- Jul 26, 2019
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GHC used to reject programs of this form: ``` newtype Age = MkAge Int deriving Eq via Const Int a ``` That's because an earlier implementation of `DerivingVia` would generate the following instance: ``` instance Eq Age where (==) = coerce @(Const Int a -> Const Int a -> Bool) @(Age -> Age -> Bool) (==) ``` Note that the `a` in `Const Int a` is not bound anywhere, which causes all sorts of issues. I figured that no one would ever want to write code like this anyway, so I simply banned "floating" `via` type variables like `a`, checking for their presence in the aptly named `reportFloatingViaTvs` function. `reportFloatingViaTvs` ended up being implemented in a subtly incorrect way, as #15831 demonstrates. Following counsel with the sage of gold fire, I decided to abandon `reportFloatingViaTvs` entirely and opt for a different approach that would _accept_ the instance above. This is because GHC now generates this instance instead: ``` instance forall a. Eq Age where (==) = coerce @(Const Int a -> Const Int a -> Bool) @(Age -> Age -> Bool) (==) ``` Notice that we now explicitly quantify the `a` in `instance forall a. Eq Age`, so everything is peachy scoping-wise. See `Note [Floating `via` type variables]` in `TcDeriv` for the full scoop. A pleasant benefit of this refactoring is that it made it much easier to catch the problem observed in #16181, so this patch fixes that issue too. Fixes #15831. Fixes #16181.
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- Jul 23, 2019
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- Jul 21, 2019
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To display the free variables for a single breakpoint, GHCi pulls out the information from the fields `modBreaks_breakInfo` and `modBreaks_vars` of the `ModBreaks` data structure. For a specific breakpoint this gives 2 lists of types 'Id` (`Var`) and `OccName`. They are used to create the Id's for the free variables and must be kept in sync: If we remove an element from the Names list, then we also must remove the corresponding element from the OccNames list.
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Kqueue/kevent implementation used to ignore events to be unsubscribed from when events to be subscribed to were provided. This resulted in a lost notification subscription, when GHC runtime didn't listen for any events, yet the kernel considered otherwise and kept waking up the IO manager thread. This commit fixes this issue by always adding and removing all of the provided subscriptions.
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- Jul 20, 2019
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This commit fixes #16874 by using `fsep` rather than `sep` when pretty printing long patterns and expressions.
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- Jul 19, 2019
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Ben Gamari authored
Fixed in #14759.
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Ben Gamari authored
This requires code loading and therefore can't be run in the profiled ways when GHC is dynamically linked.
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Ben Gamari authored
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Ben Gamari authored
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Ben Gamari authored
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Ben Gamari authored
Otherwise the unique counter starts at 0, causing us to immediately underflow.
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Ben Gamari authored
See #16803.
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Ben Gamari authored
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- Jul 16, 2019
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Unfortunately this will require more work; register allocation is quite broken. This reverts commit acd79558.
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- Jul 14, 2019
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These are unexploded minds as far as the linter is concerned. I don't want to hit in my MRs by mistake! I did this with `sed`, and then rolled back some changes in the docs, config.guess, and the linter itself.
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- Jul 12, 2019
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In one spot in kcConDecl we were passing in the return kind signature rether than the return kind. e.g. #16828 newtype instance Foo :: Type -> Type where MkFoo :: a -> Foo a We were giving kcConDecl the kind (Type -> Type), whereas it was expecting the ultimate return kind, namely Type. This "looking past arrows" was being done, independently, in several places, but we'd missed one. This patch moves it all to one place -- the new function kcConDecls (note the plural). I also took the opportunity to rename tcDataFamHeader to tcDataFamInstHeader (The previous name was consistently a source of confusion.)
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- Jul 11, 2019
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Previously, GHC would typecheck the `via` type once per class in a `deriving` clause, which caused the problems observed in #16923. This patch restructures some of the functionality in `TcDeriv` and `TcHsType` to avoid this problem. We now typecheck the `via` type exactly once per `deriving` clause and *then* typecheck all of the classes in the clause. See `Note [Don't typecheck too much in DerivingVia]` in `TcDeriv` for the full details.
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- Jul 10, 2019
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The simple optimiser was making an invalid transformation to join points -- yikes. The fix is easy. I also added some documentation about the fact that GHC uses a slightly more restrictive version of join points than does the paper. Fix #16918
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- Rename requires_th to req_th for consistency with other req functions (e.g. req_interp, req_profiling etc.) - req_th (previously requires_th) now checks for interpreter (via req_interp). With this running TH tests are skipped when running the test suite with stage=1. - Test tweaks: - T9360a, T9360b: Use req_interp - recomp009, T13938, RAE_T32a: Use req_th - Fix check-makefiles linter: it now looks for Makefiles instead of .T files (which are actually Python files) -
Renames performance metrics to include whether they are compile-time or runtime metrics.
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If the union of dependencies of imported modules change, the `mi_deps` field of the interface files should change as well. Because of that, we need to check for changes in this in recompilation checker which we are not doing right now. This adds a checks for that.
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- Jul 09, 2019
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Ryan Scott authored
To avoid having to `panic` any time a TTG extension constructor is consumed, this MR introduces an uninhabited 'NoExtCon' type and uses that in every extension constructor's type family instance where it is appropriate. This also introduces a 'noExtCon' function which eliminates a 'NoExtCon', much like 'Data.Void.absurd' eliminates a 'Void'. I also renamed the existing `NoExt` type to `NoExtField` to better distinguish it from `NoExtCon`. Unsurprisingly, there is a lot of code churn resulting from this. Bumps the Haddock submodule. Fixes #15247.
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- Jul 08, 2019
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- Jul 05, 2019
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Attach the `SrcSpan` of the first pattern synonym binding involved in the recursive group when throwing the corresponding error message, similarly to how it is done for type synonyms. Fixes #16900.
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Ticket #16247 showed that we were discarding an implication constraint that had empty ic_wanted, when we still needed to keep it so we could check whether it had a bad telescope. Happily it's a one line fix. All the rest is comments!
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In the eager unifier, when unifying (tv1 ~ tv2), when we decide to swap them over, to unify (tv2 ~ tv1), I'd forgotten to ensure that tv1's kind was fully zonked, which is an invariant of uUnfilledTyVar2. That could lead us to build an infinite kind, or (in the case of #16902) update the same unification variable twice. Yikes. Now we get an error message rather than non-termination, which is much better. The error message is not great, but it's a very strange program, and I can't see an easy way to improve it, so for now I'm just committing this fix. Here's the decl data F (a :: k) :: (a ~~ k) => Type where MkF :: F a and the rather error message of which I am not proud T16902.hs:11:10: error: • Expected a type, but found something with kind ‘a1’ • In the type ‘F a’
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Before this refactoring: * DerivInfo for data family instances was returned from tcTyAndClassDecls * DerivInfo for data declarations was generated with mkDerivInfos and added at a later stage of the pipeline in tcInstDeclsDeriv After this refactoring: * DerivInfo for both data family instances and data declarations is returned from tcTyAndClassDecls in a single list. This uniform treatment results in a more convenient arrangement to fix #16731.
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- Jul 03, 2019
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Commit cef80c0b debuted a breaking change to `template-haskell`, so in order to guard against it properly with CPP, we need to bump the `template-haskell` version number accordingly.
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This adds support for constructing vector types from Float#, Double# etc and performing arithmetic operations on them Cleaned-Up-By:Ben Gamari <ben@well-typed.com>
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- Jul 02, 2019
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- Jun 27, 2019
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- Jun 26, 2019
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Ben Gamari authored
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