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* matchLocalInst: do domination analysissheaf2022-09-281-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | When multiple Given quantified constraints match a Wanted, and there is a quantified constraint that dominates all others, we now pick it to solve the Wanted. See Note [Use only the best matching quantified constraint]. For example: [G] d1: forall a b. ( Eq a, Num b, C a b ) => D a b [G] d2: forall a . C a Int => D a Int [W] {w}: D a Int When solving the Wanted, we find that both Givens match, but we pick the second, because it has a weaker precondition, C a Int, compared to (Eq a, Num Int, C a Int). We thus say that d2 dominates d1; see Note [When does a quantified instance dominate another?]. This domination test is done purely in terms of superclass expansion, in the function GHC.Tc.Solver.Interact.impliedBySCs. We don't attempt to do a full round of constraint solving; this simple check suffices for now. Fixes #22216 and #22223
* implement proposal 106 (Define Kinds Without Promotion) (fixes #6024)Ross Paterson2022-09-274-0/+68
| | | | includes corresponding changes to haddock submodule
* users-guide: fix incorrect ghcappdata folder for unix and windowsMon Aaraj2022-09-211-6/+5
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* docs: clarify that LLVM codegen is not available in unregisterised modematoro2022-09-201-4/+3
| | | | | | | | | | | | | The current docs are misleading and suggest that it is possible to use LLVM codegen from an unregisterised build. This is not the case; attempting to pass `-fllvm` to an unregisterised build warns: ``` when making flags consistent: warning: Target platform uses unregisterised ABI, so compiling via C ``` and uses the C codegen anyway.
* Fix -Woperator-whitespace for consym (part of #19372)Vladislav Zavialov2022-09-201-0/+3
| | | | | | | | | | | | | | Due to an oversight, the initial specification and implementation of -Woperator-whitespace focused on varsym exclusively and completely ignored consym. This meant that expressions such as "x+ y" would produce a warning, while "x:+ y" would not. The specification was corrected in ghc-proposals pull request #404, and this patch updates the implementation accordingly. Regression test included.
* Document :unadd GHCi command in user guideJan Hrček2022-09-201-10/+22
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* Add links to the continuations haddocks in the docs for each primopAlexis King2022-09-161-1/+1
| | | | fixes #22176
* Fix typosKrzysztof Gogolewski2022-09-147-9/+9
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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.
* Add diagnostic codessheaf2022-09-131-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This MR adds diagnostic codes, assigning unique numeric codes to error and warnings, e.g. error: [GHC-53633] Pattern match is redundant This is achieved as follows: - a type family GhcDiagnosticCode that gives the diagnostic code for each diagnostic constructor, - a type family ConRecursInto that specifies whether to recur into an argument of the constructor to obtain a more fine-grained code (e.g. different error codes for different 'deriving' errors), - generics machinery to generate the value-level function assigning each diagnostic its error code; see Note [Diagnostic codes using generics] in GHC.Types.Error.Codes. The upshot is that, to add a new diagnostic code, contributors only need to modify the two type families mentioned above. All logic relating to diagnostic codes is thus contained to the GHC.Types.Error.Codes module, with no code duplication. This MR also refactors error message datatypes a bit, ensuring we can derive Generic for them, and cleans up the logic around constraint solver reports by splitting up 'TcSolverReportInfo' into separate datatypes (see #20772). Fixes #21684
* Add native delimited continuations to the RTSAlexis King2022-09-111-4/+13
| | | | | | | | | | | | | | | | | | | | | This patch implements GHC proposal 313, "Delimited continuation primops", by adding native support for delimited continuations to the GHC RTS. All things considered, the patch is relatively small. It almost exclusively consists of changes to the RTS; the compiler itself is essentially unaffected. The primops come with fairly extensive Haddock documentation, and an overview of the implementation strategy is given in the Notes in rts/Continuation.c. This first stab at the implementation prioritizes simplicity over performance. Most notably, every continuation is always stored as a single, contiguous chunk of stack. If one of these chunks is particularly large, it can result in poor performance, as the current implementation does not attempt to cleverly squeeze a subset of the stack frames into the existing stack: it must fit all at once. If this proves to be a performance issue in practice, a cleverer strategy would be a worthwhile target for future improvements.
* Fix :add docs in user guideJan Hrček2022-09-061-1/+1
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* Update instances.rst, clarifying InstanceSigssheaf2022-09-061-5/+30
| | | | Fixes #22103
* Change Ord defaults per CLC proposalTommy Bidne2022-09-011-0/+4
| | | | Approved by CLC in https://github.com/haskell/core-libraries-committee/issues/24#issuecomment-1233331267
* users-guide: Document system-cxx-std-libBen Gamari2022-08-311-0/+20
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* Drop make build systemBen Gamari2022-08-251-50/+0
| | | | | | | | | | | Here we at long last remove the `make`-based build system, it having been replaced with the Shake-based Hadrian build system. Users are encouraged to refer to the documentation in `hadrian/doc` and this [1] blog post for details on using Hadrian. Closes #17527. [1] https://www.haskell.org/ghc/blog/20220805-make-to-hadrian.html
* Recognize file-header pragmas in GHCi (#21507)MorrowM2022-08-212-0/+24
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* 19217 Implicitly quantify type variables in :kind commandSasha Bogicevic2022-08-191-0/+8
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* users-guide: Rephrase the rewrite rule documentationBen Gamari2022-08-161-2/+2
| | | | | | Previously the wording was a tad unclear. Fix this. Closes #21114.
* relnotes: Add "included libraries" sectionBen Gamari2022-08-161-0/+47
| | | | As noted in #21988, some users rely on this.
* users-guide: Add :ghc-flag: referenceBen Gamari2022-08-161-1/+1
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* users-guide: Fix incorrect reference to `:extension: roleBen Gamari2022-08-161-1/+1
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* users-guide: Fix reference to dead llvm-version substitutionBen Gamari2022-08-161-2/+2
| | | | Fixes #22052.
* Add support for external static plugins (#20964)Sylvain Henry2022-08-101-1/+13
| | | | | | | | | | | | | | | | | | | | This patch adds a new command-line flag: -fplugin-library=<file-path>;<unit-id>;<module>;<args> used like this: -fplugin-library=path/to/plugin.so;package-123;Plugin.Module;["Argument","List"] It allows a plugin to be loaded directly from a shared library. With this approach, GHC doesn't compile anything for the plugin and doesn't load any .hi file for the plugin and its dependencies. As such GHC doesn't need to support two environments (one for plugins, one for target code), which was the more ambitious approach tracked in #14335. Fix #20964 Co-authored-by: Josh Meredith <joshmeredith2008@gmail.com>
* Updates language extension documentationTrevis Elser2022-08-1045-59/+107
| | | | | | | | | | | | | | | | 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
* Document a divergence from the report in parsing function lhss.Andreas Klebinger2022-08-081-0/+4
| | | | | | | | GHC is happy to parse `(f) x y = x + y` when it should be a parse error based on the Haskell report. Seems harmless enough so we won't fix it but it's documented now. Fixes #19788
* users-guide: Add release notes entry for thread introspection supportwip/thread-statusBen Gamari2022-08-061-0/+5
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* Change `-fprof-late` to insert cost centres after unfolding creation.Andreas Klebinger2022-08-062-5/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | The former behaviour of adding cost centres after optimization but before unfoldings are created is not available via the flag `prof-late-inline` instead. I also reduced the overhead of -fprof-late* by pushing the cost centres into lambdas. This means the cost centres will only account for execution of functions and not their partial application. Further I made LATE_CC cost centres it's own CC flavour so they now won't clash with user defined ones if a user uses the same string for a custom scc. LateCC: Don't put cost centres inside constructor workers. With -fprof-late they are rarely useful as the worker is usually inlined. Even if the worker is not inlined or we use -fprof-late-linline they are generally not helpful but bloat compile and run time significantly. So we just don't add sccs inside constructor workers. ------------------------- Metric Decrease: T13701 -------------------------
* Remove backported items from 9.6 release notesKrzysztof Gogolewski2022-08-051-10/+1
| | | | | They have been backported to 9.4 in commits 5423d84bd9a28f, 13c81cb6be95c5, 67ccbd6b2d4b9b.
* User's guide: fix typo in hasfield.rstsheaf2022-08-021-1/+1
| | | | Fixes #21950
* Add -dsuppress-coercion-types to make coercions even smaller.Andreas Klebinger2022-08-021-0/+5
| | | | | Instead of `` `cast` <Co:11> :: (Some -> Really -> Large Type)`` simply print `` `cast` <Co:11> :: ... ``
* 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].
* rel-notes: Drop mention of #21745 fixBen Gamari2022-07-161-6/+0
| | | | Since we have backported the fix to 9.4.1.
* Identify the extistence of the `runhaskell` command and that it is ↵Mike Pilgrem2022-07-021-1/+2
| | | | equivalent to the `runghc` command. Add an entry to the index for `runhaskell`. See https://gitlab.haskell.org/ghc/ghc/-/issues/21411
* rts: gc stats: account properly for copied bytes in sequential collectionsDouglas Wilson2022-07-011-0/+6
| | | | | | | | | | | We were not updating the [copied,any_work,scav_find_work, max_n_todo_overflow] counters during sequential collections. As well, we were double counting for parallel collections. To fix this we add an `else` clause to the `if (is_par_gc())`. The par_* counters do not need to be updated in the sequential case because they must be 0.
* runhaskellEric Lindblad2022-06-221-1/+1
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* Correct documentation of defaults of the `-V` RTS optionAlexander Esgen2022-06-221-6/+7
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* Break out thNameToGhcNameIO (ref. #21730)Brandon Chinn2022-06-221-0/+2
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* Use lookupNameCache instead of lookupOrigIOBrandon Chinn2022-06-221-0/+2
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* Flags to disable local let-floating; -flocal-float-out, ↵Vanessa McHale2022-06-221-0/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | -flocal-float-out-top-level CLI flags These flags affect the behaviour of local let floating. If `-flocal-float-out` is disabled (the default) then we disable all local floating. ``` …(let x = let y = e in (a,b) in body)... ===> …(let y = e; x = (a,b) in body)... ``` Further to this, top-level local floating can be disabled on it's own by passing -fno-local-float-out-top-level. ``` x = let y = e in (a,b) ===> y = e; x = (a,b) ``` Note that this is only about local floating, ie, floating two adjacent lets past each other and doesn't say anything about the global floating pass which is controlled by `-fno-float`. Fixes #13663
* ghc-heap: Don't Box NULL pointersBen Gamari2022-06-181-0/+7
| | | | | | | | | Previously we could construct a `Box` of a NULL pointer from the `link` field of `StgWeak`. Now we take care to avoid ever introducing such pointers in `collect_pointers` and ensure that the `link` field is represented as a `Maybe` in the `Closure` type. Fixes #21622
* Deprecate TypeInType extensionHaskellMouse2022-06-061-0/+2
| | | | | | | | | | | | | | | | 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
* Make -fcompact-unwind the defaultMatthew Pickering2022-06-011-0/+2
| | | | | | | | This is a follow-up to !7247 (closed) making the inclusion of compact unwinding sections the default. Also a slight refactoring/simplification of the flag handling to add -fno-compact-unwind.
* Desugar RecordUpd in `tcExpr`wip/T18802CarrieMY2022-05-251-0/+52
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Change `Backend` type and remove direct dependencieswip/backend-as-recordNorman Ramsey2022-05-211-0/+113
| | | | | | | | | | | | | | | | | | | 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
* docs: Fix LlvmVersion in manpage (#21280)Zubin Duggal2022-05-203-5/+7
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* base: Introduce [sg]etFinalizerExceptionHandlerBen Gamari2022-05-191-0/+4
| | | | | This introduces a global hook which is called when an exception is thrown during finalization.
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