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* Module hierarchy: Iface (cf #13009)Sylvain Henry2020-01-061-1825/+0
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* Fix typos, via a Levenshtein-style correctorBrian Wignall2020-01-041-1/+1
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* TcIface: Fix inverted logic in typechecking of source ticksBen Gamari2019-12-301-1/+1
| | | | | | | | | | | | | Previously we would throw away source ticks when the debug level was non-zero. This is precisely the opposite of what was intended. Fixes #17616. Metric Decrease: T13056 T9020 T9961 T12425
* Use "OrCoVar" functions lessKrzysztof Gogolewski2019-12-161-2/+5
| | | | | | | | | | | As described in #17291, we'd like to separate coercions and expressions in a more robust fashion. This is a small step in this direction. - `mkLocalId` now panicks on a covar. Calls where this was not the case were changed to `mkLocalIdOrCoVar`. - Don't use "OrCoVar" functions in places where we know the type is not a coercion.
* Break up TyCoRepBen Gamari2019-07-311-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | This breaks up the monstrous TyCoReps module into several new modules by topic: * TyCoRep: Contains the `Coercion`, `Type`, and related type definitions and a few simple predicates but nothing further * TyCoPpr: Contains the the pretty-printer logic * TyCoFVs: Contains the free variable computations (and `tyConAppNeedsKindSig`, although I suspect this should change) * TyCoSubst: Contains the substitution logic for types and coercions * TyCoTidy: Contains the tidying logic for types While we are able to eliminate a good number of `SOURCE` imports (and make a few others smaller) with this change, we must introduce one new `hs-boot` file for `TyCoPpr` so that `TyCoRep` can define `Outputable` instances for the types it defines. Metric Increase: haddock.Cabal haddock.compiler
* Update Wiki URLs to point to GitLabTakenobu Tani2019-03-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | This moves all URL references to Trac Wiki to their corresponding GitLab counterparts. This substitution is classified as follows: 1. Automated substitution using sed with Ben's mapping rule [1] Old: ghc.haskell.org/trac/ghc/wiki/XxxYyy... New: gitlab.haskell.org/ghc/ghc/wikis/xxx-yyy... 2. Manual substitution for URLs containing `#` index Old: ghc.haskell.org/trac/ghc/wiki/XxxYyy...#Zzz New: gitlab.haskell.org/ghc/ghc/wikis/xxx-yyy...#zzz 3. Manual substitution for strings starting with `Commentary` Old: Commentary/XxxYyy... New: commentary/xxx-yyy... See also !539 [1]: https://gitlab.haskell.org/bgamari/gitlab-migration/blob/master/wiki-mapping.json
* Update Trac ticket URLs to point to GitLabRyan Scott2019-03-151-5/+5
| | | | | This moves all URL references to Trac tickets to their corresponding GitLab counterparts.
* Add AnonArgFlag to FunTySimon Peyton Jones2019-02-231-6/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Taming the Kind Inference MonsterSimon Peyton Jones2018-11-291-4/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* 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.
* Coercion Quantificationningning2018-09-151-26/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch corresponds to #15497. According to https://ghc.haskell.org/trac/ghc/wiki/DependentHaskell/Phase2, we would like to have coercion quantifications back. This will allow us to migrate (~#) to be homogeneous, instead of its current heterogeneous definition. This patch is (lots of) plumbing only. There should be no user-visible effects. An overview of changes: - Both `ForAllTy` and `ForAllCo` can quantify over coercion variables, but only in *Core*. All relevant functions are updated accordingly. - Small changes that should be irrelevant to the main task: 1. removed dead code `mkTransAppCo` in Coercion 2. removed out-dated Note Computing a coercion kind and roles in Coercion 3. Added `Eq4` in Note Respecting definitional equality in TyCoRep, and updated `mkCastTy` accordingly. 4. Various updates and corrections of notes and typos. - Haddock submodule needs to be changed too. Acknowledgments: This work was completed mostly during Ningning Xie's Google Summer of Code, sponsored by Google. It was advised by Richard Eisenberg, supported by NSF grant 1704041. Test Plan: ./validate Reviewers: goldfire, simonpj, bgamari, hvr, erikd, simonmar Subscribers: RyanGlScott, monoidal, rwbarton, carter GHC Trac Issues: #15497 Differential Revision: https://phabricator.haskell.org/D5054
* Replace most occurences of foldl with foldl'.klebinger.andreas@gmx.at2018-08-211-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Use IfaceAppArgs to store an IfaceAppTy's argumentsRyan Scott2018-07-111-9/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: Currently, an `IfaceAppTy` has no way to tell whether its argument is visible or not, so it simply treats all arguments as visible, leading to #15330. We already have a solution for this problem in the form of the `IfaceTcArgs` data structure, used by `IfaceTyConApp` to represent the arguments to a type constructor. Therefore, it makes sense to reuse this machinery for `IfaceAppTy`, so this patch does just that. This patch: 1. Renames `IfaceTcArgs` to `IfaceAppArgs` to reflect its more general purpose. 2. Changes the second field of `IfaceAppTy` from `IfaceType` to `IfaceAppArgs`, and propagates the necessary changes through. In particular, pretty-printing an `IfaceAppTy` now goes through the `IfaceAppArgs` pretty-printer, which correctly displays arguments as visible or not for free, fixing #15330. 3. Changes `toIfaceTypeX` and related functions so that when converting an `AppTy` to an `IfaceAppTy`, it flattens as many argument `AppTy`s as possible, and then converts those arguments into an `IfaceAppArgs` list, using the kind of the function `Type` as a guide. (Doing so minimizes the number of times we need to call `typeKind`, which is more expensive that finding the kind of a `TyCon`.) Test Plan: make test TEST=T15330 Reviewers: goldfire, simonpj, bgamari Reviewed By: simonpj Subscribers: rwbarton, thomie, carter GHC Trac Issues: #15330 Differential Revision: https://phabricator.haskell.org/D4938
* Refactor coercion ruleningning2018-07-091-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: The patch is an attempt on #15192. It defines a new coercion rule ``` | GRefl Role Type MCoercion ``` which correspondes to the typing rule ``` t1 : k1 ------------------------------------ GRefl r t1 MRefl: t1 ~r t1 t1 : k1 co :: k1 ~ k2 ------------------------------------ GRefl r t1 (MCo co) : t1 ~r t1 |> co ``` MCoercion wraps a coercion, which might be reflexive (MRefl) or not (MCo co). To know more about MCoercion see #14975. We keep Refl ty as a special case for nominal reflexive coercions, naemly, Refl ty :: ty ~n ty. This commit is meant to be a general performance improvement, but there are a few regressions. See #15192, comment:13 for more information. Test Plan: ./validate Reviewers: bgamari, goldfire, simonpj Subscribers: rwbarton, thomie, carter GHC Trac Issues: #15192 Differential Revision: https://phabricator.haskell.org/D4747
* Built-in Natural literals in CoreSylvain Henry2018-06-151-1/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add support for built-in Natural literals in Core. - Replace MachInt,MachWord, LitInteger, etc. with a single LitNumber constructor with a LitNumType field - Support built-in Natural literals - Add desugar warning for negative literals - Move Maybe(..) from GHC.Base to GHC.Maybe for module dependency reasons This patch introduces only a few rules for Natural literals (compared to Integer's rules). Factorization of the built-in rules for numeric literals will be done in another patch as this one is already big to review. Test Plan: validate test build with integer-simple Reviewers: hvr, bgamari, goldfire, Bodigrim, simonmar Reviewed By: bgamari Subscribers: phadej, simonpj, RyanGlScott, carter, hsyl20, rwbarton, thomie GHC Trac Issues: #14170, #14465 Differential Revision: https://phabricator.haskell.org/D4212
* vectorise: Put it out of its miseryBen Gamari2018-06-021-138/+1
| | | | | | | | | | | | | | | | | | | | | 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
* Caching coercion roles in NthCo and coercionKindsRole refactoringTobias Dammers2018-04-201-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While addressing nonlinear behavior related to coercion roles, particularly `NthCo`, we noticed that coercion roles are recalculated often even though they should be readily at hand already in most cases. This patch adds a `Role` to the `NthCo` constructor so that we can cache them rather than having to recalculate them on the fly. https://ghc.haskell.org/trac/ghc/ticket/11735#comment:23 explains the approach. Performance improvement over GHC HEAD, when compiling Grammar.hs (see below): GHC 8.2.1: ``` ghc Grammar.hs 176.27s user 0.23s system 99% cpu 2:56.81 total ``` before patch (but with other optimizations applied): ``` ghc Grammar.hs -fforce-recomp 175.77s user 0.19s system 100% cpu 2:55.78 total ``` after: ``` ../../ghc/inplace/bin/ghc-stage2 Grammar.hs 10.32s user 0.17s system 98% cpu 10.678 total ``` Introduces the following regressions: - perf/compiler/parsing001 (possibly false positive) - perf/compiler/T9872 - perf/compiler/haddock.base Reviewers: goldfire, bgamari, simonpj Reviewed By: simonpj Subscribers: rwbarton, thomie, carter GHC Trac Issues: #11735 Differential Revision: https://phabricator.haskell.org/D4394
* Fix #14934 by including axSub0R in typeNatCoAxiomRulesRyan Scott2018-03-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | For some reason, `axSub0R` was left out of `typeNatCoAxiomRules` in `TcTypeNats`, which led to disaster when trying to look up `Sub0R` from an interface file, as demonstrated in #14934. The fix is simple—just add `axSub0R` to that list. To help prevent an issue like this happening in the future, I added a `Note [Adding built-in type families]` to `TcTypeNats`, which contains a walkthrough of all the definitions in `TcTypeNats` you need to update when adding a new built-in type family. Test Plan: make test TEST=T14934 Reviewers: bgamari, simonpj Reviewed By: simonpj Subscribers: simonpj, rwbarton, thomie, carter GHC Trac Issues: #14934 Differential Revision: https://phabricator.haskell.org/D4508
* Comments and tiny refactorSimon Peyton Jones2018-03-191-7/+11
| | | | Related to Ryan's upcoming patch for Trac #14933
* Lift constructor tag allocation out of a loopBartosz Nitka2018-01-101-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before this change, for each constructor that we want to allocate a tag for we would traverse a list of all the constructors in a datatype to determine which tag a constructor should get. This is obviously quadratic and for datatypes with 10k constructors it actually makes a big difference. This change implements the plan outlined by @simonpj in https://mail.haskell.org/pipermail/ghc-devs/2017-October/014974.html which is basically about using a map and constructing it outside the loop. One place where things got a bit awkward was TysWiredIn.hs, it would have been possible to just assign the tags by hand, but that seemed error-prone to me, so I decided to go through a map there as well. Test Plan: ./validate On a file with 10k constructors Before: 8,130,522,344 bytes allocated in the heap Total time 3.682s ( 3.920s elapsed) After: 4,133,478,744 bytes allocated in the heap Total time 2.509s ( 2.750s elapsed) Reviewers: simonpj, bgamari Reviewed By: simonpj Subscribers: goldfire, rwbarton, thomie, simonmar, carter, simonpj GHC Trac Issues: #14657 Differential Revision: https://phabricator.haskell.org/D4289
* Refactor coercion holesSimon Peyton Jones2017-12-211-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In fixing Trac #14584 I found that it would be /much/ more convenient if a "hole" in a coercion (much like a unification variable in a type) acutally had a CoVar associated with it rather than just a Unique. Then I can ask what the free variables of a coercion is, and get a set of CoVars including those as-yet-un-filled in holes. Once that is done, it makes no sense to stuff coercion holes inside UnivCo. They were there before so we could know the kind and role of a "hole" coercion, but once there is a CoVar we can get that info from the CoVar. So I removed HoleProv from UnivCoProvenance and added HoleCo to Coercion. In summary: * Add HoleCo to Coercion and remove HoleProv from UnivCoProvanance * Similarly in IfaceCoercion * Make CoercionHole have a CoVar in it, not a Unique * Make tyCoVarsOfCo return the free coercion-hole variables as well as the ordinary free CoVars. Similarly, remember to zonk the CoVar in a CoercionHole We could go further, and remove CoercionHole as a distinct type altogther, just collapsing it into HoleCo. But I have not done that yet.
* Make use of boot TyThings during typechecking.Edward Z. Yang2017-11-301-20/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: Suppose that you are typechecking A.hs, which transitively imports, via B.hs, A.hs-boot. When we poke on B.hs and discover that it has a reference to a type from A, what TyThing should we wire it up with? Clearly, if we have already typechecked A, we should use the most up-to-date TyThing: the one we freshly generated when we typechecked A. But what if we haven't typechecked it yet? For the longest time, GHC adopted the policy that this was *an error condition*; that you MUST NEVER poke on B.hs's reference to a thing defined in A.hs until A.hs has gotten around to checking this. However, actually ensuring this is the case has proven to be a bug farm. The problem was especially poignant with type family consistency checks, which eagerly happen before any typechecking takes place. This patch takes a different strategy: if we ever try to access an entity from A which doesn't exist, we just fall back on the definition of A from the hs-boot file. This means that you may end up with a mix of A.hs and A.hs-boot TyThings during the course of typechecking. Signed-off-by: Edward Z. Yang <ezyang@fb.com> Test Plan: validate Reviewers: simonpj, bgamari, austin, goldfire Subscribers: thomie, rwbarton GHC Trac Issues: #14396 Differential Revision: https://phabricator.haskell.org/D4154
* Invoke lintUnfolding only on top-level unfoldings (#14430)Joachim Breitner2017-11-081-18/+19
| | | | | | | | | | | | as nested unfoldings are linted together with the top-level unfolding, and lintUnfolding does the wrong things for nestd unfoldings that mention join points. The easiest way of doing that was to pass a TopLevel flag through `tcUnfolding`, which is invoked both for top level and nested unfoldings. Differential Revision: https://phabricator.haskell.org/D4169
* Track the order of user-written tyvars in DataConRyan Scott2017-10-031-4/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After typechecking a data constructor's type signature, its type variables are partitioned into two distinct groups: the universally quantified type variables and the existentially quantified type variables. Then, when prompted for the type of the data constructor, GHC gives this: ```lang=haskell MkT :: forall <univs> <exis>. (...) ``` For H98-style datatypes, this is a fine thing to do. But for GADTs, this can sometimes produce undesired results with respect to `TypeApplications`. For instance, consider this datatype: ```lang=haskell data T a where MkT :: forall b a. b -> T a ``` Here, the user clearly intended to have `b` be available for visible type application before `a`. That is, the user would expect `MkT @Int @Char` to be of type `Int -> T Char`, //not// `Char -> T Int`. But alas, up until now that was not how GHC operated—regardless of the order in which the user actually wrote the tyvars, GHC would give `MkT` the type: ```lang=haskell MkT :: forall a b. b -> T a ``` Since `a` is universal and `b` is existential. This makes predicting what order to use for `TypeApplications` quite annoying, as demonstrated in #11721 and #13848. This patch cures the problem by tracking more carefully the order in which a user writes type variables in data constructor type signatures, either explicitly (with a `forall`) or implicitly (without a `forall`, in which case the order is inferred). This is accomplished by adding a new field `dcUserTyVars` to `DataCon`, which is a subset of `dcUnivTyVars` and `dcExTyVars` that is permuted to the order in which the user wrote them. For more details, refer to `Note [DataCon user type variables]` in `DataCon.hs`. An interesting consequence of this design is that more data constructors require wrappers. This is because the workers always expect the first arguments to be the universal tyvars followed by the existential tyvars, so when the user writes the tyvars in a different order, a wrapper type is needed to swizzle the tyvars around to match the order that the worker expects. For more details, refer to `Note [Data con wrappers and GADT syntax]` in `MkId.hs`. Test Plan: ./validate Reviewers: austin, goldfire, bgamari, simonpj Reviewed By: goldfire, simonpj Subscribers: ezyang, goldfire, rwbarton, thomie GHC Trac Issues: #11721, #13848 Differential Revision: https://phabricator.haskell.org/D3687
* compiler: introduce custom "GhcPrelude" PreludeHerbert Valerio Riedel2017-09-191-0/+2
| | | | | | | | | | | | | | | | | | This switches the compiler/ component to get compiled with -XNoImplicitPrelude and a `import GhcPrelude` is inserted in all modules. This is motivated by the upcoming "Prelude" re-export of `Semigroup((<>))` which would cause lots of name clashes in every modulewhich imports also `Outputable` Reviewers: austin, goldfire, bgamari, alanz, simonmar Reviewed By: bgamari Subscribers: goldfire, rwbarton, thomie, mpickering, bgamari Differential Revision: https://phabricator.haskell.org/D3989
* Small refactor of getRuntimeRepSimon Peyton Jones2017-08-291-1/+1
| | | | | | | | | Instead of using a string argument, use HasDebugCallStack. (Oddly, some functions were using both!) Plus, use getRuntimeRep rather than getRuntimeRep_maybe when if the caller panics on Nothing. Less code, and a better debug stack.
* Fix hs-boot knot-tying with record wild cards.Edward Z. Yang2017-07-281-1/+8
| | | | | | | | | | | | | | | | | | Fixes #13710. Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu> Test Plan: validate Reviewers: bgamari, austin, simonpj Reviewed By: simonpj Subscribers: simonpj, rwbarton, thomie GHC Trac Issues: #13710 Differential Revision: https://phabricator.haskell.org/D3743
* Preserve CoVar uniques during pretty printingRichard Eisenberg2017-07-271-0/+1
| | | | Previously, we did this for Types, but not for Coercions.
* Fix binder visiblity for default methodsSimon Peyton Jones2017-07-261-1/+1
| | | | | | | | | | | | | | | | | | | Trac #13998 showed that default methods were getting bogus tyvar binder visiblity info; and that it matters in the code genreated by the default-method fill-in mechanism * The actual fix: in TcTyDecls.mkDefaultMethodType, make TyVarBinders with the right visibility info by getting TyConBinders from the class TyCon. (Previously we made up visiblity info, but that caused #13998.) * Define TyCon.tyConTyVarBinders :: [TyConBinder] -> [TyVarBinder] which can build correct forall binders for a) default methods (Trac #13998) b) data constructors This was originally BuildTyCl.mkDataConUnivTyVarBinders * Move mkTyVarBinder, mkTyVarBinders from Type to Var
* Make IfaceAxiom typechecking lazier.Edward Z. Yang2017-07-201-1/+8
| | | | | | | | | | | | | | | | | | Fixes #13803, but adds a note about a yet to be fixed #13981. Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu> Test Plan: validate Reviewers: bgamari, austin Reviewed By: bgamari Subscribers: simonpj, rwbarton, thomie GHC Trac Issues: #13803 Differential Revision: https://phabricator.haskell.org/D3742
* Comments only [ci skip]Gabor Greif2017-03-091-1/+1
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* Read COMPLETE sets from external packagesBen Gamari2017-03-061-12/+2
| | | | | | | | | | | | | | | | | | | | | | Currently, `COMPLETE` pragmas are not read from external packages at all, which quite limits their usefulness. This extends `ExternalPackageState` to include `COMPLETE` sets from other packages, and plumbs around the appropriate values to make it work the way you'd expect it to. Requires a `binary` submodule update. Fixes #13350. Test Plan: make test TEST=T13350 Reviewers: rwbarton, mpickering, austin, simonpj, bgamari Reviewed By: simonpj Subscribers: simonpj, thomie Differential Revision: https://phabricator.haskell.org/D3257
* Revert "Read COMPLETE sets from external packages"Ben Gamari2017-03-031-2/+12
| | | | This reverts commit 0d2f733050ff656b827351108d988e09abc363fc.
* Read COMPLETE sets from external packagesRyan Scott2017-03-021-12/+2
| | | | | | | | | | | | | | | | | | | | Currently, `COMPLETE` pragmas are not read from external packages at all, which quite limits their usefulness. This extends `ExternalPackageState` to include `COMPLETE` sets from other packages, and plumbs around the appropriate values to make it work the way you'd expect it to. Fixes #13350. Test Plan: make test TEST=T13350 Reviewers: rwbarton, mpickering, austin, simonpj, bgamari Reviewed By: simonpj Subscribers: simonpj, thomie Differential Revision: https://phabricator.haskell.org/D3257
* Fix roles merging to apply only to non-rep-injective types.Edward Z. Yang2017-03-021-2/+47
| | | | | | | | Test Plan: validate Reviewers: simonpj Subscribers:
* Properly represent abstract classes in Class and IfaceDeclEdward Z. Yang2017-03-021-18/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: Previously, abstract classes looked very much like normal classes, except that they happened to have no methods, superclasses or ATs, and they came from boot files. This patch gives abstract classes a proper representation in Class and IfaceDecl, by moving the things which are never defined for abstract classes into ClassBody/IfaceClassBody. Because Class is abstract, this change had ~no disruption to any of the code in GHC; if you ask about the methods of an abstract class, we'll just give you an empty list. This also fixes a bug where abstract type classes were incorrectly treated as representationally injective (they're not!) Fixes #13347, and a TODO in the code. Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu> Test Plan: validate Reviewers: simonpj, bgamari, austin Subscribers: goldfire, thomie Differential Revision: https://phabricator.haskell.org/D3236
* Improve pretty-printing of typesSimon Peyton Jones2017-02-281-1/+1
| | | | | | | | | | | | | | | | | | | | | | | When doing debug-printing it's really important that the free vars of a type are printed with their uniques. The IfaceTcTyVar thing was a stab in that direction, but it only worked for TcTyVars, not TyVars. This patch does it properly, by keeping track of the free vars of the type when translating Type -> IfaceType, and passing that down through toIfaceTypeX. Then when we find a variable, look in that set, and translate it to IfaceFreeTyVar if so. (I renamed IfaceTcTyVar to IfaceFreeTyVar.) Fiddly but not difficult. Reviewers: austin, goldfire, bgamari Reviewed By: bgamari Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D3201
* Subtyping for roles in signatures.Edward Z. Yang2017-02-261-5/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: This commit implements the plan in #13140: * Today, roles in signature files default to representational. Let's change the default to nominal, as this is the most flexible implementation side. If a client of the signature needs to coerce with a type, the signature can be adjusted to have more stringent requirements. * If a parameter is declared as nominal in a signature, it can be implemented by a data type which is actually representational. * When merging abstract data declarations, we take the smallest role for every parameter. The roles are considered fix once we specify the structure of an ADT. * Critically, abstract types are NOT injective, so we aren't allowed to make inferences like "if T a ~R T b, then a ~N b" based on the nominal role of a parameter in an abstract type (this would be unsound if the parameter ended up being phantom.) This restriction is similar to the restriction we have on newtypes. Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu> Test Plan: validate Reviewers: simonpj, bgamari, austin, goldfire Subscribers: goldfire, thomie Differential Revision: https://phabricator.haskell.org/D3123
* Treat all TyCon with hole names as skolem abstract.Edward Z. Yang2017-02-261-2/+2
| | | | | | | | | | | | | | | Summary: Fixes #13335. Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu> Test Plan: validate Reviewers: goldfire, austin, simonpj, bgamari Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D3211
* Record full FieldLabel in ifConFields.Edward Z. Yang2017-02-241-18/+6
| | | | | | | | | | | | | | | | | | | | | | Summary: The previous implementation tried to be "efficient" by storing field names once in IfaceConDecls, and only just enough information for us to reconstruct the FieldLabel. But this came at a bit of code complexity cost. This patch undos the optimization, instead storing a full FieldLabel at each data constructor. Consequently, this fixes bugs #12699 and #13250. Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu> Test Plan: validate Reviewers: adamgundry, bgamari, austin Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D3174
* Fix a Backpack recompilation avoidance bug when signatures change.Edward Z. Yang2017-02-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: Recompilation avoidance checks if -this-unit-id has changed by relying on the "wanted module" check in readIface ("Something is amiss..."). Unfortunately, this check didn't check if the instantiation made sense, which meant that if you changed the signatures of a Backpack package, we'd still treat the old signatures as up-to-date. The way I fixed this was by having findAndReadIface take in a 'Module' representing the /actual/ module we were intending to lookup. We convert this into the 'Module' we expect to see in 'mi_module' and now do a more elaborate check that will also verify that instantiations make sense. Along the way, I robustified the logging infrastructure for recompilation checking, and folded wrongIfaceModErr (which was dead code) into the error message. Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu> Test Plan: validate Reviewers: bgamari, austin Subscribers: thomie, snowleopard Differential Revision: https://phabricator.haskell.org/D3130
* Make interface loading for COMPLETE pragmas lazyMatthew Pickering2017-02-011-2/+3
| | | | | | | | | | | | | | | | | Without this additional laziness we will loop forever trying to find the definitions of the conlikes referenced in the pragma. Fixes #13188 Reviewers: austin, RyanGlScott, bgamari Reviewed By: bgamari Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D3058 GHC Trac Issues: #13188
* Join pointsLuke Maurer2017-02-011-4/+9
| | | | | | | | | | | | | | | | | | | This major patch implements Join Points, as described in https://ghc.haskell.org/trac/ghc/wiki/SequentCore. You have to read that page, and especially the paper it links to, to understand what's going on; but it is very cool. It's Luke Maurer's work, but done in close collaboration with Simon PJ. This Phab is a squash-merge of wip/join-points branch of http://github.com/lukemaurer/ghc. There are many, many interdependent changes. Reviewers: goldfire, mpickering, bgamari, simonmar, dfeuer, austin Subscribers: simonpj, dfeuer, mpickering, Mikolaj, thomie Differential Revision: https://phabricator.haskell.org/D2853
* COMPLETE pragmas for enhanced pattern exhaustiveness checkingMatthew Pickering2017-01-261-0/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds a new pragma so that users can specify `COMPLETE` sets of `ConLike`s in order to sate the pattern match checker. A function which matches on all the patterns in a complete grouping will not cause the exhaustiveness checker to emit warnings. ``` pattern P :: () pattern P = () {-# COMPLETE P #-} foo P = () ``` This example would previously have caused the checker to warn that all cases were not matched even though matching on `P` is sufficient to make `foo` covering. With the addition of the pragma, the compiler will recognise that matching on `P` alone is enough and not emit any warnings. Reviewers: goldfire, gkaracha, alanz, austin, bgamari Reviewed By: alanz Subscribers: lelf, nomeata, gkaracha, thomie Differential Revision: https://phabricator.haskell.org/D2669 GHC Trac Issues: #8779
* Rewrite Backpack comments on never-exported TyThings.Edward Z. Yang2017-01-221-21/+29
| | | | | | | | | | | | | | | | | | | | | Summary: While thesing, I realized this part of the implementation didn't make very much sense, so I started working on some documentation updates to try to make things more explainable. The new docs are organized around the idea of a "never exported TyThing" (a non-implicit TyThing that never occurs in the export list of a module). I also removed some outdated information that predated the change of ModIface to store Names rather than OccNames. Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu> Reviewers: simonpj, bgamari, austin Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2989
* Update levity polymorphismRichard Eisenberg2017-01-191-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit implements the proposal in https://github.com/ghc-proposals/ghc-proposals/pull/29 and https://github.com/ghc-proposals/ghc-proposals/pull/35. Here are some of the pieces of that proposal: * Some of RuntimeRep's constructors have been shortened. * TupleRep and SumRep are now parameterized over a list of RuntimeReps. * This means that two types with the same kind surely have the same representation. Previously, all unboxed tuples had the same kind, and thus the fact above was false. * RepType.typePrimRep and friends now return a *list* of PrimReps. These functions can now work successfully on unboxed tuples. This change is necessary because we allow abstraction over unboxed tuple types and so cannot always handle unboxed tuples specially as we did before. * We sometimes have to create an Id from a PrimRep. I thus split PtrRep * into LiftedRep and UnliftedRep, so that the created Ids have the right strictness. * The RepType.RepType type was removed, as it didn't seem to help with * much. * The RepType.repType function is also removed, in favor of typePrimRep. * I have waffled a good deal on whether or not to keep VoidRep in TyCon.PrimRep. In the end, I decided to keep it there. PrimRep is *not* represented in RuntimeRep, and typePrimRep will never return a list including VoidRep. But it's handy to have in, e.g., ByteCodeGen and friends. I can imagine another design choice where we have a PrimRepV type that is PrimRep with an extra constructor. That seemed to be a heavier design, though, and I'm not sure what the benefit would be. * The last, unused vestiges of # (unliftedTypeKind) have been removed. * There were several pretty-printing bugs that this change exposed; * these are fixed. * We previously checked for levity polymorphism in the types of binders. * But we also must exclude levity polymorphism in function arguments. This is hard to check for, requiring a good deal of care in the desugarer. See Note [Levity polymorphism checking] in DsMonad. * In order to efficiently check for levity polymorphism in functions, it * was necessary to add a new bit of IdInfo. See Note [Levity info] in IdInfo. * It is now safe for unlifted types to be unsaturated in Core. Core Lint * is updated accordingly. * We can only know strictness after zonking, so several checks around * strictness in the type-checker (checkStrictBinds, the check for unlifted variables under a ~ pattern) have been moved to the desugarer. * Along the way, I improved the treatment of unlifted vs. banged * bindings. See Note [Strict binds checks] in DsBinds and #13075. * Now that we print type-checked source, we must be careful to print * ConLikes correctly. This is facilitated by a new HsConLikeOut constructor to HsExpr. Particularly troublesome are unlifted pattern synonyms that get an extra void# argument. * Includes a submodule update for haddock, getting rid of #. * New testcases: typecheck/should_fail/StrictBinds typecheck/should_fail/T12973 typecheck/should_run/StrictPats typecheck/should_run/T12809 typecheck/should_fail/T13105 patsyn/should_fail/UnliftedPSBind typecheck/should_fail/LevPolyBounded typecheck/should_compile/T12987 typecheck/should_compile/T11736 * Fixed tickets: #12809 #12973 #11736 #13075 #12987 * This also adds a test case for #13105. This test case is * "compile_fail" and succeeds, because I want the testsuite to monitor the error message. When #13105 is fixed, the test case will compile cleanly.
* Spelling fixes in comments [ci skip]Gabor Greif2017-01-181-1/+1
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* Typos in manual, comments and testsGabor Greif2017-01-121-1/+1
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* Improve coment in typecheckIfacesForMerging.Edward Z. Yang2017-01-111-21/+36
| | | | Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
* Fix handling of closed type families in Backpack.Edward Z. Yang2017-01-111-29/+57
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: A few related problems: - CoAxioms, like DFuns, are implicit and never exported, so we have to make sure we treat them the same way as DFuns: in RnModIface we need to rename references to them with rnIfaceImplicit and in mergeSignatures we need to NOT check them directly for compatibility (the test on the type family will do this check for us.) - But actually, we weren't checking if the axioms WERE consistent. This is because we were forwarding all embedded CoAxiom references in the type family TyThing to the merged version, but that reference was what checkBootDeclM was using as a comparison point. This is similar to a problem we saw with DFuns. To fix this, I refactored the handling of implicit entities in TcIface for Backpack. See Note [The implicit TypeEnv] for the gory details. Instead of passing the TypeEnv around explicitly, we stuffed it in IfLclEnv. Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu> Test Plan: validate Reviewers: bgamari, simonpj, austin Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2928
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