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* Module hierarchy: Hs (#13009)Sylvain Henry2019-09-201-2417/+0
| | | | | | | Add GHC.Hs module hierarchy replacing hsSyn. Metric Increase: haddock.compiler
* Banish reportFloatingViaTvs to the shadow realm (#15831, #16181)Ryan Scott2019-07-261-1/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | GHC used to reject programs of this form: ``` newtype Age = MkAge Int deriving Eq via Const Int a ``` That's because an earlier implementation of `DerivingVia` would generate the following instance: ``` instance Eq Age where (==) = coerce @(Const Int a -> Const Int a -> Bool) @(Age -> Age -> Bool) (==) ``` Note that the `a` in `Const Int a` is not bound anywhere, which causes all sorts of issues. I figured that no one would ever want to write code like this anyway, so I simply banned "floating" `via` type variables like `a`, checking for their presence in the aptly named `reportFloatingViaTvs` function. `reportFloatingViaTvs` ended up being implemented in a subtly incorrect way, as #15831 demonstrates. Following counsel with the sage of gold fire, I decided to abandon `reportFloatingViaTvs` entirely and opt for a different approach that would _accept_ the instance above. This is because GHC now generates this instance instead: ``` instance forall a. Eq Age where (==) = coerce @(Const Int a -> Const Int a -> Bool) @(Age -> Age -> Bool) (==) ``` Notice that we now explicitly quantify the `a` in `instance forall a. Eq Age`, so everything is peachy scoping-wise. See `Note [Floating `via` type variables]` in `TcDeriv` for the full scoop. A pleasant benefit of this refactoring is that it made it much easier to catch the problem observed in #16181, so this patch fixes that issue too. Fixes #15831. Fixes #16181.
* Drop unused helpers 'mkTyClGroup' and 'emptyTyClGroup'Vladislav Zavialov2019-07-241-13/+1
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* Use an empty data type in TTG extension constructors (#15247)Ryan Scott2019-07-091-91/+91
| | | | | | | | | | | | | | | To avoid having to `panic` any time a TTG extension constructor is consumed, this MR introduces an uninhabited 'NoExtCon' type and uses that in every extension constructor's type family instance where it is appropriate. This also introduces a 'noExtCon' function which eliminates a 'NoExtCon', much like 'Data.Void.absurd' eliminates a 'Void'. I also renamed the existing `NoExt` type to `NoExtField` to better distinguish it from `NoExtCon`. Unsurprisingly, there is a lot of code churn resulting from this. Bumps the Haddock submodule. Fixes #15247.
* Print role annotations in TemplateHaskell brackets (#16718)Vladislav Zavialov2019-06-101-0/+1
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* Comments only: document tcdDataCusk better.Richard Eisenberg2019-06-091-0/+5
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* Use HsTyPats in associated type family defaultsRyan Scott2019-05-221-56/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Associated type family default declarations behave strangely in a couple of ways: 1. If one tries to bind the type variables with an explicit `forall`, the `forall`'d part will simply be ignored. (#16110) 2. One cannot use visible kind application syntax on the left-hand sides of associated default equations, unlike every other form of type family equation. (#16356) Both of these issues have a common solution. Instead of using `LHsQTyVars` to represent the left-hand side arguments of an associated default equation, we instead use `HsTyPats`, which is what other forms of type family equations use. In particular, here are some highlights of this patch: * `FamEqn` is no longer parameterized by a `pats` type variable, as the `feqn_pats` field is now always `HsTyPats`. * The new design for `FamEqn` in chronicled in `Note [Type family instance declarations in HsSyn]`. * `TyFamDefltEqn` now becomes the same thing as `TyFamInstEqn`. This means that many of `TyFamDefltEqn`'s code paths can now reuse the code paths for `TyFamInstEqn`, resulting in substantial simplifications to various parts of the code dealing with associated type family defaults. Fixes #16110 and #16356.
* Guard CUSKs behind a language pragmaVladislav Zavialov2019-05-141-10/+20
| | | | | | | | | | | | | | GHC Proposal #36 describes a transition plan away from CUSKs and to top-level kind signatures: 1. Introduce a new extension, -XCUSKs, on by default, that detects CUSKs as they currently exist. 2. We turn off the -XCUSKs extension in a few releases and remove it sometime thereafter. This patch implements phase 1 of this plan, introducing a new language extension to control whether CUSKs are enabled. When top-level kind signatures are implemented, we can transition to phase 2.
* 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 Scott2019-03-151-1/+1
| | | | | This moves all URL references to Trac tickets to their corresponding GitLab counterparts.
* Visible dependent quantificationRyan Scott2019-03-011-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This implements GHC proposal 35 (https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0035-forall-arrow.rst) by adding the ability to write kinds with visible dependent quantification (VDQ). Most of the work for supporting VDQ was actually done _before_ this patch. That is, GHC has been able to reason about kinds with VDQ for some time, but it lacked the ability to let programmers directly write these kinds in the source syntax. This patch is primarly about exposing this ability, by: * Changing `HsForAllTy` to add an additional field of type `ForallVisFlag` to distinguish between invisible `forall`s (i.e, with dots) and visible `forall`s (i.e., with arrows) * Changing `Parser.y` accordingly The rest of the patch mostly concerns adding validity checking to ensure that VDQ is never used in the type of a term (as permitting this would require full-spectrum dependent types). This is accomplished by: * Adding a `vdqAllowed` predicate to `TcValidity`. * Introducing `splitLHsSigmaTyInvis`, a variant of `splitLHsSigmaTy` that only splits invisible `forall`s. This function is used in certain places (e.g., in instance declarations) to ensure that GHC doesn't try to split visible `forall`s (e.g., if it tried splitting `instance forall a -> Show (Blah a)`, then GHC would mistakenly allow that declaration!) This also updates Template Haskell by introducing a new `ForallVisT` constructor to `Type`. Fixes #16326. Also fixes #15658 by documenting this feature in the users' guide.
* Minor refactor of CUSK handlingSimon Peyton Jones2019-02-081-10/+19
| | | | | | | | | Previously, in getFamDeclInitialKind, we were figuring out whether the enclosing class decl had a CUSK very indirectly, via tcTyConIsPoly. This patch just makes the computation much more direct and easy to grok. No change in behaviour.
* A few typofixesGabor Greif2019-01-231-1/+1
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* Visible kind applicationmynguyen2019-01-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | Summary: This patch implements visible kind application (GHC Proposal 15/#12045), as well as #15360 and #15362. It also refactors unnamed wildcard handling, and requires that type equations in type families in Template Haskell be written with full type on lhs. PartialTypeSignatures are on and warnings are off automatically with visible kind application, just like in term-level. There are a few remaining issues with this patch, as documented in ticket #16082. Includes a submodule update for Haddock. Test Plan: Tests T12045a/b/c/TH1/TH2, T15362, T15592a Reviewers: simonpj, goldfire, bgamari, alanz, RyanGlScott, Iceland_jack Subscribers: ningning, Iceland_jack, RyanGlScott, int-index, rwbarton, mpickering, carter GHC Trac Issues: `#12045`, `#15362`, `#15592`, `#15788`, `#15793`, `#15795`, `#15797`, `#15799`, `#15801`, `#15807`, `#15816` Differential Revision: https://phabricator.haskell.org/D5229
* Taming the Kind Inference MonsterSimon Peyton Jones2018-11-291-34/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* More explicit foralls (GHC Proposal 0007)Matthew Yacavone2018-10-271-33/+52
| | | | | | | | | | | | | | | | | | | | | | | | | | | Allow the user to explicitly bind type/kind variables in type and data family instances (including associated instances), closed type family equations, and RULES pragmas. Follows the specification of GHC Proposal 0007, also fixes #2600. Advised by Richard Eisenberg. This modifies the Template Haskell AST -- old code may break! Other Changes: - convert HsRule to a record - make rnHsSigWcType more general - add repMaybe to DsMeta Includes submodule update for Haddock. Test Plan: validate Reviewers: goldfire, bgamari, alanz Subscribers: simonpj, RyanGlScott, goldfire, rwbarton, thomie, mpickering, carter GHC Trac Issues: #2600, #14268 Differential Revision: https://phabricator.haskell.org/D4894
* Fix #15761 by adding parensRichard Eisenberg2018-10-171-7/+9
| | | | | | This was just a pretty-printer infelicity. Fixed now. Test case: printer/T15761
* Add a solveEqualities to tcClassDecl1Simon Peyton Jones2018-08-211-3/+4
| | | | | | | | | | | | | | Trac #15505 showed that, when we have a type error, we could have an unfilled-in coercion hole. We don't want an assertion error in that case. The underlying cause is that tcClassDecl1 should call solveEqualities to fully solve all top-level equalities (or fail in the attempt). I also refactored the ClassDecl case for tcTyClDecl1 into a new function tcClassDecl1. That makes it symmetrical with the others.
* Fix pretty-printing of data declarations in splicesKrzysztof Gogolewski2018-07-221-2/+2
| | | | | | | | | | | | | | Test Plan: validate Reviewers: RyanGlScott, bgamari Reviewed By: RyanGlScott Subscribers: rwbarton, thomie, carter GHC Trac Issues: #15365 Differential Revision: https://phabricator.haskell.org/D4998
* Comments onlySimon Peyton Jones2018-07-131-0/+3
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* Improve comments about CUSKsSimon Peyton Jones2018-07-131-23/+70
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* More refactoring in TcValiditySimon Peyton Jones2018-07-101-2/+2
| | | | | | | | | | | | | | | This patch responds to Trac #15334 by making it an error to write an instance declaration for a tuple constraint like (Eq [a], Show [a]). I then discovered that instance validity checking was scattered betweeen TcInstDcls and TcValidity, so I took the time to bring it all together, into TcValidity.checkValidInstHead In doing so I discovered that there are lot of special cases. I have not changed them, but at least they are all laid out clearly now.
* Refactor the kind-checking of tyvar bindersSimon Peyton Jones2018-06-251-13/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The refactoring here is driven by the ghastly mess described in comment:24 of Trac #1520. The overall goal is to simplify the kind-checking of typev-variable binders, and in particular to narrow the use of the "in-scope tyvar binder" stuff, which is needed only for associated types: see the new Note [Kind-checking tyvar binders for associated types] in TcHsType. Now * The "in-scope tyvar binder" stuff is done only in - kcLHsQTyVars, which is used for the LHsQTyVars of a data/newtype, or type family declaration. - tcFamTyPats, which is used for associated family instances; it now calls tcImplicitQTKBndrs, which in turn usese newFlexiKindedQTyVar * tcExpicitTKBndrs (which is used only for function signatures, data con signatures, pattern synonym signatures, and expression type signatures) now does not go via the "in-scope tyvar binder" stuff at all. While I'm still not happy with all this code, the code is generally simpler, and I think this is a useful step forward. It does cure the problem too. (It's hard to trigger the problem in vanilla Haskell code, because the renamer would normally use different names for nested binders, so I can't offer a test.)
* Fix API Annotations for GADT constructorsAlan Zimmerman2018-06-191-2/+5
| | | | | | | | | | | | | | | | | | | Summary: This patch completes the work for #14529 by making sure that all API Annotations end up attached to a SrcSpan that appears in the final ParsedSource. Updates Haddock submodule Test Plan: ./validate Reviewers: goldfire, bgamari Subscribers: rwbarton, thomie, mpickering, carter GHC Trac Issues: #14529 Differential Revision: https://phabricator.haskell.org/D4867
* Embrace -XTypeInType, add -XStarIsTypeVladislav Zavialov2018-06-141-5/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: Implement the "Embrace Type :: Type" GHC proposal, .../ghc-proposals/blob/master/proposals/0020-no-type-in-type.rst GHC 8.0 included a major change to GHC's type system: the Type :: Type axiom. Though casual users were protected from this by hiding its features behind the -XTypeInType extension, all programs written in GHC 8+ have the axiom behind the scenes. In order to preserve backward compatibility, various legacy features were left unchanged. For example, with -XDataKinds but not -XTypeInType, GADTs could not be used in types. Now these restrictions are lifted and -XTypeInType becomes a redundant flag that will be eventually deprecated. * Incorporate the features currently in -XTypeInType into the -XPolyKinds and -XDataKinds extensions. * Introduce a new extension -XStarIsType to control how to parse * in code and whether to print it in error messages. Test Plan: Validate Reviewers: goldfire, hvr, bgamari, alanz, simonpj Reviewed By: goldfire, simonpj Subscribers: rwbarton, thomie, mpickering, carter GHC Trac Issues: #15195 Differential Revision: https://phabricator.haskell.org/D4748
* Introduce DerivingViaRyan Scott2018-06-041-5/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This implements the `DerivingVia` proposal put forth in https://github.com/ghc-proposals/ghc-proposals/pull/120. This introduces the `DerivingVia` deriving strategy. This is a generalization of `GeneralizedNewtypeDeriving` that permits the user to specify the type to `coerce` from. The major change in this patch is the introduction of the `ViaStrategy` constructor to `DerivStrategy`, which takes a type as a field. As a result, `DerivStrategy` is no longer a simple enumeration type, but rather something that must be renamed and typechecked. The process by which this is done is explained more thoroughly in section 3 of this paper ( https://www.kosmikus.org/DerivingVia/deriving-via-paper.pdf ), although I have inlined the relevant parts into Notes where possible. There are some knock-on changes as well. I took the opportunity to do some refactoring of code in `TcDeriv`, especially the `mkNewTypeEqn` function, since it was bundling all of the logic for (1) deriving instances for newtypes and (2) `GeneralizedNewtypeDeriving` into one huge broth. `DerivingVia` reuses much of part (2), so that was factored out as much as possible. Bumps the Haddock submodule. Test Plan: ./validate Reviewers: simonpj, bgamari, goldfire, alanz Subscribers: alanz, goldfire, rwbarton, thomie, mpickering, carter GHC Trac Issues: #15178 Differential Revision: https://phabricator.haskell.org/D4684
* vectorise: Put it out of its miseryBen Gamari2018-06-021-149/+4
| | | | | | | | | | | | | | | | | | | | | 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
* Fix #14875 by introducing PprPrec, and using itRyan Scott2018-05-131-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Trying to determine when to insert parentheses during TH conversion is a bit of a mess. There is an assortment of functions that try to detect this, such as: * `hsExprNeedsParens` * `isCompoundHsType` * `hsPatNeedsParens` * `isCompoundPat` * etc. To make things worse, each of them have slightly different semantics. Plus, they don't work well in the presence of explicit type signatures, as #14875 demonstrates. All of these problems can be alleviated with the use of an explicit precedence argument (much like what `showsPrec` currently does). To accomplish this, I introduce a new `PprPrec` data type, and define standard predences for things like function application, infix operators, function arrows, and explicit type signatures (that last one is new). I then added `PprPrec` arguments to the various `-NeedsParens` functions, and use them to make smarter decisions about when things need to be parenthesized. A nice side effect is that functions like `isCompoundHsType` are now completely unneeded, since they're simply aliases for `hsTypeNeedsParens appPrec`. As a result, I did a bit of refactoring to remove these sorts of functions. I also did a pass over various utility functions in GHC for constructing AST forms and used more appropriate precedences where convenient. Along the way, I also ripped out the existing `TyPrec` data type (which was tailor-made for pretty-printing `Type`s) and replaced it with `PprPrec` for consistency. Test Plan: make test TEST=T14875 Reviewers: alanz, goldfire, bgamari Reviewed By: bgamari Subscribers: rwbarton, thomie, carter GHC Trac Issues: #14875 Differential Revision: https://phabricator.haskell.org/D4688
* TTG : complete for balance of hsSyn ASTAlan Zimmerman2018-04-271-199/+424
| | | | | | | | | | | | | | | | | | 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
* TTG for HsBinds and Data instances Plan BAlan Zimmerman2018-04-131-33/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Restore Trees That Grow reverted commitsAlan Zimmerman2018-04-091-32/+33
| | | | | | | | | | | | | | | | | | The following commits were reverted prior to the release of GHC 8.4.1, because the time to derive Data instances was too long [1]. 438dd1cbba13d35f3452b4dcef3f94ce9a216905 Phab:D4147 e3ec2e7ae94524ebd111963faf34b84d942265b4 Phab:D4177 47ad6578ea460999b53eb4293c3a3b3017a56d65 Phab:D4186 The work is continuing, as the minimum bootstrap compiler is now GHC 8.2.1, and this allows Plan B[2] for instances to be used. This will land in a following commit. Updates Haddock submodule [1] https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow/Instances [2] https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow/Instances#PLANB
* Remove HasSourceText and SourceTextX classesAlan Zimmerman2018-04-071-69/+58
| | | | | | | | Updates haddock submodule to match. Test Plan : Validate Differential Revision: https://phabricator.haskell.org/D4199
* Track type variable scope more carefully.Richard Eisenberg2018-03-311-3/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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}
* Allow PartialTypeSignatures in standalone deriving contextsRyan Scott2018-03-231-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: At its core, this patch is a simple tweak that allows a user to write: ```lang=haskell deriving instance _ => Eq (Foo a) ``` Which is functionally equivalent to: ```lang=haskell data Foo a = ... deriving Eq ``` But with the added flexibility that `StandaloneDeriving` gives you (namely, the ability to use it anywhere, not just in the same module that `Foo` was declared in). This fixes #13324, and should hopefully address a use case brought up in #10607. Currently, only the use of a single, extra-constraints wildcard is permitted in a standalone deriving declaration. Any other wildcard is rejected, so things like `deriving instance (Eq a, _) => Eq (Foo a)` are currently forbidden. There are quite a few knock-on changes brought on by this change: * The `HsSyn` type used to represent standalone-derived instances was previously `LHsSigType`, which isn't sufficient to hold wildcard types. This needed to be changed to `LHsSigWcType` as a result. * Previously, `DerivContext` was a simple type synonym for `Maybe ThetaType`, under the assumption that you'd only ever be in the `Nothing` case if you were in a `deriving` clause. After this patch, that assumption no longer holds true, as you can also be in this situation with standalone deriving when an extra-constraints wildcard is used. As a result, I changed `DerivContext` to be a proper datatype that reflects the new wrinkle that this patch adds, and plumbed this through the relevant parts of `TcDeriv` and friends. * Relatedly, the error-reporting machinery in `TcErrors` also assumed that if you have any unsolved constraints in a derived instance, then you should be able to fix it by switching over to standalone deriving. This was always sound advice before, but with this new feature, it's possible to have unsolved constraints even when you're standalone-deriving something! To rectify this, I tweaked some constructors of `CtOrigin` a bit to reflect this new subtlety. This requires updating the Haddock submodule. See my fork at https://github.com/RyanGlScott/haddock/commit/067d52fd4be15a1842cbb05f42d9d482de0ad3a7 Test Plan: ./validate Reviewers: simonpj, goldfire, bgamari Reviewed By: simonpj Subscribers: goldfire, rwbarton, thomie, mpickering, carter GHC Trac Issues: #13324 Differential Revision: https://phabricator.haskell.org/D4383
* Fix #14817 by not double-printing data family instance kind signaturesRyan Scott2018-03-021-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | Within `pprDataFamInstDecl`, we were invoking `pprFamInstLHS` to pretty-print a data family instance header, and we were passing `Just` a kind signature to `pprFamInstLHS` to make it pretty-print the kind signature alongside it (this is a consequence of commit d1ef223cfebd23c25489a4b0c67fbaa2f91c1ec6). But this is silly, because then invoke `pp_data_defn`, which //also// pretty-prints the kind signature, resulting in the kind signature being printed twice by mistake. This fix is simple—pass `Nothing` to `pprFamInstLHS` instead. Test Plan: make test TEST=T14817 Reviewers: alanz, bgamari, mpickering Reviewed By: mpickering Subscribers: mpickering, rwbarton, thomie, carter GHC Trac Issues: #14817 Differential Revision: https://phabricator.haskell.org/D4418
* Refactor ConDecl: Trac #14529Simon Peyton Jones2017-12-071-53/+87
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch refactors HsDecls.ConDecl. Specifically * ConDeclGADT was horrible, with all the information hidden inside con_res_ty. Now it's kept separate, as it should be. * ConDeclH98: use [LHsTyVarBndr] instead of LHsQTyVars for the existentials. There is no implicit binding here. * Add a field con_forall to both ConDeclGADT and ConDeclH98 which says if there is an explicit user-written forall. * Field renamings in ConDecl con_cxt to con_mb_cxt con_details to con_args There is an accompanying submodule update to Haddock. Also the following change turned out to remove a lot of clutter: * add a smart constructor for HsAppsTy, namely mkHsAppsTy, and use it consistently. This avoids a lot of painful pattern matching for the common singleton case. Two api-annotation tests (T10278, and T10399) are broken, hence marking them as expect_broken(14529). Alan is going to fix them, probably by changing the con_forall field to con_forall :: Maybe SrcSpan instead of Bool
* Revert "trees that grow" workBen Gamari2017-11-211-104/+102
| | | | | | | | | | | | | | 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 47ad6578ea460999b53eb4293c3a3b3017a56d65. This reverts commit e3ec2e7ae94524ebd111963faf34b84d942265b4. This reverts commit 438dd1cbba13d35f3452b4dcef3f94ce9a216905. This reverts commit 0ff152c9e633accca48815e26e59d1af1fe44ceb.
* TTG3 Combined Step 1 and 3 for Trees That GrowAlan Zimmerman2017-11-141-3/+3
| | | | | | | | | | | | | | | | | | | 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
* WIP on Doing a combined Step 1 and 3 for Trees That GrowAlan Zimmerman2017-11-081-99/+101
| | | | | | | | | | | | | | | | | | | | | | | | | 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
* Revert "WIP on combining Step 1 and 3 of Trees That Grow"Ben Gamari2017-11-071-78/+76
| | | | | | | | This reverts commit 0ff152c9e633accca48815e26e59d1af1fe44ceb. Sadly this broke when bootstrapping with 8.0.2 due to #14396. Reverts haddock submodule.
* WIP on combining Step 1 and 3 of Trees That GrowAlan Zimmerman2017-11-071-76/+78
| | | | | | | | | | | | | | | | | | | | | | | | | 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
* Pretty-printing of derived multi-parameter classes omits parenthesesAlan Zimmerman2017-10-111-2/+3
| | | | | | | | | | | | | | | | | | | Summary: Pretty printing a splice with an HsAppType in the deriving clause, such as $([d| data Foo a = Foo a deriving (C a) |]) would omit the parens. Test Plan: ./validate Reviewers: RyanGlScott, austin, bgamari Subscribers: rwbarton, thomie GHC Trac Issues: #14289 Differential Revision: https://phabricator.haskell.org/D4056
* Pretty-printer missing parens for infix class declarationAlan Zimmerman2017-10-021-0/+4
| | | | | | | | | | class (a `C` b) c Is pretty printed as class a `C` b c Fixes #14306
* 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
* Refactor type family instance abstract syntax declarationsRyan Scott2017-08-291-63/+82
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This implements @simonpj's suggested refactoring of the abstract syntax for type/data family instances (from https://ghc.haskell.org/trac/ghc/ticket/14131#comment:9). This combines the previously separate `TyFamEqn` and `DataFamInstDecl` types into a single `FamEqn` datatype. This also factors the `HsImplicitBndrs` out of `HsTyPats` in favor of putting them just outside of `FamEqn` (as opposed to before, where all of the implicit binders were embedded inside of `TyFamEqn`/`DataFamInstDecl`). Finally, along the way I noticed that `dfid_fvs` and `tfid_fvs` were completely unused, so I removed them. Aside from some changes in parser test output, there is no change in behavior. Requires a Haddock submodule commit from my fork (at https://github.com/RyanGlScott/haddock/commit/815d2deb9c0222c916becccf84 64b740c26255fd) Test Plan: ./validate Reviewers: simonpj, austin, goldfire, bgamari, alanz Reviewed By: bgamari Subscribers: mpickering, goldfire, rwbarton, thomie, simonpj GHC Trac Issues: #14131 Differential Revision: https://phabricator.haskell.org/D3881
* Comments onlySimon Peyton Jones2017-08-291-3/+3
| | | | Better comment on con_qvars in ConDecl
* Comments, plus adjust debug print of TcTyThing(ATyVar)Simon Peyton Jones2017-08-251-1/+1
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* Fix #14045 by omitting an unnecessary checkRichard Eisenberg2017-07-291-8/+14
| | | | | | | | | | | | | | | | | | | | | | | Previously, we checked the number of patterns in a data instances for all data families whose kind did not end in a kind variable. But, of course, undersaturating instances can happen even without the kind ending in a kind variable. So I've omitted the arity check. Data families aren't as particular about their arity as type families are (because data families can be undersaturated). Still, this change degrades error messages when instances don't have the right arity; now, instead of reporting a simple mismatch in the number of patterns, GHC reports kind errors. The new errors are fully accurate, but perhaps not as easy to work with. Still, with the new flexibility of allowing data family instances with varying numbers of patterns, I don't see a better way. This commit also improves source fidelity in some error messages, requiring more changes than really are necessary. But without these changes, error messages around mismatched associated instance heads were poor. test cases: indexed-types/should_compile/T14045, indexed-types/should_fail/T14045a
* Udate hsSyn AST to use Trees that GrowAlan Zimmerman2017-06-061-250/+281
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Remove HsContext from ppr_mono_ty, and remove ppParendHsTypeAlan Zimmerman2017-05-281-4/+4
| | | | This is a cleanup after Trac #13238, as the context was no longer being used.
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