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* Keep track of promotion ticks in HsOpTywip/no-c-stubswip/matt-merge-batchsheaf2022-04-011-3/+3
| | | | | | | | | | | | | | | | 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 and simplify DeriveAnyClass's context inference using SubTypePredSpecRyan Scott2022-03-243-247/+425
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* 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: Refactor bracket for desugaring during tcromes2022-03-181-1/+1
| | | | | | | | | | | | | 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 bracketsromes2022-03-181-5/+5
| | | | | | | | | | | 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)
* Fix isLiftedType_maybe and handle falloutsheaf2022-03-142-2/+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
* Refactor tcDeriving to generate tyfam insts before any bindingsRyan Scott2022-03-115-166/+198
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, there was an awful hack in `genInst` (now called `genInstBinds` after this patch) where we had to return a continutation rather than directly returning the bindings for a derived instance. This was done for staging purposes, as we had to first infer the instance contexts for derived instances and then feed these contexts into the continuations to ensure the generated instance bindings had accurate instance contexts. `Note [Staging of tcDeriving]` in `GHC.Tc.Deriving` described this confusing state of affairs. The root cause of this confusing design was the fact that `genInst` was trying to generate instance bindings and associated type family instances for derived instances simultaneously. This really isn't possible, however: as `Note [Staging of tcDeriving]` explains, one needs to have access to the associated type family instances before one can properly infer the instance contexts for derived instances. The use of continuation-returning style was an attempt to circumvent this dependency, but it did so in an awkward way. This patch detangles this awkwardness by splitting up `genInst` into two functions: `genFamInsts` (for associated type family instances) and `genInstBinds` (for instance bindings). Now, the `tcDeriving` function calls `genFamInsts` and brings all the family instances into scope before calling `genInstBinds`. This removes the need for the awkward continuation-returning style seen in the previous version of `genInst`, making the code easier to understand. There are some knock-on changes as well: 1. `hasStockDeriving` now needs to return two separate functions: one that describes how to generate family instances for a stock-derived instance, and another that describes how to generate the instance bindings. I factored out this pattern into a new `StockGenFns` data type. 2. While documenting `StockGenFns`, I realized that there was some inconsistency regarding which `StockGenFns` functions needed which arguments. In particular, the function in `GHC.Tc.Deriv.Generics` which generates `Rep(1)` instances did not take a `SrcSpan` like other `gen_*` functions did, and it included an extra `[Type]` argument that was entirely redundant. As a consequence, I refactored the code in `GHC.Tc.Deriv.Generics` to more closely resemble other `gen_*` functions. A happy result of all this is that all `StockGenFns` functions now take exactly the same arguments, which makes everything more uniform. This is purely a refactoring that should not have any effect on user-observable behavior. The new design paves the way for an eventual fix for #20719.
* Delete GenericKind_ in favor of GenericKind_DCRyan Scott2022-03-071-71/+66
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When deriving a `Generic1` instance, we need to know what the last type variable of a data type is. Previously, there were two mechanisms to determine this information: * `GenericKind_`, where `Gen1_` stored the last type variable of a data type constructor (i.e., the `tyConTyVars`). * `GenericKind_DC`, where `Gen1_DC` stored the last universally quantified type variable in a data constructor (i.e., the `dataConUnivTyVars`). These had different use cases, as `GenericKind_` was used for generating `Rep(1)` instances, while `GenericKind_DC` was used for generating `from(1)` and `to(1)` implementations. This was already a bit confusing, but things went from confusing to outright wrong after !6976. This is because after !6976, the `deriving` machinery stopped using `tyConTyVars` in favor of `dataConUnivTyVars`. Well, everywhere with the sole exception of `GenericKind_`, which still continued to use `tyConTyVars`. This lead to disaster when deriving a `Generic1` instance for a GADT family instance, as the `tyConTyVars` do not match the `dataConUnivTyVars`. (See #21185.) The fix is to stop using `GenericKind_` and replace it with `GenericKind_DC`. For the most part, this proves relatively straightforward. Some highlights: * The `forgetArgVar` function was deleted entirely, as it no longer proved necessary after `GenericKind_`'s demise. * The substitution that maps from the last type variable to `Any` (see `Note [Generating a correctly typed Rep instance]`) had to be moved from `tc_mkRepTy` to `tc_mkRepFamInsts`, as `tc_mkRepTy` no longer has access to the last type variable. Fixes #21185.
* Suggestions due to hlintMatthew Pickering2022-02-241-2/+1
| | | | | It turns out this job hasn't been running for quite a while (perhaps ever) so there are quite a few failures when running the linter locally.
* Kill derived constraintsRichard Eisenberg2022-02-231-11/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Co-authored by: Sam Derbyshire Previously, GHC had three flavours of constraint: Wanted, Given, and Derived. This removes Derived constraints. Though serving a number of purposes, the most important role of Derived constraints was to enable better error messages. This job has been taken over by the new RewriterSets, as explained in Note [Wanteds rewrite wanteds] in GHC.Tc.Types.Constraint. Other knock-on effects: - Various new Notes as I learned about under-described bits of GHC - A reshuffling around the AST for implicit-parameter bindings, with better integration with TTG. - Various improvements around fundeps. These were caused by the fact that, previously, fundep constraints were all Derived, and Derived constraints would get dropped. Thus, an unsolved Derived didn't stop compilation. Without Derived, this is no longer possible, and so we have to be considerably more careful around fundeps. - A nice little refactoring in GHC.Tc.Errors to center the work on a new datatype called ErrorItem. Constraints are converted into ErrorItems at the start of processing, and this allows for a little preprocessing before the main classification. - This commit also cleans up the behavior in generalisation around functional dependencies. Now, if a variable is determined by functional dependencies, it will not be quantified. This change is user facing, but it should trim down GHC's strange behavior around fundeps. - Previously, reportWanteds did quite a bit of work, even on an empty WantedConstraints. This commit adds a fast path. - Now, GHC will unconditionally re-simplify constraints during quantification. See Note [Unconditionally resimplify constraints when quantifying], in GHC.Tc.Solver. Close #18398. Close #18406. Solve the fundep-related non-confluence in #18851. Close #19131. Close #19137. Close #20922. Close #20668. Close #19665. ------------------------- Metric Decrease: LargeRecord T9872b T9872b_defer T9872d TcPlugin_RewritePerf -------------------------
* Fix some notesMatthew Pickering2022-02-081-1/+1
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* Rework the handling of SkolemInfoMatthew Pickering2022-01-292-7/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The main purpose of this patch is to attach a SkolemInfo directly to each SkolemTv. This fixes the large number of bugs which have accumulated over the years where we failed to report errors due to having "no skolem info" for particular type variables. Now the origin of each type varible is stored on the type variable we can always report accurately where it cames from. Fixes #20969 #20732 #20680 #19482 #20232 #19752 #10946 #19760 #20063 #13499 #14040 The main changes of this patch are: * SkolemTv now contains a SkolemInfo field which tells us how the SkolemTv was created. Used when reporting errors. * Enforce invariants relating the SkolemInfoAnon and level of an implication (ic_info, ic_tclvl) to the SkolemInfo and level of the type variables in ic_skols. * All ic_skols are TcTyVars -- Check is currently disabled * All ic_skols are SkolemTv * The tv_lvl of the ic_skols agrees with the ic_tclvl * The ic_info agrees with the SkolInfo of the implication. These invariants are checked by a debug compiler by checkImplicationInvariants. * Completely refactor kcCheckDeclHeader_sig which kept doing my head in. Plus, it wasn't right because it wasn't skolemising the binders as it decomposed the kind signature. The new story is described in Note [kcCheckDeclHeader_sig]. The code is considerably shorter than before (roughly 240 lines turns into 150 lines). It still has the same awkward complexity around computing arity as before, but that is a language design issue. See Note [Arity inference in kcCheckDeclHeader_sig] * I added new type synonyms MonoTcTyCon and PolyTcTyCon, and used them to be clear which TcTyCons have "finished" kinds etc, and which are monomorphic. See Note [TcTyCon, MonoTcTyCon, and PolyTcTyCon] * I renamed etaExpandAlgTyCon to splitTyConKind, becuase that's a better name, and it is very useful in kcCheckDeclHeader_sig, where eta-expansion isn't an issue. * Kill off the nasty `ClassScopedTvEnv` entirely. Co-authored-by: Simon Peyton Jones <simon.peytonjones@gmail.com>
* DeriveGeneric: look up datacon fixities using getDataConFixityFunRyan Scott2022-01-252-19/+21
| | | | | | | | | | | | Previously, `DeriveGeneric` would look up the fixity of a data constructor using `getFixityEnv`, but this is subtly incorrect for data constructors defined in external modules. This sort of situation can happen with `StandaloneDeriving`, as noticed in #20994. In fact, the same bug has occurred in the past in #9830, and while that bug was fixed for `deriving Read` and `deriving Show`, the fix was never extended to `DeriveGeneric` due to an oversight. This patch corrects that oversight. Fixes #20994.
* Use primOpIds cache more often (#20857)Sylvain Henry2022-01-061-1/+1
| | | | | | | | Use primOpId instead of mkPrimOpId in a few places to benefit from Id caching. I had to mess a little bit with the module hierarchy to fix cycles and to avoid adding too many new dependencies to count-deps tests.
* Don't use implicit lifting when deriving LiftMatthew Pickering2021-11-251-8/+20
| | | | | | | | | | | | | | | | It isn't much more complicated to be more precise when deriving Lift so we now generate ``` data Foo = Foo Int Bool instance Lift Foo where lift (Foo a b) = [| Foo $(lift a) $(lift b) |] liftTyped (Foo a b) = [|| Foo $$(lift a) $$(lift b) |] ``` This fixes #20688 which complained about using implicit lifting in the derived code.
* Instantiate field types properly in stock-derived instancesRyan Scott2021-11-155-227/+329
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, the `deriving` machinery was very loosey-goosey about how it used the types of data constructor fields when generating code. It would usually just consult `dataConOrigArgTys`, which returns the _uninstantiated_ field types of each data constructor. Usually, you can get away with this, but issues #20375 and #20387 revealed circumstances where this approach fails. Instead, when generated code for a stock-derived instance `C (T arg_1 ... arg_n)`, one must take care to instantiate the field types of each data constructor with `arg_1 ... arg_n`. The particulars of how this is accomplished is described in the new `Note [Instantiating field types in stock deriving]` in `GHC.Tc.Deriv.Generate`. Some highlights: * `DerivInstTys` now has a new `dit_dc_inst_arg_env :: DataConEnv [Type]` field that caches the instantiated field types of each data constructor. Whenever we need to consult the field types somewhere in `GHC.Tc.Deriv.*` we avoid using `dataConOrigArgTys` and instead look it up in `dit_dc_inst_arg_env`. * Because `DerivInstTys` now stores the instantiated field types of each constructor, some of the details of the `GHC.Tc.Deriv.Generics.mkBindsRep` function were able to be simplified. In particular, we no longer need to apply a substitution to instantiate the field types in a `Rep(1)` instance, as that is already done for us by `DerivInstTys`. We still need a substitution to implement the "wrinkle" section of `Note [Generating a correctly typed Rep instance]`, but the code is nevertheless much simpler than before. * The `tyConInstArgTys` function has been removed in favor of the new `GHC.Core.DataCon.dataConInstUnivs` function, which is really the proper tool for the job. `dataConInstUnivs` is much like `tyConInstArgTys` except that it takes a data constructor, not a type constructor, as an argument, and it adds extra universal type variables from that data constructor at the end of the returned list if need be. `dataConInstUnivs` takes care to instantiate the kinds of the universal type variables at the end, thereby avoiding a bug in `tyConInstArgTys` discovered in https://gitlab.haskell.org/ghc/ghc/-/issues/20387#note_377037. Fixes #20375. Fixes #20387.
* Refactoring: Consolidate some arguments with DerivInstTysRyan Scott2021-11-154-123/+127
| | | | | | | | | | | Various functions in GHC.Tc.Deriv.* were passing around `TyCon`s and `[Type]`s that ultimately come from the same `DerivInstTys`. This patch moves the definition of `DerivInstTys` to `GHC.Tc.Deriv.Generate` so that all of these `TyCon` and `[Type]` arguments can be consolidated into a single `DerivInstTys`. Not only does this make the code easier to read (in my opinion), this will also be important in a subsequent commit where we need to add another field to `DerivInstTys` that will also be used from `GHC.Tc.Deriv.Generate` and friends.
* Flesh out Note [The stupid context] and reference itRyan Scott2021-11-093-7/+7
| | | | | | `Note [The stupid context]` in `GHC.Core.DataCon` talks about stupid contexts from `DatatypeContexts`, but prior to this commit, it was rather outdated. This commit spruces it up and references it from places where it is relevant.
* deriving: infer DatatypeContexts from data constructors, not type constructorRyan Scott2021-11-091-13/+24
| | | | | | | | | | | | | | Previously, derived instances that use `deriving` clauses would infer `DatatypeContexts` by using `tyConStupidTheta`. But this sometimes causes redundant constraints to be included in the derived instance contexts, as the constraints that appear in the `tyConStupidTheta` may not actually appear in the types of the data constructors (i.e., the `dataConStupidTheta`s). For instance, in `data Show a => T a = MkT deriving Eq`, the type of `MkT` does not require `Show`, so the derived `Eq` instance should not require `Show` either. This patch makes it so with some small tweaks to `inferConstraintsStock`. Fixes #20501.
* Change CaseAlt and LambdaExpr to FunRhs in deriving Foldable and Traversable ↵Artyom Kuznetsov2021-10-261-3/+8
| | | | (#20496)
* Eradicate TcRnUnknownMessage from GHC.Tc.DerivAlfredo Di Napoli2021-10-052-120/+88
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This (big) commit finishes porting the GHC.Tc.Deriv module to support the new diagnostic infrastructure (#18516) by getting rid of the legacy calls to `TcRnUnknownMessage`. This work ended up being quite pervasive and touched not only the Tc.Deriv module but also the Tc.Deriv.Utils and Tc.Deriv.Generics module, which needed to be adapted to use the new infrastructure. This also required generalising `Validity`. More specifically, this is a breakdown of the work done: * Add and use the TcRnUselessTypeable data constructor * Add and use TcRnDerivingDefaults data constructor * Add and use the TcRnNonUnaryTypeclassConstraint data constructor * Add and use TcRnPartialTypeSignatures * Add T13324_compile2 test to test another part of the TcRnPartialTypeSignatures diagnostic * Add and use TcRnCannotDeriveInstance data constructor, which introduces a new data constructor to TcRnMessage called TcRnCannotDeriveInstance, which is further sub-divided to carry a `DeriveInstanceErrReason` which explains the reason why we couldn't derive a typeclass instance. * Add DerivErrSafeHaskellGenericInst data constructor to DeriveInstanceErrReason * Add DerivErrDerivingViaWrongKind and DerivErrNoEtaReduce * Introduce the SuggestExtensionInOrderTo Hint, which adds (and use) a new constructor to the hint type `LanguageExtensionHint` called `SuggestExtensionInOrderTo`, which can be used to give a bit more "firm" recommendations when it's obvious what the required extension is, like in the case for the `DerivingStrategies`, which automatically follows from having enabled both `DeriveAnyClass` and `GeneralizedNewtypeDeriving`. * Wildcard-free pattern matching in mk_eqn_stock, which removes `_` in favour of pattern matching explicitly on `CanDeriveAnyClass` and `NonDerivableClass`, because that determine whether or not we can suggest to the user `DeriveAnyClass` or not.
* Make GHC.Utils.Error.Validity type polymorphicAlfredo Di Napoli2021-10-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | This commit makes the `Validity` type polymorphic: ``` data Validity' a = IsValid -- ^ Everything is fine | NotValid a -- ^ A problem, and some indication of why -- | Monomorphic version of @Validity'@ specialised for 'SDoc's. type Validity = Validity' SDoc ``` The type has been (provisionally) renamed to Validity' to not break existing code, as the monomorphic `Validity` type is quite pervasive in a lot of signatures in GHC. Why having a polymorphic Validity? Because it carries the evidence of "what went wrong", but the old type carried an `SDoc`, which clashed with the new GHC diagnostic infrastructure (#18516). Having it polymorphic it means we can carry an arbitrary, richer diagnostic type, and this is very important for things like the `checkOriginativeSideConditions` function, which needs to report the actual diagnostic error back to `GHC.Tc.Deriv`. It also generalises Validity-related functions to be polymorphic in @a@.
* deriving: Always use module prefix in dataTypeNameMatthew Pickering2021-09-181-1/+6
| | | | | | | | | | | This fixes a long standard bug where the module prefix was omitted from the data type name supplied by Data.Typeable instances. Instead of reusing the Outputable instance for TyCon, we now take matters into our own hands and explicitly print the module followed by the type constructor name. Fixes #20371
* Make Int64#/Word64# unconditionally availableJohn Ericson2021-08-191-3/+0
| | | | | | | | This prepares us to actually use them when the native size is 64 bits too. I more than saitisfied my curiosity finding they were gated since 47774449c9d66b768a70851fe82c5222c1f60689.
* Add Word64#/Int64# primopsSylvain Henry2021-07-151-1/+21
| | | | | | | | | | | | | | | | | | | | | | | Word64#/Int64# are only used on 32-bit architectures. Before this patch, operations on these types were directly using the FFI. Now we use real primops that are then lowered into ccalls. The advantage of doing this is that we can now perform constant folding on Word64#/Int64# (#19024). Most of this work was done by John Ericson in !3658. However this patch doesn't go as far as e.g. changing Word64 to always be using Word64#. Noticeable performance improvements T9203(normal) run/alloc 89870808.0 66662456.0 -25.8% GOOD haddock.Cabal(normal) run/alloc 14215777340.8 12780374172.0 -10.1% GOOD haddock.base(normal) run/alloc 15420020877.6 13643834480.0 -11.5% GOOD Metric Decrease: T9203 haddock.Cabal haddock.base
* Reword: representation instead of levitysheaf2021-06-101-1/+1
| | | | fixes #19756, updates haddock submodule
* Split GHC.Utils.Monad.State into .Strict and .LazyBen Gamari2021-05-291-1/+1
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* Remove useless {-# LANGUAGE CPP #-} pragmasSylvain Henry2021-05-124-4/+4
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* Fully remove HsVersions.hSylvain Henry2021-05-124-8/+0
| | | | | | | | | | Replace uses of WARN macro with calls to: warnPprTrace :: Bool -> SDoc -> a -> a Remove the now unused HsVersions.h Bump haddock submodule
* Replace CPP assertions with Haskell functionsSylvain Henry2021-05-123-16/+19
| | | | | | | | | | | | | | | There is no reason to use CPP. __LINE__ and __FILE__ macros are now better replaced with GHC's CallStack. As a bonus, assert error messages now contain more information (function name, column). Here is the mapping table (HasCallStack omitted): * ASSERT: assert :: Bool -> a -> a * MASSERT: massert :: Bool -> m () * ASSERTM: assertM :: m Bool -> m () * ASSERT2: assertPpr :: Bool -> SDoc -> a -> a * MASSERT2: massertPpr :: Bool -> SDoc -> m () * ASSERTM2: assertPprM :: m Bool -> SDoc -> m ()
* GHC Exactprint main commitAlan Zimmerman2021-03-204-77/+85
| | | | | | | | Metric Increase: T10370 parsing001 Updates haddock submodule
* Compute length only once in foldBalSylvain Henry2021-03-141-4/+11
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* Fix array and cleanup conversion primops (#19026)Sylvain Henry2021-03-031-21/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The first change makes the array ones use the proper fixed-size types, which also means that just like before, they can be used without explicit conversions with the boxed sized types. (Before, it was Int# / Word# on both sides, now it is fixed sized on both sides). For the second change, don't use "extend" or "narrow" in some of the user-facing primops names for conversions. - Names like `narrowInt32#` are misleading when `Int` is 32-bits. - Names like `extendInt64#` are flat-out wrong when `Int is 32-bits. - `narrow{Int,Word}<N>#` however map a type to itself, and so don't suffer from this problem. They are left as-is. These changes are batched together because Alex happend to use the array ops. We can only use released versions of Alex at this time, sadly, and I don't want to have to have a release thatwon't work for the final GHC 9.2. So by combining these we get all the changes for Alex done at once. Bump hackage state in a few places, and also make that workflow slightly easier for the future. Bump minimum Alex version Bump Cabal, array, bytestring, containers, text, and binary submodules
* Fix typosBrian Wignall2021-02-061-1/+1
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* Remove ErrDoc and MsgDocAlfredo Di Napoli2021-02-011-1/+1
| | | | | | | | | | | | | This commit boldly removes the ErrDoc and the MsgDoc from the codebase. The former was introduced with the only purpose of classifying errors according to their importance, but a similar result can be obtained just by having a simple [SDoc], and placing bullets after each of them. On top of that I have taken the perhaps controversial decision to also banish MsgDoc, as it was merely a type alias over an SDoc and as such it wasn't offering any extra type safety. Granted, it was perhaps making type signatures slightly more "focused", but at the expense of cognitive burden: if it's really just an SDoc, let's call it with its proper name.
* Enhance Data instance generationSylvain Henry2021-01-221-6/+6
| | | | | | | | | | | | | | | | Use `mkConstrTag` to explicitly pass the constructor tag instead of using `mkConstr` which queries the tag at runtime by querying the index of the constructor name (a string) in the list of constructor names. Perf improvement: T16577(normal) ghc/alloc 11325573876.0 9249786992.0 -18.3% GOOD Thanks to @sgraf812 for suggesting an additional list fusion fix during reviews. Metric Decrease: T16577
* When deriving Eq always use tag based comparisons for nullary constructorsAndreas Klebinger2021-01-221-215/+169
| | | | | | | Instead of producing auxiliary con2tag bindings we now rely on dataToTag#, eliminating a fair bit of generated code. Co-Authored-By: Ben Gamari <ben@well-typed.com>
* Make primops for `{Int,Word}32#`John Ericson2021-01-071-3/+35
| | | | | | | | | | | | | Progress towards #19026. The type was added before, but not its primops. We follow the conventions in 36fcf9edee31513db2ddbf716ee0aa79766cbe69 and 2c959a1894311e59cd2fd469c1967491c1e488f3 for names and testing. Along with the previous 8- and 16-bit primops, this will allow us to avoid many conversions for 8-, 16-, and 32-bit sized numeric types. Co-authored-by: Sylvain Henry <hsyl20@gmail.com>
* WorkWrap: Unbox constructors with existentials (#18982)Sebastian Graf2020-12-231-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Consider ```hs data Ex where Ex :: e -> Int -> Ex f :: Ex -> Int f (Ex e n) = e `seq` n + 1 ``` Worker/wrapper should build the following worker for `f`: ```hs $wf :: forall e. e -> Int# -> Int# $wf e n = e `seq` n +# 1# ``` But previously it didn't, because `Ex` binds an existential. This patch lifts that condition. That entailed having to instantiate existential binders in `GHC.Core.Opt.WorkWrap.Utils.mkWWstr` via `GHC.Core.Utils.dataConRepFSInstPat`, requiring a bit of a refactoring around what is now `DataConPatContext`. CPR W/W still won't unbox DataCons with existentials. See `Note [Which types are unboxed?]` for details. I also refactored the various `tyCon*DataCon(s)_maybe` functions in `GHC.Core.TyCon`, deleting some of them which are no longer needed (`isDataProductType_maybe` and `isDataSumType_maybe`). I cleaned up a couple of call sites, some of which weren't very explicit about whether they cared for existentials or not. The test output of `T18013` changed, because we now unbox the `Rule` data type. Its constructor carries existential state and will be w/w'd now. In the particular example, the worker functions inlines right back into the wrapper, which then unnecessarily has a (quite big) stable unfolding. I think this kind of fallout is inevitable; see also Note [Don't w/w inline small non-loop-breaker things]. There's a new regression test case `T18982`. Fixes #18982.
* Use HsOuterExplicit in instance sigs in deriving-generated codeRyan Scott2020-12-181-8/+113
| | | | | | | | | | | | | | | | | | | | | | | | | Issue #18914 revealed that `GeneralizedNewtypeDeriving` would generate code that mentions unbound type variables, which is dangerously fragile. The problem (and fix) is described in the new `Wrinkle: Use HsOuterExplicit` in `Note [GND and QuantifiedConstraints]`. The gist of it: make sure to put the top-level `forall`s in `deriving`-generated instance signatures in an `HsOuterExplicit` to ensure that they scope over the bodies of methods correctly. A side effect of this process is that it will expand any type synonyms in the instance signature, which will surface any `forall`s that are hidden underneath type synonyms (such as in the test case for #18914). While I was in town, I also performed some maintenance on `NewHsTypeX`, which powers `GeneralizedNewtypeDeriving`: * I renamed `NewHsTypeX` to `HsCoreTy`, which more accurately describes its intended purpose (#15706). I also made `HsCoreTy` a type synonym instead of a newtype, as making it a distinct data type wasn't buying us much. * To make sure that mistakes similar to #18914 do not occur later, I added an additional validity check when renaming `HsCoreTy`s that complains if an `HsCoreTy`s contains an out-of-scope type variable. See the new `Note [Renaming HsCoreTys]` in `GHC.Rename.HsType` for the details. Fixes #15706. Fixes #18914. Bumps the `haddock` submodule.
* Replace HsImplicitBndrs with HsOuterTyVarBndrsRyan Scott2020-11-061-12/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This refactors the GHC AST to remove `HsImplicitBndrs` and replace it with `HsOuterTyVarBndrs`, a type which records whether the outermost quantification in a type is explicit (i.e., with an outermost, invisible `forall`) or implicit. As a result of this refactoring, it is now evident in the AST where the `forall`-or-nothing rule applies: it's all the places that use `HsOuterTyVarBndrs`. See the revamped `Note [forall-or-nothing rule]` in `GHC.Hs.Type` (previously in `GHC.Rename.HsType`). Moreover, the places where `ScopedTypeVariables` brings lexically scoped type variables into scope are a subset of the places that adhere to the `forall`-or-nothing rule, so this also makes places that interact with `ScopedTypeVariables` easier to find. See the revamped `Note [Lexically scoped type variables]` in `GHC.Hs.Type` (previously in `GHC.Tc.Gen.Sig`). `HsOuterTyVarBndrs` are used in type signatures (see `HsOuterSigTyVarBndrs`) and type family equations (see `HsOuterFamEqnTyVarBndrs`). The main difference between the former and the latter is that the former cares about specificity but the latter does not. There are a number of knock-on consequences: * There is now a dedicated `HsSigType` type, which is the combination of `HsOuterSigTyVarBndrs` and `HsType`. `LHsSigType` is now an alias for an `XRec` of `HsSigType`. * Working out the details led us to a substantial refactoring of the handling of explicit (user-written) and implicit type-variable bindings in `GHC.Tc.Gen.HsType`. Instead of a confusing family of higher order functions, we now have a local data type, `SkolemInfo`, that controls how these binders are kind-checked. It remains very fiddly, not fully satisfying. But it's better than it was. Fixes #16762. Bumps the Haddock submodule. Co-authored-by: Simon Peyton Jones <simonpj@microsoft.com> Co-authored-by: Richard Eisenberg <rae@richarde.dev> Co-authored-by: Zubin Duggal <zubin@cmi.ac.in>
* Add the proper HLint rules and remove redundant keywords from compilerHécate2020-11-011-2/+1
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* Split GHC.Driver.TypesSylvain Henry2020-10-293-2/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I was working on making DynFlags stateless (#17957), especially by storing loaded plugins into HscEnv instead of DynFlags. It turned out to be complicated because HscEnv is in GHC.Driver.Types but LoadedPlugin isn't: it is in GHC.Driver.Plugins which depends on GHC.Driver.Types. I didn't feel like introducing yet another hs-boot file to break the loop. Additionally I remember that while we introduced the module hierarchy (#13009) we talked about splitting GHC.Driver.Types because it contained various unrelated types and functions, but we never executed. I didn't feel like making GHC.Driver.Types bigger with more unrelated Plugins related types, so finally I bit the bullet and split GHC.Driver.Types. As a consequence this patch moves a lot of things. I've tried to put them into appropriate modules but nothing is set in stone. Several other things moved to avoid loops. * Removed Binary instances from GHC.Utils.Binary for random compiler things * Moved Typeable Binary instances into GHC.Utils.Binary.Typeable: they import a lot of things that users of GHC.Utils.Binary don't want to depend on. * put everything related to Units/Modules under GHC.Unit: GHC.Unit.Finder, GHC.Unit.Module.{ModGuts,ModIface,Deps,etc.} * Created several modules under GHC.Types: GHC.Types.Fixity, SourceText, etc. * Split GHC.Utils.Error (into GHC.Types.Error) * Finally removed GHC.Driver.Types Note that this patch doesn't put loaded plugins into HscEnv. It's left for another patch. Bump haddock submodule
* Add flags for annotating Generic{,1} methods INLINE[1] (#11068)Andrzej Rybczak2020-10-152-19/+90
| | | | | | | | Makes it possible for GHC to optimize away intermediate Generic representation for more types. Metric Increase: T12227
* Lint the compiler for extraneous LANGUAGE pragmasHécate2020-10-103-12/+11
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* Implement Quick Look impredicativitySimon Peyton Jones2020-09-241-15/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch implements Quick Look impredicativity (#18126), sticking very closely to the design in A quick look at impredicativity, Serrano et al, ICFP 2020 The main change is that a big chunk of GHC.Tc.Gen.Expr has been extracted to two new modules GHC.Tc.Gen.App GHC.Tc.Gen.Head which deal with typechecking n-ary applications, and the head of such applications, respectively. Both contain a good deal of documentation. Three other loosely-related changes are in this patch: * I implemented (partly by accident) points (2,3)) of the accepted GHC proposal "Clean up printing of foralls", namely https://github.com/ghc-proposals/ghc-proposals/blob/ master/proposals/0179-printing-foralls.rst (see #16320). In particular, see Note [TcRnExprMode] in GHC.Tc.Module - :type instantiates /inferred/, but not /specified/, quantifiers - :type +d instantiates /all/ quantifiers - :type +v is killed off That completes the implementation of the proposal, since point (1) was done in commit df08468113ab46832b7ac0a7311b608d1b418c4d Author: Krzysztof Gogolewski <krzysztof.gogolewski@tweag.io> Date: Mon Feb 3 21:17:11 2020 +0100 Always display inferred variables using braces * HsRecFld (which the renamer introduces for record field selectors), is now preserved by the typechecker, rather than being rewritten back to HsVar. This is more uniform, and turned out to be more convenient in the new scheme of things. * The GHCi debugger uses a non-standard unification that allows the unification variables to unify with polytypes. We used to hack this by using ImpredicativeTypes, but that doesn't work anymore so I introduces RuntimeUnkTv. See Note [RuntimeUnkTv] in GHC.Runtime.Heap.Inspect Updates haddock submodule. WARNING: this patch won't validate on its own. It was too hard to fully disentangle it from the following patch, on type errors and kind generalisation. Changes to tests * Fixes #9730 (test added) * Fixes #7026 (test added) * Fixes most of #8808, except function `g2'` which uses a section (which doesn't play with QL yet -- see #18126) Test added * Fixes #1330. NB Church1.hs subsumes Church2.hs, which is now deleted * Fixes #17332 (test added) * Fixes #4295 * This patch makes typecheck/should_run/T7861 fail. But that turns out to be a pre-existing bug: #18467. So I have just made T7861 into expect_broken(18467)
* DynFlags: disentangle OutputableSylvain Henry2020-08-125-1/+5
| | | | | | | | | - put panic related functions into GHC.Utils.Panic - put trace related functions using DynFlags in GHC.Driver.Ppr One step closer making Outputable fully independent of DynFlags. Bump haddock submodule
* Filter out unreachable constructors when deriving stock instances (#16431)Brandon Chinn2020-07-293-18/+103
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* Pass tc_args to gen_fnBrandon Chinn2020-07-293-32/+33
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