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* Convert diagnostics in GHC.Rename.HsType to proper TcRnMessageHaskell-mouse2023-04-033-4/+5
| | | | | | | | | | | | | | | | | | 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 & RecGadtCsheaf2023-04-014-9/+6
| | | | | | | 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 Schmits2023-04-012-4/+4
| | | | | | | | | Tracking ticket: #20117 MR: !10183 This converts uses of `mkTcRnUnknownMessage` to newly added constructors of `TcRnMessage`.
* Fix testsBodigrim2023-03-302-0/+2
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* Handle records in the renamersheaf2023-03-2911-38/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch moves the field-based logic for disambiguating record updates to the renamer. The type-directed logic, scheduled for removal, remains in the typechecker. To do this properly (and fix the myriad of bugs surrounding the treatment of duplicate record fields), we took the following main steps: 1. Create GREInfo, a renamer-level equivalent to TyThing which stores information pertinent to the renamer. This allows us to uniformly treat imported and local Names in the renamer, as described in Note [GREInfo]. 2. Remove GreName. Instead of a GlobalRdrElt storing GreNames, which distinguished between normal names and field names, we now store simple Names in GlobalRdrElt, along with the new GREInfo information which allows us to recover the FieldLabel for record fields. 3. Add namespacing for record fields, within the OccNames themselves. This allows us to remove the mangling of duplicate field selectors. This change ensures we don't print mangled names to the user in error messages, and allows us to handle duplicate record fields in Template Haskell. 4. Move record disambiguation to the renamer, and operate on the level of data constructors instead, to handle #21443. The error message text for ambiguous record updates has also been changed to reflect that type-directed disambiguation is on the way out. (3) means that OccEnv is now a bit more complex: we first key on the textual name, which gives an inner map keyed on NameSpace: OccEnv a ~ FastStringEnv (UniqFM NameSpace a) Note that this change, along with (2), both increase the memory residency of GlobalRdrEnv = OccEnv [GlobalRdrElt], which causes a few tests to regress somewhat in compile-time allocation. Even though (3) simplified a lot of code (in particular the treatment of field selectors within Template Haskell and in error messages), it came with one important wrinkle: in the situation of -- M.hs-boot module M where { data A; foo :: A -> Int } -- M.hs module M where { data A = MkA { foo :: Int } } we have that M.hs-boot exports a variable foo, which is supposed to match with the record field foo that M exports. To solve this issue, we add a new impedance-matching binding to M foo{var} = foo{fld} This mimics the logic that existed already for impedance-binding DFunIds, but getting it right was a bit tricky. See Note [Record field impedance matching] in GHC.Tc.Module. We also needed to be careful to avoid introducing space leaks in GHCi. So we dehydrate the GlobalRdrEnv before storing it anywhere, e.g. in ModIface. This means stubbing out all the GREInfo fields, with the function forceGlobalRdrEnv. When we read it back in, we rehydrate with rehydrateGlobalRdrEnv. This robustly avoids any space leaks caused by retaining old type environments. Fixes #13352 #14848 #17381 #17551 #19664 #21443 #21444 #21720 #21898 #21946 #21959 #22125 #22160 #23010 #23062 #23063 Updates haddock submodule ------------------------- Metric Increase: MultiComponentModules MultiLayerModules MultiLayerModulesDefsGhci MultiLayerModulesNoCode T13701 T14697 hard_hole_fits -------------------------
* Add structured error messages for GHC.Tc.Utils.EnvTorsten Schmits2023-03-217-7/+7
| | | | | | | | | Tracking ticket: #20119 MR: !10129 This converts uses of `mkTcRnUnknownMessage` to newly added constructors of `TcRnMessage`.
* Rename () into Unit, (,,...,,) into Tuple<n> (#21294)Andrei Borzenkov2023-03-211-1/+1
| | | | | | | | | | | | | | | | | | | | | This patch implements a part of GHC Proposal #475. The key change is in GHC.Tuple.Prim: - data () = () - data (a,b) = (a,b) - data (a,b,c) = (a,b,c) ... + data Unit = () + data Tuple2 a b = (a,b) + data Tuple3 a b c = (a,b,c) ... And the rest of the patch makes sure that Unit and Tuple<n> are pretty-printed as () and (,,...,,) in various contexts. Updates the haddock submodule. Co-authored-by: Vladislav Zavialov <vlad.z.4096@gmail.com>
* fix: Consider strictness annotation in rep_bindromes2023-03-013-0/+35
| | | | Fixes #23036
* Fix two bugs in TypeData TH reificationRyan Scott2023-01-305-0/+36
| | | | | | | | | | | 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.
* Replace errors from badOrigBinding with new one (#22839)Andrei Borzenkov2023-01-271-2/+2
| | | | | | | | | | | | | | | | | | | | 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.
* Fix printing of promoted MkSolo datacon (#22785)Andrei Borzenkov2023-01-183-8/+8
| | | | | | | | | | | | Problem: In 2463df2f, the Solo data constructor was renamed to MkSolo, and Solo was turned into a pattern synonym for backwards compatibility. Since pattern synonyms can not be promoted, the old code that pretty-printed promoted single-element tuples started producing ill-typed code: t :: Proxy ('Solo Int) This fails with "Pattern synonym ‘Solo’ used as a type" The solution is to track the distinction between type constructors and data constructors more carefully when printing single-element tuples.
* Add missing parenthesizeHsType in cvtSigTypeKindRyan Scott2023-01-183-1/+15
| | | | | | | | We need to ensure that the output of `cvtSigTypeKind` is parenthesized (at precedence `sigPrec`) so that any type signatures with an outermost, explicit kind signature can parse correctly. Fixes #22784.
* Fixes around primitive literalsKrzysztof Gogolewski2022-12-082-3/+16
| | | | | | | | | * The SourceText of primitive characters 'a'# did not include the #, unlike for other primitive literals 1#, 1##, 1.0#, 1.0##, "a"#. We can now remove the function pp_st_suffix, which was a hack to add the # back. * Negative primitive literals shouldn't use parentheses, as described in Note [Printing of literals in Core]. Added a testcase to T14681.
* Change printing of sized literals to match the proposalKrzysztof Gogolewski2022-11-291-2/+2
| | | | | | | | Literals in Core were printed as e.g. 0xFF#16 :: Int16#. The proposal 451 now specifies syntax 0xFF#Int16. This change affects the Core printer only - more to be done later. Part of #21422.
* Convert diagnostics in GHC.Rename.Expr to proper TcRnMessage (#20115)Andrei Borzenkov2022-11-242-3/+3
| | | | | | | | | | | | | | | | | | | | Problem: avoid usage of TcRnMessageUnknown Solution: The following `TcRnMessage` messages has been introduced: TcRnNoRebindableSyntaxRecordDot TcRnNoFieldPunsRecordDot TcRnIllegalStaticExpression TcRnIllegalStaticFormInSplice TcRnListComprehensionDuplicateBinding TcRnEmptyStmtsGroup TcRnLastStmtNotExpr TcRnUnexpectedStatementInContext TcRnIllegalTupleSection TcRnIllegalImplicitParameterBindings TcRnSectionWithoutParentheses Co-authored-by: sheaf <sam.derbyshire@gmail.com>
* Type vs Constraint: finally nailedSimon Peyton Jones2022-11-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This big patch addresses the rats-nest of issues that have plagued us for years, about the relationship between Type and Constraint. See #11715/#21623. The main payload of the patch is: * To introduce CONSTRAINT :: RuntimeRep -> Type * To make TYPE and CONSTRAINT distinct throughout the compiler Two overview Notes in GHC.Builtin.Types.Prim * Note [TYPE and CONSTRAINT] * Note [Type and Constraint are not apart] This is the main complication. The specifics * New primitive types (GHC.Builtin.Types.Prim) - CONSTRAINT - ctArrowTyCon (=>) - tcArrowTyCon (-=>) - ccArrowTyCon (==>) - funTyCon FUN -- Not new See Note [Function type constructors and FunTy] and Note [TYPE and CONSTRAINT] * GHC.Builtin.Types: - New type Constraint = CONSTRAINT LiftedRep - I also stopped nonEmptyTyCon being built-in; it only needs to be wired-in * Exploit the fact that Type and Constraint are distinct throughout GHC - Get rid of tcView in favour of coreView. - Many tcXX functions become XX functions. e.g. tcGetCastedTyVar --> getCastedTyVar * Kill off Note [ForAllTy and typechecker equality], in (old) GHC.Tc.Solver.Canonical. It said that typechecker-equality should ignore the specified/inferred distinction when comparein two ForAllTys. But that wsa only weakly supported and (worse) implies that we need a separate typechecker equality, different from core equality. No no no. * GHC.Core.TyCon: kill off FunTyCon in data TyCon. There was no need for it, and anyway now we have four of them! * GHC.Core.TyCo.Rep: add two FunTyFlags to FunCo See Note [FunCo] in that module. * GHC.Core.Type. Lots and lots of changes driven by adding CONSTRAINT. The key new function is sORTKind_maybe; most other changes are built on top of that. See also `funTyConAppTy_maybe` and `tyConAppFun_maybe`. * Fix a longstanding bug in GHC.Core.Type.typeKind, and Core Lint, in kinding ForAllTys. See new tules (FORALL1) and (FORALL2) in GHC.Core.Type. (The bug was that before (forall (cv::t1 ~# t2). blah), where blah::TYPE IntRep, would get kind (TYPE IntRep), but it should be (TYPE LiftedRep). See Note [Kinding rules for types] in GHC.Core.Type. * GHC.Core.TyCo.Compare is a new module in which we do eqType and cmpType. Of course, no tcEqType any more. * GHC.Core.TyCo.FVs. I moved some free-var-like function into this module: tyConsOfType, visVarsOfType, and occCheckExpand. Refactoring only. * GHC.Builtin.Types. Compiletely re-engineer boxingDataCon_maybe to have one for each /RuntimeRep/, rather than one for each /Type/. This dramatically widens the range of types we can auto-box. See Note [Boxing constructors] in GHC.Builtin.Types The boxing types themselves are declared in library ghc-prim:GHC.Types. GHC.Core.Make. Re-engineer the treatment of "big" tuples (mkBigCoreVarTup etc) GHC.Core.Make, so that it auto-boxes unboxed values and (crucially) types of kind Constraint. That allows the desugaring for arrows to work; it gathers up free variables (including dictionaries) into tuples. See Note [Big tuples] in GHC.Core.Make. There is still work to do here: #22336. But things are better than before. * GHC.Core.Make. We need two absent-error Ids, aBSENT_ERROR_ID for types of kind Type, and aBSENT_CONSTRAINT_ERROR_ID for vaues of kind Constraint. Ditto noInlineId vs noInlieConstraintId in GHC.Types.Id.Make; see Note [inlineId magic]. * GHC.Core.TyCo.Rep. Completely refactor the NthCo coercion. It is now called SelCo, and its fields are much more descriptive than the single Int we used to have. A great improvement. See Note [SelCo] in GHC.Core.TyCo.Rep. * GHC.Core.RoughMap.roughMatchTyConName. Collapse TYPE and CONSTRAINT to a single TyCon, so that the rough-map does not distinguish them. * GHC.Core.DataCon - Mainly just improve documentation * Some significant renamings: GHC.Core.Multiplicity: Many --> ManyTy (easier to grep for) One --> OneTy GHC.Core.TyCo.Rep TyCoBinder --> GHC.Core.Var.PiTyBinder GHC.Core.Var TyCoVarBinder --> ForAllTyBinder AnonArgFlag --> FunTyFlag ArgFlag --> ForAllTyFlag GHC.Core.TyCon TyConTyCoBinder --> TyConPiTyBinder Many functions are renamed in consequence e.g. isinvisibleArgFlag becomes isInvisibleForAllTyFlag, etc * I refactored FunTyFlag (was AnonArgFlag) into a simple, flat data type data FunTyFlag = FTF_T_T -- (->) Type -> Type | FTF_T_C -- (-=>) Type -> Constraint | FTF_C_T -- (=>) Constraint -> Type | FTF_C_C -- (==>) Constraint -> Constraint * GHC.Tc.Errors.Ppr. Some significant refactoring in the TypeEqMisMatch case of pprMismatchMsg. * I made the tyConUnique field of TyCon strict, because I saw code with lots of silly eval's. That revealed that GHC.Settings.Constants.mAX_SUM_SIZE can only be 63, because we pack the sum tag into a 6-bit field. (Lurking bug squashed.) Fixes * #21530 Updates haddock submodule slightly. Performance changes ~~~~~~~~~~~~~~~~~~~ I was worried that compile times would get worse, but after some careful profiling we are down to a geometric mean 0.1% increase in allocation (in perf/compiler). That seems fine. There is a big runtime improvement in T10359 Metric Decrease: LargeRecord MultiLayerModulesTH_OneShot T13386 T13719 Metric Increase: T8095
* ThToHs: fix overzealous parenthesizationVladislav Zavialov2022-11-016-3/+23
| | | | | | | | | | | | | | | | | | Before this patch, when converting from TH.Exp to LHsExpr GhcPs, the compiler inserted more parentheses than required: ((f a) (b + c)) d This was happening because the LHS of the function application was parenthesized as if it was the RHS. Now we use funPrec and appPrec appropriately and produce sensibly parenthesized expressions: f a (b + c) d I also took the opportunity to remove the special case for LamE, which was not special at all and simply duplicated code.
* Convert Diagnostics in GHC.Tc.Gen.Splice (#20116)Aaron Allen2022-10-2446-49/+50
| | | | | | | Replaces uses of `TcRnUnknownMessage` in `GHC.Tc.Gen.Splice` with structured diagnostics. closes #20116
* Rename Solo[constructor] to MkSoloTorsten Schmits2022-09-2111-32/+32
| | | | | | | | | | | Part of proposal 475 (https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0475-tuple-syntax.rst) Moves all tuples to GHC.Tuple.Prim Updates ghc-prim version (and bumps bounds in dependents) updates haddock submodule updates deepseq submodule updates text submodule
* Fix typosKrzysztof Gogolewski2022-09-141-1/+1
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* Diagnostic codes: acccept test changessheaf2022-09-1346-78/+85
| | | | | | | | The testsuite output now contains diagnostic codes, so many tests need to be updated at once. We decided it was best to keep the diagnostic codes in the testsuite output, so that contributors don't inadvertently make changes to the diagnostic codes.
* Test for issue #21942Mario Blažević2022-08-223-0/+10
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* Fix and test for issue #21723Mario Blažević2022-08-223-0/+11
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* Added pprType with precedence argument, as a prerequisite to fix issues ↵Mario Blažević2022-08-224-7/+7
| | | | | | | | | | | #21723 and #21942. * refines the precedence levels, adding `qualPrec` and `funPrec` to better control parenthesization * `pprParendType`, `pprFunArgType`, and `instance Ppr Type` all just call `pprType` with proper precedence * `ParensT` constructor is now always printed parenthesized * adds the precedence argument to `pprTyApp` as well, as it needs to keep track and pass it down * using `>=` instead of former `>` to match the Core type printing logic * some test outputs have changed, losing extraneous parentheses
* Print constraints in quotes (#21167)Swann Moreau2022-08-191-1/+1
| | | | | | | This patch improves the uniformity of error message formatting by printing constraints in quotes, as we do for types. Fix #21167
* Fix TH + defer-type-errors interaction (#21920)Krzysztof Gogolewski2022-08-044-1/+21
| | | | | | Previously, we had to disable defer-type-errors in splices because of #7276. But this fix is no longer necessary, the test T7276 no longer segfaults and is now correctly deferred.
* testsuite: Mark T13366Cxx as unbroken on DarwinBen Gamari2022-07-161-3/+1
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* testsuite: Use system-cxx-std-lib instead of config.stdcxx_implBen Gamari2022-07-161-1/+1
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* testsuite: Use normalise_version more consistentlyBen Gamari2022-06-271-1/+1
| | | | | Previously several tests' output were unnecessarily dependent on version numbers, particularly of `base`. Fix this.
* Deprecate TypeInType extensionHaskellMouse2022-06-061-1/+1
| | | | | | | | | | | | | | | | This commit fixes #20312 It deprecates "TypeInType" extension according to the following proposal: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0083-no-type-in-type.rst It has been already implemented. The migration strategy: 1. Disable TypeInType 2. Enable both DataKinds and PolyKinds extensions Metric Decrease: T16875
* TTG: Rework and improve splicesromes2022-06-014-9/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 -------------------------
* Consider the stage of typeable evidence when checking stage restrictionMatthew Pickering2022-05-224-0/+30
| | | | | | | | | | | | | | 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 Ramsey2022-05-211-1/+1
| | | | | | | | | | | | | | | | | | | 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
* template-haskell: Fix representation of OPAQUE pragmasMatthew Pickering2022-05-062-0/+11
| | | | | | | | | | There is a mis-match between the TH representation of OPAQUE pragmas and GHC's internal representation due to how OPAQUE pragmas disallow phase annotations. It seemed most in keeping to just fix the wired in name issue by adding a special case to the desugaring of INLINE pragmas rather than making TH/GHC agree with how the representation should look. Fixes #21463
* testsuite: Mark T10420 as broken on WindowsBen Gamari2022-04-071-1/+2
| | | | Due to #21322.
* testsuite: Mark TH_spliceE5_prof as unbroken on WindowsBen Gamari2022-04-061-2/+1
| | | | | | | It was previously failing due to #18721 and now passes with the new toolchain. Closes #18721.
* testsuite: Split T13366 into two testsBen Gamari2022-04-065-17/+30
| | | | | Split up the C and C++ uses since the latter is significantly more platform-dependent.
* testsuite: Clean up tests depending on C++ std libBen Gamari2022-04-061-4/+1
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* Change GHC.Prim to GHC.Exts in docs and testsKrzysztof Gogolewski2022-04-012-2/+2
| | | | | Users are supposed to import GHC.Exts rather than GHC.Prim. Part of #18749.
* T13366 requires c++ & c++abi libraries on OpenBSDGreg Steuck2022-04-011-1/+1
| | | | | | | | | | | | | | Fixes this failure: =====> 1 of 1 [0, 0, 0] T13366(normal) 1 of 1 [0, 0, 0] Compile failed (exit code 1) errors were: <no location info>: error: user specified .o/.so/.DLL could not be loaded (File not found) Whilst trying to load: (dynamic) stdc++ Additional directories searched: (none) *** unexpected failure for T13366(normal)
* Add instance Lift ByteArrayBodigrim2022-03-253-0/+14
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* TH: Fix pretty printing of newtypes with operators and GADT syntax (#20868)Zubin Duggal2022-03-195-9/+34
| | | | | | | | The pretty printer for regular data types already accounted for these, and had some duplication with the newtype pretty printer. Factoring the logic out into a common function and using it for both newtypes and data declarations is enough to fix the bug.
* TTG: TH brackets finishing touchesromes2022-03-181-3/+6
| | | | | | | | | | | | | | | | | | | | | | 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 -------------------------
* TH: allow negative patterns in quotes (#20711)Zubin Duggal2022-03-163-0/+14
| | | | | | We still don't allow negative overloaded patterns. Earler all negative patterns were treated as negative overloaded patterns. Now, we expliclty check the extension field to see if the pattern is actually a negative overloaded pattern
* Fix isLiftedType_maybe and handle falloutsheaf2022-03-141-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As #20837 pointed out, `isLiftedType_maybe` returned `Just False` in many situations where it should return `Nothing`, because it didn't take into account type families or type variables. In this patch, we fix this issue. We rename `isLiftedType_maybe` to `typeLevity_maybe`, which now returns a `Levity` instead of a boolean. We now return `Nothing` for types with kinds of the form `TYPE (F a1 ... an)` for a type family `F`, as well as `TYPE (BoxedRep l)` where `l` is a type variable. This fix caused several other problems, as other parts of the compiler were relying on `isLiftedType_maybe` returning a `Just` value, and were now panicking after the above fix. There were two main situations in which panics occurred: 1. Issues involving the let/app invariant. To uphold that invariant, we need to know whether something is lifted or not. If we get an answer of `Nothing` from `isLiftedType_maybe`, then we don't know what to do. As this invariant isn't particularly invariant, we can change the affected functions to not panic, e.g. by behaving the same in the `Just False` case and in the `Nothing` case (meaning: no observable change in behaviour compared to before). 2. Typechecking of data (/newtype) constructor patterns. Some programs involving patterns with unknown representations were accepted, such as T20363. Now that we are stricter, this caused further issues, culminating in Core Lint errors. However, the behaviour was incorrect the whole time; the incorrectness only being revealed by this change, not triggered by it. This patch fixes this by overhauling where the representation polymorphism involving pattern matching are done. Instead of doing it in `tcMatches`, we instead ensure that the `matchExpected` functions such as `matchExpectedFunTys`, `matchActualFunTySigma`, `matchActualFunTysRho` allow return argument pattern types which have a fixed RuntimeRep (as defined in Note [Fixed RuntimeRep]). This ensures that the pattern matching code only ever handles types with a known runtime representation. One exception was that patterns with an unknown representation type could sneak in via `tcConPat`, which points to a missing representation-polymorphism check, which this patch now adds. This means that we now reject the program in #20363, at least until we implement PHASE 2 of FixedRuntimeRep (allowing type families in RuntimeRep positions). The aforementioned refactoring, in which checks have been moved to `matchExpected` functions, is a first step in implementing PHASE 2 for patterns. Fixes #20837
* Error on anon wildcards in tcAnonWildCardOccsheaf2022-02-265-0/+43
| | | | | | | | | | | | | | | | | The code in tcAnonWildCardOcc assumed that it could never encounter anonymous wildcards in illegal positions, because the renamer would have ruled them out. However, it's possible to sneak past the checks in the renamer by using Template Haskell. It isn't possible to simply pass on additional information when renaming Template Haskell brackets, because we don't know in advance in what context the bracket will be spliced in (see test case T15433b). So we accept that we might encounter these bogus wildcards in the typechecker and throw the appropriate error. This patch also migrates the error messages for illegal wildcards in types to use the diagnostic infrastructure. Fixes #15433
* template-haskell: Fix two prettyprinter issuesMario Blažević2022-02-253-0/+39
| | | | | | Fix two issues regarding printing numeric literals. Fixing #20454.
* TH: fix pretty printing of GADTs with multiple constuctors (#20842)Zubin Duggal2022-02-244-1/+15
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* Look through untyped TH splices in tcInferAppHead_maybeRyan Scott2022-02-092-0/+17
| | | | | | | | | | | Previously, surrounding a head expression with a TH splice would defeat `tcInferAppHead_maybe`, preventing some expressions from typechecking that used to typecheck in previous GHC versions (see #21038 for examples). This is simple enough to fix: just look through `HsSpliceE`s in `tcInferAppHead_maybe`. I've added some additional prose to `Note [Application chains and heads]` in `GHC.Tc.Gen.App` to accompany this change. Fixes #21038.
* compiler: Introduce and use RoughMap for instance environmentsBen Gamari2022-02-045-21/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Here we introduce a new data structure, RoughMap, inspired by the previous `RoughTc` matching mechanism for checking instance matches. This allows [Fam]InstEnv to be implemented as a trie indexed by these RoughTc signatures, reducing the complexity of instance lookup and FamInstEnv merging (done during the family instance conflict test) from O(n) to O(log n). The critical performance improvement currently realised by this patch is in instance matching. In particular the RoughMap mechanism allows us to discount many potential instances which will never match for constraints involving type variables (see Note [Matching a RoughMap]). In realistic code bases matchInstEnv was accounting for 50% of typechecker time due to redundant work checking instances when simplifying instance contexts when deriving instances. With this patch the cost is significantly reduced. The larger constants in InstEnv creation do mean that a few small tests regress in allocations slightly. However, the runtime of T19703 is reduced by a factor of 4. Moreover, the compilation time of the Cabal library is slightly improved. A couple of test cases are included which demonstrate significant improvements in compile time with this patch. This unfortunately does not fix the testcase provided in #19703 but does fix #20933 ------------------------- Metric Decrease: T12425 Metric Increase: T13719 T9872a T9872d hard_hole_fits ------------------------- Co-authored-by: Matthew Pickering <matthewtpickering@gmail.com>