summaryrefslogtreecommitdiff
path: root/compiler/GHC/Tc
Commit message (Collapse)AuthorAgeFilesLines
...
* Be more careful when reporting unbound RULE bindersSimon Peyton Jones2022-11-191-1/+2
| | | | | | See Note [Variables unbound on the LHS] in GHC.HsToCore.Binds. Fixes #22471.
* Misc cleanupKrzysztof Gogolewski2022-11-161-1/+1
| | | | | | | * Replace catMaybes . map f with mapMaybe f * Use concatFS to concatenate multiple FastStrings * Fix documentation of -exclude-module * Cleanup getIgnoreCount in GHCi.UI
* Type vs Constraint: finally nailedSimon Peyton Jones2022-11-1150-1371/+1237
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Use TcRnDiagnostic in GHC.Tc.TyCl.Instance (#20117)Giles Anderson2022-11-093-48/+151
| | | | | | | | | | | | The following `TcRnDiagnostic` messages have been introduced: TcRnWarnUnsatisfiedMinimalDefinition TcRnMisplacedInstSig TcRnBadBootFamInstDeclErr TcRnIllegalFamilyInstance TcRnAssocInClassErr TcRnBadFamInstDecl TcRnNotOpenFamily
* Fix TypeData issues (fixes #22315 and #22332)Ross Paterson2022-11-083-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | There were two bugs here: 1. Treating type-level constructors as PromotedDataCon doesn't always work, in particular because constructors promoted via DataKinds are called both T and 'T. (Tests T22332a, T22332b, T22315a, T22315b) Fix: guard these cases with isDataKindsPromotedDataCon. 2. Type-level constructors were sent to the code generator, producing things like constructor wrappers. (Tests T22332a, T22332b) Fix: test for them in isDataTyCon. Other changes: * changed the marking of "type data" DataCon's as suggested by SPJ. * added a test TDGADT for a type-level GADT. * comment tweaks * change tcIfaceTyCon to ignore IfaceTyConInfo, so that IfaceTyConInfo is used only for pretty printing, not for typechecking. (SPJ)
* Define `Infinite` list and use where appropriate.M Farkas-Dyck2022-11-085-21/+24
| | | | | | | | Also add perf test for infinite list fusion. In particular, in `GHC.Core`, often we deal with infinite lists of roles. Also in a few locations we deal with infinite lists of names. Thanks to simonpj for helping to write the Note [Fusion for `Infinite` lists].
* Minor refactor around FastStringsKrzysztof Gogolewski2022-11-056-11/+14
| | | | | | | Pass FastStrings to functions directly, to make sure the rule for fsLit "literal" fires. Remove SDoc indirection in GHCi.UI.Tags and GHC.Unit.Module.Graph.
* Export pprTrace and friends from GHC.Prelude.Andreas Klebinger2022-11-033-3/+0
| | | | | Introduces GHC.Prelude.Basic which can be used in modules which are a dependency of the ppr code.
* Add accurate skolem info when quantifyingSimon Peyton Jones2022-11-014-62/+74
| | | | | | | 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.
* Minor SDoc-related cleanupKrzysztof Gogolewski2022-10-282-21/+18
| | | | | | | | | | | * Rename pprCLabel to pprCLabelStyle, and use the name pprCLabel for a function using CStyle (analogous to pprAsmLabel) * Move LabelStyle to the CLabel module, it no longer needs to be in Outputable. * Move calls to 'text' right next to literals, to make sure the text/str rule is triggered. * Remove FastString/String roundtrip in Tc.Deriv.Generate * Introduce showSDocForUser', which abstracts over a pattern in GHCi.UI
* Use TcRnVDQInTermType in noNestedForallsContextsErr (#20115)Vladislav Zavialov2022-10-263-9/+19
| | | | | | | | | | | | | | | | | | | | | When faced with VDQ in the type of a term, GHC generates the following error message: Illegal visible, dependent quantification in the type of a term (GHC does not yet support this) Prior to this patch, there were two ways this message could have been generated and represented: 1. with the dedicated constructor TcRnVDQInTermType (see check_type in GHC.Tc.Validity) 2. with the transitional constructor TcRnUnknownMessage (see noNestedForallsContextsErr in GHC.Rename.Utils) Not only this led to duplication of code generating the final SDoc, it also made it tricky to track the origin of the error message. This patch fixes the problem by using TcRnVDQInTermType exclusively.
* Introduce TcRnWithHsDocContext (#22346)Vladislav Zavialov2022-10-263-15/+22
| | | | | | | | | | | | | | | | | Before this patch, GHC used withHsDocContext to attach an HsDocContext to an error message: addErr $ mkTcRnUnknownMessage $ mkPlainError noHints (withHsDocContext ctxt msg) The problem with this approach is that it only works with TcRnUnknownMessage. But could we attach an HsDocContext to a structured error message in a generic way? This patch solves the problem by introducing a new constructor to TcRnMessage: data TcRnMessage where ... TcRnWithHsDocContext :: !HsDocContext -> !TcRnMessage -> TcRnMessage ...
* Cleanup String/FastString conversionsKrzysztof Gogolewski2022-10-251-4/+4
| | | | | | | Remove unused mkPtrString and isUnderscoreFS. We no longer use mkPtrString since 1d03d8bef96. Remove unnecessary conversions between FastString and String and back.
* Convert Diagnostics in GHC.Tc.Gen.Splice (#20116)Aaron Allen2022-10-245-79/+538
| | | | | | | Replaces uses of `TcRnUnknownMessage` in `GHC.Tc.Gen.Splice` with structured diagnostics. closes #20116
* TyEq:N assertion: only for saturated applicationssheaf2022-10-192-6/+17
| | | | | | | | | | The assertion that checked TyEq:N in canEqCanLHSFinish incorrectly triggered in the case of an unsaturated newtype TyCon heading the RHS, even though we can't unwrap such an application. Now, we only trigger an assertion failure in case of a saturated application of a newtype TyCon. Fixes #22310
* Rename unsafeOverlap_matches -> unsafeOverlap_match in UnsafeOverlapsheaf2022-10-193-6/+4
|
* More precise types for fields of OverlappingInstances and UnsafeOverlap in ↵Bodigrim2022-10-193-34/+23
| | | | | | | | | | TcSolverReportMsg It's clear from asserts in `GHC.Tc.Errors` that `overlappingInstances_matches` and `unsafeOverlapped` are supposed to be non-empty, and `unsafeOverlap_matches` contains a single instance, but these invariants are immediately lost afterwards and not encoded in types. This patch enforces the invariants by pattern matching and makes types more precise, avoiding asserts and partial functions such as `head`.
* Enforce invariant of `ListBag` constructor.M Farkas-Dyck2022-10-191-2/+2
|
* Scrub various partiality involving lists (again).M Farkas-Dyck2022-10-196-26/+29
| | | | Lets us avoid some use of `head` and `tail`, and some panics.
* Add -fsuppress-error-contexts to disable printing error contexts in errorswip/diagnostics-configMatthew Pickering2022-10-181-5/+16
| | | | | | | | | | | | | In many development environments, the source span is the primary means of seeing what an error message relates to, and the In the expression: and In an equation for: clauses are not particularly relevant. However, they can grow to be quite long, which can make the message itself both feel overwhelming and interact badly with limited-space areas. It's simple to implement this flag so we might as well do it and give the user control about how they see their messages. Fixes #21722
* Allow configuration of error message printingMatthew Pickering2022-10-186-22/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This MR implements the idea of #21731 that the printing of a diagnostic method should be configurable at the printing time. The interface of the `Diagnostic` class is modified from: ``` class Diagnostic a where diagnosticMessage :: a -> DecoratedSDoc diagnosticReason :: a -> DiagnosticReason diagnosticHints :: a -> [GhcHint] ``` to ``` class Diagnostic a where type DiagnosticOpts a defaultDiagnosticOpts :: DiagnosticOpts a diagnosticMessage :: DiagnosticOpts a -> a -> DecoratedSDoc diagnosticReason :: a -> DiagnosticReason diagnosticHints :: a -> [GhcHint] ``` and so each `Diagnostic` can implement their own configuration record which can then be supplied by a client in order to dictate how to print out the error message. At the moment this only allows us to implement #21722 nicely but in future it is more natural to separate the configuration of how much information we put into an error message and how much we decide to print out of it. Updates Haddock submodule
* Clearer error msg for newtype GADTs with defaulted kindFinley McIlwaine2022-10-133-41/+97
| | | | | | | | | | | 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
* Export symbolSing, SSymbol, and friends (CLC#85)wip/clc-85Ryan Scott2022-10-061-4/+4
| | | | | | | | | | | | | | | This implements this Core Libraries Proposal: https://github.com/haskell/core-libraries-committee/issues/85 In particular, it: 1. Exposes the `symbolSing` method of `KnownSymbol`, 2. Exports the abstract `SSymbol` type used in `symbolSing`, and 3. Defines an API for interacting with `SSymbol`. This also makes corresponding changes for `natSing`/`KnownNat`/`SNat` and `charSing`/`KnownChar`/`SChar`. This fixes #15183 and addresses part (2) of #21568.
* Scrub various partiality involving empty lists.M Farkas-Dyck2022-09-301-16/+17
| | | | Avoids some uses of `head` and `tail`, and some panics when an argument is null.
* Avoid Data.List.group; prefer Data.List.NonEmpty.groupBodigrim2022-09-281-2/+3
| | | | | This allows to avoid further partiality, e. g., map head . group is replaced by map NE.head . NE.group, and there are less panic calls.
* Refactor UnfoldingSource and IfaceUnfoldingSimon Peyton Jones2022-09-281-2/+2
| | | | | | | | | | | | | | | | | | | | | | I finally got tired of the way that IfaceUnfolding reflected a previous structure of unfoldings, not the current one. This MR refactors UnfoldingSource and IfaceUnfolding to be simpler and more consistent. It's largely just a refactor, but in UnfoldingSource (which moves to GHC.Types.Basic, since it is now used in IfaceSyn too), I distinguish between /user-specified/ and /system-generated/ stable unfoldings. data UnfoldingSource = VanillaSrc | StableUserSrc -- From a user-specified pragma | StableSystemSrc -- From a system-generated unfolding | CompulsorySrc This has a minor effect in CSE (see the use of isisStableUserUnfolding in GHC.Core.Opt.CSE), which I tripped over when working on specialisation, but it seems like a Good Thing to know anyway.
* matchLocalInst: do domination analysissheaf2022-09-284-90/+219
| | | | | | | | | | | | | | | | | | | | | | | | | | When multiple Given quantified constraints match a Wanted, and there is a quantified constraint that dominates all others, we now pick it to solve the Wanted. See Note [Use only the best matching quantified constraint]. For example: [G] d1: forall a b. ( Eq a, Num b, C a b ) => D a b [G] d2: forall a . C a Int => D a Int [W] {w}: D a Int When solving the Wanted, we find that both Givens match, but we pick the second, because it has a weaker precondition, C a Int, compared to (Eq a, Num Int, C a Int). We thus say that d2 dominates d1; see Note [When does a quantified instance dominate another?]. This domination test is done purely in terms of superclass expansion, in the function GHC.Tc.Solver.Interact.impliedBySCs. We don't attempt to do a full round of constraint solving; this simple check suffices for now. Fixes #22216 and #22223
* implement proposal 106 (Define Kinds Without Promotion) (fixes #6024)Ross Paterson2022-09-274-6/+79
| | | | includes corresponding changes to haddock submodule
* Minor refactor around OutputableKrzysztof Gogolewski2022-09-221-2/+1
| | | | | | | * Replace 'text . show' and 'ppr' with 'int'. * Remove Outputable.hs-boot, no longer needed * Use pprWithCommas * Factor out instructions in AArch64 codegen
* Scrub partiality about `NewOrData`.M Farkas-Dyck2022-09-192-72/+64
| | | | | | | | Rather than a list of constructors and a `NewOrData` flag, we define `data DataDefnCons a = NewTypeCon a | DataTypeCons [a]`, which enforces a newtype to have exactly one constructor. Closes #22070. Bump haddock submodule.
* DeriveFunctor: Check for last type variables using dataConUnivTyVarsRyan Scott2022-09-183-22/+82
| | | | | | | | | | | | | | | | Previously, derived instances of `Functor` (as well as the related classes `Foldable`, `Traversable`, and `Generic1`) would determine which constraints to infer by checking for fields that contain the last type variable. The problem was that this last type variable was taken from `tyConTyVars`. For GADTs, the type variables in each data constructor are _not_ the same type variables as in `tyConTyVars`, leading to #22167. This fixes the issue by instead checking for the last type variable using `dataConUnivTyVars`. (This is very similar in spirit to the fix for #21185, which also replaced an errant use of `tyConTyVars` with type variables from each data constructor.) Fixes #22167.
* Clean up some. In particular:M Farkas-Dyck2022-09-177-20/+21
| | | | | | | | | | • Delete some dead code, largely under `GHC.Utils`. • Clean up a few definitions in `GHC.Utils.(Misc, Monad)`. • Clean up `GHC.Types.SrcLoc`. • Derive stock `Functor, Foldable, Traversable` for more types. • Derive more instances for newtypes. Bump haddock submodule.
* Fix typosKrzysztof Gogolewski2022-09-1414-21/+21
|
* Fix typosEric Lindblad2022-09-1439-101/+101
| | | | | | | This fixes various typos and spelling mistakes in the compiler. Fixes #21891
* Add diagnostic codessheaf2022-09-1318-693/+867
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This MR adds diagnostic codes, assigning unique numeric codes to error and warnings, e.g. error: [GHC-53633] Pattern match is redundant This is achieved as follows: - a type family GhcDiagnosticCode that gives the diagnostic code for each diagnostic constructor, - a type family ConRecursInto that specifies whether to recur into an argument of the constructor to obtain a more fine-grained code (e.g. different error codes for different 'deriving' errors), - generics machinery to generate the value-level function assigning each diagnostic its error code; see Note [Diagnostic codes using generics] in GHC.Types.Error.Codes. The upshot is that, to add a new diagnostic code, contributors only need to modify the two type families mentioned above. All logic relating to diagnostic codes is thus contained to the GHC.Types.Error.Codes module, with no code duplication. This MR also refactors error message datatypes a bit, ensuring we can derive Generic for them, and cleans up the logic around constraint solver reports by splitting up 'TcSolverReportInfo' into separate datatypes (see #20772). Fixes #21684
* Remove Outputable Char instanceKrzysztof Gogolewski2022-09-071-1/+1
| | | | | Use 'text' instead of 'ppr'. Using 'ppr' on the list "hello" rendered as "h,e,l,l,o".
* Minor SDoc cleanupKrzysztof Gogolewski2022-09-071-7/+0
| | | | | | | Change calls to renderWithContext with showSDocOneLine; it's more efficient and explanatory. Remove polyPatSig (unused)
* Minor cleanupKrzysztof Gogolewski2022-09-011-4/+3
| | | | | | | | | - Remove mkHeteroCoercionType, sdocImpredicativeTypes, isStateType (unused), isCoVar_maybe (duplicated by getCoVar_maybe) - Replace a few occurrences of voidPrimId with (# #). void# is a deprecated synonym for the unboxed tuple. - Use showSDoc in :show linker. This makes it consistent with the other :show commands
* Use TcRnDiagnostic in GHC.Tc.TyCl.Class (#20117)Giles Anderson2022-08-294-48/+155
| | | | | | | | | | | | The following `TcRnDiagnostic` messages have been introduced: TcRnIllegalHsigDefaultMethods TcRnBadGenericMethod TcRnWarningMinimalDefIncomplete TcRnDefaultMethodForPragmaLacksBinding TcRnIgnoreSpecialisePragmaOnDefMethod TcRnBadMethodErr TcRnNoExplicitAssocTypeOrDefaultDeclaration
* 19217 Implicitly quantify type variables in :kind commandSasha Bogicevic2022-08-191-6/+13
|
* Print constraints in quotes (#21167)Swann Moreau2022-08-191-1/+1
| | | | | | | This patch improves the uniformity of error message formatting by printing constraints in quotes, as we do for types. Fix #21167
* tc: warn about lazy annotations on unlifted arguments (fixes #21951)Zachary Wood2022-08-193-0/+24
|
* Be more careful in chooseInferredQuantifiersSimon Peyton Jones2022-08-181-24/+45
| | | | | | | This fixes #22065. We were failing to retain a quantifier that was mentioned in the kind of another retained quantifier. Easy to fix.
* EPA: DotFieldOcc does not have exact print annotationsAlan Zimmerman2022-08-1111-18/+42
| | | | | | | | | | | | | | | | | For the code {-# LANGUAGE OverloadedRecordUpdate #-} operatorUpdate f = f{(+) = 1} There are no exact print annotations for the parens around the + symbol, nor does normal ppr print them. This MR fixes that. Closes #21805 Updates haddock submodule
* Fix TH + defer-type-errors interaction (#21920)Krzysztof Gogolewski2022-08-041-6/+0
| | | | | | Previously, we had to disable defer-type-errors in splices because of #7276. But this fix is no longer necessary, the test T7276 no longer segfaults and is now correctly deferred.
* Remove TCvSubst and use Subst for both term and type-level substYiyun Liu2022-08-0418-121/+113
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch removes the TCvSubst data type and instead uses Subst as the environment for both term and type level substitution. This change is partially motivated by the existential type proposal, which will introduce types that contain expressions and therefore forces us to carry around an "IdSubstEnv" even when substituting for types. It also reduces the amount of code because "Subst" and "TCvSubst" share a lot of common operations. There isn't any noticeable impact on performance (geo. mean for ghc/alloc is around 0.0% but we have -94 loc and one less data type to worry abount). Currently, the "TCvSubst" data type for substitution on types is identical to the "Subst" data type except the former doesn't store "IdSubstEnv". Using "Subst" for type-level substitution means there will be a redundant field stored in the data type. However, in cases where the substitution starts from the expression, using "Subst" for type-level substitution saves us from having to project "Subst" into a "TCvSubst". This probably explains why the allocation is mostly even despite the redundant field. The patch deletes "TCvSubst" and moves "Subst" and its relevant functions from "GHC.Core.Subst" into "GHC.Core.TyCo.Subst". Substitution on expressions is still defined in "GHC.Core.Subst" so we don't have to expose the definition of "Expr" in the hs-boot file that "GHC.Core.TyCo.Subst" must import to refer to "IdSubstEnv" (whose codomain is "CoreExpr"). Most functions named fooTCvSubst are renamed into fooSubst with a few exceptions (e.g. "isEmptyTCvSubst" is a distinct function from "isEmptySubst"; the former ignores the emptiness of "IdSubstEnv"). These exceptions mainly exist for performance reasons and will go away when "Expr" and "Type" are mutually recursively defined (we won't be able to take those shortcuts if we can't make the assumption that expressions don't appear in types).
* Get the in-scope set right in FamInstEnv.injectiveBranchesSimon Peyton Jones2022-07-257-87/+109
| | | | | | | | | | | | | 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.
* Fix the interaction of operator sections and deep subsumptionSimon Peyton Jones2022-07-252-8/+40
| | | | Fixes DeepSubsumption08
* Implement DeepSubsumptionSimon Peyton Jones2022-07-2510-173/+595
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 2b792facab46f7cdd09d12e79499f4e0dcd4293f 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].
* Make withDict opaque to the specialisersheaf2022-07-211-34/+60
| | | | | | | | | | | | | | | | | As pointed out in #21575, it is not sufficient to set withDict to inline after the typeclass specialiser, because we might inline withDict in one module and then import it in another, and we run into the same problem. This means we could still end up with incorrect runtime results because the typeclass specialiser would assume that distinct typeclass evidence terms at the same type are equal, when this is not necessarily the case when using withDict. Instead, this patch introduces a new magicId, 'nospec', which is only inlined in CorePrep. We make use of it in the definition of withDict to ensure that the typeclass specialiser does not common up distinct typeclass evidence terms. Fixes #21575
View Lorry Controller Status