bindings (decorated variables: type signatures, parens, ~ annotations and ! annotations).
* Fix scoping of TyCon binders in TcTyClsDeclsSimon Peyton Jones2020-02-011-5/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes #17566 by refactoring the way we decide the final identity of the tyvars in the TyCons of a possibly-recursive nest of type and class decls, possibly with associated types. It's all laid out in Note [Swizzling the tyvars before generaliseTcTyCon] Main changes: * We have to generalise each decl (with its associated types) all at once: TcTyClsDecls.generaliseTyClDecl * The main new work is done in TcTyClsDecls.swizzleTcTyConBndrs * The mysterious TcHsSyn.zonkRecTyVarBndrs dies altogether Other smaller things: * A little refactoring, moving bindTyClTyVars from tcTyClDecl1 to tcDataDefn, tcSynRhs, etc. Clearer, reduces the number of parameters * Reduce the amount of swizzling required. Specifically, bindExplicitTKBndrs_Q_Tv doesn't need to clone a new Name for the TyVarTv, and not cloning means that in the vasly common case, swizzleTyConBndrs is a no-op In detail: Rename newTyVarTyVar --> cloneTyVarTyVar Add newTyVarTyTyVar that doesn't clone Use the non-cloning newTyVarTyVar in bindExplicitTKBndrs_Q_Tv Rename newFlexiKindedTyVarTyVar --> cloneFlexiKindedTyVarTyVar * Define new utility function and use it HsDecls.familyDeclName :: FamilyDecl (GhcPass p) -> IdP (GhcPass p) Updates haddock submodule.
* Disable two warnings for files that trigger themTom Ellis2020-01-273-0/+6
| | | | | | incomplete-uni-patterns and incomplete-record-updates will be in -Wall at a future date, so prepare for that by disabling those warnings on files that trigger them.
* Use splitLHs{ForAll,Sigma}TyInvis throughout the codebaseRyan Scott2020-01-271-31/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Richard points out in #17688 that we use `splitLHsForAllTy` and `splitLHsSigmaTy` in places that we ought to be using the corresponding `-Invis` variants instead, identifying two bugs that are caused by this oversight: * Certain TH-quoted type signatures, such as those that appear in quoted `SPECIALISE` pragmas, silently turn visible `forall`s into invisible `forall`s. * When quoted, the type `forall a -> (a ~ a) => a` will turn into `forall a -> a` due to a bug in `DsMeta.repForall` that drops contexts that follow visible `forall`s. These are both ultimately caused by the fact that `splitLHsForAllTy` and `splitLHsSigmaTy` split apart visible `forall`s in addition to invisible ones. This patch cleans things up: * We now use `splitLHsForAllTyInvis` and `splitLHsSigmaTyInvis` throughout the codebase. Relatedly, the `splitLHsForAllTy` and `splitLHsSigmaTy` have been removed, as they are easy to misuse. * `DsMeta.repForall` now only handles invisible `forall`s to reduce the chance for confusion with visible `forall`s, which need to be handled differently. I also renamed it from `repForall` to `repForallT` to emphasize that its distinguishing characteristic is the fact that it desugars down to `L.H.TH.Syntax.ForallT`. Fixes #17688.
* Do not bring visible foralls into scope in hsScopedTvswip/T17687Ryan Scott2020-01-251-14/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, `hsScopedTvs` (and its cousin `hsWcScopedTvs`) pretended that visible dependent quantification could not possibly happen at the term level, and cemented that assumption with an `ASSERT`: ```hs hsScopedTvs (HsForAllTy { hst_fvf = vis_flag, ... }) = ASSERT( vis_flag == ForallInvis ) ... ``` It turns out that this assumption is wrong. You can end up tripping this `ASSERT` if you stick it to the man and write a type for a term that uses visible dependent quantification anyway, like in this example: ```hs {-# LANGUAGE ScopedTypeVariables #-} x :: forall a -> a -> a x = x ``` That won't typecheck, but that's not the point. Before the typechecker has a chance to reject this, the renamer will try to use `hsScopedTvs` to bring `a` into scope over the body of `x`, since `a` is quantified by a `forall`. This, in turn, causes the `ASSERT` to fail. Bummer. Instead of walking on this dangerous ground, this patch makes GHC adopt a more hardline stance by pattern-matching directly on `ForallInvis` in `hsScopedTvs`: ```hs hsScopedTvs (HsForAllTy { hst_fvf = ForallInvis, ... }) = ... ``` Now `a` will not be brought over the body of `x` at all (which is how it should be), there's no chance of the `ASSERT` failing anymore (as it's gone), and best of all, the behavior of `hsScopedTvs` does not change. Everyone wins! Fixes #17687.
* Handle local fixity declarations in DsMeta properlyRyan Scott2020-01-251-15/+62
| | | | | | | | | | | | | | | | | | | | | `DsMeta.rep_sig` used to skip over `FixSig` entirely, which had the effect of causing local fixity declarations to be dropped when quoted in Template Haskell. But there is no good reason for this state of affairs, as the code in `DsMeta.repFixD` (which handles top-level fixity declarations) handles local fixity declarations just fine. This patch factors out the necessary parts of `repFixD` so that they can be used in `rep_sig` as well. There was one minor complication: the fixity signatures for class methods in each `HsGroup` were stored both in `FixSig`s _and_ the list of `LFixitySig`s for top-level fixity signatures, so I needed to take action to prevent fixity signatures for class methods being converted to `Dec`s twice. I tweaked `RnSource.add` to avoid putting these fixity signatures in two places and added `Note [Top-level fixity signatures in an HsGroup]` in `GHC.Hs.Decls` to explain the new design. Fixes #17608. Bumps the Haddock submodule.
* Fix more typos, via an improved Levenshtein-style correctorBrian Wignall2020-01-124-10/+10
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* Overloaded Quotation Brackets (#246)Matthew Pickering2020-01-121-2/+4
| | | | | | | | | | | | | | | | | | This patch implements overloaded quotation brackets which generalise the desugaring of all quotation forms in terms of a new minimal interface. The main change is that a quotation, for example, [e| 5 |], will now have type `Quote m => m Exp` rather than `Q Exp`. The `Quote` typeclass contains a single method for generating new names which is used when desugaring binding structures. The return type of functions from the `Lift` type class, `lift` and `liftTyped` have been restricted to `forall m . Quote m => m Exp` rather than returning a result in a Q monad. More details about the feature can be read in the GHC proposal. https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0246-overloaded-bracket.rst
* Module hierarchy: Renamer (cf #13009)Sylvain Henry2020-01-085-17/+18
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* Module hierarchy: Iface (cf #13009)Sylvain Henry2020-01-061-1/+1
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* Fix typos, via a Levenshtein-style correctorBrian Wignall2020-01-042-2/+2
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* Pretty-printing of the * kindVladislav Zavialov2019-12-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before this patch, GHC always printed the * kind unparenthesized. This led to two issues: 1. Sometimes GHC printed invalid or incorrect code. For example, GHC would print: type F @* x = x when it meant to print: type F @(*) x = x In the former case, instead of a kind application we were getting a type operator (@*). 2. Sometimes GHC printed kinds that were correct but hard to read. Should Either * Int be read as Either (*) Int or as (*) Either Int ? This depends on whether -XStarIsType is enabled, but it would be easier if we didn't have to check for the flag when reading the code. We can solve both problems by assigning (*) a different precedence. Note that Haskell98 kinds are not affected: ((* -> *) -> *) -> * does NOT become (((*) -> (*)) -> (*)) -> (*) The parentheses are added when (*) is used in a function argument position: F * * * becomes F (*) (*) (*) F A * B becomes F A (*) B Proxy * becomes Proxy (*) a * -> * becomes a (*) -> *
* More Haddock syntax in GHC.Hs.UtilsBen Gamari2019-12-021-15/+16
| | | | As suggested by RyanGlScott in !2163.
* Remove HasSrcSpan (#17494)Vladislav Zavialov2019-11-304-73/+69
| | | | | Metric Decrease: haddock.compiler
* Factor out HsSCC/HsCoreAnn/HsTickPragma into HsPragEwip/hs-pragVladislav Zavialov2019-11-283-59/+77
| | | | | | | | | | | | | | | | | | | | | | | This is a refactoring with no user-visible changes (except for GHC API users). Consider the HsExpr constructors that correspond to user-written pragmas: HsSCC representing {-# SCC ... #-} HsCoreAnn representing {-# CORE ... #-} HsTickPragma representing {-# GENERATED ... #-} We can factor them out into a separate datatype, HsPragE. It makes the code a bit tidier, especially in the parser. Before this patch: hpc_annot :: { Located ( (([AddAnn],SourceText),(StringLiteral,(Int,Int),(Int,Int))), ((SourceText,SourceText),(SourceText,SourceText)) ) } After this patch: prag_hpc :: { Located ([AddAnn], HsPragE GhcPs) }
* Fix typos, using Wikipedia list of common typosBrian Wignall2019-11-281-1/+1
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* Whitespace-sensitive bang patterns (#1087, #17162)wip/whitespace-and-lookaheadVladislav Zavialov2019-11-271-14/+9
| | | | | | | | | | | | | | | | | | This patch implements a part of GHC Proposal #229 that covers five operators: * the bang operator (!) * the tilde operator (~) * the at operator (@) * the dollar operator ($) * the double dollar operator ($$) Based on surrounding whitespace, these operators are disambiguated into bang patterns, lazy patterns, strictness annotations, type applications, splices, and typed splices. This patch doesn't cover the (-) operator or the -Woperator-whitespace warning, which are left as future work.
* Make warnings for TH splices opt-inSebastian Graf2019-11-271-11/+14
| | | | | | | | | | | | | | | | | | | | | | | In #17270 we have the pattern-match checker emit incorrect warnings. The reason for that behavior is ultimately an inconsistency in whether we treat TH splices as written by the user (`FromSource :: Origin`) or as generated code (`Generated`). This was first reported in #14838. The current solution is to TH splices as `Generated` by default and only treat them as `FromSource` when the user requests so (-fenable-th-splice-warnings). There are multiple reasons for opt-in rather than opt-out: * It's not clear that the user that compiles a splice is the author of the code that produces the warning. Think of the situation where she just splices in code from a third-party library that produces incomplete pattern matches. In this scenario, the user isn't even able to fix that warning. * Gathering information for producing the warnings (pattern-match check warnings in particular) is costly. There's no point in doing so if the user is not interested in those warnings. Fixes #17270, but not #14838, because the proper solution needs a GHC proposal extending the TH AST syntax.
* Remove prefix arrow support for GADTs (#17211)Krzysztof Gogolewski2019-11-251-16/+0
| | | | | | | This reverts the change in #9096. The specialcasing done for prefix (->) is brittle and does not support VTA, type families, type synonyms etc.
* Strip parentheses in expressions contexts in error messagesVladislav Zavialov2019-11-191-0/+4
| | | | This makes error messages a tad less noisy.
* Turn some comments into GHC.Hs.Utils into haddocksAndreas Klebinger2019-11-171-37/+46
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* Fix random typos [skip ci]nineonine2019-11-171-1/+1
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* Print name prefixly in the Outputable instance for StandaloneKindSigRyan Scott2019-11-131-1/+2
| | | | | | | | | Issue #17461 was occurring because the `Outputable` instance for standalone kind signatures was simply calling `ppr` on the name in the kind signature, which does not add parentheses to infix names. The solution is simple: use `pprPrefixOcc` instead. Fixes #17461.
* Ensure that coreView/tcView are able to inlineBen Gamari2019-11-131-1/+2
| | | | | | | | | | | | | | | | | | | | Previously an import cycle between Type and TyCoRep meant that several functions in TyCoRep ended up SOURCE import coreView. This is quite unfortunate as coreView is intended to be fused into a larger pattern match and not incur an extra call. Fix this with a bit of restructuring: * Move the functions in `TyCoRep` which depend upon things in `Type` into `Type` * Fold contents of `Kind` into `Type` and turn `Kind` into a simple wrapper re-exporting kind-ish things from `Type` * Clean up the redundant imports that popped up as a result Closes #17441. Metric Decrease: T4334
* Improve SPECIALIZE pragma error messages (Fixes #12126)Alina Banerjee2019-11-101-3/+5
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* Clean up TH's treatment of unary tuples (or, #16881 part two)Ryan Scott2019-11-073-3/+30
| | | | | | | | | | | | | | !1906 left some loose ends in regards to Template Haskell's treatment of unary tuples. This patch ends to tie up those loose ends: * In addition to having `TupleT 1` produce unary tuples, `TupE [exp]` and `TupP [pat]` also now produce unary tuples. * I have added various special cases in GHC's pretty-printers to ensure that explicit 1-tuples are printed using the `Unit` type. See `testsuite/tests/th/T17380`. * The GHC 8.10.1 release notes entry has been tidied up a little. Fixes #16881. Fixes #17371. Fixes #17380.
* Separate `LPat` from `Pat` on the type-levelSebastian Graf2019-11-023-32/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since the Trees That Grow effort started, we had `type LPat = Pat`. This is so that `SrcLoc`s would only be annotated in GHC's AST, which is the reason why all GHC passes use the extension constructor `XPat` to attach source locations. See #15495 for the design discussion behind that. But now suddenly there are `XPat`s everywhere! There are several functions which dont't cope with `XPat`s by either crashing (`hsPatType`) or simply returning incorrect results (`collectEvVarsPat`). This issue was raised in #17330. I also came up with a rather clean and type-safe solution to the problem: We define ```haskell type family XRec p (f :: * -> *) = r | r -> p f type instance XRec (GhcPass p) f = Located (f (GhcPass p)) type instance XRec TH f = f p type LPat p = XRec p Pat ``` This is a rather modular embedding of the old "ping-pong" style, while we only pay for the `Located` wrapper within GHC. No ping-ponging in a potential Template Haskell AST, for example. Yet, we miss no case where we should've handled a `SrcLoc`: `hsPatType` and `collectEvVarsPat` are not callable at an `LPat`. Also, this gets rid of one indirection in `Located` variants: Previously, we'd have to go through `XPat` and `Located` to get from `LPat` to the wrapped `Pat`. Now it's just `Located` again. Thus we fix #17330.
* Use FlexibleInstances for `Outputable (* p)` instead of match-all instances ↵Sebastian Graf2019-10-2810-193/+196
| | | | | | | | | | | | | | with equality constraints In #17304, Richard and Simon dicovered that using `-XFlexibleInstances` for `Outputable` instances of AST data types means users can provide orphan `Outputable` instances for passes other than `GhcPass`. Type inference doesn't currently to suffer, and Richard gave an example in #17304 that shows how rare a case would be where the slightly worse type inference would matter. So I went ahead with the refactoring, attempting to fix #17304.
* Fix #15344: use fail when desugaring applicative-doJosef Svenningsson2019-10-282-17/+26
| | | | | | | | | | | | | | | | Applicative-do has a bug where it fails to use the monadic fail method when desugaring patternmatches which can fail. See #15344. This patch fixes that problem. It required more rewiring than I had expected. Applicative-do happens mostly in the renamer; that's where decisions about scheduling are made. This schedule is then carried through the typechecker and into the desugarer which performs the actual translation. Fixing this bug required sending information about the fail method from the renamer, through the type checker and into the desugarer. Previously, the desugarer didn't have enough information to actually desugar pattern matches correctly. As a side effect, we also fix #16628, where GHC wouldn't catch missing MonadFail instances with -XApplicativeDo.
* Solve constraints from top-level groups soonerRichard Eisenberg2019-10-081-107/+8
| | | | | | | | | | | | | | | | | | | | | | | | | Previously, all constraints from all top-level groups (as separated by top-level splices) were lumped together and solved at the end. This could leak metavariables to TH, though, and that's bad. This patch solves each group's constraints before running the next group's splice. Naturally, we now report fewer errors in some cases. One nice benefit is that this also fixes #11680, but in a much simpler way than the original fix for that ticket. Admittedly, the error messages degrade just a bit from the fix from #11680 (previously, we informed users about variables that will be brought into scope below a top-level splice, and now we just report an out-of-scope error), but the amount of complexity required throughout GHC to get that error was just not worth it. This patch thus reverts much of f93c9517a2c6e158e4a5c5bc7a3d3f88cb4ed119. Fixes #16980 Test cases: th/T16980{,a}
* Improve documentation around empty tuples/listsRichard Eisenberg2019-10-031-0/+67
| | | | | | | | | | | | | | This patch also changes the way we handle empty lists, simplifying them somewhat. See Note [Empty lists]. Previously, we had to special-case empty lists in the type-checker. Now no more! Finally, this patch improves some documentation around the ir_inst field used in the type-checker. This breaks a test case, but I really think the problem is #17251, not really related to this patch. Test case: typecheck/should_compile/T13680
* Standalone kind signatures (#16794)wip/top-level-kind-signaturesVladislav Zavialov2019-09-254-54/+120
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implements GHC Proposal #54: .../ghc-proposals/blob/master/proposals/0054-kind-signatures.rst With this patch, a type constructor can now be given an explicit standalone kind signature: {-# LANGUAGE StandaloneKindSignatures #-} type Functor :: (Type -> Type) -> Constraint class Functor f where fmap :: (a -> b) -> f a -> f b This is a replacement for CUSKs (complete user-specified kind signatures), which are now scheduled for deprecation. User-facing changes ------------------- * A new extension flag has been added, -XStandaloneKindSignatures, which implies -XNoCUSKs. * There is a new syntactic construct, a standalone kind signature: type <name> :: <kind> Declarations of data types, classes, data families, type families, and type synonyms may be accompanied by a standalone kind signature. * A standalone kind signature enables polymorphic recursion in types, just like a function type signature enables polymorphic recursion in terms. This obviates the need for CUSKs. * TemplateHaskell AST has been extended with 'KiSigD' to represent standalone kind signatures. * GHCi :info command now prints the kind signature of type constructors: ghci> :info Functor type Functor :: (Type -> Type) -> Constraint ... Limitations ----------- * 'forall'-bound type variables of a standalone kind signature do not scope over the declaration body, even if the -XScopedTypeVariables is enabled. See #16635 and #16734. * Wildcards are not allowed in standalone kind signatures, as partial signatures do not allow for polymorphic recursion. * Associated types may not be given an explicit standalone kind signature. Instead, they are assumed to have a CUSK if the parent class has a standalone kind signature and regardless of the -XCUSKs flag. * Standalone kind signatures do not support multiple names at the moment: type T1, T2 :: Type -> Type -- rejected type T1 = Maybe type T2 = Either String See #16754. * Creative use of equality constraints in standalone kind signatures may lead to GHC panics: type C :: forall (a :: Type) -> a ~ Int => Constraint class C a where f :: C a => a -> Int See #16758. Implementation notes -------------------- * The heart of this patch is the 'kcDeclHeader' function, which is used to kind-check a declaration header against its standalone kind signature. It does so in two rounds: 1. check user-written binders 2. instantiate invisible binders a la 'checkExpectedKind' * 'kcTyClGroup' now partitions declarations into declarations with a standalone kind signature or a CUSK (kinded_decls) and declarations without either (kindless_decls): * 'kinded_decls' are kind-checked with 'checkInitialKinds' * 'kindless_decls' are kind-checked with 'getInitialKinds' * DerivInfo has been extended with a new field: di_scoped_tvs :: ![(Name,TyVar)] These variables must be added to the context in case the deriving clause references tcTyConScopedTyVars. See #16731.
* Module hierarchy: Hs (#13009)Sylvain Henry2019-09-2015-0/+13320
Add GHC.Hs module hierarchy replacing hsSyn. Metric Increase: haddock.compiler