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* Handle ConcreteTvs in inferResultToTypewip/T23153sheaf2023-04-156-31/+53
| | | | | | | | | | inferResultToType was discarding the ir_frr information, which meant some metavariables ended up being MetaTvs instead of ConcreteTvs. This function now creates new ConcreteTvs as necessary, instead of always creating MetaTvs. Fixes #23154
* Show an error when we cannot default a concrete tyvarKrzysztof Gogolewski2023-04-153-0/+22
| | | | Fixes #23153
* Make approximateWC a bit clevererwip/T22194-flagsSimon Peyton Jones2023-04-141-61/+94
| | | | | | | | | | | This MR fixes #23224: making approximateWC more clever See the long `Note [ApproximateWC]` in GHC.Tc.Solver All this is delicate and ad-hoc -- but it /has/ to be: we are talking about inferring a type for a binding in the presence of GADTs, type families and whatnot: known difficult territory. We just try as hard as we can.
* Improve partial signaturesSimon Peyton Jones2023-04-144-104/+137
| | | | | | | | | | | | | | | | | | | | | | | This MR fixes #23223. The changes are in two places: * GHC.Tc.Bind.checkMonomorphismRestriction See the new `Note [When the MR applies]` We now no longer stupidly attempt to apply the MR when the user specifies a context, e.g. f :: Eq a => _ -> _ * GHC.Tc.Solver.decideQuantification See rewritten `Note [Constraints in partial type signatures]` Fixing this bug apparently breaks three tests: * partial-sigs/should_compile/T11192 * partial-sigs/should_fail/Defaulting1MROff * partial-sigs/should_fail/T11122 However they are all symptoms of #23232, so I'm marking them as expect_broken(23232). I feel happy about this MR. Nice.
* Add some documentation about redundant constraintsSimon Peyton Jones2023-04-142-5/+28
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* Major refactor in the handling of equality constraintsSimon Peyton Jones2023-04-1411-1096/+1895
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This MR substantially refactors the way in which the constraint solver deals with equality constraints. The big thing is: * Intead of a pipeline in which we /first/ canonicalise and /then/ interact (the latter including performing unification) the two steps are more closely integreated into one. That avoids the current rather indirect communication between the two steps. The proximate cause for this refactoring is fixing #22194, which involve solving [W] alpha[2] ~ Maybe (F beta[4]) by doing this: alpha[2] := Maybe delta[2] [W] delta[2] ~ F beta[4] That is, we don't promote beta[4]! This is very like introducing a cycle breaker, and was very awkward to do before, but now it is all nice. See GHC.Tc.Utils.Unify Note [Promotion and level-checking] and Note [Family applications in canonical constraints]. The big change is this: * Several canonicalisation checks (occurs-check, cycle-breaking, checking for concreteness) are combined into one new function: GHC.Tc.Utils.Unify.checkTyEqRhs This function is controlled by `TyEqFlags`, which says what to do for foralls, type families etc. * `canEqCanLHSFinish` now sees if unification is possible, and if so, actually does it: see `canEqCanLHSFinish_try_unification`. There are loads of smaller changes: * The on-the-fly unifier `GHC.Tc.Utils.Unify.unifyType` has a cheap-and-cheerful version of `checkTyEqRhs`, called `simpleUnifyCheck`. If `simpleUnifyCheck` succeeds, it can unify, otherwise it defers by emitting a constraint. This is simpler than before. * I simplified the swapping code in `GHC.Tc.Solver.Equality.canEqCanLHS`. Especially the nasty stuff involving `swap_for_occurs` and `canEqTyVarFunEq`. Much nicer now. See Note [Orienting TyVarLHS/TyFamLHS] Note [Orienting TyFamLHS/TyFamLHS] * Added `cteSkolemOccurs`, `cteConcrete`, and `cteCoercionHole` to the problems that can be discovered by `checkTyEqRhs`. * I fixed #23199 `pickQuantifiablePreds`, which actually allows GHC to to accept both cases in #22194 rather than rejecting both. Yet smaller: * Added a `synIsConcrete` flag to `SynonymTyCon` (alongside `synIsFamFree`) to reduce the need for synonym expansion when checking concreteness. Use it in `isConcreteType`. * Renamed `isConcrete` to `isConcreteType` * Defined `GHC.Core.TyCo.FVs.isInjectiveInType` as a more efficient way to find if a particular type variable is used injectively than finding all the injective variables. It is called in `GHC.Tc.Utils.Unify.definitely_poly`, which in turn is used quite a lot. * Moved `rewriterView` to `GHC.Core.Type`, so we can use it from the constraint solver. Fixes #22194, #23199 Compile times decrease by an average of 0.1%; but there is a 7.4% drop in compiler allocation on T15703. Metric Decrease: T15703
* Stop if type constructors have kind errorsSimon Peyton Jones2023-04-141-1/+7
| | | | | | | | | Otherwise we get knock-on errors, such as #23252. This makes GHC fail a bit sooner, and I have not attempted to add recovery code, to add a fake TyCon place of the erroneous one, in an attempt to get more type errors in one pass. We could do that (perhaps) if there was a call for it.
* Add structured error messages for GHC.Tc.TyCl.UtilsTorsten Schmits2023-04-073-15/+38
| | | | | | | | | Tracking ticket: #20117 MR: !10251 This converts uses of `mkTcRnUnknownMessage` to newly added constructors of `TcRnMessage`.
* Fixes around unsafeCoerce#Krzysztof Gogolewski2023-04-031-10/+16
| | | | | | | | | | | | 1. `unsafeCoerce#` was documented in `GHC.Prim`. But since the overhaul in 74ad75e87317, `unsafeCoerce#` is no longer defined there. I've combined the documentation in `GHC.Prim` with the `Unsafe.Coerce` module. 2. The documentation of `unsafeCoerce#` stated that you should not cast a function to an algebraic type, even if you later cast it back before applying it. But ghci was doing that type of cast, as can be seen with 'ghci -ddump-ds' and typing 'x = not'. I've changed it to use Any following the documentation.
* Convert diagnostics in GHC.Rename.HsType to proper TcRnMessageHaskell-mouse2023-04-032-1/+277
| | | | | | | | | | | | | | | | | | I've turned all occurrences of TcRnUnknownMessage in GHC.Rename.HsType module into a proper TcRnMessage. Instead, these TcRnMessage messages were introduced: TcRnDataKindsError TcRnUnusedQuantifiedTypeVar TcRnIllegalKindSignature TcRnUnexpectedPatSigType TcRnSectionPrecedenceError TcRnPrecedenceParsingError TcRnIllegalKind TcRnNegativeNumTypeLiteral TcRnUnexpectedKindVar TcRnBindMultipleVariables TcRnBindVarAlreadyInScope
* TH: revert changes to GadtC & RecGadtCsheaf2023-04-013-3/+8
| | | | | | | Commit 3f374399 included a breaking-change to the template-haskell library when it made the GadtC and RecGadtC constructors take non-empty lists of names. As this has the potential to break many users' packages, we decided to revert these changes for now.
* Add structured error messages for GHC.Tc.TyClTorsten Schmits2023-04-016-297/+728
| | | | | | | | | Tracking ticket: #20117 MR: !10183 This converts uses of `mkTcRnUnknownMessage` to newly added constructors of `TcRnMessage`.
* driver: Unit State Data.Map -> GHC.Unique.UniqMapdoyougnu2023-04-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | In pursuit of #22426. The driver and unit state are major contributors. This commit also bumps the haddock submodule to reflect the API changes in UniqMap. ------------------------- Metric Decrease: MultiComponentModules MultiComponentModulesRecomp T10421 T10547 T12150 T12234 T12425 T13035 T16875 T18140 T18304 T18698a T18698b T18923 T20049 T5837 T6048 T9198 -------------------------
* Handle records in the renamersheaf2023-03-2920-1151/+1185
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 -------------------------
* Allow WARNING pragmas to be controlled with custom categoriesAdam Gundry2023-03-243-6/+31
| | | | | | | | | | | | | | | | Closes #17209. This implements GHC Proposal 541, allowing a WARNING pragma to be annotated with a category like so: {-# WARNING in "x-partial" head "This function is undefined on empty lists." #-} The user can then enable, disable and set the severity of such warnings using command-line flags `-Wx-partial`, `-Werror=x-partial` and so on. There is a new warning group `-Wextended-warnings` containing all these warnings. Warnings without a category are treated as if the category was `deprecations`, and are (still) controlled by the flags `-Wdeprecations` and `-Wwarnings-deprecations`. Updates Haddock submodule.
* Add structured error messages for GHC.Tc.TyCl.PatSynTorsten Schmits2023-03-233-57/+133
| | | | | | | | | Tracking ticket: #20117 MR: !10158 This converts uses of `mkTcRnUnknownMessage` to newly added constructors of `TcRnMessage`.
* Add structured error messages for GHC.Tc.Utils.TcMTypeTorsten Schmits2023-03-226-60/+126
| | | | | | | | | Tracking ticket: #20119 MR: !10138 This converts uses of `mkTcRnUnknownMessage` to newly added constructors of `TcRnMessage`.
* Refactor the constraint solver pipelinewip/T23070Simon Peyton Jones2023-03-2211-4112/+4249
| | | | | | | | | | | | | | | | The big change is to put the entire type-equality solver into GHC.Tc.Solver.Equality, rather than scattering it over Canonical and Interact. Other changes * EqCt becomes its own data type, a bit like QCInst. This is great because EqualCtList is then just [EqCt] * New module GHC.Tc.Solver.Dict has come of the class-contraint solver. In due course it will be all. One step at a time. This MR is intended to have zero change in behaviour: it is a pure refactor. It opens the way to subsequent tidying up, we believe.
* Be more careful about quantificationSimon Peyton Jones2023-03-227-160/+215
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This MR is driven by #23051. It does several things: * It is guided by the generalisation plan described in #20686. But it is still far from a complete implementation of that plan. * Add Note [Inferred type with escaping kind] to GHC.Tc.Gen.Bind. This explains that we don't (yet, pending #20686) directly prevent generalising over escaping kinds. * In `GHC.Tc.Utils.TcMType.defaultTyVar` we default RuntimeRep and Multiplicity variables, beause we don't want to quantify over them. We want to do the same for a Concrete tyvar, but there is nothing sensible to default it to (unless it has kind RuntimeRep, in which case it'll be caught by an earlier case). So we promote instead. * Pure refactoring in GHC.Tc.Solver: * Rename decideMonoTyVars to decidePromotedTyVars, since that's what it does. * Move the actual promotion of the tyvars-to-promote from `defaultTyVarsAndSimplify` to `decidePromotedTyVars`. This is a no-op; just tidies up the code. E.g then we don't need to return the promoted tyvars from `decidePromotedTyVars`. * A little refactoring in `defaultTyVarsAndSimplify`, but no change in behaviour. * When making a TauTv unification variable into a ConcreteTv (in GHC.Tc.Utils.Concrete.makeTypeConcrete), preserve the occ-name of the type variable. This just improves error messages. * Kill off dead code: GHC.Tc.Utils.TcMType.newConcreteHole
* Add structured error messages for GHC.Tc.Utils.EnvTorsten Schmits2023-03-2110-92/+224
| | | | | | | | | Tracking ticket: #20119 MR: !10129 This converts uses of `mkTcRnUnknownMessage` to newly added constructors of `TcRnMessage`.
* Add structured error messages for GHC.Tc.Utils.BackpackTorsten Schmits2023-03-173-22/+95
| | | | | | | | | | | | Tracking ticket: #20119 MR: !10127 This converts uses of `mkTcRnUnknownMessage` to newly added constructors of `TcRnMessage`. One occurrence, when handing a nested error from the interface loading machinery, was omitted. It will be handled by a subsequent changeset that addresses interface errors.
* Fixes #19627.Apoorv Ingle2023-03-091-2/+2
| | | | | | | | | Previously the solver failed with an unhelpful "solver reached too may iterations" error. With the fix for #21909 in place we no longer have the possibility of generating such an error if we have `-fconstraint-solver-iteration` > `-fgivens-fuel > `-fwanteds-fuel`. This is true by default, and the said fix also gives programmers a knob to control how hard the solver should try before giving up. This commit adds: * Reference to ticket #19627 in the Note [Expanding Recursive Superclasses and ExpansionFuel] * Test `typecheck/should_fail/T19627.hs` for regression purposes
* Constraint simplification loop now depends on `ExpansionFuel`Apoorv Ingle2023-03-064-95/+246
| | | | | | | | | | | | | | instead of a boolean flag for `CDictCan.cc_pend_sc`. Pending givens get a fuel of 3 while Wanted and quantified constraints get a fuel of 1. This helps pending given constraints to keep up with pending wanted constraints in case of `UndecidableSuperClasses` and superclass expansions while simplifying the infered type. Adds 3 dynamic flags for controlling the fuels for each type of constraints `-fgivens-expansion-fuel` for givens `-fwanteds-expansion-fuel` for wanteds and `-fqcs-expansion-fuel` for quantified constraints Fixes #21909 Added Tests T21909, T21909b Added Note [Expanding Recursive Superclasses and ExpansionFuel]
* Convert diagnostics in GHC.Rename.Module to proper TcRnMessage (#20115)Andrei Borzenkov2023-03-062-0/+371
| | | | | | | | | | | | | | | | | | | | | | | | | I've turned almost all occurrences of TcRnUnknownMessage in GHC.Rename.Module module into a proper TcRnMessage. Instead, these TcRnMessage messages were introduced: TcRnIllegalInstanceHeadDecl TcRnUnexpectedStandaloneDerivingDecl TcRnUnusedVariableInRuleDecl TcRnUnexpectedStandaloneKindSig TcRnIllegalRuleLhs TcRnBadAssocRhs TcRnDuplicateRoleAnnot TcRnDuplicateKindSig TcRnIllegalDerivStrategy TcRnIllegalMultipleDerivClauses TcRnNoDerivStratSpecified TcRnStupidThetaInGadt TcRnBadImplicitSplice TcRnShadowedTyVarNameInFamResult TcRnIncorrectTyVarOnLhsOfInjCond TcRnUnknownTyVarsOnRhsOfInjCond Was introduced one helper type: RuleLhsErrReason
* More fixes for `type data` declarationsSimon Peyton Jones2023-03-031-1/+2
| | | | | | | | | | | | | | | | | | | | | | This MR fixes #23022 and #23023. Specifically * Beef up Note [Type data declarations] in GHC.Rename.Module, to make invariant (I1) explicit, and to name the several wrinkles. And add references to these specific wrinkles. * Add a Lint check for invariant (I1) above. See GHC.Core.Lint.checkTypeDataConOcc * Disable the `caseRules` for dataToTag# for `type data` values. See Wrinkle (W2c) in the Note above. Fixes #23023. * Refine the assertion in dataConRepArgTys, so that it does not complain about the absence of a wrapper for a `type data` constructor Fixes #23022. Acked-by: Simon Peyton Jones <simon.peytonjones@gmail.com>
* Check for platform support for JavaScript foreign importsLuite Stegeman2023-03-021-1/+2
| | | | | | | | | GHC was accepting `foreign import javascript` declarations on non-JavaScript platforms. This adds a check so that these are only supported on an platform that supports the JavaScript calling convention. Fixes #22774
* Don't suppress *all* WantedsRichard Eisenberg2023-03-022-17/+24
| | | | | | | | | | | | | | Code in GHC.Tc.Errors.reportWanteds suppresses a Wanted if its rewriters have unfilled coercion holes; see Note [Wanteds rewrite Wanteds] in GHC.Tc.Types.Constraint. But if we thereby suppress *all* errors that's really confusing, and as #22707 shows, GHC goes on without even realising that the program is broken. Disaster. This MR arranges to un-suppress them all if they all get suppressed. Close #22707
* Refine the test for naughty record selectorsSimon Peyton Jones2023-03-011-36/+51
| | | | | | | The test for naughtiness in record selectors is surprisingly subtle. See the revised Note [Naughty record selectors] in GHC.Tc.TyCl.Utils. Fixes #23038.
* Don't specialise incoherent instance applicationsGergő Érdi2023-02-278-120/+135
| | | | | | | | | | | | | | 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
* Fix ParallelListComp out of scope suggestionAaron Allen2023-02-241-7/+30
| | | | | | | | | This patch makes it so vars from one block of a parallel list comprehension are not in scope in a subsequent block during type checking. This was causing GHC to emit a faulty suggestion when an out of scope variable shared the occ name of a var from a different block. Fixes #22940
* Explicit migration timeline for loopy SC solvingsheaf2023-02-231-1/+1
| | | | | | | | | This patch updates the warning message introduced in commit 9fb4ca89bff9873e5f6a6849fa22a349c94deaae to specify an explicit migration timeline: GHC will no longer support this constraint solving mechanism starting from GHC 9.10. Fixes #22912
* GHC proposal 496 - Nullary record wildcardsGeorgi Lyubenov2023-02-215-24/+25
| | | | | | | | | | | | | | | | | | | This patch implements GHC proposal 496, which allows record wildcards to be used for nullary constructors, e.g. data A = MkA1 | MkA2 { fld1 :: Int } f :: A -> Int f (MkA1 {..}) = 0 f (MkA2 {..}) = fld1 To achieve this, we add arity information to the record field environment, so that we can accept a constructor which has no fields while continuing to reject non-record constructors with more than 1 field. See Note [Nullary constructors and empty record wildcards], as well as the more general overview in Note [Local constructor info in the renamer], both in the newly introduced GHC.Types.ConInfo module. Fixes #22161
* Disallow `tagToEnum#` on `type data` typeswip/T22948Ryan Scott2023-02-203-0/+24
| | | | | We don't want to allow users to conjure up values of a `type data` type using `tagToEnum#`, as these simply don't exist at the value level.
* Improve GHC.Tc.Gen.App.tcInstFunwip/T22908Simon Peyton Jones2023-02-201-16/+12
| | | | | | | | | | | | | | It wasn't behaving right when inst_final=False, and the function had no type variables f :: Foo => Int Rather a corner case, but we might as well do it right. Fixes #22908 Unexpectedly, three test cases (all using :type in GHCi) got slightly better output as a result: T17403, T14796, T12447
* Narrow the dont-decompose-newtype testSimon Peyton Jones2023-02-163-165/+152
| | | | | | | | | | | | | | | | | | | | | | | | | | Following #22924 this patch narrows the test that stops us decomposing newtypes. The key change is the use of noGivenNewtypeReprEqs in GHC.Tc.Solver.Canonical.canTyConApp. We went to and fro on the solution, as you can see in #22924. The result is carefully documented in Note [Decomoposing newtype equalities] On the way I had revert most of commit 3e827c3f74ef76d90d79ab6c4e71aa954a1a6b90 Author: Richard Eisenberg <rae@cs.brynmawr.edu> Date: Mon Dec 5 10:14:02 2022 -0500 Do newtype unwrapping in the canonicaliser and rewriter See Note [Unwrap newtypes first], which has the details. It turns out that (a) 3e827c3f makes GHC behave worse on some recursive newtypes (see one of the tests on this commit) (b) the finer-grained test (namely noGivenNewtypeReprEqs) renders 3e827c3f unnecessary
* Introduce warning for loopy superclass solvesheaf2023-02-147-54/+150
| | | | | | | | | | | | | | | | | Commit aed1974e completely re-engineered the treatment of loopy superclass dictionaries in instance declarations. Unfortunately, it has the potential to break (albeit in a rather minor way) user code. To alleviate migration concerns, this commit re-introduces the old behaviour. Any reliance on this old behaviour triggers a warning, controlled by `-Wloopy-superclass-solve`. The warning text explains that GHC might produce bottoming evidence, and provides a migration strategy. This allows us to provide a graceful migration period, alerting users when they are relying on this unsound behaviour. Fixes #22912 #22891 #20666 #22894 #22905
* Minor refactorKrzysztof Gogolewski2023-02-043-8/+5
| | | | | | | | * Introduce refactorDupsOn f = refactorDups (comparing f) * Make mkBigTupleCase and coreCaseTuple monadic. Every call to those functions was preceded by calling newUniqueSupply. * Use mkUserLocalOrCoVar, which is equivalent to combining mkLocalIdOrCoVar with mkInternalName.
* Fix CallerCC potentially shadowing other cost centres.Andreas Klebinger2023-02-031-2/+2
| | | | | | Add a CallerCC cost centre flavour for cost centres added by the CallerCC pass. This avoids potential accidental shadowing between CCs added by user annotations and ones added by CallerCC.
* Improve treatment of type applications in patternswip/T19847Simon Peyton Jones2023-02-011-105/+222
| | | | | | | | | | This patch fixes a subtle bug in the typechecking of type applications in patterns, e.g. f (MkT @Int @a x y) = ... See Note [Type applications in patterns] in GHC.Tc.Gen.Pat. This fixes #19847, #22383, #19577, #21501
* Support "unusable UNPACK pragma" warning with -O0Krzysztof Gogolewski2023-01-313-13/+13
| | | | Fixes #11270
* Improve exprOkForSpeculation for classopsSimon Peyton Jones2023-01-311-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes #22745 and #15205, which are about GHC's failure to discard unnecessary superclass selections that yield coercions. See GHC.Core.Utils Note [exprOkForSpeculation and type classes] The main changes are: * Write new Note [NON-BOTTOM_DICTS invariant] in GHC.Core, and refer to it * Define new function isTerminatingType, to identify those guaranteed-terminating dictionary types. * exprOkForSpeculation has a new (very simple) case for ClassOpId * ClassOpId has a new field that says if the return type is an unlifted type, or a terminating type. This was surprisingly tricky to get right. In particular note that unlifted types are not terminating types; you can write an expression of unlifted type, that diverges. Not so for dictionaries (or, more precisely, for the dictionaries that GHC constructs). Metric Decrease: LargeRecord
* Fix two bugs in TypeData TH reificationRyan Scott2023-01-301-6/+22
| | | | | | | | | | | This patch fixes two issues in the way that `type data` declarations were reified with Template Haskell: * `type data` data constructors are now properly reified using `DataConI`. This is accomplished with a special case in `reifyTyCon`. Fixes #22818. * `type data` type constructors are now reified in `reifyTyCon` using `TypeDataD` instead of `DataD`. Fixes #22819.
* Convert diagnostics in GHC.Rename.Bind to proper TcRnMessage (#20115)Andrei Borzenkov2023-01-282-0/+281
| | | | | | | | | | | | | | | | I removed all occurrences of TcRnUnknownMessage in GHC.Rename.Bind module. Instead, these TcRnMessage messages were introduced: TcRnMultipleFixityDecls TcRnIllegalPatternSynonymDecl TcRnIllegalClassBiding TcRnOrphanCompletePragma TcRnEmptyCase TcRnNonStdGuards TcRnDuplicateSigDecl TcRnMisplacedSigDecl TcRnUnexpectedDefaultSig TcRnBindInBootFile TcRnDuplicateMinimalSig
* Report family instance orphans correctlySimon Peyton Jones2023-01-278-105/+114
| | | | | | | | | | | | | | | | | 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
* Detect family instance orphans correctlySimon Peyton Jones2023-01-272-3/+3
| | | | | | | | | We were treating a type-family instance as a non-orphan if there was a type constructor on its /right-hand side/ that was local. Boo! Utterly wrong. With this patch, we correctly check the /left-hand side/ instead! Fixes #22717
* Replace errors from badOrigBinding with new one (#22839)Andrei Borzenkov2023-01-272-39/+23
| | | | | | | | | | | | | | | | | | | | Problem: in 02279a9c the type-level [] syntax was changed from a built-in name to an alias for the GHC.Types.List constructor. badOrigBinding assumes that if a name is not built-in then it must have come from TH quotation, but this is not necessarily the case with []. The outdated assumption in badOrigBinding leads to incorrect error messages. This code: data [] Fails with "Cannot redefine a Name retrieved by a Template Haskell quote: []" Unfortunately, there is not enough information in RdrName to directly determine if the name was constructed via TH or by the parser, so this patch changes the error message instead. It unifies TcRnIllegalBindingOfBuiltIn and TcRnNameByTemplateHaskellQuote into a new error TcRnBindingOfExistingName and changes its wording to avoid guessing the origin of the name.
* Do newtype unwrapping in the canonicaliser and rewriterRichard Eisenberg2023-01-265-78/+192
| | | | | | See Note [Unwrap newtypes first], which has the details. Close #22519.
* EPA: Add SourceText to HsOverLabelAlan Zimmerman2023-01-232-2/+2
| | | | | | To be able to capture string literals with possible escape codes as labels. Close #22771
* Enable -Wstar-is-type by default (#22759)Vladislav Zavialov2023-01-181-1/+1
| | | | | | | | | | | | | Following the plan in GHC Proposal #143 "Remove the * kind syntax", which states: In the next release (or 3 years in), enable -fwarn-star-is-type by default. The "next release" happens to be 9.6.1 I also moved the T21583 test case from should_fail to should_compile, because the only reason it was failing was -Werror=compat in our test suite configuration.
* Add a missing checkEscapingKindSimon Peyton Jones2023-01-133-48/+55
| | | | | | | | Ticket #22743 pointed out that there is a missing check, for type-inferred bindings, that the inferred type doesn't have an escaping kind. The fix is easy.
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