- 11 Jan, 2019 1 commit
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Matthew Pickering authored
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
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- 03 Dec, 2018 1 commit
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Simon Peyton Jones authored
In the type checker Constraint and * are distinct; and the function that takes the kind of a type should respect that distinction (Trac #15971). This patch implements the change: * Introduce Type.tcTypeKind, and use it throughout the type inference engine * Add new Note [Kinding rules for types] for the kinding rules, especially for foralls. * Redefine isPredTy ty = tcIsConstraintKind (tcTypeKind ty) (it had a much more complicated definition before) Some miscellaneous refactoring * Get rid of TyCoRep.isTYPE, Kind.isTYPEApp, in favour of TyCoRep.kindRep, kindRep_maybe * Rename Type.getRuntimeRepFromKind_maybe to getRuntimeRep_maybe I did some spot-checks on compiler perf, and it really doesn't budge (as expected).
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- 29 Nov, 2018 1 commit
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Simon Peyton Jones authored
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 5e45ad10 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
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- 24 Nov, 2018 1 commit
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Shayan-Najd authored
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
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- 22 Nov, 2018 1 commit
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David Eichmann authored
This patch fixes a fairly long-standing bug (dating back to 2015) in RdrName.bestImport, namely commit 9376249b 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
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- 29 Oct, 2018 2 commits
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Richard Eisenberg authored
In type-incorrect code, we can sometimes let a coercion hole make it through the zonker. If this coercion hole then ends up in the environment (e.g., in the type of a data constructor), then it causes trouble later. This patch avoids trouble by substituting the coercion hole for its representative CoVar. Really, any coercion would do, but the CoVar was very handy. test case: polykinds/T15787
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Tobias Dammers authored
The real change that fixes the ticket is described in Note [Naughty quantification candidates] in TcMType. Fixing this required reworking candidateQTyVarsOfType, the function that extracts free variables as candidates for quantification. One consequence is that we now must be more careful when quantifying: any skolems around must be quantified manually, and quantifyTyVars will now only quantify over metavariables. This makes good sense, as skolems are generally user-written and are listed in the AST. As a bonus, we now have more control over the ordering of such skolems. Along the way, this commit fixes #15711 and refines the fix to #14552 (by accepted a program that was previously rejected, as we can now accept that program by zapping variables to Any). This commit also does a fair amount of rejiggering kind inference of datatypes. Notably, we now can skip the generalization step in kcTyClGroup for types with CUSKs, because we get the kind right the first time. This commit also thus fixes #15743 and #15592, which both concern datatype kind generalisation. (#15591 is also very relevant.) For this aspect of the commit, see Note [Required, Specified, and Inferred in types] in TcTyClsDecls. Test cases: dependent/should_fail/T14880{,-2}, dependent/should_fail/T15743[cd] dependent/should_compile/T15743{,e} ghci/scripts/T15743b polykinds/T15592 dependent/should_fail/T15591[bc] ghci/scripts/T15591
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- 27 Oct, 2018 1 commit
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mayac authored
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
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- 15 Sep, 2018 1 commit
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Ningning Xie authored
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
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- 31 Aug, 2018 1 commit
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Simon Peyton Jones authored
There was a subtle knot-tying bug in TcHsSyn.zonkTyVarOcc, revealed in Trac #15552. I fixed it by * Eliminating the short-circuiting optimisation in zonkTyVarOcc, instead adding a finite map to get sharing of zonked unification variables. See Note [Sharing when zonking to Type] in TcHsSyn * On the way I /added/ the short-circuiting optimisation to TcMType.zonkTcTyVar, which has no such problem. This turned out (based on non-systematic measurements) to be a modest win. See Note [Sharing in zonking] in TcMType On the way I renamed some of the functions in TcHsSyn: * Ones ending in "X" (like zonkTcTypeToTypeX) take a ZonkEnv * Ones that do not end in "x" (like zonkTcTypeToType), don't. Instead they whiz up an empty ZonkEnv.
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- 24 Aug, 2018 1 commit
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Simon Peyton Jones authored
Triggered by Trac #15552, I'd been looking at ZonkEnv in TcHsSyn. This patch does some minor refactoring * Make ZonkEnv into a record with named fields, and use them. (I'm planning to add a new field, for TyCons, so this prepares the way.) * Replace UnboundTyVarZonker (a higer order function) with the simpler and more self-descriptive ZonkFlexi data type, below. It's just much more perspicuous and direct, and (I suspect) a tiny bit faster too -- no unknown function calls. data ZonkFlexi -- See Note [Un-unified unification variables] = DefaultFlexi -- Default unbound unificaiton variables to Any | SkolemiseFlexi -- Skolemise unbound unification variables -- See Note [Zonking the LHS of a RULE] | RuntimeUnkFlexi -- Used in the GHCi debugger There was one knock-on effect in the GHCi debugger -- the RuntimeUnkFlexi case. Somehow previously, these RuntimeUnk variables were sometimes getting SystemNames (and hence printed as 'a0', 'a1', etc) and sometimes not (and hence printed as 'a', 'b' etc). I'm not sure precisely why, but the new behaviour seems more uniform, so I just accepted the (small) renaming wibbles in some ghci.debugger tests. I had a quick look at perf: any changes are tiny.
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- 01 Aug, 2018 1 commit
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Richard Eisenberg authored
Bug #15380 hangs because a knot-tied TyCon ended up in a kind. Looking at the code in tcInferApps, I'm amazed this hasn't happened before! I couldn't think of a good way to fix it (with dependent types, we can't really keep types out of kinds, after all), so I just went ahead and removed the knot. This was remarkably easy to do. In tcTyVar, when we find a TcTyCon, just use it. (Previously, we looked up the knot-tied TyCon and used that.) Then, during the final zonk, replace TcTyCons with the real, full-blooded TyCons in the global environment. It's all very easy. The new bit is explained in the existing Note [Type checking recursive type and class declarations] in TcTyClsDecls. Naturally, I removed various references to the knot and the zonkTcTypeInKnot (and related) functions. Now, we can print types during type checking with abandon! NB: There is a teensy error message regression with this patch, around the ordering of quantified type variables. This ordering problem is fixed (I believe) with the patch for #14880. The ordering affects only internal variables that cannot be instantiated with any kind of visible type application. There is also a teensy regression around the printing of types in TH splices. I think this is really a TH bug and will file separately. Test case: dependent/should_fail/T15380
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- 25 Jul, 2018 1 commit
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Simon Peyton Jones authored
The cloneWC, cloneWanted, cloneImplication family are used by * TcHoleErrors * TcRule to clone the /bindings/ in a constraint, so that solving the constraint will not add bindings to the program. The idea is only to affect unifications. But I had it wrong -- I failed to clone the EvBindsVar of an implication. That gave an assert failure, I think, as well as useless dead code. The fix is easy. I'm not adding a test case. In the type 'TcEvidence.EvBindsVar', I also renamed the 'NoEvBindsVar' constructor to 'CoEvBindsVar'. It's not that we have /no/ evidence bindings, just that we can only have coercion bindings, done via HoleDest.
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- 22 Jun, 2018 1 commit
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Alan Zimmerman authored
The standard[1] for extension naming is to use the XC prefix for the internal extension points, rather than for a new constructor. This is violated for IPBind, having data IPBind id = IPBind (XIPBind id) (Either (Located HsIPName) (IdP id)) (LHsExpr id) | XCIPBind (XXIPBind id) Swap the usage of XIPBind and XCIPBind [1] https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow#Namingconventions Closes #15302
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- 04 Jun, 2018 1 commit
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Simon Peyton Jones authored
We have wanted quantified constraints for ages and, as I hoped, they proved remarkably simple to implement. All the machinery was already in place. The main ticket is Trac #2893, but also relevant are #5927 #8516 #9123 (especially! higher kinded roles) #14070 #14317 The wiki page is https://ghc.haskell.org/trac/ghc/wiki/QuantifiedConstraints which in turn contains a link to the GHC Proposal where the change is specified. Here is the relevant Note: Note [Quantified constraints] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The -XQuantifiedConstraints extension allows type-class contexts like this: data Rose f x = Rose x (f (Rose f x)) instance (Eq a, forall b. Eq b => Eq (f b)) => Eq (Rose f a) where (Rose x1 rs1) == (Rose x2 rs2) = x1==x2 && rs1 >= rs2 Note the (forall b. Eq b => Eq (f b)) in the instance contexts. This quantified constraint is needed to solve the [W] (Eq (f (Rose f x))) constraint which arises form the (==) definition. Here are the moving parts * Language extension {-# LANGUAGE QuantifiedConstraints #-} and add it to ghc-boot-th:GHC.LanguageExtensions.Type.Extension * A new form of evidence, EvDFun, that is used to discharge such wanted constraints * checkValidType gets some changes to accept forall-constraints only in the right places. * Type.PredTree gets a new constructor ForAllPred, and and classifyPredType analyses a PredType to decompose the new forall-constraints * Define a type TcRnTypes.QCInst, which holds a given quantified constraint in the inert set * TcSMonad.InertCans gets an extra field, inert_insts :: [QCInst], which holds all the Given forall-constraints. In effect, such Given constraints are like local instance decls. * When trying to solve a class constraint, via TcInteract.matchInstEnv, use the InstEnv from inert_insts so that we include the local Given forall-constraints in the lookup. (See TcSMonad.getInstEnvs.) * topReactionsStage calls doTopReactOther for CIrredCan and CTyEqCan, so they can try to react with any given quantified constraints (TcInteract.matchLocalInst) * TcCanonical.canForAll deals with solving a forall-constraint. See Note [Solving a Wanted forall-constraint] Note [Solving a Wanted forall-constraint] * We augment the kick-out code to kick out an inert forall constraint if it can be rewritten by a new type equality; see TcSMonad.kick_out_rewritable Some other related refactoring ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * Move SCC on evidence bindings to post-desugaring, which fixed #14735, and is generally nicer anyway because we can use existing CoreSyn free-var functions. (Quantified constraints made the free-vars of an ev-term a bit more complicated.) * In LookupInstResult, replace GenInst with OneInst and NotSure, using the latter for multiple matches and/or one or more unifiers
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- 02 Jun, 2018 1 commit
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Ben Gamari authored
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
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- 27 Apr, 2018 1 commit
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Alan Zimmerman authored
Summary: - remove PostRn/PostTc fields - remove the HsVect In/Out distinction for Type, Class and Instance - remove PlaceHolder in favour of NoExt - Simplify OutputableX constraint Updates haddock submodule Test Plan: ./validate Reviewers: goldfire, bgamari Subscribers: goldfire, thomie, mpickering, carter Differential Revision: https://phabricator.haskell.org/D4625
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- 13 Apr, 2018 1 commit
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Alan Zimmerman authored
Summary: - Add the balance of the TTG extensions for hsSyn/HsBinds - Move all the (now orphan) data instances into hsSyn/HsInstances and use TTG Data instances Plan B https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow/Instances#PLANB Updates haddock submodule. Illustrative numbers Compiling HsInstances before using Plan B. Max residency ~ 5G <<ghc: 629,864,691,176 bytes, 5300 GCs, 321075437/1087762592 avg/max bytes residency (23 samples), 2953M in use, 0.000 INIT (0.000 elapsed), 383.511 MUT (384.986 elapsed), 37.426 GC (37.444 elapsed) :ghc>> Using Plan B Max residency 1.1G <<ghc: 78,832,782,968 bytes, 2884 GCs, 222140352/386470152 avg/max bytes residency (34 samples), 1062M in use, 0.001 INIT (0.001 elapsed), 56.612 MUT (62.917 elapsed), 32.974 GC (32.923 elapsed) :ghc>> Test Plan: ./validate Reviewers: shayan-najd, goldfire, bgamari Subscribers: goldfire, thomie, mpickering, carter Differential Revision: https://phabricator.haskell.org/D4581
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- 09 Apr, 2018 1 commit
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Alan Zimmerman authored
The following commits were reverted prior to the release of GHC 8.4.1, because the time to derive Data instances was too long [1]. 438dd1cb Phab:D4147 e3ec2e7a Phab:D4177 47ad6578 Phab:D4186 The work is continuing, as the minimum bootstrap compiler is now GHC 8.2.1, and this allows Plan B[2] for instances to be used. This will land in a following commit. Updates Haddock submodule [1] https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow/Instances [2] https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow/Instances#PLANB
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- 01 Apr, 2018 1 commit
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Richard Eisenberg authored
The main job of this commit is to track more accurately the scope of tyvars introduced by user-written foralls. For example, it would be to have something like this: forall a. Int -> (forall k (b :: k). Proxy '[a, b]) -> Bool In that type, a's kind must be k, but k isn't in scope. We had a terrible way of doing this before (not worth repeating or describing here, but see the old tcImplicitTKBndrs and friends), but now we have a principled approach: make an Implication when kind-checking a forall. Doing so then hooks into the existing machinery for preventing skolem-escape, performing floating, etc. This also means that we bump the TcLevel whenever going into a forall. The new behavior is done in TcHsType.scopeTyVars, but see also TcHsType.tc{Im,Ex}plicitTKBndrs, which have undergone significant rewriting. There are several Notes near there to guide you. Of particular interest there is that Implication constraints can now have skolems that are out of order; this situation is reported in TcErrors. A major consequence of this is a slightly tweaked process for type- checking type declarations. The new Note [Use SigTvs in kind-checking pass] in TcTyClsDecls lays it out. The error message for dependent/should_fail/TypeSkolEscape has become noticeably worse. However, this is because the code in TcErrors goes to some length to preserve pre-8.0 error messages for kind errors. It's time to rip off that plaster and get rid of much of the kind-error-specific error messages. I tried this, and doing so led to a lovely error message for TypeSkolEscape. So: I'm accepting the error message quality regression for now, but will open up a new ticket to fix it, along with a larger error-message improvement I've been pondering. This applies also to dependent/should_fail/{BadTelescope2,T14066,T14066e}, polykinds/T11142. Other minor changes: - isUnliftedTypeKind didn't look for tuples and sums. It does now. - check_type used check_arg_type on both sides of an AppTy. But the left side of an AppTy isn't an arg, and this was causing a bad error message. I've changed it to use check_type on the left-hand side. - Some refactoring around when we print (TYPE blah) in error messages. The changes decrease the times when we do so, to good effect. Of course, this is still all controlled by -fprint-explicit-runtime-reps Fixes #14066 #14749 Test cases: dependent/should_compile/{T14066a,T14749}, dependent/should_fail/T14066{,c,d,e,f,g,h}
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- 26 Jan, 2018 1 commit
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Joachim Breitner authored
Ideally, I'd like to do type EvTerm = CoreExpr and the type checker builds the evidence terms as it goes. This failed, becuase the evidence for `Typeable` refers to local identifiers that are added *after* the typechecker solves constraints. Therefore, `EvTerm` stays a data type with two constructors: `EvExpr` for `CoreExpr` evidence, and `EvTypeable` for the others. Delted `Note [Memoising typeOf]`, its reference (and presumably relevance) was removed in 8fa4bf9a. Differential Revision: https://phabricator.haskell.org/D4341
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- 21 Dec, 2017 2 commits
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Simon Peyton Jones authored
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.
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Simon Peyton Jones authored
This is a pure refactoring. Use HsConDetails to implement HsPatSynDetails, instead of defining a whole new data type. Less code, fewer types, all good.
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- 21 Nov, 2017 1 commit
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Ben Gamari authored
As documented in #14490, the Data instances currently blow up compilation time by too much to stomach. Alan will continue working on this in a branch and we will perhaps merge to 8.2 before 8.2.1 to avoid having to perform painful cherry-picks in 8.2 minor releases. Reverts haddock submodule. This reverts commit 47ad6578. This reverts commit e3ec2e7a. This reverts commit 438dd1cb. This reverts commit 0ff152c9.
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- 14 Nov, 2017 1 commit
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Alan Zimmerman authored
Further progress on implementing Trees that Grow on hsSyn AST. See https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow Trees that grow extension points are added for - Rest of HsExpr.hs Updates haddock submodule Test Plan: ./validate Reviewers: bgamari, shayan-najd, goldfire Subscribers: goldfire, rwbarton, thomie, mpickering Differential Revision: https://phabricator.haskell.org/D4186
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- 11 Nov, 2017 1 commit
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Alan Zimmerman authored
See https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow Trees that grow extension points are added for - HsExpr Updates haddock submodule Test Plan: ./validate Reviewers: bgamari, goldfire Subscribers: rwbarton, thomie, shayan-najd, mpickering Differential Revision: https://phabricator.haskell.org/D4177
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- 08 Nov, 2017 1 commit
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Alan Zimmerman authored
See https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow Trees that grow extension points are added for - ValBinds - HsPat - HsLit - HsOverLit - HsType - HsTyVarBndr - HsAppType - FieldOcc - AmbiguousFieldOcc Updates haddock submodule Test Plan: ./validate Reviewers: shayan-najd, simonpj, austin, goldfire, bgamari Subscribers: goldfire, rwbarton, thomie, mpickering Differential Revision: https://phabricator.haskell.org/D4147
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- 07 Nov, 2017 2 commits
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Ben Gamari authored
This reverts commit 0ff152c9. Sadly this broke when bootstrapping with 8.0.2 due to #14396. Reverts haddock submodule.
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Alan Zimmerman authored
See https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow Trees that grow extension points are added for - ValBinds - HsPat - HsLit - HsOverLit - HsType - HsTyVarBndr - HsAppType - FieldOcc - AmbiguousFieldOcc Updates haddock submodule Test Plan: ./validate Reviewers: shayan-najd, simonpj, austin, goldfire, bgamari Subscribers: goldfire, rwbarton, thomie, mpickering Differential Revision: https://phabricator.haskell.org/D4147
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- 27 Oct, 2017 1 commit
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Simon Marlow authored
Summary: It's simple to treat BodyStmt just like a BindStmt with a wildcard pattern, which is enough to fix #12143 without going all the way to using `<*` and `*>` (#10892). Test Plan: * new test cases in `ado004.hs` * validate Reviewers: niteria, simonpj, bgamari, austin, erikd Subscribers: rwbarton, thomie GHC Trac Issues: #12143 Differential Revision: https://phabricator.haskell.org/D4128
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- 05 Oct, 2017 1 commit
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Joachim Breitner authored
this is a remains from supporting Result Type Signaturs in the ancient past. Differential Revision: https://phabricator.haskell.org/D4066
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- 19 Sep, 2017 1 commit
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Herbert Valerio Riedel authored
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
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- 31 Jul, 2017 2 commits
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Simon Peyton Jones authored
This is refactoring only... elimiante all positional uses of the data constructor Match in favour of field names. No change in behaviour.
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Simon Peyton Jones authored
Trac #14035 showed that -XStrict was generating some TERRIBLE desugarings, espcially for bindings with INLINE pragmas. Reason: with -XStrict, all AbsBinds (even for non-recursive functions) went via the general-case deguaring for AbsBinds, namely "generate a tuple and select from it", even though in this case there was only one variable in the tuple. And that in turn interacts terribly badly with INLINE pragmas. This patch cleans things up: * I killed off AbsBindsSig completely, in favour of a boolean flag abs_sig in AbsBinds. See Note [The abs_sig field of AbsBinds] This allowed me to delete lots of code; and instance-method declarations can enjoy the benefits too. (They could have before, but no one had changed them to use AbsBindsSig.) * I refactored all the AbsBinds handling in DsBinds into a new function DsBinds.dsAbsBinds. This allowed me to handle the strict case uniformly
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- 27 Jul, 2017 1 commit
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Richard Eisenberg authored
Previously, a data family's kind had to end in `Type`, and data instances had to list all the type patterns for the family. However, both of these restrictions were unnecessary: - A data family's kind can usefully end in a kind variable `k`. See examples on #12369. - A data instance need not list all patterns, much like how a GADT-style data declaration need not list all type parameters, when a kind signature is in place. This is useful, for example, here: data family Sing (a :: k) data instance Sing :: Bool -> Type where ... This patch also improved a few error messages, as some error plumbing had to be moved around. See new Note [Arity of data families] in FamInstEnv for more info. test case: indexed-types/should_compile/T12369
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- 05 Jun, 2017 1 commit
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Alan Zimmerman authored
Summary: See https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow This commit prepares the ground for a full extensible AST, by replacing the type parameter for the hsSyn data types with a set of indices into type families, data GhcPs -- ^ Index for GHC parser output data GhcRn -- ^ Index for GHC renamer output data GhcTc -- ^ Index for GHC typechecker output These are now used instead of `RdrName`, `Name` and `Id`/`TcId`/`Var` Where the original name type is required in a polymorphic context, this is accessible via the IdP type family, defined as type family IdP p type instance IdP GhcPs = RdrName type instance IdP GhcRn = Name type instance IdP GhcTc = Id These types are declared in the new 'hsSyn/HsExtension.hs' module. To gain a better understanding of the extension mechanism, it has been applied to `HsLit` only, also replacing the `SourceText` fields in them with extension types. To preserve extension generality, a type class is introduced to capture the `SourceText` interface, which must be honoured by all of the extension points which originally had a `SourceText`. The class is defined as class HasSourceText a where -- Provide setters to mimic existing constructors noSourceText :: a sourceText :: String -> a setSourceText :: SourceText -> a getSourceText :: a -> SourceText And the constraint is captured in `SourceTextX`, which is a constraint type listing all the extension points that make use of the class. Updating Haddock submodule to match. Test Plan: ./validate Reviewers: simonpj, shayan-najd, goldfire, austin, bgamari Subscribers: rwbarton, thomie, mpickering Differential Revision: https://phabricator.haskell.org/D3609
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- 26 May, 2017 1 commit
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Simon Peyton Jones authored
The big change here is to fix an outright bug in flattening of Givens, albeit one that is very hard to exhibit. Suppose we have the constraint forall a. (a ~ F b) => ..., (forall c. ....(F b)...) ... Then - we'll flatten the (F) b to a fsk, say (F b ~ fsk1) - we'll rewrite the (F b) inside the inner implication to 'fsk1' - when we leave the outer constraint we are suppose to unflatten; but that fsk1 will still be there - if we re-simplify the entire outer implication, we'll re-flatten the Given (F b) to, say, (F b ~ fsk2) Now we have two fsks standing for the same thing, and that is very wrong. Solution: make fsks behave more like fmvs: - A flatten-skolem is now a MetaTyVar, whose MetaInfo is FlatSkolTv - We "fill in" that meta-tyvar when leaving the implication - The old FlatSkol form of TcTyVarDetails is gone completely - We track the flatten-skolems for the current implication in a new field of InertSet, inert_fsks. See Note [The flattening story] in TcFlatten. In doing this I found various other things to fix: * I removed the zonkSimples from TcFlatten.unflattenWanteds; it wasn't needed. But I added one in TcSimplify.floatEqualities, which does the zonk precisely when it is needed. * Trac #13674 showed up a case where we had - an insoluble Given, e.g. a ~ [a] - the same insoluble Wanted a ~ [a] We don't use the Given to rewwrite the Wanted (obviously), but we therefore ended up reporting Can't deduce (a ~ [a]) from (a ~ [a]) which is silly. Conclusion: when reporting errors, make the occurs check "win" See Note [Occurs check wins] in TcErrors
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- 08 May, 2017 1 commit
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Nolan authored
Reviewers: austin, goldfire, bgamari Reviewed By: bgamari Subscribers: rwbarton, thomie, mpickering GHC Trac Issues: #13211 Differential Revision: https://phabricator.haskell.org/D3543
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- 18 Feb, 2017 1 commit
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Ben Gamari authored
This at long last realizes the ideas for type-indexed Typeable discussed in A Reflection on Types (#11011). The general sketch of the project is described on the Wiki (Typeable/BenGamari). The general idea is that we are adding a type index to `TypeRep`, data TypeRep (a :: k) This index allows the typechecker to reason about the type represented by the `TypeRep`. This index representation mechanism is exposed as `Type.Reflection`, which also provides a number of patterns for inspecting `TypeRep`s, ```lang=haskell pattern TRFun :: forall k (fun :: k). () => forall (r1 :: RuntimeRep) (r2 :: RuntimeRep) (arg :: TYPE r1) (res :: TYPE r2). (k ~ Type, fun ~~ (arg -> res)) => TypeRep arg -> TypeRep res -> TypeRep fun pattern TRApp :: forall k2 (t :: k2). () => forall k1 (a :: k1 -> k2) (b :: k1). (t ~ a b) => TypeRep a -> TypeRep b -> TypeRep t -- | Pattern match on a type constructor. pattern TRCon :: forall k (a :: k). TyCon -> TypeRep a -- | Pattern match on a type constructor including its instantiated kind -- variables. pattern TRCon' :: forall k (a :: k). TyCon -> [SomeTypeRep] -> TypeRep a ``` In addition, we give the user access to the kind of a `TypeRep` (#10343), typeRepKind :: TypeRep (a :: k) -> TypeRep k Moreover, all of this plays nicely with 8.2's levity polymorphism, including the newly levity polymorphic (->) type constructor. Library changes --------------- The primary change here is the introduction of a Type.Reflection module to base. This module provides access to the new type-indexed TypeRep introduced in this patch. We also continue to provide the unindexed Data.Typeable interface, which is simply a type synonym for the existentially quantified SomeTypeRep, data SomeTypeRep where SomeTypeRep :: TypeRep a -> SomeTypeRep Naturally, this change also touched Data.Dynamic, which can now export the Dynamic data constructor. Moreover, I removed a blanket reexport of Data.Typeable from Data.Dynamic (which itself doesn't even import Data.Typeable now). We also add a kind heterogeneous type equality type, (:~~:), to Data.Type.Equality. Implementation -------------- The implementation strategy is described in Note [Grand plan for Typeable] in TcTypeable. None of it was difficult, but it did exercise a number of parts of the new levity polymorphism story which had not yet been exercised, which took some sorting out. The rough idea is that we augment the TyCon produced for each type constructor with information about the constructor's kind (which we call a KindRep). This allows us to reconstruct the monomorphic result kind of an particular instantiation of a type constructor given its kind arguments. Unfortunately all of this takes a fair amount of work to generate and send through the compilation pipeline. In particular, the KindReps can unfortunately get quite large. Moreover, the simplifier will float out various pieces of them, resulting in numerous top-level bindings. Consequently we mark the KindRep bindings as noinline, ensuring that the float-outs don't make it into the interface file. This is important since there is generally little benefit to inlining KindReps and they would otherwise strongly affect compiler performance. Performance ----------- Initially I was hoping to also clear up the remaining holes in Typeable's coverage by adding support for both unboxed tuples (#12409) and unboxed sums (#13276). While the former was fairly straightforward, the latter ended up being quite difficult: while the implementation can support them easily, enabling this support causes thousands of Typeable bindings to be emitted to the GHC.Types as each arity-N sum tycon brings with it N promoted datacons, each of which has a KindRep whose size which itself scales with N. Doing this was simply too expensive to be practical; consequently I've disabled support for the time being. Even after disabling sums this change regresses compiler performance far more than I would like. In particular there are several testcases in the testsuite which consist mostly of types which regress by over 30% in compiler allocations. These include (considering the "bytes allocated" metric), * T1969: +10% * T10858: +23% * T3294: +19% * T5631: +41% * T6048: +23% * T9675: +20% * T9872a: +5.2% * T9872d: +12% * T9233: +10% * T10370: +34% * T12425: +30% * T12234: +16% * 13035: +17% * T4029: +6.1% I've spent quite some time chasing down the source of this regression and while I was able to make som improvements, I think this approach of generating Typeable bindings at time of type definition is doomed to give us unnecessarily large compile-time overhead. In the future I think we should consider moving some of all of the Typeable binding generation logic back to the solver (where it was prior to 91c6b1f5). I've opened #13261 documenting this proposal.
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- 14 Feb, 2017 1 commit
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Adam Gundry authored
This implements automatic constraint solving for the new HasField class and modifies the existing OverloadedLabels extension, as described in the GHC proposal (https://github.com/ghc-proposals/ghc-proposals/pull/6). Per the current form of the proposal, it does *not* currently introduce a separate `OverloadedRecordFields` extension. This replaces D1687. The users guide documentation still needs to be written, but I'll do that after the implementation is merged, in case there are further design changes. Test Plan: new and modified tests in overloadedrecflds Reviewers: simonpj, goldfire, dfeuer, bgamari, austin, hvr Reviewed By: bgamari Subscribers: maninalift, dfeuer, ysangkok, thomie, mpickering Differential Revision: https://phabricator.haskell.org/D2708
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