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* docs: Remove mentions of ArrayArray# from unlifted FFI sectionRodrigo Mesquita2023-05-051-21/+18
| | | | Fixes #23277
* Add sized primitive literal syntaxBen Orchard2023-05-034-0/+54
| | | | | | | | | | | | | | Adds a new LANGUAGE pragma ExtendedLiterals, which enables defining unboxed numeric literals such as `0xFF#Word8 :: Word8#`. Implements GHC proposal 0451: https://github.com/ghc-proposals/ghc-proposals/blob/b384a538b34f79d18a0201455b7b3c473bc8c936/proposals/0451-sized-literals.rst Fixes #21422. Bumps haddock submodule. Co-authored-by: Krzysztof Gogolewski <krzysztof.gogolewski@tweag.io>
* Give more guarntees about ImplicitParams (#23289)Andrei Borzenkov2023-04-251-2/+21
| | | | | | | | | | | | | | | | - Added new section in the GHC user's guide that legends behavior of nested implicit parameter bindings in these two cases: let ?f = 1 in let ?f = 2 in ?f and data T where MkT :: (?f :: Int) => T f :: T -> T -> Int f MkT MkT = ?f - Added new test case to examine this behavior.
* User's guide: DeepSubsumption is implied by Haskell{98,2010}amesgen2023-04-211-0/+2
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* Minor doc fixesKrzysztof Gogolewski2023-04-211-0/+8
| | | | | | | | | - Add docs/index.html to .gitignore. It is created by ./hadrian/build docs, and it was the only file in Hadrian's templateRules not present in .gitignore. - Mention that MultiWayIf supports non-boolean guards - Remove documentation of optdll - removed in 2007, 763daed95 - Fix markdown syntax
* Allow WARNING pragmas to be controlled with custom categoriesAdam Gundry2023-03-241-6/+21
| | | | | | | | | | | | | | | | 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.
* fix: Update documentation linksromes2023-02-211-2/+2
| | | | | | | Closes #23008 Additionally batches some fixes to pointers to the Note [Wired-in units], and a typo in said note.
* Mention new `Foreign.Marshal.Pool` implementation in User's Guideamesgen2023-02-141-5/+3
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* Remove extraneous word in Roles user guideJan Hrček2023-02-061-1/+1
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* compiler: Implement higher order patterns in the rule matcherJaro Reinders2023-02-021-0/+26
| | | | | | | | This implements proposal 555 and closes ticket #22465. See the proposal and ticket for motivation. The core changes of this patch are in the GHC.Core.Rules.match function and they are explained in the Note [Matching higher order patterns].
* User's guide: Clarify overlapping instance candidate eliminationJason Shipman2023-01-301-2/+2
| | | | | | | | | | | | This commit updates the user's guide section on overlapping instance candidate elimination to use "or" verbiage instead of "either/or" in regards to the current pair of candidates' being overlappable or overlapping. "Either IX is overlappable, or IY is overlapping" can cause confusion as it suggests "Either IX is overlappable, or IY is overlapping, but not both". This was initially discussed on this Discourse topic: https://discourse.haskell.org/t/clarification-on-overlapping-instance-candidate-elimination/5677
* CApiFFI: add ConstPtr for encoding const-qualified pointer return typesnineonine2023-01-281-0/+12
| | | | | | | | | | | | | Previously, when using `capi` calling convention in foreign declarations, code generator failed to handle const-cualified pointer return types. This resulted in CC toolchain throwing `-Wincompatible-pointer-types-discards-qualifiers` warning. `Foreign.C.Types.ConstPtr` newtype was introduced to handle these cases - special treatment was put in place to generate appropritetly qualified C wrapper that no longer triggers the above mentioned warning. Fixes #22043.
* Revert "CApiFFI: add ConstPtr for encoding const-qualified pointer return ↵Ben Gamari2023-01-281-12/+0
| | | | | | types (#22043)" This reverts commit 99aca26b652603bc62953157a48e419f737d352d.
* Set "since: 9.8" for TypeAbstractions and -Wterm-variable-captureVladislav Zavialov2023-01-231-1/+1
| | | | | These flags did not make it into the 9.6 release series, so the "since" annotations must be corrected.
* Move documentation of deferred type error flags out of warnings sectionAdam Gundry2023-01-181-1/+59
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* Document the semantics of pattern bindings a bit betterSimon Peyton Jones2023-01-172-67/+163
| | | | This MR is in response to the discussion on #22719
* Refactor the treatment of loopy superclass dictswip/T20666Richard Eisenberg2023-01-111-10/+94
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch completely re-engineers how we deal with loopy superclass dictionaries in instance declarations. It fixes #20666 and #19690 The highlights are * Recognise that the loopy-superclass business should use precisely the Paterson conditions. This is much much nicer. See Note [Recursive superclasses] in GHC.Tc.TyCl.Instance * With that in mind, define "Paterson-smaller" in Note [Paterson conditions] in GHC.Tc.Validity, and the new data type `PatersonSize` in GHC.Tc.Utils.TcType, along with functions to compute and compare PatsonSizes * Use the new PatersonSize stuff when solving superclass constraints See Note [Solving superclass constraints] in GHC.Tc.TyCl.Instance * In GHC.Tc.Solver.Monad.lookupInInerts, add a missing call to prohibitedSuperClassSolve. This was the original cause of #20666. * Treat (TypeError "stuff") as having PatersonSize zero. See Note [Paterson size for type family applications] in GHC.Tc.Utils.TcType. * Treat the head of a Wanted quantified constraint in the same way as the superclass of an instance decl; this is what fixes #19690. See GHC.Tc.Solver.Canonical Note [Solving a Wanted forall-constraint] (Thanks to Matthew Craven for this insight.) This entailed refactoring the GivenSc constructor of CtOrigin a bit, to say whether it comes from an instance decl or quantified constraint. * Some refactoring way in which redundant constraints are reported; we don't want to complain about the extra, apparently-redundant constraints that we must add to an instance decl because of the loopy-superclass thing. I moved some work from GHC.Tc.Errors to GHC.Tc.Solver. * Add a new section to the user manual to describe the loopy superclass issue and what rules it follows.
* Introduce the TypeAbstractions language flagVladislav Zavialov2023-01-114-80/+99
| | | | | | | | | | | | | | | | | | | | | | | | | GHC Proposals #448 "Modern scoped type variables" and #425 "Invisible binders in type declarations" introduce a new language extension flag: TypeAbstractions. Part of the functionality guarded by this flag has already been implemented, namely type abstractions in constructor patterns, but it was guarded by a combination of TypeApplications and ScopedTypeVariables instead of a dedicated language extension flag. This patch does the following: * introduces a new language extension flag TypeAbstractions * requires TypeAbstractions for @a-syntax in constructor patterns instead of TypeApplications and ScopedTypeVariables * creates a User's Guide page for TypeAbstractions and moves the "Type Applications in Patterns" section there To avoid a breaking change, the new flag is implied by ScopedTypeVariables and is retroactively added to GHC2021. Metric Decrease: MultiLayerModulesTH_OneShot
* Misc cleanupKrzysztof Gogolewski2023-01-052-2/+5
| | | | | | | | | - Remove unused uniques and hs-boot declarations - Fix types of seq and unsafeCoerce# - Remove FastString/String roundtrip in JS - Use TTG to enforce totality - Remove enumeration in Heap/Inspect; the 'otherwise' clause serves the primitive types well.
* Drop support for kind constraints.wip/p547Richard Eisenberg2022-12-241-34/+2
| | | | | | | | | | | | | | | | | | | | | | | | This implements proposal 547 and closes ticket #22298. See the proposal and ticket for motivation. Compiler perf improves a bit Metrics: compile_time/bytes allocated ------------------------------------- CoOpt_Singletons(normal) -2.4% GOOD T12545(normal) +1.0% T13035(normal) -13.5% GOOD T18478(normal) +0.9% T9872d(normal) -2.2% GOOD geo. mean -0.2% minimum -13.5% maximum +1.0% Metric Decrease: CoOpt_Singletons T13035 T9872d
* Fix #22300 Document GHC's extensions to valid whitespaceMike Pilgrem2022-12-092-0/+30
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* Document TH splices' interaction with INCOHERENT instancesRyan Scott2022-12-091-0/+72
| | | | | | | | | Top-level declaration splices can having surprising interactions with `INCOHERENT` instances, as observed in #22492. This patch resolves #22492 by documenting this strange interaction in the GHC User's Guide. [ci skip]
* CApiFFI: add ConstPtr for encoding const-qualified pointer return types (#22043)nineonine2022-11-231-0/+12
| | | | | | | | | | | | | Previously, when using `capi` calling convention in foreign declarations, code generator failed to handle const-cualified pointer return types. This resulted in CC toolchain throwing `-Wincompatible-pointer-types-discards-qualifiers` warning. `Foreign.C.Types.ConstPtr` newtype was introduced to handle these cases - special treatment was put in place to generate appropritetly qualified C wrapper that no longer triggers the above mentioned warning. Fixes #22043
* Add documentation on custom Prelude modules (#22228)Lawton Nichols2022-11-231-3/+42
| | | | Specifically, custom Prelude modules that are named `Prelude`.
* Implement UNPACK support for sum types.Madeline Haraj2022-11-141-1/+7
| | | | | | | This is based on osa's unpack_sums PR from ages past. The meat of the patch is implemented in dataConArgUnpackSum and described in Note [UNPACK for sum types].
* Fix syntaxKrzysztof Gogolewski2022-10-211-1/+1
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* Document how to quote certain names with spacesDavid Feuer2022-10-211-7/+8
| | | | | | | Quoting a name for Template Haskell is a bit tricky if the second character of that name is a single quote. The User's Guide falsely claimed that it was impossible. Document how to do it. Fixes #22236
* Fix docs for pattern synonymsBrandon Chinn2022-10-041-2/+2
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* implement proposal 106 (Define Kinds Without Promotion) (fixes #6024)Ross Paterson2022-09-273-0/+62
| | | | includes corresponding changes to haddock submodule
* Fix typosKrzysztof Gogolewski2022-09-145-6/+6
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* Allow imports to reference multiple fields with the same name (#21625)Adam Gundry2022-09-131-1/+8
| | | | | | | | | | | | | | If a module `M` exports two fields `f` (using DuplicateRecordFields), we can still accept import M (f) import M hiding (f) and treat `f` as referencing both of them. This was accepted in GHC 9.0, but gave rise to an ambiguity error in GHC 9.2. See #21625. This patch also documents this behaviour in the user's guide, and updates the test for #16745 which is now treated differently.
* Update instances.rst, clarifying InstanceSigssheaf2022-09-061-5/+30
| | | | Fixes #22103
* users-guide: Rephrase the rewrite rule documentationBen Gamari2022-08-161-2/+2
| | | | | | Previously the wording was a tad unclear. Fix this. Closes #21114.
* users-guide: Fix incorrect reference to `:extension: roleBen Gamari2022-08-161-1/+1
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* Updates language extension documentationTrevis Elser2022-08-1044-59/+105
| | | | | | | | | | | | | | | | Adding a 'Status' field with a few values: - Deprecated - Experimental - InternalUseOnly - Noting if included in 'GHC2021', 'Haskell2010' or 'Haskell98' Those values are pulled from the existing descriptions or elsewhere in the documentation. While at it, include the :implied by: where appropriate, to provide more detail. Fixes #21475
* User's guide: fix typo in hasfield.rstsheaf2022-08-021-1/+1
| | | | Fixes #21950
* Docs: fix mistaken claim about kind signaturessheaf2022-07-281-8/+37
| | | | | | | | | This patch fixes #21806 by rectifying an incorrect claim about the usage of kind variables in the header of a data declaration with a standalone kind signature. It also adds some clarifications about the number of parameters expected in GADT declarations and in type family declarations.
* docs: Fix documentation of \casesSimon Jakobi2022-07-251-3/+3
| | | | Fixes #21902.
* Docs: clarify ConstraintKinds infelicitysheaf2022-07-251-11/+17
| | | | | | | | | | | GHC doesn't consistently require the ConstraintKinds extension to be enabled, as it allows programs such as type families returning a constraint without this extension. MR !7784 fixes this infelicity, but breaking user programs was deemed to not be worth it, so we document it instead. Fixes #21061.
* Implement DeepSubsumptionSimon Peyton Jones2022-07-252-10/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This MR adds the language extension -XDeepSubsumption, implementing GHC proposal #511. This change mitigates the impact of GHC proposal The changes are highly localised, by design. See Note [Deep subsumption] in GHC.Tc.Utils.Unify. The main changes are: * Add -XDeepSubsumption, which is on by default in Haskell98 and Haskell2010, but off in Haskell2021. -XDeepSubsumption largely restores the behaviour before the "simple subsumption" change. -XDeepSubsumpition has a similar flavour as -XNoMonoLocalBinds: it makes type inference more complicated and less predictable, but it may be convenient in practice. * The main changes are in: * GHC.Tc.Utils.Unify.tcSubType, which does deep susumption and eta-expanansion * GHC.Tc.Utils.Unify.tcSkolemiseET, which does deep skolemisation * In GHC.Tc.Gen.App.tcApp we call tcSubTypeNC to match the result type. Without deep subsumption, unifyExpectedType would be sufficent. See Note [Deep subsumption] in GHC.Tc.Utils.Unify. * There are no changes to Quick Look at all. * The type of `withDict` becomes ambiguous; so add -XAllowAmbiguousTypes to GHC.Magic.Dict * I fixed a small but egregious bug in GHC.Core.FVs.varTypeTyCoFVs, where we'd forgotten to take the free vars of the multiplicity of an Id. * I also had to fix tcSplitNestedSigmaTys When I did the shallow-subsumption patch commit 2b792facab46f7cdd09d12e79499f4e0dcd4293f Date: Sun Feb 2 18:23:11 2020 +0000 Simple subsumption I changed tcSplitNestedSigmaTys to not look through function arrows any more. But that was actually an un-forced change. This function is used only in * Improving error messages in GHC.Tc.Gen.Head.addFunResCtxt * Validity checking for default methods: GHC.Tc.TyCl.checkValidClass * A couple of calls in the GHCi debugger: GHC.Runtime.Heap.Inspect All to do with validity checking and error messages. Acutally its fine to look under function arrows here, and quite useful a test DeepSubsumption05 (a test motivated by a build failure in the `lens` package) shows. The fix is easy. I added Note [tcSplitNestedSigmaTys].
* Allow `let` just before pure/return in ApplicativeDoZiyang Liu2022-05-061-5/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following is currently rejected: ```haskell -- F is an Applicative but not a Monad x :: F (Int, Int) x = do a <- pure 0 let b = 1 pure (a, b) ``` This has bitten me multiple times. This MR contains a simple fix: only allow a "let only" segment to be merged with the next (and not the previous) segment. As a result, when the last one or more statements before pure/return are `LetStmt`s, there will be one more segment containing only those `LetStmt`s. Note that if the `let` statement mentions a name bound previously, then the program is still rejected, for example ```haskell x = do a <- pure 0 let b = a + 1 pure (a, b) ``` or the example in #18559. To support this would require a more complex approach, but this is IME much less common than the previous case.
* Update user guide example rewrite rules formattingMarius Ghita2022-04-301-3/+3
| | | | | | | | | | | | | | Change the rewrite rule examples to include a space between the composition of `f` and `g` in the map rewrite rule examples. Without this change, if the user has locally enabled the extension OverloadedRecordDot the copied example will result in a compile time error that `g` is not a field of `f`. ``` • Could not deduce (GHC.Records.HasField "g" (a -> b) (a1 -> b)) arising from selecting the field ‘g’ ```
* Ensure that Any is Boxed in FFI imports/exportssheaf2022-04-271-2/+3
| | | | | | | | | | 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
* Document behaviour of RULES with KnownNatBodigrim2022-04-251-0/+9
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* Document that DuplicateRecordFields doesn't tolerates ambiguous fieldsHécate Moonlight2022-04-123-106/+70
| | | | Fix #19891
* Fixes to 9.4 release notesKrzysztof Gogolewski2022-04-081-2/+2
| | | | | | - Mention -Wforall-identifier - Improve description of withDict - Fix formatting
* Properly explain where INLINE pragmas can appear.Andreas Klebinger2022-04-071-6/+41
| | | | Fixes #20676
* Implement \cases (Proposal 302)Jakob Bruenker2022-04-012-5/+19
| | | | | | | | | | | | 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
* Change GHC.Prim to GHC.Exts in docs and testsKrzysztof Gogolewski2022-04-013-5/+4
| | | | | Users are supposed to import GHC.Exts rather than GHC.Prim. Part of #18749.
* Document typed splices inhibiting unused bind detection (#16524)jberryman2022-03-281-0/+3
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