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* Add the Unsatisfiable classsheaf2023-04-292-11/+22
| | | | | | | | | This commit implements GHC proposal #433, adding the Unsatisfiable class to the GHC.TypeError module. This provides an alternative to TypeError for which error reporting is more predictable: we report it when we are reporting unsolved Wanted constraints. Fixes #14983 #16249 #16906 #18310 #20835
* Handle records in the renamersheaf2023-03-291-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch moves the field-based logic for disambiguating record updates to the renamer. The type-directed logic, scheduled for removal, remains in the typechecker. To do this properly (and fix the myriad of bugs surrounding the treatment of duplicate record fields), we took the following main steps: 1. Create GREInfo, a renamer-level equivalent to TyThing which stores information pertinent to the renamer. This allows us to uniformly treat imported and local Names in the renamer, as described in Note [GREInfo]. 2. Remove GreName. Instead of a GlobalRdrElt storing GreNames, which distinguished between normal names and field names, we now store simple Names in GlobalRdrElt, along with the new GREInfo information which allows us to recover the FieldLabel for record fields. 3. Add namespacing for record fields, within the OccNames themselves. This allows us to remove the mangling of duplicate field selectors. This change ensures we don't print mangled names to the user in error messages, and allows us to handle duplicate record fields in Template Haskell. 4. Move record disambiguation to the renamer, and operate on the level of data constructors instead, to handle #21443. The error message text for ambiguous record updates has also been changed to reflect that type-directed disambiguation is on the way out. (3) means that OccEnv is now a bit more complex: we first key on the textual name, which gives an inner map keyed on NameSpace: OccEnv a ~ FastStringEnv (UniqFM NameSpace a) Note that this change, along with (2), both increase the memory residency of GlobalRdrEnv = OccEnv [GlobalRdrElt], which causes a few tests to regress somewhat in compile-time allocation. Even though (3) simplified a lot of code (in particular the treatment of field selectors within Template Haskell and in error messages), it came with one important wrinkle: in the situation of -- M.hs-boot module M where { data A; foo :: A -> Int } -- M.hs module M where { data A = MkA { foo :: Int } } we have that M.hs-boot exports a variable foo, which is supposed to match with the record field foo that M exports. To solve this issue, we add a new impedance-matching binding to M foo{var} = foo{fld} This mimics the logic that existed already for impedance-binding DFunIds, but getting it right was a bit tricky. See Note [Record field impedance matching] in GHC.Tc.Module. We also needed to be careful to avoid introducing space leaks in GHCi. So we dehydrate the GlobalRdrEnv before storing it anywhere, e.g. in ModIface. This means stubbing out all the GREInfo fields, with the function forceGlobalRdrEnv. When we read it back in, we rehydrate with rehydrateGlobalRdrEnv. This robustly avoids any space leaks caused by retaining old type environments. Fixes #13352 #14848 #17381 #17551 #19664 #21443 #21444 #21720 #21898 #21946 #21959 #22125 #22160 #23010 #23062 #23063 Updates haddock submodule ------------------------- Metric Increase: MultiComponentModules MultiLayerModules MultiLayerModulesDefsGhci MultiLayerModulesNoCode T13701 T14697 hard_hole_fits -------------------------
* Add structured error messages for GHC.Tc.Utils.EnvTorsten Schmits2023-03-211-35/+3
| | | | | | | | | Tracking ticket: #20119 MR: !10129 This converts uses of `mkTcRnUnknownMessage` to newly added constructors of `TcRnMessage`.
* Don't specialise incoherent instance applicationsGergő Érdi2023-02-271-63/+68
| | | | | | | | | | | | | | Using incoherent instances, there can be situations where two occurrences of the same overloaded function at the same type use two different instances (see #22448). For incoherently resolved instances, we must mark them with `nospec` to avoid the specialiser rewriting one to the other. This marking is done during the desugaring of the `WpEvApp` wrapper. Fixes #22448 Metric Increase: T15304
* Report family instance orphans correctlySimon Peyton Jones2023-01-271-41/+0
| | | | | | | | | | | | | | | | | 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
* Do newtype unwrapping in the canonicaliser and rewriterRichard Eisenberg2023-01-261-4/+4
| | | | | | See Note [Unwrap newtypes first], which has the details. Close #22519.
* Typeable: Fix module locations of some definitions in GHC.TypesMatthew Pickering2022-12-081-4/+17
| | | | | | | | | | | | | There was some confusion in Data.Typeable about which module certain wired-in things were defined in. Just because something is wired-in doesn't mean it comes from GHC.Prim, in particular things like LiftedRep and RuntimeRep are defined in GHC.Types and that's the end of the story. Things like Int#, Float# etc are defined in GHC.Prim as they have no Haskell definition site at all so we need to generate type representations for them (which live in GHC.Types). Fixes #22510
* Type vs Constraint: finally nailedSimon Peyton Jones2022-11-113-71/+105
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Fix TypeData issues (fixes #22315 and #22332)Ross Paterson2022-11-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | 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)
* Minor refactor around FastStringsKrzysztof Gogolewski2022-11-051-1/+1
| | | | | | | 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 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.
* Clean up some. In particular:M Farkas-Dyck2022-09-171-4/+2
| | | | | | | | | | • 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 typosEric Lindblad2022-09-143-3/+3
| | | | | | | This fixes various typos and spelling mistakes in the compiler. Fixes #21891
* EPA: DotFieldOcc does not have exact print annotationsAlan Zimmerman2022-08-111-1/+4
| | | | | | | | | | | | | | | | | 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
* Remove TCvSubst and use Subst for both term and type-level substYiyun Liu2022-08-041-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 Jones2022-07-251-64/+76
| | | | | | | | | | | | | 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.
* 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
* Remove many GHC dependencies from L.H.Sromes2022-07-061-1/+1
| | | | | | | | | | | | | | | | | | Continue to prune the `Language.Haskell.Syntax.*` modules out of GHC imports according to the plan in the linked issue. Moves more GHC-specific declarations to `GHC.*` and brings more required GHC-independent declarations to `Language.Haskell.Syntax.*` (extending e.g. `Language.Haskell.Syntax.Basic`). Progress towards #21592 Bump haddock submodule for !8308 ------------------------- Metric Decrease: hard_hole_fits -------------------------
* Prune L.H.S modules of GHC dependenciesromes2022-07-061-1/+1
| | | | | | | | | | Move around datatypes, functions and instances that are GHC-specific out of the `Language.Haskell.Syntax.*` modules to reduce the GHC dependencies in them -- progressing towards #21592 Creates a module `Language.Haskell.Syntax.Basic` to hold basic definitions required by the other L.H.S modules (and don't belong in any of them)
* Use a class to check validity of withDictwip/withdictKrzysztof Gogolewski2022-05-271-1/+179
| | | | | | | | | | | | This moves handling of the magic 'withDict' function from the desugarer to the typechecker. Details in Note [withDict]. I've extracted a part of T16646Fail to a separate file T16646Fail2, because the new error in 'reify' hides the errors from 'f' and 'g'. WithDict now works with casts, this fixes #21328. Part of #19915
* Consider the stage of typeable evidence when checking stage restrictionMatthew Pickering2022-05-221-10/+23
| | | | | | | | | | | | | | We were considering all Typeable evidence to be "BuiltinInstance"s which meant the stage restriction was going unchecked. In-fact, typeable has evidence and so we need to apply the stage restriction. This is complicated by the fact we don't generate typeable evidence and the corresponding DFunIds until after typechecking is concluded so we introcue a new `InstanceWhat` constructor, BuiltinTypeableInstance which records whether the evidence is going to be local or not. Fixes #21547
* decideMonoTyVars: account for CoVars in candidatessheaf2022-04-221-2/+4
| | | | | | | | | | | | The "candidates" passed to decideMonoTyVars can contain coercion holes. This is because we might well decide to quantify over some unsolved equality constraints, as long as they are not definitely insoluble. In that situation, decideMonoTyVars was passing a set of type variables that was not closed over kinds to closeWrtFunDeps, which was tripping up an assertion failure. Fixes #21404
* Kill derived constraintsRichard Eisenberg2022-02-231-20/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Co-authored by: Sam Derbyshire Previously, GHC had three flavours of constraint: Wanted, Given, and Derived. This removes Derived constraints. Though serving a number of purposes, the most important role of Derived constraints was to enable better error messages. This job has been taken over by the new RewriterSets, as explained in Note [Wanteds rewrite wanteds] in GHC.Tc.Types.Constraint. Other knock-on effects: - Various new Notes as I learned about under-described bits of GHC - A reshuffling around the AST for implicit-parameter bindings, with better integration with TTG. - Various improvements around fundeps. These were caused by the fact that, previously, fundep constraints were all Derived, and Derived constraints would get dropped. Thus, an unsolved Derived didn't stop compilation. Without Derived, this is no longer possible, and so we have to be considerably more careful around fundeps. - A nice little refactoring in GHC.Tc.Errors to center the work on a new datatype called ErrorItem. Constraints are converted into ErrorItems at the start of processing, and this allows for a little preprocessing before the main classification. - This commit also cleans up the behavior in generalisation around functional dependencies. Now, if a variable is determined by functional dependencies, it will not be quantified. This change is user facing, but it should trim down GHC's strange behavior around fundeps. - Previously, reportWanteds did quite a bit of work, even on an empty WantedConstraints. This commit adds a fast path. - Now, GHC will unconditionally re-simplify constraints during quantification. See Note [Unconditionally resimplify constraints when quantifying], in GHC.Tc.Solver. Close #18398. Close #18406. Solve the fundep-related non-confluence in #18851. Close #19131. Close #19137. Close #20922. Close #20668. Close #19665. ------------------------- Metric Decrease: LargeRecord T9872b T9872b_defer T9872d TcPlugin_RewritePerf -------------------------
* compiler: Introduce and use RoughMap for instance environmentsBen Gamari2022-02-043-16/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Here we introduce a new data structure, RoughMap, inspired by the previous `RoughTc` matching mechanism for checking instance matches. This allows [Fam]InstEnv to be implemented as a trie indexed by these RoughTc signatures, reducing the complexity of instance lookup and FamInstEnv merging (done during the family instance conflict test) from O(n) to O(log n). The critical performance improvement currently realised by this patch is in instance matching. In particular the RoughMap mechanism allows us to discount many potential instances which will never match for constraints involving type variables (see Note [Matching a RoughMap]). In realistic code bases matchInstEnv was accounting for 50% of typechecker time due to redundant work checking instances when simplifying instance contexts when deriving instances. With this patch the cost is significantly reduced. The larger constants in InstEnv creation do mean that a few small tests regress in allocations slightly. However, the runtime of T19703 is reduced by a factor of 4. Moreover, the compilation time of the Cabal library is slightly improved. A couple of test cases are included which demonstrate significant improvements in compile time with this patch. This unfortunately does not fix the testcase provided in #19703 but does fix #20933 ------------------------- Metric Decrease: T12425 Metric Increase: T13719 T9872a T9872d hard_hole_fits ------------------------- Co-authored-by: Matthew Pickering <matthewtpickering@gmail.com>
* Fix a few Note inconsistenciesBen Gamari2022-02-011-1/+1
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* Multiple Home UnitsMatthew Pickering2021-12-281-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Multiple home units allows you to load different packages which may depend on each other into one GHC session. This will allow both GHCi and HLS to support multi component projects more naturally. Public Interface ~~~~~~~~~~~~~~~~ In order to specify multiple units, the -unit @⟨filename⟩ flag is given multiple times with a response file containing the arguments for each unit. The response file contains a newline separated list of arguments. ``` ghc -unit @unitLibCore -unit @unitLib ``` where the `unitLibCore` response file contains the normal arguments that cabal would pass to `--make` mode. ``` -this-unit-id lib-core-0.1.0.0 -i -isrc LibCore.Utils LibCore.Types ``` The response file for lib, can specify a dependency on lib-core, so then modules in lib can use modules from lib-core. ``` -this-unit-id lib-0.1.0.0 -package-id lib-core-0.1.0.0 -i -isrc Lib.Parse Lib.Render ``` Then when the compiler starts in --make mode it will compile both units lib and lib-core. There is also very basic support for multiple home units in GHCi, at the moment you can start a GHCi session with multiple units but only the :reload is supported. Most commands in GHCi assume a single home unit, and so it is additional work to work out how to modify the interface to support multiple loaded home units. Options used when working with Multiple Home Units There are a few extra flags which have been introduced specifically for working with multiple home units. The flags allow a home unit to pretend it’s more like an installed package, for example, specifying the package name, module visibility and reexported modules. -working-dir ⟨dir⟩ It is common to assume that a package is compiled in the directory where its cabal file resides. Thus, all paths used in the compiler are assumed to be relative to this directory. When there are multiple home units the compiler is often not operating in the standard directory and instead where the cabal.project file is located. In this case the -working-dir option can be passed which specifies the path from the current directory to the directory the unit assumes to be it’s root, normally the directory which contains the cabal file. When the flag is passed, any relative paths used by the compiler are offset by the working directory. Notably this includes -i and -I⟨dir⟩ flags. -this-package-name ⟨name⟩ This flag papers over the awkward interaction of the PackageImports and multiple home units. When using PackageImports you can specify the name of the package in an import to disambiguate between modules which appear in multiple packages with the same name. This flag allows a home unit to be given a package name so that you can also disambiguate between multiple home units which provide modules with the same name. -hidden-module ⟨module name⟩ This flag can be supplied multiple times in order to specify which modules in a home unit should not be visible outside of the unit it belongs to. The main use of this flag is to be able to recreate the difference between an exposed and hidden module for installed packages. -reexported-module ⟨module name⟩ This flag can be supplied multiple times in order to specify which modules are not defined in a unit but should be reexported. The effect is that other units will see this module as if it was defined in this unit. The use of this flag is to be able to replicate the reexported modules feature of packages with multiple home units. Offsetting Paths in Template Haskell splices ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ When using Template Haskell to embed files into your program, traditionally the paths have been interpreted relative to the directory where the .cabal file resides. This causes problems for multiple home units as we are compiling many different libraries at once which have .cabal files in different directories. For this purpose we have introduced a way to query the value of the -working-dir flag to the Template Haskell API. By using this function we can implement a makeRelativeToProject function which offsets a path which is relative to the original project root by the value of -working-dir. ``` import Language.Haskell.TH.Syntax ( makeRelativeToProject ) foo = $(makeRelativeToProject "./relative/path" >>= embedFile) ``` > If you write a relative path in a Template Haskell splice you should use the makeRelativeToProject function so that your library works correctly with multiple home units. A similar function already exists in the file-embed library. The function in template-haskell implements this function in a more robust manner by honouring the -working-dir flag rather than searching the file system. Closure Property for Home Units ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For tools or libraries using the API there is one very important closure property which must be adhered to: > Any dependency which is not a home unit must not (transitively) depend on a home unit. For example, if you have three packages p, q and r, then if p depends on q which depends on r then it is illegal to load both p and r as home units but not q, because q is a dependency of the home unit p which depends on another home unit r. If you are using GHC by the command line then this property is checked, but if you are using the API then you need to check this property yourself. If you get it wrong you will probably get some very confusing errors about overlapping instances. Limitations of Multiple Home Units ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ There are a few limitations of the initial implementation which will be smoothed out on user demand. * Package thinning/renaming syntax is not supported * More complicated reexports/renaming are not yet supported. * It’s more common to run into existing linker bugs when loading a large number of packages in a session (for example #20674, #20689) * Backpack is not yet supported when using multiple home units. * Dependency chasing can be quite slow with a large number of modules and packages. * Loading wired-in packages as home units is currently not supported (this only really affects GHC developers attempting to load template-haskell). * Barely any normal GHCi features are supported, it would be good to support enough for ghcid to work correctly. Despite these limitations, the implementation works already for nearly all packages. It has been testing on large dependency closures, including the whole of head.hackage which is a total of 4784 modules from 452 packages. Internal Changes ~~~~~~~~~~~~~~~~ * The biggest change is that the HomePackageTable is replaced with the HomeUnitGraph. The HomeUnitGraph is a map from UnitId to HomeUnitEnv, which contains information specific to each home unit. * The HomeUnitEnv contains: - A unit state, each home unit can have different package db flags - A set of dynflags, each home unit can have different flags - A HomePackageTable * LinkNode: A new node type is added to the ModuleGraph, this is used to place the linking step into the build plan so linking can proceed in parralel with other packages being built. * New invariant: Dependencies of a ModuleGraphNode can be completely determined by looking at the value of the node. In order to achieve this, downsweep now performs a more complete job of downsweeping and then the dependenices are recorded forever in the node rather than being computed again from the ModSummary. * Some transitive module calculations are rewritten to use the ModuleGraph which is more efficient. * There is always an active home unit, which simplifies modifying a lot of the existing API code which is unit agnostic (for example, in the driver). The road may be bumpy for a little while after this change but the basics are well-tested. One small metric increase, which we accept and also submodule update to haddock which removes ExtendedModSummary. Closes #10827 ------------------------- Metric Increase: MultiLayerModules ------------------------- Co-authored-by: Fendor <power.walross@gmail.com>
* Make Word64 use Word64# on every architectureSylvain Henry2021-11-061-12/+3
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* Introduce Concrete# for representation polymorphism checkssheaf2021-10-171-5/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | PHASE 1: we never rewrite Concrete# evidence. This patch migrates all the representation polymorphism checks to the typechecker, using a new constraint form Concrete# :: forall k. k -> TupleRep '[] Whenever a type `ty` must be representation-polymorphic (e.g. it is the type of an argument to a function), we emit a new `Concrete# ty` Wanted constraint. If this constraint goes unsolved, we report a representation-polymorphism error to the user. The 'FRROrigin' datatype keeps track of the context of the representation-polymorphism check, for more informative error messages. This paves the way for further improvements, such as allowing type families in RuntimeReps and improving the soundness of typed Template Haskell. This is left as future work (PHASE 2). fixes #17907 #20277 #20330 #20423 #20426 updates haddock submodule ------------------------- Metric Decrease: T5642 -------------------------
* Make GHC.Utils.Error.Validity type polymorphicAlfredo Di Napoli2021-10-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | This commit makes the `Validity` type polymorphic: ``` data Validity' a = IsValid -- ^ Everything is fine | NotValid a -- ^ A problem, and some indication of why -- | Monomorphic version of @Validity'@ specialised for 'SDoc's. type Validity = Validity' SDoc ``` The type has been (provisionally) renamed to Validity' to not break existing code, as the monomorphic `Validity` type is quite pervasive in a lot of signatures in GHC. Why having a polymorphic Validity? Because it carries the evidence of "what went wrong", but the old type carried an `SDoc`, which clashed with the new GHC diagnostic infrastructure (#18516). Having it polymorphic it means we can carry an arbitrary, richer diagnostic type, and this is very important for things like the `checkOriginativeSideConditions` function, which needs to report the actual diagnostic error back to `GHC.Tc.Deriv`. It also generalises Validity-related functions to be polymorphic in @a@.
* Canonicalize bignum literalsSylvain Henry2021-09-111-2/+2
| | | | | | | | | | | | | | | | | | Before this patch Integer and Natural literals were desugared into "real" Core in Core prep. Now we desugar them directly into their final ConApp form in HsToCore. We only keep the double representation for BigNat# (literals larger than a machine Word/Int) which are still desugared in Core prep. Using the final form directly allows case-of-known-constructor to fire for bignum literals, fixing #20245. Slight increase (+2.3) in T4801 which is a pathological case with Integer literals. Metric Increase: T4801 T11545
* Add and use new constructors to TcRnMessageAlfredo Di Napoli2021-09-071-65/+29
| | | | | | | | | | | | | This commit adds the following constructors to the TcRnMessage type and uses them to replace sdoc-based diagnostics in some parts of GHC (e.g. TcRnUnknownMessage). It includes: * Add TcRnMonomorphicBindings diagnostic * Convert TcRnUnknownMessage in Tc.Solver.Interact * Add and use the TcRnOrphanInstance constructor to TcRnMessage * Add TcRnFunDepConflict and TcRnDupInstanceDecls constructors to TcRnMessage * Add and use TcRnConflictingFamInstDecls constructor to TcRnMessage * Get rid of TcRnUnknownMessage from GHC.Tc.Instance.Family
* Use Reductions to keep track of rewritingssheaf2021-08-041-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | We define Reduction = Reduction Coercion !Type. A reduction of the form 'Reduction co new_ty' witnesses an equality ty ~co~> new_ty. That is, the rewriting happens left-to-right: the right-hand-side type of the coercion is the rewritten type, and the left-hand-side type the original type. Sticking to this convention makes the codebase more consistent, helping to avoid certain applications of SymCo. This replaces the parts of the codebase which represented reductions as pairs, (Coercion,Type) or (Type,Coercion). Reduction being strict in the Type argument improves performance in some programs that rewrite many type families (such as T9872). Fixes #20161 ------------------------- Metric Decrease: T5321Fun T9872a T9872b T9872c T9872d -------------------------
* Try to simplify zoo of functions in `Tc.Utils.Monad`Alfredo Di Napoli2021-06-281-5/+11
| | | | | | | | | | | This commit tries to untangle the zoo of diagnostic-related functions in `Tc.Utils.Monad` so that we can have the interfaces mentions only `TcRnMessage`s while we push the creation of these messages upstream. It also ports TcRnMessage diagnostics to use the new API, in particular this commit switch to use TcRnMessage in the external interfaces of the diagnostic functions, and port the old SDoc to be wrapped into TcRnUnknownMessage.
* Use GHC's State monad consistentlyBen Gamari2021-05-291-1/+1
| | | | | | | | | | | | | GHC's internal State monad benefits from oneShot annotations on its state, allowing for more aggressive eta expansion. We currently don't have monad transformers with the same optimisation, so we only change uses of the pure State monad here. See #19657 and 19380. Metric Decrease: hie002
* Rip GHC.Tc.Solver.Monad asunder (only)Richard Eisenberg2021-05-291-2/+2
| | | | | | | | | | | This creates new modules GHC.Tc.Solver.InertSet and GHC.Tc.Solver.Types. The Monad module is still pretty big, but this is an improvement. Moreover, it means that GHC.HsToCore.Pmc.Solver.Types no longer depends on the constraint solver (it now depends on GHC.Tc.Solver.InertSet), making the error-messages work easier. This patch thus contributes to #18516.
* Remove useless {-# LANGUAGE CPP #-} pragmasSylvain Henry2021-05-124-4/+4
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* Fully remove HsVersions.hSylvain Henry2021-05-124-8/+0
| | | | | | | | | | Replace uses of WARN macro with calls to: warnPprTrace :: Bool -> SDoc -> a -> a Remove the now unused HsVersions.h Bump haddock submodule
* Replace CPP assertions with Haskell functionsSylvain Henry2021-05-122-5/+6
| | | | | | | | | | | | | | | There is no reason to use CPP. __LINE__ and __FILE__ macros are now better replaced with GHC's CallStack. As a bonus, assert error messages now contain more information (function name, column). Here is the mapping table (HasCallStack omitted): * ASSERT: assert :: Bool -> a -> a * MASSERT: massert :: Bool -> m () * ASSERTM: assertM :: m Bool -> m () * ASSERT2: assertPpr :: Bool -> SDoc -> a -> a * MASSERT2: massertPpr :: Bool -> SDoc -> m () * ASSERTM2: assertPprM :: m Bool -> SDoc -> m ()
* Avoid fundep-caused loop in the typecheckerSimon Peyton Jones2021-03-311-8/+8
| | | | | | | | | | | Ticket #19415 showed a nasty typechecker loop, which can happen with fundeps that do not satisfy the coverage condition. This patch fixes the problem. It's described in GHC.Tc.Solver.Interact Note [Fundeps with instances] It's not a perfect solution, as the Note explains, but it's better than the status quo.
* Add compiler linting to CIHécate2021-03-251-2/+1
| | | | | This commit adds the `lint:compiler` Hadrian target to the CI runner. It does also fixes hints in the compiler/ and libraries/base/ codebases.
* Implement BoxedRep proposalwip/boxed-repBen Gamari2021-03-071-8/+20
| | | | | | | | | | | | | | | | | | | | | | | This implements the BoxedRep proposal, refactoring the `RuntimeRep` hierarchy from: ```haskell data RuntimeRep = LiftedPtrRep | UnliftedPtrRep | ... ``` to ```haskell data RuntimeRep = BoxedRep Levity | ... data Levity = Lifted | Unlifted ``` Updates binary, haddock submodules. Closes #17526. Metric Increase: T12545
* Make sure HasField use counts for -Wunused-top-bindsAdam Gundry2021-02-161-2/+18
| | | | | | This is a small fix that depends on the previous commit, because it corrected the rnExpr free variable calculation for HsVars which refer to ambiguous fields. Fixes #19213.
* Fix a serious bug in roughMatchTcsSimon Peyton Jones2021-02-131-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | The roughMatchTcs function enables a quick definitely-no-match test in lookupInstEnv. Unfortunately, it didn't account for type families. This didn't matter when type families were flattened away, but now they aren't flattened it matters a lot. The fix is very easy. See INVARIANT in GHC.Core.InstEnv Note [ClsInst laziness and the rough-match fields] Fixes #19336 The change makes compiler perf worse on two very-type-family-heavy benchmarks, T9872{a,d}: T9872a(normal) ghc/alloc 2172536442.7 2216337648.0 +2.0% T9872d(normal) ghc/alloc 614584024.0 621081384.0 +1.1% (Everything else is 0.0% or at most 0.1%.) I think we just have to put up with this. Some cases were being wrongly filtered out by roughMatchTcs that might actually match, which could lead to false apartness checks. And it only affects these very type-family-heavy cases. Metric Increase: T9872a T9872d
* The Char kind (#11342)Daniel Rogozin2021-02-062-1/+21
| | | | | | | | | | | | | | | | | | | | | | Co-authored-by: Rinat Stryungis <rinat.stryungis@serokell.io> Implement GHC Proposal #387 * Parse char literals 'x' at the type level * New built-in type families CmpChar, ConsSymbol, UnconsSymbol * New KnownChar class (cf. KnownSymbol and KnownNat) * New SomeChar type (cf. SomeSymbol and SomeNat) * CharTyLit support in template-haskell Updated submodules: binary, haddock. Metric Decrease: T5205 haddock.base Metric Increase: Naperian T13035
* Make matchableGivens more reliably correct.Richard Eisenberg2021-01-231-3/+1
| | | | | | | | | | | | | | | | | | | | | | | This has two fixes: 1. Take TyVarTvs into account in matchableGivens. This fixes #19106. 2. Don't allow unifying alpha ~ Maybe alpha. This fixes #19107. This patch also removes a redundant Note and redirects references to a better replacement. Also some refactoring/improvements around the BindFun in the pure unifier, which now can take the RHS type into account. Close #19106. Close #19107. Test case: partial-sigs/should_compile/T19106, typecheck/should_compile/T19107
* Revert "Implement BoxedRep proposal"Ben Gamari2020-12-151-19/+8
| | | | | | This was inadvertently merged. This reverts commit 6c2eb2232b39ff4720fda0a4a009fb6afbc9dcea.
* Implement BoxedRep proposalAndrew Martin2020-12-141-8/+19
| | | | | | | | | | | | | | | | | | This implements the BoxedRep proposal, refacoring the `RuntimeRep` hierarchy from: ```haskell data RuntimeRep = LiftedPtrRep | UnliftedPtrRep | ... ``` to ```haskell data RuntimeRep = BoxedRep Levity | ... data Levity = Lifted | Unlifted ``` Closes #17526.
* Remove flattening variablesRichard Eisenberg2020-12-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch redesigns the flattener to simplify type family applications directly instead of using flattening meta-variables and skolems. The key new innovation is the CanEqLHS type and the new CEqCan constraint (Ct). A CanEqLHS is either a type variable or exactly-saturated type family application; either can now be rewritten using a CEqCan constraint in the inert set. Because the flattener no longer reduces all type family applications to variables, there was some performance degradation if a lengthy type family application is now flattened over and over (not making progress). To compensate, this patch contains some extra optimizations in the flattener, leading to a number of performance improvements. Close #18875. Close #18910. There are many extra parts of the compiler that had to be affected in writing this patch: * The family-application cache (formerly the flat-cache) sometimes stores coercions built from Given inerts. When these inerts get kicked out, we must kick out from the cache as well. (This was, I believe, true previously, but somehow never caused trouble.) Kicking out from the cache requires adding a filterTM function to TrieMap. * This patch obviates the need to distinguish "blocking" coercion holes from non-blocking ones (which, previously, arose from CFunEqCans). There is thus some simplification around coercion holes. * Extra commentary throughout parts of the code I read through, to preserve the knowledge I gained while working. * A change in the pure unifier around unifying skolems with other types. Unifying a skolem now leads to SurelyApart, not MaybeApart, as documented in Note [Binding when looking up instances] in GHC.Core.InstEnv. * Some more use of MCoercion where appropriate. * Previously, class-instance lookup automatically noticed that e.g. C Int was a "unifier" to a target [W] C (F Bool), because the F Bool was flattened to a variable. Now, a little more care must be taken around checking for unifying instances. * Previously, tcSplitTyConApp_maybe would split (Eq a => a). This is silly, because (=>) is not a tycon in Haskell. Fixed now, but there are some knock-on changes in e.g. TrieMap code and in the canonicaliser. * New function anyFreeVarsOf{Type,Co} to check whether a free variable satisfies a certain predicate. * Type synonyms now remember whether or not they are "forgetful"; a forgetful synonym drops at least one argument. This is useful when flattening; see flattenView. * The pattern-match completeness checker invokes the solver. This invocation might need to look through newtypes when checking representational equality. Thus, the desugarer needs to keep track of the in-scope variables to know what newtype constructors are in scope. I bet this bug was around before but never noticed. * Extra-constraints wildcards are no longer simplified before printing. See Note [Do not simplify ConstraintHoles] in GHC.Tc.Solver. * Whether or not there are Given equalities has become slightly subtler. See the new HasGivenEqs datatype. * Note [Type variable cycles in Givens] in GHC.Tc.Solver.Canonical explains a significant new wrinkle in the new approach. * See Note [What might match later?] in GHC.Tc.Solver.Interact, which explains the fix to #18910. * The inert_count field of InertCans wasn't actually used, so I removed it. Though I (Richard) did the implementation, Simon PJ was very involved in design and review. This updates the Haddock submodule to avoid #18932 by adding a type signature. ------------------------- Metric Decrease: T12227 T5030 T9872a T9872b T9872c Metric Increase: T9872d -------------------------
* Move core flattening algorithm to Core.UnifyRichard Eisenberg2020-12-011-1/+1
| | | | | | | | | | This sets the stage for a later change, where this algorithm will be needed from GHC.Core.InstEnv. This commit also splits GHC.Core.Map into GHC.Core.Map.Type and GHC.Core.Map.Expr, in order to avoid module import cycles with GHC.Core.
* Name (tc)SplitForAll- functions more consistentlyRyan Scott2020-11-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is a zoo of `splitForAll-` functions in `GHC.Core.Type` (as well as `tcSplitForAll-` functions in `GHC.Tc.Utils.TcType`) that all do very similar things, but vary in the particular form of type variable that they return. To make things worse, the names of these functions are often quite misleading. Some particularly egregious examples: * `splitForAllTys` returns `TyCoVar`s, but `splitSomeForAllTys` returns `VarBndr`s. * `splitSomeForAllTys` returns `VarBndr`s, but `tcSplitSomeForAllTys` returns `TyVar`s. * `splitForAllTys` returns `TyCoVar`s, but `splitForAllTysInvis` returns `InvisTVBinder`s. (This in particular arose in the context of #18939, and this finally motivated me to bite the bullet and improve the status quo vis-à-vis how we name these functions.) In an attempt to bring some sanity to how these functions are named, I have opted to rename most of these functions en masse to use consistent suffixes that describe the particular form of type variable that each function returns. In concrete terms, this amounts to: * Functions that return a `TyVar` now use the suffix `-TyVar`. This caused the following functions to be renamed: * `splitTyVarForAllTys` -> `splitForAllTyVars` * `splitForAllTy_ty_maybe` -> `splitForAllTyVar_maybe` * `tcSplitForAllTys` -> `tcSplitForAllTyVars` * `tcSplitSomeForAllTys` -> `tcSplitSomeForAllTyVars` * Functions that return a `CoVar` now use the suffix `-CoVar`. This caused the following functions to be renamed: * `splitForAllTy_co_maybe` -> `splitForAllCoVar_maybe` * Functions that return a `TyCoVar` now use the suffix `-TyCoVar`. This caused the following functions to be renamed: * `splitForAllTy` -> `splitForAllTyCoVar` * `splitForAllTys` -> `splitForAllTyCoVars` * `splitForAllTys'` -> `splitForAllTyCoVars'` * `splitForAllTy_maybe` -> `splitForAllTyCoVar_maybe` * Functions that return a `VarBndr` now use the suffix corresponding to the most relevant type synonym. This caused the following functions to be renamed: * `splitForAllVarBndrs` -> `splitForAllTyCoVarBinders` * `splitForAllTysInvis` -> `splitForAllInvisTVBinders` * `splitForAllTysReq` -> `splitForAllReqTVBinders` * `splitSomeForAllTys` -> `splitSomeForAllTyCoVarBndrs` * `tcSplitForAllVarBndrs` -> `tcSplitForAllTyVarBinders` * `tcSplitForAllTysInvis` -> `tcSplitForAllInvisTVBinders` * `tcSplitForAllTysReq` -> `tcSplitForAllReqTVBinders` * `tcSplitForAllTy_maybe` -> `tcSplitForAllTyVarBinder_maybe` Note that I left the following functions alone: * Functions that split apart things besides `ForAllTy`s, such as `splitFunTys` or `splitPiTys`. Thankfully, there are far fewer of these functions than there are functions that split apart `ForAllTy`s, so there isn't much of a pressing need to apply the new naming convention elsewhere. * Functions that split apart `ForAllCo`s in `Coercion`s, such as `GHC.Core.Coercion.splitForAllCo_maybe`. We could theoretically apply the new naming convention here, but then we'd have to figure out how to disambiguate `Type`-splitting functions from `Coercion`-splitting functions. Ultimately, the `Coercion`-splitting functions aren't used nearly as much as the `Type`-splitting functions, so I decided to leave the former alone. This is purely refactoring and should cause no change in behavior.
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