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* Fix TcRnPragmaWarning meaninguhbif192022-06-092-20/+20
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* Remove TcRnUnknownMessage usage from GHC.Rename.Env #20115uhbif192022-06-092-0/+102
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* Typecheck remaining ValArgs in rebuildHsAppssheaf2022-06-094-361/+454
| | | | | | | | | | | | | | | | | This patch refactors hasFixedRuntimeRep_remainingValArgs, renaming it to tcRemainingValArgs. The logic is moved to rebuildHsApps, which ensures consistent behaviour across tcApp and quickLookArg1/tcEValArg. This patch also refactors the treatment of stupid theta for data constructors, changing the place we drop stupid theta arguments from dsConLike to mkDataConRep (now the datacon wrapper drops these arguments). We decided not to implement PHASE 2 of the FixedRuntimeRep plan for these remaining ValArgs. Future directions are outlined on the wiki: https://gitlab.haskell.org/ghc/ghc/-/wikis/Remaining-ValArgs Fixes #21544 and #21650
* Core.Lint: Reduce `DynFlags` and `HscEnv`wip/no-state-core-lintJohn Ericson2022-06-071-1/+3
| | | | Co-Authored-By: Andre Marianiello <andremarianiello@users.noreply.github.com>
* Diagnostics conversions, part 6 (#20116)Aaron Allen2022-06-065-71/+217
| | | | | | Replaces uses of `TcRnUnknownMessage` with proper diagnostics constructors in `GHC.Tc.Gen.Match`, `GHC.Tc.Gen.Pat`, and `GHC.Tc.Gen.Sig`.
* TTG: Rework and improve splicesromes2022-06-0111-384/+608
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit redefines the structure of Splices in the AST. We get rid of `HsSplice` which used to represent typed and untyped splices, quasi quotes, and the result of splicing either an expression, a type or a pattern. Instead we have `HsUntypedSplice` which models an untyped splice or a quasi quoter, which works in practice just like untyped splices. The `HsExpr` constructor `HsSpliceE` which used to be constructed with an `HsSplice` is split into `HsTypedSplice` and `HsUntypedSplice`. The former is directly constructed with an `HsExpr` and the latter now takes an `HsUntypedSplice`. Both `HsType` and `Pat` constructors `HsSpliceTy` and `SplicePat` now take an `HsUntypedSplice` instead of a `HsSplice` (remember only /untyped splices/ can be spliced as types or patterns). The result of splicing an expression, type, or pattern is now comfortably stored in the extension fields `XSpliceTy`, `XSplicePat`, `XUntypedSplice` as, respectively, `HsUntypedSpliceResult (HsType GhcRn)`, `HsUntypedSpliceResult (Pat GhcRn)`, and `HsUntypedSpliceResult (HsExpr GhcRn)` Overall the TTG extension points are now better used to make invalid states unrepresentable and model the progression between stages better. See Note [Lifecycle of an untyped splice, and PendingRnSplice] and Note [Lifecycle of an typed splice, and PendingTcSplice] for more details. Updates haddock submodule Fixes #21263 ------------------------- Metric Decrease: hard_hole_fits -------------------------
* Use a class to check validity of withDictwip/withdictKrzysztof Gogolewski2022-05-272-2/+180
| | | | | | | | | | | | 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
* Generalize breakTyVarCycle to work with TyFamLHSRichard Eisenberg2022-05-266-71/+102
| | | | | | | | | | | | | | | | | The function breakTyVarCycle_maybe has been installed in a dark corner of GHC to catch some gremlins (a.k.a. occurs-check failures) who lurk there. But it previously only caught gremlins of the form (a ~ ... F a ...), where some of our intrepid users have spawned gremlins of the form (G a ~ ... F (G a) ...). This commit improves breakTyVarCycle_maybe (and renames it to breakTyEqCycle_maybe) to catch the new gremlins. Happily, the change is remarkably small. The gory details are in Note [Type equality cycles]. Test cases: typecheck/should_compile/{T21515,T21473}.
* TTG: Move MatchGroup Origin field and MatchGroupTc to GHC.Hswip/romes/ttg-matchgroup-originromes2022-05-264-17/+14
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* Desugar RecordUpd in `tcExpr`wip/T18802CarrieMY2022-05-255-404/+571
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch typechecks record updates by desugaring them inside the typechecker using the HsExpansion mechanism, and then typechecking this desugared result. Example: data T p q = T1 { x :: Int, y :: Bool, z :: Char } | T2 { v :: Char } | T3 { x :: Int } | T4 { p :: Float, y :: Bool, x :: Int } | T5 The record update `e { x=e1, y=e2 }` desugars as follows e { x=e1, y=e2 } ===> let { x' = e1; y' = e2 } in case e of T1 _ _ z -> T1 x' y' z T4 p _ _ -> T4 p y' x' The desugared expression is put into an HsExpansion, and we typecheck that. The full details are given in Note [Record Updates] in GHC.Tc.Gen.Expr. Fixes #2595 #3632 #10808 #10856 #16501 #18311 #18802 #21158 #21289 Updates haddock submodule
* Use UnionListsOrd instead of UnionLists in most places.Andreas Klebinger2022-05-241-3/+3
| | | | This should get rid of most, if not all "Overlong lists" errors and fix #20016
* Consider the stage of typeable evidence when checking stage restrictionMatthew Pickering2022-05-223-21/+100
| | | | | | | | | | | | | | 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
* Change `Backend` type and remove direct dependencieswip/backend-as-recordNorman Ramsey2022-05-214-48/+32
| | | | | | | | | | | | | | | | | | | With this change, `Backend` becomes an abstract type (there are no more exposed value constructors). Decisions that were formerly made by asking "is the current back end equal to (or different from) this named value constructor?" are now made by interrogating the back end about its properties, which are functions exported by `GHC.Driver.Backend`. There is a description of how to migrate code using `Backend` in the user guide. Clients using the GHC API can find a backdoor to access the Backend datatype in GHC.Driver.Backend.Internal. Bumps haddock submodule. Fixes #20927
* TcPlugin: access to irreducible givens + fix passed ev_binds_varPavol Vargovcik2022-05-164-12/+19
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* Misc cleanupKrzysztof Gogolewski2022-05-162-4/+3
| | | | | | | | - Remove groupWithName (unused) - Use the RuntimeRepType synonym where possible - Replace getUniqueM + mkSysLocalOrCoVar with mkSysLocalOrCoVarM No functional changes.
* Add arity to the INLINE pragmas for pattern synonymsSimon Peyton Jones2022-05-162-34/+77
| | | | | The lack of INLNE arity was exposed by #21531. The fix is simple enough, if a bit clumsy.
* Comments only around HsWrapperSimon Peyton Jones2022-05-131-4/+11
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* Fix printing of brackets in multiplicities (#20315)jackohughes2022-05-131-1/+3
| | | | | | | | | Change mulArrow to allow for printing of correct application precedence where necessary and update callers of mulArrow to reflect this. As part of this, move mulArrow from GHC/Utils/Outputtable to GHC/Iface/Type. Fixes #20315
* Check for uninferrable variables in tcInferPatSynDeclSimon Peyton Jones2022-05-104-38/+64
| | | | | | | | | | This fixes #21479 See Note [Unquantified tyvars in a pattern synonym] While doing this, I found that some error messages pointed at the pattern synonym /name/, rather than the /declaration/ so I widened the SrcSpan to encompass the declaration.
* Comments only: Note [AppCtxt]Simon Peyton Jones2022-05-061-2/+36
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* Fix several note references, part 2Krzysztof Gogolewski2022-05-0513-28/+19
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* Ensure Any is not levity-polymorphic in FFIsheaf2022-05-041-2/+2
| | | | | | | | The previous patch forgot to account for a type such as Any @(TYPE (BoxedRep l)) for a quantified levity variable l.
* Improve error reporting in generated codeSimon Peyton Jones2022-05-045-60/+89
| | | | | | Our error reporting in generated code (via desugaring before typechecking) only worked when the generated code was just a simple call. This commit makes it work in nested cases.
* Fix several note referencesKrzysztof Gogolewski2022-05-027-12/+12
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* Convert More Diagnostics (#20116)Ben Gamari2022-04-306-173/+482
| | | | | Replaces uses of `TcRnUnknownMessage` with proper diagnostics constructors.
* Fix unification of ConcreteTvs, removing IsRefl#sheaf2022-04-2829-852/+1457
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes the unification of concrete type variables. The subtlety was that unifying concrete metavariables is more subtle than other metavariables, as decomposition is possible. See the Note [Unifying concrete metavariables], which explains how we unify a concrete type variable with a type 'ty' by concretising 'ty', using the function 'GHC.Tc.Utils.Concrete.concretise'. This can be used to perform an eager syntactic check for concreteness, allowing us to remove the IsRefl# special predicate. Instead of emitting two constraints `rr ~# concrete_tv` and `IsRefl# rr concrete_tv`, we instead concretise 'rr'. If this succeeds we can fill 'concrete_tv', and otherwise we directly emit an error message to the typechecker environment instead of deferring. We still need the error message to be passed on (instead of directly thrown), as we might benefit from further unification in which case we will need to zonk the stored types. To achieve this, we change the 'wc_holes' field of 'WantedConstraints' to 'wc_errors', which stores general delayed errors. For the moement, a delayed error is either a hole, or a syntactic equality error. hasFixedRuntimeRep_MustBeRefl is now hasFixedRuntimeRep_syntactic, and hasFixedRuntimeRep has been refactored to directly return the most useful coercion for PHASE 2 of FixedRuntimeRep. This patch also adds a field ir_frr to the InferResult datatype, holding a value of type Maybe FRROrigin. When this value is not Nothing, this means that we must fill the ir_ref field with a type which has a fixed RuntimeRep. When it comes time to fill such an ExpType, we ensure that the type has a fixed RuntimeRep by performing a representation-polymorphism check with the given FRROrigin This is similar to what we already do to ensure we fill an Infer ExpType with a type of the correct TcLevel. This allows us to properly perform representation-polymorphism checks on 'Infer' 'ExpTypes'. The fillInferResult function had to be moved to GHC.Tc.Utils.Unify to avoid a cyclic import now that it calls hasFixedRuntimeRep. This patch also changes the code in matchExpectedFunTys to make use of the coercions, which is now possible thanks to the previous change. This implements PHASE 2 of FixedRuntimeRep in some situations. For example, the test cases T13105 and T17536b are now both accepted. Fixes #21239 and #21325 ------------------------- Metric Decrease: T18223 T5631 -------------------------
* Ensure that Any is Boxed in FFI imports/exportssheaf2022-04-272-9/+44
| | | | | | | | | | We should only accept the type `Any` in foreign import/export declarations when it has type `Type` or `UnliftedType`. This patch adds a kind check, and a special error message triggered by occurrences of `Any` in foreign import/export declarations at other kinds. Fixes #21305
* decideMonoTyVars: account for CoVars in candidatessheaf2022-04-222-3/+5
| | | | | | | | | | | | 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
* Relax "suppressing errors" assert in reportWantedssheaf2022-04-221-4/+9
| | | | | | | | | | | The assertion in reportWanteds that we aren't suppressing all the Wanted constraints was too strong: it might be the case that we are inside an implication, and have already reported an unsolved Wanted from outside the implication. It is possible that all Wanteds inside the implication have been rewritten by the outer Wanted, so we shouldn't throw an assertion failure in that case. Fixes #21405
* Remove LevityInfoKrzysztof Gogolewski2022-04-202-6/+3
| | | | | | Every Id was storing a boolean whether it could be levity-polymorphic. This information is no longer needed since representation-checking has been moved to the typechecker.
* Docs: datacon eta-expansion, rep-poly checkssheaf2022-04-083-31/+87
| | | | | | | | | | | | | | | | | | | The existing notes weren't very clear on how the eta-expansion of data constructors that occurs in tcInferDataCon/dsConLike interacts with the representation polymorphism invariants. So we explain with a few more details how we ensure that the representation-polymorphic lambdas introduced by tcInferDataCon/dsConLike don't end up causing problems, by checking they are properly instantiated and then relying on the simple optimiser to perform beta reduction. A few additional changes: - ConLikeTc just take type variables instead of binders, as we never actually used the binders. - Removed the FRRApp constructor of FRROrigin; it was no longer used now that we use ExpectedFunTyOrigin. - Adds a bit of documentation to the constructors of ExpectedFunTyOrigin.
* Correctly report SrcLoc of redundant constraintssheaf2022-04-083-9/+21
| | | | | | | | | We were accidentally dropping the source location information in certain circumstances when reporting redundant constraints. This patch makes sure that we set the TcLclEnv correctly before reporting the warning. Fixes #21315
* Fix the free-var test in validDerivPredSimon Peyton Jones2022-04-071-57/+42
| | | | | | | | | | The free-var test (now documented as (VD3)) was too narrow, affecting only class predicates. #21302 demonstrated that this wasn't enough! Fixes #21302. Co-authored-by: Ryan Scott <ryan.gl.scott@gmail.com>
* Ensure implicit parameters are liftedsheaf2022-04-011-5/+3
| | | | | | | | `tcExpr` typechecked implicit parameters by introducing a metavariable of kind `TYPE kappa`, without enforcing that `kappa ~ LiftedRep`. This patch instead creates a metavariable of kind `Type`. Fixes #21327
* Implement \cases (Proposal 302)Jakob Bruenker2022-04-017-124/+147
| | | | | | | | | | | | This commit implements proposal 302: \cases - Multi-way lambda expressions. This adds a new expression heralded by \cases, which works exactly like \case, but can match multiple apats instead of a single pat. Updates submodule haddock to support the ITlcases token. Closes #20768
* Keep track of promotion ticks in HsOpTywip/no-c-stubswip/matt-merge-batchsheaf2022-04-017-22/+34
| | | | | | | | | | | | | | | | This patch adds a PromotionFlag field to HsOpTy, which is used in pretty-printing and when determining whether to emit warnings with -fwarn-unticked-promoted-constructors. This allows us to correctly report tick-related warnings for things like: type A = Int : '[] type B = [Int, Bool] Updates haddock submodule Fixes #19984
* Minor cleanupKrzysztof Gogolewski2022-04-011-2/+2
| | | | | | | | | | | - Remove unused functions exprToCoercion_maybe, applyTypeToArg, typeMonoPrimRep_maybe, runtimeRepMonoPrimRep_maybe. - Replace orValid with a simpler check - Use splitAtList in applyTysX - Remove calls to extra_clean in the testsuite; it does not do anything. Metric Decrease: T18223
* Fix all invalid haddock comments in the compilerZubin Duggal2022-03-298-29/+30
| | | | Fixes #20935 and #20924
* Add Red Herring to Note [What might equal later?]Richard Eisenberg2022-03-283-87/+130
| | | | Close #21208.
* Make -ddump-rn-ast and -ddump-tc-ast work in GHCiMatthew Pickering2022-03-251-0/+6
| | | | Fixes #17830
* Fix and simplify DeriveAnyClass's context inference using SubTypePredSpecRyan Scott2022-03-245-260/+467
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As explained in `Note [Gathering and simplifying constraints for DeriveAnyClass]` in `GHC.Tc.Deriv.Infer`, `DeriveAnyClass` infers instance contexts by emitting implication constraints. Previously, these implication constraints were constructed by hand. This is a terribly trick thing to get right, as it involves a delicate interplay of skolemisation, metavariable instantiation, and `TcLevel` bumping. Despite much effort, we discovered in #20719 that the implementation was subtly incorrect, leading to valid programs being rejected. While we could scrutinize the code that manually constructs implication constraints and repair it, there is a better, less error-prone way to do things. After all, the heart of `DeriveAnyClass` is generating code which fills in each class method with defaults, e.g., `foo = $gdm_foo`. Typechecking this sort of code is tantamount to calling `tcSubTypeSigma`, as we much ensure that the type of `$gdm_foo` is a subtype of (i.e., more polymorphic than) the type of `foo`. As an added bonus, `tcSubTypeSigma` is a battle-tested function that handles skolemisation, metvariable instantiation, `TcLevel` bumping, and all other means of tricky bookkeeping correctly. With this insight, the solution to the problems uncovered in #20719 is simple: use `tcSubTypeSigma` to check if `$gdm_foo`'s type is a subtype of `foo`'s type. As a side effect, `tcSubTypeSigma` will emit exactly the implication constraint that we were attempting to construct by hand previously. Moreover, it does so correctly, fixing #20719 as a consequence. This patch implements the solution thusly: * The `PredSpec` data type (previously named `PredOrigin`) is now split into `SimplePredSpec`, which directly stores a `PredType`, and `SubTypePredSpec`, which stores the actual and expected types in a subtype check. `SubTypePredSpec` is only used for `DeriveAnyClass`; all other deriving strategies use `SimplePredSpec`. * Because `tcSubTypeSigma` manages the finer details of type variable instantiation and constraint solving under the hood, there is no longer any need to delicately split apart the method type signatures in `inferConstraintsAnyclass`. This greatly simplifies the implementation of `inferConstraintsAnyclass` and obviates the need to store skolems, metavariables, or given constraints in a `ThetaSpec` (previously named `ThetaOrigin`). As a bonus, this means that `ThetaSpec` now simply becomes a synonym for a list of `PredSpec`s, which is conceptually much simpler than it was before. * In `simplifyDeriv`, each `SubTypePredSpec` results in a call to `tcSubTypeSigma`. This is only performed for its side effect of emitting an implication constraint, which is fed to the rest of the constraint solving machinery in `simplifyDeriv`. I have updated `Note [Gathering and simplifying constraints for DeriveAnyClass]` to explain this in more detail. To make the changes in `simplifyDeriv` more manageable, I also performed some auxiliary refactoring: * Previously, every iteration of `simplifyDeriv` was skolemising the type variables at the start, simplifying, and then performing a reverse substitution at the end to un-skolemise the type variables. This is not necessary, however, since we can just as well skolemise once at the beginning of the `deriving` pipeline and zonk the `TcTyVar`s after `simplifyDeriv` is finished. This patch does just that, having been made possible by prior work in !7613. I have updated `Note [Overlap and deriving]` in `GHC.Tc.Deriv.Infer` to explain this, and I have also left comments on the relevant data structures (e.g., `DerivEnv` and `DerivSpec`) to explain when things might be `TcTyVar`s or `TyVar`s. * All of the aforementioned cleanup allowed me to remove an ad hoc deriving-related in `checkImplicationInvariants`, as all of the skolems in a `tcSubTypeSigma`–produced implication constraint should now be `TcTyVar` at the time the implication is created. * Since `simplifyDeriv` now needs a `SkolemInfo` and `UserTypeCtxt`, I have added `ds_skol_info` and `ds_user_ctxt` fields to `DerivSpec` to store these. Similarly, I have also added a `denv_skol_info` field to `DerivEnv`, which ultimately gets used to initialize the `ds_skol_info` in a `DerivSpec`. Fixes #20719.
* hi haddock: Lex and store haddock docs in interface filesZubin Duggal2022-03-238-68/+111
| | | | | | | | | | | | | | | | | | Names appearing in Haddock docstrings are lexed and renamed like any other names appearing in the AST. We currently rename names irrespective of the namespace, so both type and constructor names corresponding to an identifier will appear in the docstring. Haddock will select a given name as the link destination based on its own heuristics. This patch also restricts the limitation of `-haddock` being incompatible with `Opt_KeepRawTokenStream`. The export and documenation structure is now computed in GHC and serialised in .hi files. This can be used by haddock to directly generate doc pages without reparsing or renaming the source. At the moment the operation of haddock is not modified, that's left to a future patch. Updates the haddock submodule with the minimum changes needed.
* Revamp derived Eq instance code generation (#17240)nineonine2022-03-201-59/+82
| | | | | | | | | | | | | This patch improves code generation for derived Eq instances. The idea is to use 'dataToTag' to evaluate both arguments. This allows to 'short-circuit' when tags do not match. Unfortunately, inner evals are still present when we branch on tags. This is due to the way 'dataToTag#' primop evaluates its argument in the code generator. #21207 was created to explore further optimizations. Metric Decrease: LargeRecord
* TTG: TH brackets finishing touchesromes2022-03-183-46/+41
| | | | | | | | | | | | | | | | | | | | | | Rewrite the critical notes and fix outdated ones, use `HsQuote GhcRn` (in `HsBracketTc`) for desugaring regardless of the bracket being typed or untyped, remove unused `EpAnn` from `Hs*Bracket GhcRn`, zonkExpr factor out common brackets code, ppr_expr factor out common brackets code, and fix tests, to finish MR https://gitlab.haskell.org/ghc/ghc/-/merge_requests/4782. ------------------------- Metric Decrease: hard_hole_fits -------------------------
* TTG: Make HsQuote GhcTc isomorphic to NoExtFieldromes2022-03-181-8/+2
| | | | | | | | | | | | | | | | An untyped bracket `HsQuote p` can never be constructed with `p ~ GhcTc`. This is because we don't typecheck `HsQuote` at all. That's OK, because we also never use `HsQuote GhcTc`. To enforce this at the type level we make `HsQuote GhcTc` isomorphic to `NoExtField` and impossible to construct otherwise, by using TTG field extensions to make all constructors, except for `XQuote` (which takes `NoExtField`), unconstructable, with `DataConCantHappen` This is explained more in detail in Note [The life cycle of a TH quotation] Related discussion: https://gitlab.haskell.org/ghc/ghc/-/merge_requests/4782
* TTG: Refactor bracket for desugaring during tcromes2022-03-184-24/+33
| | | | | | | | | | | | | When desugaring a bracket we want to desugar /renamed/ rather than /typechecked/ code; So in (HsExpr GhcTc) tree, we must have a (HsExpr GhcRn) for the quotation itself. This commit reworks the TTG refactor on typed and untyped brackets by storing the /renamed/ code in the bracket field extension rather than in the constructor extension in `HsQuote` (previously called `HsUntypedBracket`) See Note [The life cycle of a TH quotation] and https://gitlab.haskell.org/ghc/ghc/-/merge_requests/4782
* Separate constructors for typed and untyped bracketsromes2022-03-186-32/+41
| | | | | | | | | | | Split HsBracket into HsTypedBracket and HsUntypedBracket. Unfortunately, we still cannot get rid of instance XXTypedBracket GhcTc = HsTypedBracket GhcRn despite no longer requiring it for typechecking, but rather because the TH desugarer works on GhcRn rather than GhcTc (See GHC.HsToCore.Quote)
* Type-checking untyped bracketsromes2022-03-181-2/+2
| | | | | | | | | | When HsExpr GhcTc, the HsBracket constructor should hold a HsBracket GhcRn, rather than an HsBracket GhcTc. We make use of the HsBracket p extension constructor (XBracket (XXBracket p)) to hold an HsBracket GhcRn when the pass is GhcTc See !4782 https://gitlab.haskell.org/ghc/ghc/-/merge_requests/4782
* TTG: Refactor HsBracketromes2022-03-184-11/+7
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* Suggest FFI extensions as hints (#20116)Aaron Allen2022-03-162-5/+5
| | | | | | - Use extension suggestion hints instead of suggesting extensions in the error message body for several FFI errors. - Adds a test case for `TcRnForeignImportPrimExtNotSet`