- Jul 05, 2023
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Numerous tests make use of CUSKs (complete user-supplied kinds), a legacy feature scheduled for deprecation. In order to proceed with the said deprecation, the tests have been updated to use SAKS instead (standalone kind signatures). This also allows us to remove the Haskell2010 language pragmas that were added in 115cd3c8 to work around the lack of CUSKs in GHC2021.
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- Jul 03, 2023
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This addresses the work of ticket #20118 Created the following constructors for TcRnMessage - TcRnInaccessibleCoAxBranch - TcRnPatersonCondFailure
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- Jun 17, 2023
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GHC Proposal #425 "Invisible binders in type declarations" restricts the scope of type and data family instances as follows: In type family and data family instances, require that every variable mentioned on the RHS must also occur on the LHS. For example, here are three equivalent type instance definitions accepted before this patch: type family F1 a :: k type instance F1 Int = Any :: j -> j type family F2 a :: k type instance F2 @(j -> j) Int = Any :: j -> j type family F3 a :: k type instance forall j. F3 Int = Any :: j -> j - In F1, j is implicitly quantified and it occurs only on the RHS; - In F2, j is implicitly quantified and it occurs both on the LHS and the RHS; - In F3, j is explicitly quantified. Now F1 is rejected with an out-of-scope error, while F2 and F3 continue to be accepted.
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- Jun 07, 2023
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Vladislav Zavialov authored
This patch implements @k-binders introduced in GHC Proposal #425 and guarded behind the TypeAbstractions extension: type D :: forall k j. k -> j -> Type data D @k @j a b = ... ^^ ^^ To represent the new syntax, we modify LHsQTyVars as follows: - hsq_explicit :: [LHsTyVarBndr () pass] + hsq_explicit :: [LHsTyVarBndr (HsBndrVis pass) pass] HsBndrVis is a new data type that records the distinction between type variable binders written with and without the @ sign: data HsBndrVis pass = HsBndrRequired | HsBndrInvisible (LHsToken "@" pass) The rest of the patch updates GHC, template-haskell, and haddock to handle the new syntax. Parser: The PsErrUnexpectedTypeAppInDecl error message is removed. The syntax it used to reject is now permitted. Renamer: The @ sign does not affect the scope of a binder, so the changes to the renamer are minimal. See rnLHsTyVarBndrVisFlag. Type checker: There are three code paths that were updated to deal with the newly introduced invisible type variable binders: 1. checking SAKS: see kcCheckDeclHeader_sig, matchUpSigWithDecl 2. checking CUSK: see kcCheckDeclHeader_cusk 3. inference: see kcInferDeclHeader, rejectInvisibleBinders Helper functions bindExplicitTKBndrs_Q_Skol and bindExplicitTKBndrs_Q_Tv are generalized to work with HsBndrVis. Updates the haddock submodule. Metric Increase: MultiLayerModulesTH_OneShot Co-authored-by:
Simon Peyton Jones <simon.peytonjones@gmail.com>
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- May 24, 2023
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This patch migrates the error messages in GHC.Tc.Validity to use the new diagnostic infrastructure. It adds the constructors: - TcRnSimplifiableConstraint - TcRnArityMismatch - TcRnIllegalInstanceDecl, with sub-datatypes for HasField errors and fundep coverage condition errors.
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- May 23, 2023
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This refactoring makes a substantial improvement in the structure of the type-checker's constraint solver: #23070. Specifically: * Introduced the SolverStage monad. See GHC.Tc.Solver.Monad Note [The SolverStage monad] * Make each solver pipeline (equalities, dictionaries, irreds etc) deal with updating the inert set, as a separate SolverStage. There is sometimes special stuff to do, and it means that each full pipeline can have type SolverStage Void, indicating that they never return anything. * Made GHC.Tc.Solver.Equality.zonkEqTypes into a SolverStage. Much nicer. * Combined the remnants of GHC.Tc.Solver.Canonical and GHC.Tc.Solver.Interact into a new module GHC.Tc.Solver.Solve. (Interact and Canonical are removed.) * Gave the same treatment to dictionary and irred constraints as I have already done for equality constraints: * New types (akin to EqCt): IrredCt and DictCt * Ct is now just a simple sum type data Ct = CDictCan DictCt | CIrredCan IrredCt | CEqCan EqCt | CQuantCan QCInst | CNonCanonical CtEvidence * inert_dicts can now have the better type DictMap DictCt, instead of DictMap Ct; and similarly inert_irreds. * Significantly simplified the treatment of implicit parameters. Previously we had a number of special cases * interactGivenIP, an entire function * special case in maybeKickOut * special case in findDict, when looking up dictionaries But actually it's simpler than that. When adding a new Given, implicit parameter constraint to the InertSet, we just need to kick out any existing inert constraints that mention that implicit parameter. The main work is done in GHC.Tc.Solver.InertSet.delIPDict, along with its auxiliary GHC.Core.Predicate.mentionsIP. See Note [Shadowing of implicit parameters] in GHC.Tc.Solver.Dict. * Add a new fast-path in GHC.Tc.Errors.Hole.tcCheckHoleFit. See Note [Fast path for tcCheckHoleFit]. This is a big win in some cases: test hard_hole_fits gets nearly 40% faster (at compile time). * Add a new fast-path for solving /boxed/ equality constraints (t1 ~ t2). See Note [Solving equality classes] in GHC.Tc.Solver.Dict. This makes a big difference too: test T17836 compiles 40% faster. * Implement the PermissivePlan of #23413, which concerns what happens with insoluble Givens. Our previous treatment was wildly inconsistent as that ticket pointed out. A part of this, I simplified GHC.Tc.Validity.checkAmbiguity: now we simply don't run the ambiguity check at all if -XAllowAmbiguousTypes is on. Smaller points: * In `GHC.Tc.Errors.misMatchOrCND` instead of having a special case for insoluble /occurs/ checks, broaden in to all insouluble constraints. Just generally better. See Note [Insoluble mis-match] in that module. As noted above, compile time perf gets better. Here are the changes over 0.5% on Fedora. (The figures are slightly larger on Windows for some reason.) Metrics: compile_time/bytes allocated ------------------------------------- LargeRecord(normal) -0.9% MultiLayerModulesTH_OneShot(normal) +0.5% T11822(normal) -0.6% T12227(normal) -1.8% GOOD T12545(normal) -0.5% T13035(normal) -0.6% T15703(normal) -1.4% GOOD T16875(normal) -0.5% T17836(normal) -40.7% GOOD T17836b(normal) -12.3% GOOD T17977b(normal) -0.5% T5837(normal) -1.1% T8095(normal) -2.7% GOOD T9020(optasm) -1.1% hard_hole_fits(normal) -37.0% GOOD geo. mean -1.3% minimum -40.7% maximum +0.5% Metric Decrease: T12227 T15703 T17836 T17836b T8095 hard_hole_fits LargeRecord T9198 T13035
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- May 19, 2023
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This patch addresses #23408, a tricky case with data family newtype instances. Consider type family TF a where TF Char = Bool data family DF a newtype instance DF Bool = MkDF Int and [W] Int ~R# DF (TF a), with a Given (a ~# Char). We must fully rewrite the Wanted so the tpye family can fire; that wasn't happening.
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Oleg Grenrus authored
This change makes command line argument parsing use diagnostic framework for producing warnings.
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- May 18, 2023
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Addresses #23398. The demand analyser usually does not unpack class dictionaries: see Note [Do not unbox class dictionaries] in GHC.Core.Opt.DmdAnal. This patch makes an exception for tuple dictionaries and equality dictionaries, for reasons explained in wrinkles (DNB1) and (DNB2) of the above Note. Compile times fall by 0.1% for some reason (max 0.7% on T18698b).
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- May 15, 2023
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This commit migrates the errors in GHC.Tc.Module to use the new diagnostic infrastructure. It required a significant overhaul of the compatibility checks between an hs-boot or signature module and its implementation; we now use a Writer monad to accumulate errors; see the BootMismatch datatype in GHC.Tc.Errors.Types, with its panoply of subtypes. For the sake of readability, several local functions inside the 'checkBootTyCon' function were split off into top-level functions. We split off GHC.Types.HscSource into a "boot or sig" vs "normal hs file" datatype, as this mirrors the logic in several other places where we want to treat hs-boot and hsig files in a similar fashion. This commit also refactors the Backpack checks for type synonyms implementing abstract data, to correctly reject implementations that contain qualified or quantified types (this fixes #23342 and #23344).
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- May 13, 2023
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This patch continues the refactoring of the constraint solver described in #23070. The Big Deal in this patch is to call the regular, eager unifier from the constraint solver, when we want to create new equalities. This replaces the existing, unifyWanted which amounted to yet-another-unifier, so it reduces duplication of a rather subtle piece of technology. See * Note [The eager unifier] in GHC.Tc.Utils.Unify * GHC.Tc.Solver.Monad.wrapUnifierTcS I did lots of other refactoring along the way * I simplified the treatment of right hand sides that contain CoercionHoles. Now, a constraint that contains a hetero-kind CoercionHole is non-canonical, and cannot be used for rewriting or unification alike. This required me to add the ch_hertero_kind flag to CoercionHole, with consequent knock-on effects. See wrinkle (2) of `Note [Equalities with incompatible kinds]` in GHC.Tc.Solver.Equality. * I refactored the StopOrContinue type to add StartAgain, so that after a fundep improvement (for example) we can simply start the pipeline again. * I got rid of the unpleasant (and inefficient) rewriterSetFromType/Co functions. With Richard I concluded that they are never needed. * I discovered Wrinkle (W1) in Note [Wanteds rewrite Wanteds] in GHC.Tc.Types.Constraint, and therefore now prioritise non-rewritten equalities. Quite a few error messages change, I think always for the better. Compiler runtime stays about the same, with one outlier: a 17% improvement in T17836 Metric Decrease: T17836 T18223
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- May 05, 2023
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Tracking ticket: #20115 MR: !10350 This converts uses of `mkTcRnUnknownMessage` to newly added constructors of `TcRnMessage`.
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- Apr 14, 2023
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This MR substantially refactors the way in which the constraint solver deals with equality constraints. The big thing is: * Intead of a pipeline in which we /first/ canonicalise and /then/ interact (the latter including performing unification) the two steps are more closely integreated into one. That avoids the current rather indirect communication between the two steps. The proximate cause for this refactoring is fixing #22194, which involve solving [W] alpha[2] ~ Maybe (F beta[4]) by doing this: alpha[2] := Maybe delta[2] [W] delta[2] ~ F beta[4] That is, we don't promote beta[4]! This is very like introducing a cycle breaker, and was very awkward to do before, but now it is all nice. See GHC.Tc.Utils.Unify Note [Promotion and level-checking] and Note [Family applications in canonical constraints]. The big change is this: * Several canonicalisation checks (occurs-check, cycle-breaking, checking for concreteness) are combined into one new function: GHC.Tc.Utils.Unify.checkTyEqRhs This function is controlled by `TyEqFlags`, which says what to do for foralls, type families etc. * `canEqCanLHSFinish` now sees if unification is possible, and if so, actually does it: see `canEqCanLHSFinish_try_unification`. There are loads of smaller changes: * The on-the-fly unifier `GHC.Tc.Utils.Unify.unifyType` has a cheap-and-cheerful version of `checkTyEqRhs`, called `simpleUnifyCheck`. If `simpleUnifyCheck` succeeds, it can unify, otherwise it defers by emitting a constraint. This is simpler than before. * I simplified the swapping code in `GHC.Tc.Solver.Equality.canEqCanLHS`. Especially the nasty stuff involving `swap_for_occurs` and `canEqTyVarFunEq`. Much nicer now. See Note [Orienting TyVarLHS/TyFamLHS] Note [Orienting TyFamLHS/TyFamLHS] * Added `cteSkolemOccurs`, `cteConcrete`, and `cteCoercionHole` to the problems that can be discovered by `checkTyEqRhs`. * I fixed #23199 `pickQuantifiablePreds`, which actually allows GHC to to accept both cases in #22194 rather than rejecting both. Yet smaller: * Added a `synIsConcrete` flag to `SynonymTyCon` (alongside `synIsFamFree`) to reduce the need for synonym expansion when checking concreteness. Use it in `isConcreteType`. * Renamed `isConcrete` to `isConcreteType` * Defined `GHC.Core.TyCo.FVs.isInjectiveInType` as a more efficient way to find if a particular type variable is used injectively than finding all the injective variables. It is called in `GHC.Tc.Utils.Unify.definitely_poly`, which in turn is used quite a lot. * Moved `rewriterView` to `GHC.Core.Type`, so we can use it from the constraint solver. Fixes #22194, #23199 Compile times decrease by an average of 0.1%; but there is a 7.4% drop in compiler allocation on T15703. Metric Decrease: T15703
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- Apr 01, 2023
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Tracking ticket: #20117 MR: !10183 This converts uses of `mkTcRnUnknownMessage` to newly added constructors of `TcRnMessage`.
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- Mar 06, 2023
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I've turned almost all occurrences of TcRnUnknownMessage in GHC.Rename.Module module into a proper TcRnMessage. Instead, these TcRnMessage messages were introduced: TcRnIllegalInstanceHeadDecl TcRnUnexpectedStandaloneDerivingDecl TcRnUnusedVariableInRuleDecl TcRnUnexpectedStandaloneKindSig TcRnIllegalRuleLhs TcRnBadAssocRhs TcRnDuplicateRoleAnnot TcRnDuplicateKindSig TcRnIllegalDerivStrategy TcRnIllegalMultipleDerivClauses TcRnNoDerivStratSpecified TcRnStupidThetaInGadt TcRnBadImplicitSplice TcRnShadowedTyVarNameInFamResult TcRnIncorrectTyVarOnLhsOfInjCond TcRnUnknownTyVarsOnRhsOfInjCond Was introduced one helper type: RuleLhsErrReason
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- Jan 28, 2023
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This fixes the fact that we were not reporting orphan family instances at all. The fix here is easy, but touches a bit of code. I refactored the code to be much more similar to the way that class instances are done: - Add a fi_orphan field to FamInst, like the is_orphan field in ClsInst - Make newFamInst initialise this field, just like newClsInst - And make newFamInst report a warning for an orphan, just like newClsInst - I moved newFamInst from GHC.Tc.Instance.Family to GHC.Tc.Utils.Instantiate, just like newClsInst. - I added mkLocalFamInst to FamInstEnv, just like mkLocalClsInst in InstEnv - TcRnOrphanInstance and SuggestFixOrphanInstance are now parametrised over class instances vs type/data family instances. Fixes #19773 -
We were treating a type-family instance as a non-orphan if there was a type constructor on its /right-hand side/ that was local. Boo! Utterly wrong. With this patch, we correctly check the /left-hand side/ instead! Fixes #22717
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- Jan 11, 2023
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This patch completely re-engineers how we deal with loopy superclass dictionaries in instance declarations. It fixes #20666 and #19690 The highlights are * Recognise that the loopy-superclass business should use precisely the Paterson conditions. This is much much nicer. See Note [Recursive superclasses] in GHC.Tc.TyCl.Instance * With that in mind, define "Paterson-smaller" in Note [Paterson conditions] in GHC.Tc.Validity, and the new data type `PatersonSize` in GHC.Tc.Utils.TcType, along with functions to compute and compare PatsonSizes * Use the new PatersonSize stuff when solving superclass constraints See Note [Solving superclass constraints] in GHC.Tc.TyCl.Instance * In GHC.Tc.Solver.Monad.lookupInInerts, add a missing call to prohibitedSuperClassSolve. This was the original cause of #20666. * Treat (TypeError "stuff") as having PatersonSize zero. See Note [Paterson size for type family applications] in GHC.Tc.Utils.TcType. * Treat the head of a Wanted quantified constraint in the same way as the superclass of an instance decl; this is what fixes #19690. See GHC.Tc.Solver.Canonical Note [Solving a Wanted forall-constraint] (Thanks to Matthew Craven for this insight.) This entailed refactoring the GivenSc constructor of CtOrigin a bit, to say whether it comes from an instance decl or quantified constraint. * Some refactoring way in which redundant constraints are reported; we don't want to complain about the extra, apparently-redundant constraints that we must add to an instance decl because of the loopy-superclass thing. I moved some work from GHC.Tc.Errors to GHC.Tc.Solver. * Add a new section to the user manual to describe the loopy superclass issue and what rules it follows.
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- Dec 15, 2022
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The Lint check for branch compatiblity within an axiom, in GHC.Core.Lint.compatible_branches was subtly different to the check made when contructing an axiom, in GHC.Core.FamInstEnv.compatibleBranches. The latter is correct, so I killed the former and am now using the latter. On the way I did some improvements to pretty-printing and documentation.
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- Nov 29, 2022
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Sylvain Henry authored
Add JS backend adapted from the GHCJS project by Luite Stegeman. Some features haven't been ported or implemented yet. Tests for these features have been disabled with an associated gitlab ticket. Bump array submodule Work funded by IOG. Co-authored-by:
Jeffrey Young <jeffrey.young@iohk.io> Co-authored-by:
Luite Stegeman <stegeman@gmail.com> Co-authored-by:
Josh Meredith <joshmeredith2008@gmail.com>
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Fixes: #217093 Associated to #19415 This change * Flips the orientation of the the generated kind equality coercion in canEqLHSHetero; * Removes `cc_fundeps` in CDictCan as the check was incomplete; * Changes `canDecomposableTyConAppOk` to ensure we process kind equalities before type equalities and avoiding a call to `canEqLHSHetero` while processing wanted TyConApp equalities * Adds 2 new tests for validating the change - testsuites/typecheck/should_compile/T21703.hs and - testsuites/typecheck/should_fail/T19415b.hs (a simpler version of T19415.hs) * Misc: Due to the change in the equality direction some error messages now have flipped type mismatch errors * Changes in Notes: - Note [Fundeps with instances, and equality orientation] supercedes Note [Fundeps with instances] - Added Note [Kind Equality Orientation] to visualize the kind flipping - Added Note [Decomposing Dependent TyCons and Processing Wanted Equalties]
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- Nov 25, 2022
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Before this patch, GHC unconditionally printed ticks before promoted data constructors: ghci> type T = True -- unticked (user-written) ghci> :kind! T T :: Bool = 'True -- ticked (compiler output) After this patch, GHC prints ticks only when necessary: ghci> type F = False -- unticked (user-written) ghci> :kind! F F :: Bool = False -- unticked (compiler output) ghci> data False -- introduce ambiguity ghci> :kind! F F :: Bool = 'False -- ticked by necessity (compiler output) The old behavior can be enabled by -fprint-redundant-promotion-ticks. Summary of changes: * Rename PrintUnqualified to NamePprCtx * Add QueryPromotionTick to it * Consult the GlobalRdrEnv to decide whether to print a tick (see mkPromTick) * Introduce -fprint-redundant-promotion-ticks Co-authored-by:Artyom Kuznetsov <hi@wzrd.ht>
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- Nov 11, 2022
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This big patch addresses the rats-nest of issues that have plagued us for years, about the relationship between Type and Constraint. See #11715/#21623. The main payload of the patch is: * To introduce CONSTRAINT :: RuntimeRep -> Type * To make TYPE and CONSTRAINT distinct throughout the compiler Two overview Notes in GHC.Builtin.Types.Prim * Note [TYPE and CONSTRAINT] * Note [Type and Constraint are not apart] This is the main complication. The specifics * New primitive types (GHC.Builtin.Types.Prim) - CONSTRAINT - ctArrowTyCon (=>) - tcArrowTyCon (-=>) - ccArrowTyCon (==>) - funTyCon FUN -- Not new See Note [Function type constructors and FunTy] and Note [TYPE and CONSTRAINT] * GHC.Builtin.Types: - New type Constraint = CONSTRAINT LiftedRep - I also stopped nonEmptyTyCon being built-in; it only needs to be wired-in * Exploit the fact that Type and Constraint are distinct throughout GHC - Get rid of tcView in favour of coreView. - Many tcXX functions become XX functions. e.g. tcGetCastedTyVar --> getCastedTyVar * Kill off Note [ForAllTy and typechecker equality], in (old) GHC.Tc.Solver.Canonical. It said that typechecker-equality should ignore the specified/inferred distinction when comparein two ForAllTys. But that wsa only weakly supported and (worse) implies that we need a separate typechecker equality, different from core equality. No no no. * GHC.Core.TyCon: kill off FunTyCon in data TyCon. There was no need for it, and anyway now we have four of them! * GHC.Core.TyCo.Rep: add two FunTyFlags to FunCo See Note [FunCo] in that module. * GHC.Core.Type. Lots and lots of changes driven by adding CONSTRAINT. The key new function is sORTKind_maybe; most other changes are built on top of that. See also `funTyConAppTy_maybe` and `tyConAppFun_maybe`. * Fix a longstanding bug in GHC.Core.Type.typeKind, and Core Lint, in kinding ForAllTys. See new tules (FORALL1) and (FORALL2) in GHC.Core.Type. (The bug was that before (forall (cv::t1 ~# t2). blah), where blah::TYPE IntRep, would get kind (TYPE IntRep), but it should be (TYPE LiftedRep). See Note [Kinding rules for types] in GHC.Core.Type. * GHC.Core.TyCo.Compare is a new module in which we do eqType and cmpType. Of course, no tcEqType any more. * GHC.Core.TyCo.FVs. I moved some free-var-like function into this module: tyConsOfType, visVarsOfType, and occCheckExpand. Refactoring only. * GHC.Builtin.Types. Compiletely re-engineer boxingDataCon_maybe to have one for each /RuntimeRep/, rather than one for each /Type/. This dramatically widens the range of types we can auto-box. See Note [Boxing constructors] in GHC.Builtin.Types The boxing types themselves are declared in library ghc-prim:GHC.Types. GHC.Core.Make. Re-engineer the treatment of "big" tuples (mkBigCoreVarTup etc) GHC.Core.Make, so that it auto-boxes unboxed values and (crucially) types of kind Constraint. That allows the desugaring for arrows to work; it gathers up free variables (including dictionaries) into tuples. See Note [Big tuples] in GHC.Core.Make. There is still work to do here: #22336. But things are better than before. * GHC.Core.Make. We need two absent-error Ids, aBSENT_ERROR_ID for types of kind Type, and aBSENT_CONSTRAINT_ERROR_ID for vaues of kind Constraint. Ditto noInlineId vs noInlieConstraintId in GHC.Types.Id.Make; see Note [inlineId magic]. * GHC.Core.TyCo.Rep. Completely refactor the NthCo coercion. It is now called SelCo, and its fields are much more descriptive than the single Int we used to have. A great improvement. See Note [SelCo] in GHC.Core.TyCo.Rep. * GHC.Core.RoughMap.roughMatchTyConName. Collapse TYPE and CONSTRAINT to a single TyCon, so that the rough-map does not distinguish them. * GHC.Core.DataCon - Mainly just improve documentation * Some significant renamings: GHC.Core.Multiplicity: Many --> ManyTy (easier to grep for) One --> OneTy GHC.Core.TyCo.Rep TyCoBinder --> GHC.Core.Var.PiTyBinder GHC.Core.Var TyCoVarBinder --> ForAllTyBinder AnonArgFlag --> FunTyFlag ArgFlag --> ForAllTyFlag GHC.Core.TyCon TyConTyCoBinder --> TyConPiTyBinder Many functions are renamed in consequence e.g. isinvisibleArgFlag becomes isInvisibleForAllTyFlag, etc * I refactored FunTyFlag (was AnonArgFlag) into a simple, flat data type data FunTyFlag = FTF_T_T -- (->) Type -> Type | FTF_T_C -- (-=>) Type -> Constraint | FTF_C_T -- (=>) Constraint -> Type | FTF_C_C -- (==>) Constraint -> Constraint * GHC.Tc.Errors.Ppr. Some significant refactoring in the TypeEqMisMatch case of pprMismatchMsg. * I made the tyConUnique field of TyCon strict, because I saw code with lots of silly eval's. That revealed that GHC.Settings.Constants.mAX_SUM_SIZE can only be 63, because we pack the sum tag into a 6-bit field. (Lurking bug squashed.) Fixes * #21530 Updates haddock submodule slightly. Performance changes ~~~~~~~~~~~~~~~~~~~ I was worried that compile times would get worse, but after some careful profiling we are down to a geometric mean 0.1% increase in allocation (in perf/compiler). That seems fine. There is a big runtime improvement in T10359 Metric Decrease: LargeRecord MultiLayerModulesTH_OneShot T13386 T13719 Metric Increase: T8095
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- Nov 09, 2022
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The following `TcRnDiagnostic` messages have been introduced: TcRnWarnUnsatisfiedMinimalDefinition TcRnMisplacedInstSig TcRnBadBootFamInstDeclErr TcRnIllegalFamilyInstance TcRnAssocInClassErr TcRnBadFamInstDecl TcRnNotOpenFamily
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- Nov 01, 2022
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Ticket #22379 revealed that skolemiseQuantifiedTyVar was dropping the passed-in skol_info on the floor when it encountered a SkolemTv. Bad! Several TyCons thereby share a single SkolemInfo on their binders, which lead to bogus error reports.
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- Oct 26, 2022
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Sylvain Henry authored
Necessary for newer cross-compiling backends (JS, Wasm) that don't support TH yet.
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- Oct 13, 2022
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When a newtype introduces GADT eq_specs due to a defaulted RuntimeRep, we detect this and print the error message with explicit kinds. This also refactors newtype type checking to use the new diagnostic infra. Fixes #21447
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- Sep 28, 2022
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This patch fixes #21286, by not unboxing dictionaries in worker/wrapper (ever). The main payload is tiny: * In `GHC.Core.Opt.DmdAnal.finaliseArgBoxities`, do not unbox dictionaries in `get_dmd`. See Note [Do not unbox class dictionaries] in that module * I also found that imported wrappers were being fruitlessly specialised, so I fixed that too, in canSpecImport. See Note [Specialising imported functions] point (2). In doing due diligence in the testsuite I fixed a number of other things: * Improve Note [Specialising unfoldings] in GHC.Core.Unfold.Make, and Note [Inline specialisations] in GHC.Core.Opt.Specialise, and remove duplication between the two. The new Note describes how we specialise functions with an INLINABLE pragma. And simplify the defn of `spec_unf` in `GHC.Core.Opt.Specialise.specCalls`. * Improve Note [Worker/wrapper for INLINABLE functions] in GHC.Core.Opt.WorkWrap. And (critially) make an actual change which is to propagate the user-written pragma from the original function to the wrapper; see `mkStrWrapperInlinePrag`. * Write new Note [Specialising imported functions] in GHC.Core.Opt.Specialise All this has a big effect on some compile times. This is compiler/perf, showing only changes over 1%: Metrics: compile_time/bytes allocated ------------------------------------- LargeRecord(normal) -50.2% GOOD ManyConstructors(normal) +1.0% MultiLayerModulesTH_OneShot(normal) +2.6% PmSeriesG(normal) -1.1% T10547(normal) -1.2% T11195(normal) -1.2% T11276(normal) -1.0% T11303b(normal) -1.6% T11545(normal) -1.4% T11822(normal) -1.3% T12150(optasm) -1.0% T12234(optasm) -1.2% T13056(optasm) -9.3% GOOD T13253(normal) -3.8% GOOD T15164(normal) -3.6% GOOD T16190(normal) -2.1% T16577(normal) -2.8% GOOD T16875(normal) -1.6% T17836(normal) +2.2% T17977b(normal) -1.0% T18223(normal) -33.3% GOOD T18282(normal) -3.4% GOOD T18304(normal) -1.4% T18698a(normal) -1.4% GOOD T18698b(normal) -1.3% GOOD T19695(normal) -2.5% GOOD T5837(normal) -2.3% T9630(normal) -33.0% GOOD WWRec(normal) -9.7% GOOD hard_hole_fits(normal) -2.1% GOOD hie002(normal) +1.6% geo. mean -2.2% minimum -50.2% maximum +2.6% I diligently investigated some of the big drops. * Caused by not doing w/w for dictionaries: T13056, T15164, WWRec, T18223 * Caused by not fruitlessly specialising wrappers LargeRecord, T9630 For runtimes, here is perf/should+_run: Metrics: runtime/bytes allocated -------------------------------- T12990(normal) -3.8% T5205(normal) -1.3% T9203(normal) -10.7% GOOD haddock.Cabal(normal) +0.1% haddock.base(normal) -1.1% haddock.compiler(normal) -0.3% lazy-bs-alloc(normal) -0.2% ------------------------------------------ geo. mean -0.3% minimum -10.7% maximum +0.1% I did not investigate exactly what happens in T9203. Nofib is a wash: +-------------------------------++--+-----------+-----------+ | || | tsv (rel) | std. err. | +===============================++==+===========+===========+ | real/anna || | -0.13% | 0.0% | | real/fem || | +0.13% | 0.0% | | real/fulsom || | -0.16% | 0.0% | | real/lift || | -1.55% | 0.0% | | real/reptile || | -0.11% | 0.0% | | real/smallpt || | +0.51% | 0.0% | | spectral/constraints || | +0.20% | 0.0% | | spectral/dom-lt || | +1.80% | 0.0% | | spectral/expert || | +0.33% | 0.0% | +===============================++==+===========+===========+ | geom mean || | | | +-------------------------------++--+-----------+-----------+ I spent quite some time investigating dom-lt, but it's pretty complicated. See my note on !7847. Conclusion: it's just a delicate inlining interaction, and we have plenty of those. Metric Decrease: LargeRecord T13056 T13253 T15164 T16577 T18223 T18282 T18698a T18698b T19695 T9630 WWRec hard_hole_fits T9203
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- Sep 13, 2022
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- Aug 19, 2022
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This patch improves the uniformity of error message formatting by printing constraints in quotes, as we do for types. Fix #21167
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- Jul 28, 2022
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Fixes #21866
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- Jul 25, 2022
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There was an assert error, as Gergo pointed out in #21896. I fixed this by adding an InScopeSet argument to tcUnifyTyWithTFs. And also to GHC.Core.Unify.niFixTCvSubst. I also took the opportunity to get a couple more InScopeSets right, and to change some substTyUnchecked into substTy. This MR touches a lot of other files, but only because I also took the opportunity to introduce mkInScopeSetList, and use it.
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This MR adds the language extension -XDeepSubsumption, implementing GHC proposal #511. This change mitigates the impact of GHC proposal The changes are highly localised, by design. See Note [Deep subsumption] in GHC.Tc.Utils.Unify. The main changes are: * Add -XDeepSubsumption, which is on by default in Haskell98 and Haskell2010, but off in Haskell2021. -XDeepSubsumption largely restores the behaviour before the "simple subsumption" change. -XDeepSubsumpition has a similar flavour as -XNoMonoLocalBinds: it makes type inference more complicated and less predictable, but it may be convenient in practice. * The main changes are in: * GHC.Tc.Utils.Unify.tcSubType, which does deep susumption and eta-expanansion * GHC.Tc.Utils.Unify.tcSkolemiseET, which does deep skolemisation * In GHC.Tc.Gen.App.tcApp we call tcSubTypeNC to match the result type. Without deep subsumption, unifyExpectedType would be sufficent. See Note [Deep subsumption] in GHC.Tc.Utils.Unify. * There are no changes to Quick Look at all. * The type of `withDict` becomes ambiguous; so add -XAllowAmbiguousTypes to GHC.Magic.Dict * I fixed a small but egregious bug in GHC.Core.FVs.varTypeTyCoFVs, where we'd forgotten to take the free vars of the multiplicity of an Id. * I also had to fix tcSplitNestedSigmaTys When I did the shallow-subsumption patch commit 2b792fac Date: Sun Feb 2 18:23:11 2020 +0000 Simple subsumption I changed tcSplitNestedSigmaTys to not look through function arrows any more. But that was actually an un-forced change. This function is used only in * Improving error messages in GHC.Tc.Gen.Head.addFunResCtxt * Validity checking for default methods: GHC.Tc.TyCl.checkValidClass * A couple of calls in the GHCi debugger: GHC.Runtime.Heap.Inspect All to do with validity checking and error messages. Acutally its fine to look under function arrows here, and quite useful a test DeepSubsumption05 (a test motivated by a build failure in the `lens` package) shows. The fix is easy. I added Note [tcSplitNestedSigmaTys].
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- Jun 27, 2022
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Previously several tests' output were unnecessarily dependent on version numbers, particularly of `base`. Fix this.
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To 0.9.0 and 4.17.0 respectively. Bumps array, deepseq, directory, filepath, haskeline, hpc, parsec, stm, terminfo, text, unix, haddock, and hsc2hs submodules. (cherry picked from commit ba47b951)
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- Jun 06, 2022
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This commit fixes #20312 It deprecates "TypeInType" extension according to the following proposal: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0083-no-type-in-type.rst It has been already implemented. The migration strategy: 1. Disable TypeInType 2. Enable both DataKinds and PolyKinds extensions Metric Decrease: T16875
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- May 27, 2022
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The function breakTyVarCycle_maybe has been installed in a dark corner of GHC to catch some gremlins (a.k.a. occurs-check failures) who lurk there. But it previously only caught gremlins of the form (a ~ ... F a ...), where some of our intrepid users have spawned gremlins of the form (G a ~ ... F (G a) ...). This commit improves breakTyVarCycle_maybe (and renames it to breakTyEqCycle_maybe) to catch the new gremlins. Happily, the change is remarkably small. The gory details are in Note [Type equality cycles]. Test cases: typecheck/should_compile/{T21515,T21473}.
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- Apr 01, 2022
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Users are supposed to import GHC.Exts rather than GHC.Prim. Part of #18749.
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- Remove unused functions exprToCoercion_maybe, applyTypeToArg, typeMonoPrimRep_maybe, runtimeRepMonoPrimRep_maybe. - Replace orValid with a simpler check - Use splitAtList in applyTysX - Remove calls to extra_clean in the testsuite; it does not do anything. Metric Decrease: T18223
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