- Jul 03, 2023
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Rather than statically enabling breakpoints only for the interpreter, this adds a new flag. Tracking ticket: #23057 MR: !10466
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- Jun 29, 2023
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Polymorphic specialisation has led to a number of hard to diagnose incorrect runtime result bugs (see #23469, #23109, #21229, #23445) so this commit introduces a flag `-fpolymorhphic-specialisation` which allows users to turn on this experimental optimisation if they are willing to buy into things going very wrong. Ticket #23469
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- Jun 27, 2023
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- Jun 21, 2023
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This is an implementation of the deprecated exports proposal #134. The proposal introduces an ability to introduce warnings to exports. This allows for deprecating a name only when it is exported from a specific module, rather than always depreacting its usage. In this example: module A ({-# DEPRECATED "do not use" #-} x) where x = undefined --- module B where import A(x) `x` will emit a warning when it is explicitly imported. Like the declaration warnings, export warnings are first accumulated within the `Warnings` struct, then passed into the ModIface, from which they are then looked up and warned about in the importing module in the `lookup_ie` helpers of the `filterImports` function (for the explicitly imported names) and in the `addUsedGRE(s)` functions where they warn about regular usages of the imported name. In terms of the AST information, the custom warning is stored in the extension field of the variants of the `IE` type (see Trees that Grow for more information). The commit includes a bump to the haddock submodule added in MR #28 Signed-off-by:
Bartłomiej Cieślar <bcieslar2001@gmail.com>
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- Jun 19, 2023
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Finley McIlwaine authored
IPE data resulting from the `-finfo-table-map` flag may now be compressed by configuring the GHC build with the `--enable-ipe-data-compression` flag. This results in about a 20% reduction in the size of IPE-enabled build results. The compression library, zstd, may optionally be statically linked by configuring with the `--enabled-static-libzstd` flag (on non-darwin platforms) libzstd version 1.4.0 or greater is required.
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- Jun 17, 2023
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GHC Proposal #425 "Invisible binders in type declarations" restricts the scope of type and data family instances as follows: In type family and data family instances, require that every variable mentioned on the RHS must also occur on the LHS. For example, here are three equivalent type instance definitions accepted before this patch: type family F1 a :: k type instance F1 Int = Any :: j -> j type family F2 a :: k type instance F2 @(j -> j) Int = Any :: j -> j type family F3 a :: k type instance forall j. F3 Int = Any :: j -> j - In F1, j is implicitly quantified and it occurs only on the RHS; - In F2, j is implicitly quantified and it occurs both on the LHS and the RHS; - In F3, j is explicitly quantified. Now F1 is rejected with an out-of-scope error, while F2 and F3 continue to be accepted.
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- Jun 16, 2023
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- Jun 15, 2023
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GHC Proposal #425 "Invisible binders in type declarations" forbids implicit quantification of type variables that occur free on the right-hand side of a type synonym but are not mentioned on the left-hand side. The users are expected to rewrite this using invisible binders: type T1 :: forall a . Maybe a type T1 = 'Nothing :: Maybe a -- old type T1 @a = 'Nothing :: Maybe a -- new Since the @k-binders are a new feature, we need to wait for three releases before we require the use of the new syntax. In the meantime, we ought to provide users with a new warning, -Wimplicit-rhs-quantification, that would detect when such implicit quantification takes place, and include it in -Wcompat.
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- Jun 14, 2023
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Implements #22826 This is a restricted version of -Wmissing-kind-signatures shown only for polykinded types.
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- Jun 13, 2023
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Co-authored-by:Tilde Rose <t1lde@protonmail.com>
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- Jun 09, 2023
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Introduce a `-ddump-spec-constr` flag which debugs specialisations from `SpecConstr`. These are no longer shown when you use `-ddump-spec`.
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- Jun 07, 2023
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This reverts commit 3ded9a1c.
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Vladislav Zavialov authoredThis patch implements @k-binders introduced in GHC Proposal #425 and guarded behind the TypeAbstractions extension: type D :: forall k j. k -> j -> Type data D @k @j a b = ... ^^ ^^ To represent the new syntax, we modify LHsQTyVars as follows: - hsq_explicit :: [LHsTyVarBndr () pass] + hsq_explicit :: [LHsTyVarBndr (HsBndrVis pass) pass] HsBndrVis is a new data type that records the distinction between type variable binders written with and without the @ sign: data HsBndrVis pass = HsBndrRequired | HsBndrInvisible (LHsToken "@" pass) The rest of the patch updates GHC, template-haskell, and haddock to handle the new syntax. Parser: The PsErrUnexpectedTypeAppInDecl error message is removed. The syntax it used to reject is now permitted. Renamer: The @ sign does not affect the scope of a binder, so the changes to the renamer are minimal. See rnLHsTyVarBndrVisFlag. Type checker: There are three code paths that were updated to deal with the newly introduced invisible type variable binders: 1. checking SAKS: see kcCheckDeclHeader_sig, matchUpSigWithDecl 2. checking CUSK: see kcCheckDeclHeader_cusk 3. inference: see kcInferDeclHeader, rejectInvisibleBinders Helper functions bindExplicitTKBndrs_Q_Skol and bindExplicitTKBndrs_Q_Tv are generalized to work with HsBndrVis. Updates the haddock submodule. Metric Increase: MultiLayerModulesTH_OneShot Co-authored-by:
Simon Peyton Jones <simon.peytonjones@gmail.com>
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- Jun 01, 2023
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Add mention of IPE data compression to user's guide and the release notes for 9.8.1. Also note the impact compression has on binary size in both places. Change IpeBufferListNode compression check so only the value `1` indicates compression. See ticket #21766
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- May 31, 2023
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Fixes ghc/ghc#23444
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- May 26, 2023
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This allows API users to configure how messages are rendered when they are emitted from the load function. For an example see how 'loadWithCache' is used in GHCi.
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- May 24, 2023
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- May 23, 2023
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This refactoring makes a substantial improvement in the structure of the type-checker's constraint solver: #23070. Specifically: * Introduced the SolverStage monad. See GHC.Tc.Solver.Monad Note [The SolverStage monad] * Make each solver pipeline (equalities, dictionaries, irreds etc) deal with updating the inert set, as a separate SolverStage. There is sometimes special stuff to do, and it means that each full pipeline can have type SolverStage Void, indicating that they never return anything. * Made GHC.Tc.Solver.Equality.zonkEqTypes into a SolverStage. Much nicer. * Combined the remnants of GHC.Tc.Solver.Canonical and GHC.Tc.Solver.Interact into a new module GHC.Tc.Solver.Solve. (Interact and Canonical are removed.) * Gave the same treatment to dictionary and irred constraints as I have already done for equality constraints: * New types (akin to EqCt): IrredCt and DictCt * Ct is now just a simple sum type data Ct = CDictCan DictCt | CIrredCan IrredCt | CEqCan EqCt | CQuantCan QCInst | CNonCanonical CtEvidence * inert_dicts can now have the better type DictMap DictCt, instead of DictMap Ct; and similarly inert_irreds. * Significantly simplified the treatment of implicit parameters. Previously we had a number of special cases * interactGivenIP, an entire function * special case in maybeKickOut * special case in findDict, when looking up dictionaries But actually it's simpler than that. When adding a new Given, implicit parameter constraint to the InertSet, we just need to kick out any existing inert constraints that mention that implicit parameter. The main work is done in GHC.Tc.Solver.InertSet.delIPDict, along with its auxiliary GHC.Core.Predicate.mentionsIP. See Note [Shadowing of implicit parameters] in GHC.Tc.Solver.Dict. * Add a new fast-path in GHC.Tc.Errors.Hole.tcCheckHoleFit. See Note [Fast path for tcCheckHoleFit]. This is a big win in some cases: test hard_hole_fits gets nearly 40% faster (at compile time). * Add a new fast-path for solving /boxed/ equality constraints (t1 ~ t2). See Note [Solving equality classes] in GHC.Tc.Solver.Dict. This makes a big difference too: test T17836 compiles 40% faster. * Implement the PermissivePlan of #23413, which concerns what happens with insoluble Givens. Our previous treatment was wildly inconsistent as that ticket pointed out. A part of this, I simplified GHC.Tc.Validity.checkAmbiguity: now we simply don't run the ambiguity check at all if -XAllowAmbiguousTypes is on. Smaller points: * In `GHC.Tc.Errors.misMatchOrCND` instead of having a special case for insoluble /occurs/ checks, broaden in to all insouluble constraints. Just generally better. See Note [Insoluble mis-match] in that module. As noted above, compile time perf gets better. Here are the changes over 0.5% on Fedora. (The figures are slightly larger on Windows for some reason.) Metrics: compile_time/bytes allocated ------------------------------------- LargeRecord(normal) -0.9% MultiLayerModulesTH_OneShot(normal) +0.5% T11822(normal) -0.6% T12227(normal) -1.8% GOOD T12545(normal) -0.5% T13035(normal) -0.6% T15703(normal) -1.4% GOOD T16875(normal) -0.5% T17836(normal) -40.7% GOOD T17836b(normal) -12.3% GOOD T17977b(normal) -0.5% T5837(normal) -1.1% T8095(normal) -2.7% GOOD T9020(optasm) -1.1% hard_hole_fits(normal) -37.0% GOOD geo. mean -1.3% minimum -40.7% maximum +0.5% Metric Decrease: T12227 T15703 T17836 T17836b T8095 hard_hole_fits LargeRecord T9198 T13035
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- May 20, 2023
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Using the directive automatically formats and links the ticket appropiately.
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- May 18, 2023
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In relation to #23056
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- May 17, 2023
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Currently this merely explains the meaning of "technology preview" in the context of released features.
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- May 16, 2023
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Oleg Grenrus authored
Implements #22702
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- May 12, 2023
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- Make explicit that default flag values correspond to their -O0 value. - Fix -fignore-interface-pragmas, -fstg-cse, -fdo-eta-reduction, -fcross-module-specialise, -fsolve-constant-dicts, -fworker-wrapper.
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- May 11, 2023
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This patch adds eight new primops that fuse a multiplication and an addition or subtraction: - `{fmadd,fmsub,fnmadd,fnmsub}{Float,Double}#` fmadd x y z is x * y + z, computed with a single rounding step. This patch implements code generation for these primops in the following backends: - X86, AArch64 and PowerPC NCG, - LLVM - C WASM uses the C implementation. The primops are unsupported in the JavaScript backend. The following constant folding rules are also provided: - compute a * b + c when a, b, c are all literals, - x * y + 0 ==> x * y, - ±1 * y + z ==> z ± y and x * ±1 + z ==> z ± x. NB: the constant folding rules incorrectly handle signed zero. This is a known limitation with GHC's floating-point constant folding rules (#21227), which we hope to resolve in the future.
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- May 06, 2023
- May 04, 2023
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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>
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- Apr 29, 2023
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sheaf authored
This commit implements GHC proposal #433, adding the Unsatisfiable class to the GHC.TypeError module. This provides an alternative to TypeError for which error reporting is more predictable: we report it when we are reporting unsolved Wanted constraints. Fixes #14983 #16249 #16906 #18310 #20835
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- Apr 25, 2023
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- 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.
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- Apr 21, 2023
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- 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, 763daed9 - Fix markdown syntax
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- Apr 20, 2023
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See https://github.com/ghc-proposals/ghc-proposals/pull/540/ for a complete description for the motivation for this feature. The `-jsem` option allows a build tool to pass a semaphore to GHC which GHC can use in order to control how much parallelism it requests. GHC itself acts as a client in the GHC jobserver protocol. ``` GHC Jobserver Protocol ~~~~~~~~~~~~~~~~~~~~~~ This proposal introduces the GHC Jobserver Protocol. This protocol allows a server to dynamically invoke many instances of a client process, while restricting all of those instances to use no more than <n> capabilities. This is achieved by coordination over a system semaphore (either a POSIX semaphore [6]_ in the case of Linux and Darwin, or a Win32 semaphore [7]_ in the case of Windows platforms). There are two kinds of participants in the GHC Jobserver protocol: - The *jobserver* creates a system semaphore with a certain number of available tokens. Each time the jobserver wants to spawn a new jobclient subprocess, it **must** first acquire a single token from the semaphore, before spawning the subprocess. This token **must** be released once the subprocess terminates. Once work is finished, the jobserver **must** destroy the semaphore it created. - A *jobclient* is a subprocess spawned by the jobserver or another jobclient. Each jobclient starts with one available token (its *implicit token*, which was acquired by the parent which spawned it), and can request more tokens through the Jobserver Protocol by waiting on the semaphore. Each time a jobclient wants to spawn a new jobclient subprocess, it **must** pass on a single token to the child jobclient. This token can either be the jobclient's implicit token, or another token which the jobclient acquired from the semaphore. Each jobclient **must** release exactly as many tokens as it has acquired from the semaphore (this does not include the implicit tokens). ``` Build tools such as cabal act as jobservers in the protocol and are responsibile for correctly creating, cleaning up and managing the semaphore. Adds a new submodule (semaphore-compat) for managing and interacting with semaphores in a cross-platform way. Fixes #19349
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Recent egrep displays the following message, breaking golden tests: egrep: warning: egrep is obsolescent; using grep -E Switch to using "grep -E" instead
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- Apr 17, 2023
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This brings the `IrredPred` case in sync with the treatment of `ClassPred`s as described in `Note [Valid 'deriving' predicate]` in `GHC.Tc.Validity`. Namely, we should reject `IrredPred`s that are inferred from `deriving` clauses whose arguments contain other type constructors, as described in `(VD2) Reject exotic constraints` of that Note. This has the nice property that `deriving` clauses whose inferred instance context mention `TypeError` will now emit the type error in the resulting error message, which better matches existing intuitions about how `TypeError` should work. While I was in town, I noticed that much of `Note [Valid 'deriving' predicate]` was duplicated in a separate `Note [Exotic derived instance contexts]` in `GHC.Tc.Deriv.Infer`. I decided to fold the latter Note into the former so that there is a single authority on describing the conditions under which an inferred `deriving` constraint can be considered valid. This changes the behavior of `deriving` in a way that existing code might break, so I have made a mention of this in the GHC User's Guide. It seems very, very unlikely that much code is relying on this strange behavior, however, and even if there is, there is a clear, backwards-compatible migration path using `StandaloneDeriving`. Fixes #22696.
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