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* Use setSrcSpan rather than setLclEnv in solveForAllMatthew Pickering2023-05-172-5/+7
| | | | | | | | | In subsequent MRs (#23409) we want to remove the TcLclEnv argument from a CtLoc. This MR prepares us for that by removing the one place where the entire TcLclEnv is used, by using it more precisely to just set the contexts source location. Fixes #23390
* Add -Wmissing-role-annotationsOleg Grenrus2023-05-163-3/+59
| | | | Implements #22702
* Migrate errors to diagnostics in GHC.Tc.Modulesheaf2023-05-1510-801/+1219
| | | | | | | | | | | | | | | | | | | | This commit migrates the errors in GHC.Tc.Module to use the new diagnostic infrastructure. It required a significant overhaul of the compatibility checks between an hs-boot or signature module and its implementation; we now use a Writer monad to accumulate errors; see the BootMismatch datatype in GHC.Tc.Errors.Types, with its panoply of subtypes. For the sake of readability, several local functions inside the 'checkBootTyCon' function were split off into top-level functions. We split off GHC.Types.HscSource into a "boot or sig" vs "normal hs file" datatype, as this mirrors the logic in several other places where we want to treat hs-boot and hsig files in a similar fashion. This commit also refactors the Backpack checks for type synonyms implementing abstract data, to correctly reject implementations that contain qualified or quantified types (this fixes #23342 and #23344).
* Split up tyThingToIfaceDecl from GHC.Iface.Makesheaf2023-05-151-3/+3
| | | | | | | This commit moves tyThingToIfaceDecl and coAxiomToIfaceDecl from GHC.Iface.Make into GHC.Iface.Decl. This avoids GHC.Types.TyThing.Ppr, which needs tyThingToIfaceDecl, transitively depending on e.g. GHC.Iface.Load and GHC.Tc.Utils.Monad.
* Split DynFlags structure into own moduleOleg Grenrus2023-05-152-2/+2
| | | | | This will allow to make command line parsing to depend on diagnostic system (which depends on dynflags)
* Improve "ambiguous occurrence" error messagessheaf2023-05-153-17/+48
| | | | | | | | | This error was sometimes a bit confusing, especially when data families were involved. This commit improves the general presentation of the "ambiguous occurrence" error, and adds a bit of extra context in the case of data families. Fixes #23301
* Cleanup of dynflags override in export renamingBartłomiej Cieślar2023-05-123-58/+51
| | | | The deprecation warnings are normally emitted whenever the name's GRE is being looked up, which calls the GHC.Rename.Env.addUsedGRE function. We do not want those warnings to be emitted when renaming export lists, so they are artificially turned off by removing all warning categories from DynFlags at the beginning of GHC.Tc.Gen.Export.rnExports. This commit removes that dependency by unifying the function used for GRE lookup in lookup_ie to lookupGreAvailRn and disabling the call to addUsedGRE in said function (the warnings are also disabled in a call to lookupSubBndrOcc_helper in lookupChildrenExport), as per #17957. This commit also changes the setting for whether to warn about deprecated names in addUsedGREs to be an explicit enum instead of a boolean.
* Use the eager unifier in the constraint solverSimon Peyton Jones2023-05-1221-948/+1324
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch continues the refactoring of the constraint solver described in #23070. The Big Deal in this patch is to call the regular, eager unifier from the constraint solver, when we want to create new equalities. This replaces the existing, unifyWanted which amounted to yet-another-unifier, so it reduces duplication of a rather subtle piece of technology. See * Note [The eager unifier] in GHC.Tc.Utils.Unify * GHC.Tc.Solver.Monad.wrapUnifierTcS I did lots of other refactoring along the way * I simplified the treatment of right hand sides that contain CoercionHoles. Now, a constraint that contains a hetero-kind CoercionHole is non-canonical, and cannot be used for rewriting or unification alike. This required me to add the ch_hertero_kind flag to CoercionHole, with consequent knock-on effects. See wrinkle (2) of `Note [Equalities with incompatible kinds]` in GHC.Tc.Solver.Equality. * I refactored the StopOrContinue type to add StartAgain, so that after a fundep improvement (for example) we can simply start the pipeline again. * I got rid of the unpleasant (and inefficient) rewriterSetFromType/Co functions. With Richard I concluded that they are never needed. * I discovered Wrinkle (W1) in Note [Wanteds rewrite Wanteds] in GHC.Tc.Types.Constraint, and therefore now prioritise non-rewritten equalities. Quite a few error messages change, I think always for the better. Compiler runtime stays about the same, with one outlier: a 17% improvement in T17836 Metric Decrease: T17836 T18223
* Don't panic in mkNewTyConRhssheaf2023-05-122-25/+42
| | | | | | | | | | | | | This function could come across invalid newtype constructors, as we only perform validity checking of newtypes once we are outside the knot-tied typechecking loop. This patch changes this function to fake up a stub type in the case of an invalid newtype, instead of panicking. This patch also changes "checkNewDataCon" so that it reports as many errors as possible at once. Fixes #23308
* Add a test for #17284Krzysztof Gogolewski2023-05-111-1/+1
| | | | Since !10123 we now reject this program.
* Look both ways when looking for quantified equalitiesSimon Peyton Jones2023-05-114-51/+69
| | | | | When looking up (t1 ~# t2) in the quantified constraints, check both orientations. Forgetting this led to #23333.
* Add structured error messages for GHC.Rename.ModuleTorsten Schmits2023-05-052-0/+132
| | | | | | | | | | | Tracking ticket: #20115 MR: !10361 This converts uses of `mkTcRnUnknownMessage` to newly added constructors of `TcRnMessage`. Only addresses the single warning missing from the previous MR.
* Add structured error messages for GHC.Rename.UtilsTorsten Schmits2023-05-053-3/+327
| | | | | | | | | Tracking ticket: #20115 MR: !10350 This converts uses of `mkTcRnUnknownMessage` to newly added constructors of `TcRnMessage`.
* Fix type variable substitution in gen_Newtype_fam_instsRyan Scott2023-05-042-9/+69
| | | | | | | | | | | | | Previously, `gen_Newtype_fam_insts` was substituting the type variable binders of a type family instance using `substTyVars`, which failed to take type variable dependencies into account. There is similar code in `GHC.Tc.TyCl.Class.tcATDefault` that _does_ perform this substitution properly, so this patch: 1. Factors out this code into a top-level `substATBndrs` function, and 2. Uses `substATBndrs` in `gen_Newtype_fam_insts`. Fixes #23329.
* linear types: Don't add external names to the usage envKrzysztof Gogolewski2023-05-041-2/+2
| | | | This has no observable effect, but avoids storing useless data.
* Don't forget to check the parent in an export listsheaf2023-05-031-26/+23
| | | | | | | | Commit 3f374399 introduced a bug which caused us to forget to include the parent of an export item of the form T(..) (that is, IEThingAll) when checking for duplicate exports. Fixes #23318
* Add structured error messages for GHC.Rename.NamesTorsten Schmits2023-04-302-78/+373
| | | | | | | | | Tracking ticket: #20115 MR: !10336 This converts uses of `mkTcRnUnknownMessage` to newly added constructors of `TcRnMessage`.
* Add the Unsatisfiable classsheaf2023-04-2913-68/+453
| | | | | | | | | 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
* More informative errors for bad imports (#21826)Soham Chowdhury2023-04-253-15/+116
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* Don't panic in ltPatersonSizesheaf2023-04-181-20/+35
| | | | | | | | | | | | | | | | The function GHC.Tc.Utils.TcType.ltPatersonSize would panic when it encountered a type family on the RHS, as usually these are not allowed (type families are not allowed on the RHS of class instances or of quantified constraints). However, it is possible to still encounter type families on the RHS after doing a bit of constraint solving, as seen in test case T23171. This could trigger the panic in the call to ltPatersonSize in GHC.Tc.Solver.Canonical.mk_strict_superclasses, which is involved in avoiding loopy superclass constraints. This patch simply changes ltPatersonSize to return "I don't know, because there's a type family involved" in these cases. Fixes #23171
* Convert interface file loading errors into proper diagnosticsMatthew Pickering2023-04-186-59/+65
| | | | | | | | | | | | | | This patch converts all the errors to do with loading interface files into proper structured diagnostics. * DriverMessage: Sometimes in the driver we attempt to load an interface file so we embed the IfaceMessage into the DriverMessage. * TcRnMessage: Most the time we are loading interface files during typechecking, so we embed the IfaceMessage This patch also removes the TcRnInterfaceLookupError constructor which is superceded by the IfaceMessage, which is now structured compared to just storing an SDoc before.
* validDerivPred: Reject exotic constraints in IrredPredsRyan Scott2023-04-172-99/+175
| | | | | | | | | | | | | | | | | | | | | | | | | This brings the `IrredPred` case in sync with the treatment of `ClassPred`s as described in `Note [Valid 'deriving' predicate]` in `GHC.Tc.Validity`. Namely, we should reject `IrredPred`s that are inferred from `deriving` clauses whose arguments contain other type constructors, as described in `(VD2) Reject exotic constraints` of that Note. This has the nice property that `deriving` clauses whose inferred instance context mention `TypeError` will now emit the type error in the resulting error message, which better matches existing intuitions about how `TypeError` should work. While I was in town, I noticed that much of `Note [Valid 'deriving' predicate]` was duplicated in a separate `Note [Exotic derived instance contexts]` in `GHC.Tc.Deriv.Infer`. I decided to fold the latter Note into the former so that there is a single authority on describing the conditions under which an inferred `deriving` constraint can be considered valid. This changes the behavior of `deriving` in a way that existing code might break, so I have made a mention of this in the GHC User's Guide. It seems very, very unlikely that much code is relying on this strange behavior, however, and even if there is, there is a clear, backwards-compatible migration path using `StandaloneDeriving`. Fixes #22696.
* Add import lists to few GHC.Driver.Session importsOleg Grenrus2023-04-161-1/+1
| | | | | | Related to https://gitlab.haskell.org/ghc/ghc/-/issues/23261. There are a lot of GHC.Driver.Session which only use DynFlags, but not the parsing code.
* 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