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* package imports: Take into account package visibility when renamingMatthew Pickering2021-12-091-2/+2
| | | | | | | | | | | | In 806e49ae the package imports refactoring code was modified to rename package imports. There was a small oversight which meant the code didn't account for module visibility. This patch fixes that oversight. In general the "lookupPackageName" function is unsafe to use as it doesn't account for package visiblity/thinning/renaming etc, there is just one use in the compiler which would be good to audit. Fixes #20779
* Perf: remove an indirection when fetching the unique maskSylvain Henry2021-12-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Slight decrease but still noticeable on CI: Baseline Test Metric value New value Change ----------------------------------------------------------------------------- ManyAlternatives(normal) ghc/alloc 747607676.0 747458936.0 -0.0% ManyConstructors(normal) ghc/alloc 4003722296.0 4003530032.0 -0.0% MultiLayerModules(normal) ghc/alloc 3064539560.0 3063984552.0 -0.0% MultiLayerModulesRecomp(normal) ghc/alloc 894700016.0 894700624.0 +0.0% PmSeriesG(normal) ghc/alloc 48410952.0 48262496.0 -0.3% PmSeriesS(normal) ghc/alloc 61561848.0 61415768.0 -0.2% PmSeriesT(normal) ghc/alloc 90975784.0 90829360.0 -0.2% PmSeriesV(normal) ghc/alloc 60405424.0 60259008.0 -0.2% T10421(normal) ghc/alloc 113275928.0 113137168.0 -0.1% T10421a(normal) ghc/alloc 79195676.0 79050112.0 -0.2% T10547(normal) ghc/alloc 28720176.0 28710008.0 -0.0% T10858(normal) ghc/alloc 180992412.0 180857400.0 -0.1% T11195(normal) ghc/alloc 283452220.0 283293832.0 -0.1% T11276(normal) ghc/alloc 137882128.0 137745840.0 -0.1% T11303b(normal) ghc/alloc 44453956.0 44309184.0 -0.3% T11374(normal) ghc/alloc 248118668.0 247979880.0 -0.1% T11545(normal) ghc/alloc 971994728.0 971852696.0 -0.0% T11822(normal) ghc/alloc 131544864.0 131399024.0 -0.1% T12150(optasm) ghc/alloc 79336468.0 79191888.0 -0.2% T12227(normal) ghc/alloc 495064180.0 494943040.0 -0.0% T12234(optasm) ghc/alloc 57198468.0 57053568.0 -0.3% T12425(optasm) ghc/alloc 90928696.0 90793440.0 -0.1% T12545(normal) ghc/alloc 1695417772.0 1695275744.0 -0.0% T12707(normal) ghc/alloc 956258984.0 956138864.0 -0.0% T13035(normal) ghc/alloc 102279484.0 102132616.0 -0.1% T13056(optasm) ghc/alloc 367196556.0 367066408.0 -0.0% T13253(normal) ghc/alloc 334365844.0 334255264.0 -0.0% T13253-spj(normal) ghc/alloc 125474884.0 125328672.0 -0.1% T13379(normal) ghc/alloc 359185604.0 359036960.0 -0.0% T13701(normal) ghc/alloc 2403026480.0 2402677464.0 -0.0% T13719(normal) ghc/alloc 4192234752.0 4192039448.0 -0.0% T14052(ghci) ghc/alloc 2745868552.0 2747706176.0 +0.1% T14052Type(ghci) ghc/alloc 7335937964.0 7336283280.0 +0.0% T14683(normal) ghc/alloc 2992557736.0 2992436872.0 -0.0% T14697(normal) ghc/alloc 363391248.0 363222920.0 -0.0% T15164(normal) ghc/alloc 1292578008.0 1292434240.0 -0.0% T15304(normal) ghc/alloc 1279603472.0 1279465944.0 -0.0% T15630(normal) ghc/alloc 161707776.0 161602632.0 -0.1% T16190(normal) ghc/alloc 276904644.0 276555264.0 -0.1% T16577(normal) ghc/alloc 7573033016.0 7572982752.0 -0.0% T16875(normal) ghc/alloc 34937980.0 34796592.0 -0.4% T17096(normal) ghc/alloc 287436348.0 287299368.0 -0.0% T17516(normal) ghc/alloc 1714727484.0 1714617664.0 -0.0% T17836(normal) ghc/alloc 1091095748.0 1090958168.0 -0.0% T17836b(normal) ghc/alloc 52467912.0 52321296.0 -0.3% T17977(normal) ghc/alloc 44971660.0 44826480.0 -0.3% T17977b(normal) ghc/alloc 40941128.0 40793160.0 -0.4% T18140(normal) ghc/alloc 82363124.0 82213056.0 -0.2% T18223(normal) ghc/alloc 1168448128.0 1168333624.0 -0.0% T18282(normal) ghc/alloc 131577844.0 131440400.0 -0.1% T18304(normal) ghc/alloc 86988664.0 86844432.0 -0.2% T18478(normal) ghc/alloc 742992400.0 742871136.0 -0.0% T18698a(normal) ghc/alloc 337654412.0 337526792.0 -0.0% T18698b(normal) ghc/alloc 398840772.0 398716472.0 -0.0% T18923(normal) ghc/alloc 68964992.0 68818768.0 -0.2% T1969(normal) ghc/alloc 764285884.0 764156168.0 -0.0% T19695(normal) ghc/alloc 1395577984.0 1395552552.0 -0.0% T20049(normal) ghc/alloc 89159032.0 89012952.0 -0.2% T3064(normal) ghc/alloc 191194856.0 191051816.0 -0.1% T3294(normal) ghc/alloc 1604762016.0 1604656488.0 -0.0% T4801(normal) ghc/alloc 296829368.0 296687824.0 -0.0% T5030(normal) ghc/alloc 364720540.0 364580152.0 -0.0% T5321FD(normal) ghc/alloc 271090004.0 270950824.0 -0.1% T5321Fun(normal) ghc/alloc 301244320.0 301102960.0 -0.0% T5631(normal) ghc/alloc 576154548.0 576022904.0 -0.0% T5642(normal) ghc/alloc 471105876.0 470967552.0 -0.0% T5837(normal) ghc/alloc 36328620.0 36186720.0 -0.4% T6048(optasm) ghc/alloc 103125988.0 102981024.0 -0.1% T783(normal) ghc/alloc 386945556.0 386795984.0 -0.0% T9020(optasm) ghc/alloc 247835012.0 247696704.0 -0.1% T9198(normal) ghc/alloc 47556208.0 47413784.0 -0.3% T9233(normal) ghc/alloc 682210596.0 682069960.0 -0.0% T9630(normal) ghc/alloc 1429689648.0 1429581168.0 -0.0% T9675(optasm) ghc/alloc 431092812.0 430943192.0 -0.0% T9872a(normal) ghc/alloc 1705052592.0 1705042064.0 -0.0% T9872b(normal) ghc/alloc 2180406760.0 2180395784.0 -0.0% T9872c(normal) ghc/alloc 1760508464.0 1760497936.0 -0.0% T9872d(normal) ghc/alloc 501517968.0 501309464.0 -0.0% T9961(normal) ghc/alloc 354037204.0 353891576.0 -0.0% TcPlugin_RewritePerf(normal) ghc/alloc 2381708520.0 2381550824.0 -0.0% WWRec(normal) ghc/alloc 589553520.0 589407216.0 -0.0% hard_hole_fits(normal) ghc/alloc 492122188.0 492470648.0 +0.1% hie002(normal) ghc/alloc 9336434800.0 9336443496.0 +0.0% parsing001(normal) ghc/alloc 537680944.0 537659824.0 -0.0% geo. mean -0.1%
* TTG: replace Void/NoExtCon with DataConCantHappenKrzysztof Gogolewski2021-11-291-1/+1
| | | | | | | | There were two ways to indicate that a TTG constructor is unused in a phase: `NoExtCon` and `Void`. This unifies the code, and uses the name 'DataConCantHappen', following the discussion at MR 7041. Updates haddock submodule
* Allow boring class declarations in hs-boot filessheaf2021-11-251-1/+9
| | | | | | | | | | | | | | | | | | | | | | | There are two different ways of declaring a class in an hs-boot file: - a full declaration, where everything is written as it is in the .hs file, - an abstract declaration, where class methods and superclasses are left out. However, a declaration with no methods and a trivial superclass, such as: class () => C a was erroneously considered to be an abstract declaration, because the superclass is trivial. This is remedied by a one line fix in GHC.Tc.TyCl.tcClassDecl1. This patch also further clarifies the documentation around class declarations in hs-boot files. Fixes #20661, #20588.
* Don't use implicit lifting when deriving LiftMatthew Pickering2021-11-251-8/+20
| | | | | | | | | | | | | | | | It isn't much more complicated to be more precise when deriving Lift so we now generate ``` data Foo = Foo Int Bool instance Lift Foo where lift (Foo a b) = [| Foo $(lift a) $(lift b) |] liftTyped (Foo a b) = [|| Foo $$(lift a) $$(lift b) |] ``` This fixes #20688 which complained about using implicit lifting in the derived code.
* Misc cleanupKrzysztof Gogolewski2021-11-254-11/+9
| | | | | | | | | | | | | | | | | | | | | * Remove `getTag_RDR` (unused), `tidyKind` and `tidyOpenKind` (already available as `tidyType` and `tidyOpenType`) * Remove Note [Explicit Case Statement for Specificity]. Since 0a709dd9876e40 we require GHC 8.10 for bootstrapping. * Change the warning to `cmpAltCon` to a panic. This shouldn't happen. If it ever does, the code was wrong anyway: it shouldn't always return `LT`, but rather `LT` in one case and `GT` in the other case. * Rename `verifyLinearConstructors` to `verifyLinearFields` * Fix `Note [Local record selectors]` which was not referenced * Remove vestiges of `type +v` * Minor fixes to StaticPointers documentation, part of #15603
* Enable UnboxedTuples in `genInst`, Fixes #20524CarrieMY2021-11-251-0/+3
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* Ensure new Ct/evidence invariantChristiaan Baaij2021-11-253-30/+73
| | | | | | | | | | The `ctev_pred` field of a `CtEvidence` is a just a cache for the type of the evidence. More precisely: * For Givens, `ctev_pred` = `varType ctev_evar` * For Wanteds, `ctev_pred` = `evDestType ctev_dest` This new invariant is needed because evidence can become part of a type, via `Castty ty kco`.
* Add a warning for GADT match + NoMonoLocalBinds (#20485)Krzysztof Gogolewski2021-11-233-10/+33
| | | | | | | | | Previously, it was an error to pattern match on a GADT without GADTs or TypeFamilies. This is now allowed. Instead, we check the flag MonoLocalBinds; if it is not enabled, we issue a warning, controlled by -Wgadt-mono-local-binds. Also fixes #20485: pattern synonyms are now checked too.
* Include "not more specific" info in overlap msgsheaf2021-11-201-45/+151
| | | | | | | | | When instances overlap, we now include additional information about why we weren't able to select an instance: perhaps one instance overlapped another but was not strictly more specific, so we aren't able to directly choose it. Fixes #20542
* More support for optional home-unitSylvain Henry2021-11-204-31/+36
| | | | | | | | | This is a preliminary refactoring for #14335 (supporting plugins in cross-compilers). In many places the home-unit must be optional because there won't be one available in the plugin environment (we won't be compiling anything in this environment). Hence we replace "HomeUnit" with "Maybe HomeUnit" in a few places and we avoid the use of "hsc_home_unit" (which is partial) in some few others.
* Increase type sharingBen Gamari2021-11-172-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | Fixes #20541 by making mkTyConApp do more sharing of types. In particular, replace * BoxedRep Lifted ==> LiftedRep * BoxedRep Unlifted ==> UnliftedRep * TupleRep '[] ==> ZeroBitRep * TYPE ZeroBitRep ==> ZeroBitType In each case, the thing on the right is a type synonym for the thing on the left, declared in ghc-prim:GHC.Types. See Note [Using synonyms to compress types] in GHC.Core.Type. The synonyms for ZeroBitRep and ZeroBitType are new, but absolutely in the same spirit as the other ones. (These synonyms are mainly for internal use, though the programmer can use them too.) I also renamed GHC.Core.Ty.Rep.isVoidTy to isZeroBitTy, to be compatible with the "zero-bit" nomenclature above. See discussion on !6806. There is a tricky wrinkle: see GHC.Core.Types Note [Care using synonyms to compress types] Compiler allocation decreases by up to 0.8%.
* Instantiate field types properly in stock-derived instancesRyan Scott2021-11-156-244/+344
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, the `deriving` machinery was very loosey-goosey about how it used the types of data constructor fields when generating code. It would usually just consult `dataConOrigArgTys`, which returns the _uninstantiated_ field types of each data constructor. Usually, you can get away with this, but issues #20375 and #20387 revealed circumstances where this approach fails. Instead, when generated code for a stock-derived instance `C (T arg_1 ... arg_n)`, one must take care to instantiate the field types of each data constructor with `arg_1 ... arg_n`. The particulars of how this is accomplished is described in the new `Note [Instantiating field types in stock deriving]` in `GHC.Tc.Deriv.Generate`. Some highlights: * `DerivInstTys` now has a new `dit_dc_inst_arg_env :: DataConEnv [Type]` field that caches the instantiated field types of each data constructor. Whenever we need to consult the field types somewhere in `GHC.Tc.Deriv.*` we avoid using `dataConOrigArgTys` and instead look it up in `dit_dc_inst_arg_env`. * Because `DerivInstTys` now stores the instantiated field types of each constructor, some of the details of the `GHC.Tc.Deriv.Generics.mkBindsRep` function were able to be simplified. In particular, we no longer need to apply a substitution to instantiate the field types in a `Rep(1)` instance, as that is already done for us by `DerivInstTys`. We still need a substitution to implement the "wrinkle" section of `Note [Generating a correctly typed Rep instance]`, but the code is nevertheless much simpler than before. * The `tyConInstArgTys` function has been removed in favor of the new `GHC.Core.DataCon.dataConInstUnivs` function, which is really the proper tool for the job. `dataConInstUnivs` is much like `tyConInstArgTys` except that it takes a data constructor, not a type constructor, as an argument, and it adds extra universal type variables from that data constructor at the end of the returned list if need be. `dataConInstUnivs` takes care to instantiate the kinds of the universal type variables at the end, thereby avoiding a bug in `tyConInstArgTys` discovered in https://gitlab.haskell.org/ghc/ghc/-/issues/20387#note_377037. Fixes #20375. Fixes #20387.
* Refactoring: Consolidate some arguments with DerivInstTysRyan Scott2021-11-155-141/+135
| | | | | | | | | | | Various functions in GHC.Tc.Deriv.* were passing around `TyCon`s and `[Type]`s that ultimately come from the same `DerivInstTys`. This patch moves the definition of `DerivInstTys` to `GHC.Tc.Deriv.Generate` so that all of these `TyCon` and `[Type]` arguments can be consolidated into a single `DerivInstTys`. Not only does this make the code easier to read (in my opinion), this will also be important in a subsequent commit where we need to add another field to `DerivInstTys` that will also be used from `GHC.Tc.Deriv.Generate` and friends.
* Implement -Wforall-identifier (#20609)Vladislav Zavialov2021-11-122-0/+20
| | | | | | | | | | In accordance with GHC Proposal #281 "Visible forall in types of terms": For three releases before this change takes place, include a new warning -Wforall-identifier in -Wdefault. This warning will be triggered at definition sites (but not use sites) of forall as an identifier. Updates the haddock submodule.
* Use local instances with least superclass depthRichard Eisenberg2021-11-127-82/+180
| | | | | | | | | | See new Note [Use only the best local instance] in GHC.Tc.Solver.Interact. This commit also refactors the InstSC/OtherSC mechanism slightly. Close #20582.
* Improve redundant-constraints warningRichard Eisenberg2021-11-127-92/+157
| | | | | | | | | | | | | | Previously, we reported things wrong with f :: (Eq a, Ord a) => a -> Bool f x = x == x saying that Eq a was redundant. This is fixed now, along with some simplification in Note [Replacement vs keeping]. There's a tiny bit of extra complexity in setImplicationStatus, but it's explained in Note [Tracking redundant constraints]. Close #20602
* Flesh out Note [The stupid context] and reference itRyan Scott2021-11-099-12/+20
| | | | | | `Note [The stupid context]` in `GHC.Core.DataCon` talks about stupid contexts from `DatatypeContexts`, but prior to this commit, it was rather outdated. This commit spruces it up and references it from places where it is relevant.
* deriving: infer DatatypeContexts from data constructors, not type constructorRyan Scott2021-11-091-13/+24
| | | | | | | | | | | | | | Previously, derived instances that use `deriving` clauses would infer `DatatypeContexts` by using `tyConStupidTheta`. But this sometimes causes redundant constraints to be included in the derived instance contexts, as the constraints that appear in the `tyConStupidTheta` may not actually appear in the types of the data constructors (i.e., the `dataConStupidTheta`s). For instance, in `data Show a => T a = MkT deriving Eq`, the type of `MkT` does not require `Show`, so the derived `Eq` instance should not require `Show` either. This patch makes it so with some small tweaks to `inferConstraintsStock`. Fixes #20501.
* Default kind vars in tyfams with -XNoPolyKindssheaf2021-11-086-44/+66
| | | | | | | | | | | | | | | We should still default kind variables in type families in the presence of -XNoPolyKinds, to avoid suggesting enabling -XPolyKinds just because the function arrow introduced kind variables, e.g. type family F (t :: Type) :: Type where F (a -> b) = b With -XNoPolyKinds, we should still default `r :: RuntimeRep` in `a :: TYPE r`. Fixes #20584
* Make Word64 use Word64# on every architectureSylvain Henry2021-11-061-12/+3
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* Export `withTcPlugins` and `withHoleFitPlugins`Ziyang Liu2021-11-061-0/+2
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* Generalize the type of wrapLocSndMAVladislav Zavialov2021-11-031-4/+13
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* EPA: Get rid of bare SrcSpan's in the ParsedSourceAlan Zimmerman2021-11-0210-33/+32
| | | | | | | | | | | | | The ghc-exactPrint library has had to re-introduce the relatavise phase. This is needed if you change the length of an identifier and want the layout to be preserved afterwards. It is not possible to relatavise a bare SrcSpan, so introduce `SrcAnn NoEpAnns` for them instead. Updates haddock submodule.
* HsToken for let/in (#19623)Vladislav Zavialov2021-11-024-9/+9
| | | | One more step towards the new design of EPA.
* Show family TyCons in mk_dict_error in the case of a single matchZiyang Liu2021-10-291-2/+26
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* Change CaseAlt and LambdaExpr to FunRhs in deriving Foldable and Traversable ↵Artyom Kuznetsov2021-10-261-3/+8
| | | | (#20496)
* Don't default type variables in type familiessheaf2021-10-266-32/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | This patch removes the following defaulting of type variables in type and data families: - type variables of kind RuntimeRep defaulting to LiftedRep - type variables of kind Levity defaulting to Lifted - type variables of kind Multiplicity defaulting to Many It does this by passing "defaulting options" to the `defaultTyVars` function; when calling from `tcTyFamInstEqnGuts` or `tcDataFamInstHeader` we pass options that avoid defaulting. This avoids wildcards being defaulted, which caused type families to unexpectedly fail to reduce. Note that kind defaulting, applicable only with -XNoPolyKinds, is not changed by this patch. Fixes #17536 ------------------------- Metric Increase: T12227 -------------------------
* EPA: Use LocatedA for ModuleNameAlan Zimmerman2021-10-241-2/+2
| | | | | This allows us to use an Anchor with a DeltaPos in it when exact printing.
* Refactor package importsSylvain Henry2021-10-223-50/+31
| | | | | | | | | Use an (Raw)PkgQual datatype instead of `Maybe FastString` to represent package imports. Factorize the code that renames RawPkgQual into PkgQual in function `rnPkgQual`. Renaming consists in checking if the FastString is the magic "this" keyword, the home-unit unit-id or something else. Bump haddock submodule
* Remove IndefiniteSylvain Henry2021-10-221-2/+2
| | | | We no longer need it after previous IndefUnitId refactoring.
* Use tcEqType in GHC.Core.Unify.uVarsheaf2021-10-221-0/+4
| | | | | | | | | | | | | | | | | Because uVar used eqType instead of tcEqType, it was possible to accumulate a substitution that unified Type and Constraint. For example, a call to `tc_unify_tys` with arguments tys1 = [ k, k ] tys2 = [ Type, Constraint ] would first add `k = Type` to the substitution. That's fine, but then the second call to `uVar` would claim that the substitution also unifies `k` with `Constraint`. This could then be used to cause trouble, as per #20521. Fixes #20521
* Make fields of GlobalRdrElt strictMatthew Pickering2021-10-201-1/+6
| | | | | | | | In order to do this I thought it was prudent to change the list type to a bag type to avoid doing a lot of premature work in plusGRE because of ++. Fixes #19201
* Care about specificity in pattern type argsRichard Eisenberg2021-10-191-4/+6
| | | | Close #20443.
* InteractiveContext: Smarter caching when rebuilding the ic_rn_gbl_envJoachim Breitner2021-10-191-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | The GlobalRdrEnv of a GHCI session changes in odd ways: New bindings are not just added "to the end", but also "in the middle", namely when changing the set of imports: These are treated as if they happened before all bindings from the prompt, even those that happened earlier. Previously, this meant that the `ic_rn_gbl_env` is recalculated from the `ic_tythings`. But this wasteful if `ic_tythings` has many entries that define the same unqualified name. By separately keeping track of a `GlobalRdrEnv` of all the locally defined things we can speed this operation up significantly. This change improves `T14052Type` by 60% (It used to be 70%, but it looks that !6723 already reaped some of the rewards). But more importantly, it hopefully unblocks #20455, becaues with this smarter caching, the change needed to fix that issue will no longer make `T14052` explode. I hope. It does regress `T14052` by 30%; caching isn’t free. Oh well. Metric Decrease: T14052Type Metric Increase: T14052
* Introduce Concrete# for representation polymorphism checkssheaf2021-10-1732-411/+1816
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 -------------------------
* Be more careful about retaining KnotVarsMatthew Pickering2021-10-122-2/+2
| | | | | | | | | | | | | | | | | | | | | It is quite easy to end up accidently retaining a KnotVars, which contains pointers to a stale TypeEnv because they are placed in the HscEnv. One place in particular we have to be careful is when loading a module into the EPS in `--make` mode, we have to remove the reference to KnotVars as otherwise the interface loading thunks will forever retain reference to the KnotVars which are live at the time the interface was loaded. These changes do not go as far as to enforce the invariant described in Note [KnotVar invariants] * At the end of upsweep, there should be no live KnotVars but at least improve the situation. This is left for future work (#20491)
* Reject GADT pattern matches in arrow notationsheaf2021-10-094-35/+76
| | | | | | | | | | | | Tickets #20469 and #20470 showed that the current implementation of arrows is not at all up to the task of supporting GADTs: GHC produces ill-scoped Core programs because it doesn't propagate the evidence introduced by a GADT pattern match. For the time being, we reject GADT pattern matches in arrow notation. Hopefully we are able to add proper support for GADTs in arrows in the future.
* Add defaulting plugins.Andrei Barbu2021-10-085-26/+108
| | | | | | | | | | | | | | | Like the built-in type defaulting rules these plugins can propose candidates to resolve ambiguous type variables. Machine learning and other large APIs like those for game engines introduce new numeric types and other complex typed APIs. The built-in defaulting mechanism isn't powerful enough to resolve ambiguous types in these cases forcing users to specify minutia that they might not even know how to do. There is an example defaulting plugin linked in the documentation. Applications include defaulting the device a computation executes on, if a gradient should be computed for a tensor, or the size of a tensor. See https://github.com/ghc-proposals/ghc-proposals/pull/396 for details.
* Improve overlap error for polykinded constraintssheaf2021-10-061-19/+6
| | | | | | | | | | | | | | There were two problems around `mkDictErr`: 1. An outdated call to `flattenTys` meant that we missed out on some instances. As we no longer flatten type-family applications, the logic is obsolete and can be removed. 2. We reported "out of scope" errors in a poly-kinded situation because `BoxedRep` and `Lifted` were considered out of scope. We fix this by using `pretendNameIsInScope`. fixes #20465
* Eradicate TcRnUnknownMessage from GHC.Tc.DerivAlfredo Di Napoli2021-10-055-318/+870
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This (big) commit finishes porting the GHC.Tc.Deriv module to support the new diagnostic infrastructure (#18516) by getting rid of the legacy calls to `TcRnUnknownMessage`. This work ended up being quite pervasive and touched not only the Tc.Deriv module but also the Tc.Deriv.Utils and Tc.Deriv.Generics module, which needed to be adapted to use the new infrastructure. This also required generalising `Validity`. More specifically, this is a breakdown of the work done: * Add and use the TcRnUselessTypeable data constructor * Add and use TcRnDerivingDefaults data constructor * Add and use the TcRnNonUnaryTypeclassConstraint data constructor * Add and use TcRnPartialTypeSignatures * Add T13324_compile2 test to test another part of the TcRnPartialTypeSignatures diagnostic * Add and use TcRnCannotDeriveInstance data constructor, which introduces a new data constructor to TcRnMessage called TcRnCannotDeriveInstance, which is further sub-divided to carry a `DeriveInstanceErrReason` which explains the reason why we couldn't derive a typeclass instance. * Add DerivErrSafeHaskellGenericInst data constructor to DeriveInstanceErrReason * Add DerivErrDerivingViaWrongKind and DerivErrNoEtaReduce * Introduce the SuggestExtensionInOrderTo Hint, which adds (and use) a new constructor to the hint type `LanguageExtensionHint` called `SuggestExtensionInOrderTo`, which can be used to give a bit more "firm" recommendations when it's obvious what the required extension is, like in the case for the `DerivingStrategies`, which automatically follows from having enabled both `DeriveAnyClass` and `GeneralizedNewtypeDeriving`. * Wildcard-free pattern matching in mk_eqn_stock, which removes `_` in favour of pattern matching explicitly on `CanDeriveAnyClass` and `NonDerivableClass`, because that determine whether or not we can suggest to the user `DeriveAnyClass` or not.
* Make GHC.Utils.Error.Validity type polymorphicAlfredo Di Napoli2021-10-053-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | 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@.
* Reject type family equation with wrong name (#20260)Krzysztof Gogolewski2021-10-051-25/+24
| | | | | | We should reject "type family Foo where Bar = ()". This check was done in kcTyFamInstEqn but not in tcTyFamInstEqn. I factored out arity checking, which was duplicated.
* Speed up valid hole-fits by adding early abort and checks.Matthías Páll Gissurarson2021-10-053-61/+108
| | | | | | | | | | | | | | By adding an early abort flag in `TcSEnv`, we can fail fast in the presence of insoluble constraints. This helps us avoid a lot of work in valid hole-fits, and we geta massive speed-up by avoiding a lot of useless work solving constraints that never come into play. Additionally, we add a simple check for degenerate hole types, such as when the type of the hole is an immutable type variable (as is the case when the hole is completely unconstrained). Then the only valid fits are the locals, so we can ignore the global candidates. This fixes #16875
* Bump TcLevel of failing kind equality implicationsheaf2021-10-041-8/+28
| | | | | | | | Not bumping the TcLevel meant that we could end up trying to add evidence terms for the implication constraint created to wrap failing kind equalities (to avoid their deferral). fixes #20043
* Use eqType, not tcEqType, in metavar kind checkRichard Eisenberg2021-10-024-41/+10
| | | | | | | | | | | | Close #20356. See addendum to Note [coreView vs tcView] in GHC.Core.Type for the details. Also killed old Note about metaTyVarUpdateOK, which has been gone for some time. test case: typecheck/should_fail/T20356
* Convert Diagnostics GHC.Tc.Gen.* (Part 3)Aaron Allen2021-10-013-107/+266
| | | | | | Converts all diagnostics in the `GHC.Tc.Gen.Expr` module. (#20116)
* Trees That Grow refactor for HsTick and HsBinTickAndrea Condoluci2021-09-302-4/+0
| | | | | | Move HsTick and HsBinTick to XExpr, the extension tree of HsExpr. Part of #16830 .
* compiler: occEnvElts -> nonDetOccEnvEltsBen Gamari2021-09-291-2/+2
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* compiler: Rename nameEnvElts -> nonDetNameEnvEltsBen Gamari2021-09-293-5/+5
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