| Commit message (Collapse) | Author | Age | Files | Lines |
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SourceText is serialized along with INLINE pragmas into interface files. Many of
these SourceTexts are identical, for example "{-# INLINE#". When deserialized,
each such SourceText was previously expanded out into a [Char], which is highly
wasteful of memory, and each such instance of the text would allocate an
independent list with its contents as deserializing breaks any sharing that might
have existed.
Instead, we use a `FastString` to represent these, so that each instance unique
text will be interned and stored in a memory efficient manner.
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This commit migrates the errors in GHC.Tc.Module to use the new
diagnostic infrastructure.
It required a significant overhaul of the compatibility checks between
an hs-boot or signature module and its implementation; we now use
a Writer monad to accumulate errors; see the BootMismatch datatype
in GHC.Tc.Errors.Types, with its panoply of subtypes.
For the sake of readability, several local functions inside the
'checkBootTyCon' function were split off into top-level functions.
We split off GHC.Types.HscSource into a "boot or sig" vs "normal hs file"
datatype, as this mirrors the logic in several other places where we
want to treat hs-boot and hsig files in a similar fashion.
This commit also refactors the Backpack checks for type synonyms
implementing abstract data, to correctly reject implementations that
contain qualified or quantified types (this fixes #23342 and #23344).
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This will allow to make command line parsing to depend on
diagnostic system (which depends on dynflags)
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The function tyConAppFunCo_maybe produces a multiplicity coercion
for the multiplicity argument of the function arrow, except that
it could be at the wrong role if asked to produce a representational
coercion. We fix this by using the 'funRole' function, which computes
the right roles for arguments to the function arrow TyCon.
Fixes #23386
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This patch continues the refactoring of the constraint solver
described in #23070.
The Big Deal in this patch is to call the regular, eager unifier from the
constraint solver, when we want to create new equalities. This
replaces the existing, unifyWanted which amounted to
yet-another-unifier, so it reduces duplication of a rather subtle
piece of technology. See
* Note [The eager unifier] in GHC.Tc.Utils.Unify
* GHC.Tc.Solver.Monad.wrapUnifierTcS
I did lots of other refactoring along the way
* I simplified the treatment of right hand sides that contain CoercionHoles.
Now, a constraint that contains a hetero-kind CoercionHole is non-canonical,
and cannot be used for rewriting or unification alike. This required me
to add the ch_hertero_kind flag to CoercionHole, with consequent knock-on
effects. See wrinkle (2) of `Note [Equalities with incompatible kinds]` in
GHC.Tc.Solver.Equality.
* I refactored the StopOrContinue type to add StartAgain, so that after a
fundep improvement (for example) we can simply start the pipeline again.
* I got rid of the unpleasant (and inefficient) rewriterSetFromType/Co functions.
With Richard I concluded that they are never needed.
* I discovered Wrinkle (W1) in Note [Wanteds rewrite Wanteds] in
GHC.Tc.Types.Constraint, and therefore now prioritise non-rewritten equalities.
Quite a few error messages change, I think always for the better.
Compiler runtime stays about the same, with one outlier: a 17% improvement in T17836
Metric Decrease:
T17836
T18223
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A consequence of the previous change is that checkAxInstCo is no longer
called during coercion optimization, so it can be moved back where it belongs.
Also includes some edits to Note [Conflict checking with AxiomInstCo] as
suggested by @simonpj.
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See Note [Push transitivity inside newtype axioms only] for an explanation
of the change here. This change substantially improves the performance of
coercion optimization for programs involving transitive type family reductions.
-------------------------
Metric Decrease:
CoOpt_Singletons
LargeRecord
T12227
T12545
T13386
T15703
T5030
T8095
-------------------------
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setNominalRole_maybe is supposed to output a nominal coercion.
In the SelCo case, it was not updating the stored role to Nominal,
causing #23362.
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This function could come across invalid newtype constructors, as we
only perform validity checking of newtypes once we are outside the
knot-tied typechecking loop.
This patch changes this function to fake up a stub type in the case of
an invalid newtype, instead of panicking.
This patch also changes "checkNewDataCon" so that it reports as many
errors as possible at once.
Fixes #23308
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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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This has no observable effect, but avoids storing useless data.
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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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In #23208 we observed that the demand signature of a binder occuring in a RULE
wasn't unleashed, leading to a transitively used binder being discarded as
absent. The solution was to use the same code path that we already use for
handling exported bindings.
See the changes to `Note [Absence analysis for stable unfoldings and RULES]`
for more details.
I took the chance to factor out the old notion of a `PlusDmdArg` (a pair of a
`VarEnv Demand` and a `Divergence`) into `DmdEnv`, which fits nicely into our
existing framework. As a result, I had to touch quite a few places in the code.
This refactoring exposed a few small bugs around correct handling of bottoming
demand environments. As a result, some strictness signatures now mention uniques
that weren't there before which caused test output changes to T13143, T19969 and
T22112. But these tests compared whole -ddump-simpl listings which is a very
fragile thing to begin with. I changed what exactly they test for based on the
symptoms in the corresponding issues.
There is a single regression in T18894 because we are more conservative around
stable unfoldings now. Unfortunately it is not easily fixed; let's wait until
there is a concrete motivation before invest more time.
Fixes #23208.
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- Use dedicated list functions
- Make cloneBndrs and cloneRecIdBndrs monadic
- Fix invalid haddock comments in libraries/base
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Whether a binding is a DFunId or not has consequences for the `-fdicts-strict`
flag, essentially if we are doing demand analysis for a DFunId then `-fdicts-strict` does
not apply because the constraint solver can create recursive groups of dictionaries.
In #22549 this was fixed for the "normal" case, see
Note [Do not strictify the argument dictionaries of a dfun].
However the loop still existed if the DFunId was being specialised.
The problem was that the specialiser would specialise a DFunId and
turn it into a VanillaId and so the demand analyser didn't know to
apply special treatment to the binding anymore and the whole recursive
group was optimised to bottom.
The solution is to transfer over the DFunId-ness of the binding in the specialiser so
that the demand analyser knows not to apply the `-fstrict-dicts`.
Fixes #22549
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This MR substantially refactors the way in which the constraint
solver deals with equality constraints. The big thing is:
* Intead of a pipeline in which we /first/ canonicalise and /then/
interact (the latter including performing unification) the two steps
are more closely integreated into one. That avoids the current
rather indirect communication between the two steps.
The proximate cause for this refactoring is fixing #22194, which involve
solving [W] alpha[2] ~ Maybe (F beta[4])
by doing this:
alpha[2] := Maybe delta[2]
[W] delta[2] ~ F beta[4]
That is, we don't promote beta[4]! This is very like introducing a cycle
breaker, and was very awkward to do before, but now it is all nice.
See GHC.Tc.Utils.Unify Note [Promotion and level-checking] and
Note [Family applications in canonical constraints].
The big change is this:
* Several canonicalisation checks (occurs-check, cycle-breaking,
checking for concreteness) are combined into one new function:
GHC.Tc.Utils.Unify.checkTyEqRhs
This function is controlled by `TyEqFlags`, which says what to do
for foralls, type families etc.
* `canEqCanLHSFinish` now sees if unification is possible, and if so,
actually does it: see `canEqCanLHSFinish_try_unification`.
There are loads of smaller changes:
* The on-the-fly unifier `GHC.Tc.Utils.Unify.unifyType` has a
cheap-and-cheerful version of `checkTyEqRhs`, called
`simpleUnifyCheck`. If `simpleUnifyCheck` succeeds, it can unify,
otherwise it defers by emitting a constraint. This is simpler than
before.
* I simplified the swapping code in `GHC.Tc.Solver.Equality.canEqCanLHS`.
Especially the nasty stuff involving `swap_for_occurs` and
`canEqTyVarFunEq`. Much nicer now. See
Note [Orienting TyVarLHS/TyFamLHS]
Note [Orienting TyFamLHS/TyFamLHS]
* Added `cteSkolemOccurs`, `cteConcrete`, and `cteCoercionHole` to the
problems that can be discovered by `checkTyEqRhs`.
* I fixed #23199 `pickQuantifiablePreds`, which actually allows GHC to
to accept both cases in #22194 rather than rejecting both.
Yet smaller:
* Added a `synIsConcrete` flag to `SynonymTyCon` (alongside `synIsFamFree`)
to reduce the need for synonym expansion when checking concreteness.
Use it in `isConcreteType`.
* Renamed `isConcrete` to `isConcreteType`
* Defined `GHC.Core.TyCo.FVs.isInjectiveInType` as a more efficient
way to find if a particular type variable is used injectively than
finding all the injective variables. It is called in
`GHC.Tc.Utils.Unify.definitely_poly`, which in turn is used quite a
lot.
* Moved `rewriterView` to `GHC.Core.Type`, so we can use it from the
constraint solver.
Fixes #22194, #23199
Compile times decrease by an average of 0.1%; but there is a 7.4%
drop in compiler allocation on T15703.
Metric Decrease:
T15703
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(x / l1) / l2
l1 and l2 /= 0
l1*l2 doesn't overflow
==> x / (l1 * l2)
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case quotRemInt# x y of
(# q, _ #) -> body
====>
case quotInt# x y of
q -> body
case quotRemInt# x y of
(# _, r #) -> body
====>
case remInt# x y of
r -> body
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unify_ty was incorrectly saying that F x y ~ T x are surely apart,
where F x y is an oversaturated type family and T x is a tyconapp.
As a result, the simplifier dropped a live case alternative (#23134).
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This patch moves the field-based logic for disambiguating record updates
to the renamer. The type-directed logic, scheduled for removal, remains
in the typechecker.
To do this properly (and fix the myriad of bugs surrounding the treatment
of duplicate record fields), we took the following main steps:
1. Create GREInfo, a renamer-level equivalent to TyThing which stores
information pertinent to the renamer.
This allows us to uniformly treat imported and local Names in the
renamer, as described in Note [GREInfo].
2. Remove GreName. Instead of a GlobalRdrElt storing GreNames, which
distinguished between normal names and field names, we now store
simple Names in GlobalRdrElt, along with the new GREInfo information
which allows us to recover the FieldLabel for record fields.
3. Add namespacing for record fields, within the OccNames themselves.
This allows us to remove the mangling of duplicate field selectors.
This change ensures we don't print mangled names to the user in
error messages, and allows us to handle duplicate record fields
in Template Haskell.
4. Move record disambiguation to the renamer, and operate on the
level of data constructors instead, to handle #21443.
The error message text for ambiguous record updates has also been
changed to reflect that type-directed disambiguation is on the way
out.
(3) means that OccEnv is now a bit more complex: we first key on the
textual name, which gives an inner map keyed on NameSpace:
OccEnv a ~ FastStringEnv (UniqFM NameSpace a)
Note that this change, along with (2), both increase the memory residency
of GlobalRdrEnv = OccEnv [GlobalRdrElt], which causes a few tests to
regress somewhat in compile-time allocation.
Even though (3) simplified a lot of code (in particular the treatment of
field selectors within Template Haskell and in error messages), it came
with one important wrinkle: in the situation of
-- M.hs-boot
module M where { data A; foo :: A -> Int }
-- M.hs
module M where { data A = MkA { foo :: Int } }
we have that M.hs-boot exports a variable foo, which is supposed to match
with the record field foo that M exports. To solve this issue, we add a
new impedance-matching binding to M
foo{var} = foo{fld}
This mimics the logic that existed already for impedance-binding DFunIds,
but getting it right was a bit tricky.
See Note [Record field impedance matching] in GHC.Tc.Module.
We also needed to be careful to avoid introducing space leaks in GHCi.
So we dehydrate the GlobalRdrEnv before storing it anywhere, e.g. in
ModIface. This means stubbing out all the GREInfo fields, with the
function forceGlobalRdrEnv.
When we read it back in, we rehydrate with rehydrateGlobalRdrEnv.
This robustly avoids any space leaks caused by retaining old type
environments.
Fixes #13352 #14848 #17381 #17551 #19664 #21443 #21444 #21720 #21898 #21946 #21959 #22125 #22160 #23010 #23062 #23063
Updates haddock submodule
-------------------------
Metric Increase:
MultiComponentModules
MultiLayerModules
MultiLayerModulesDefsGhci
MultiLayerModulesNoCode
T13701
T14697
hard_hole_fits
-------------------------
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Addresses #23159.
See Note Note [Exploit occ-info in exprIsConApp_maybe]
in GHC.Core.SimpleOpt.
Compile times go down very slightly, but always go down,
never up. Good!
Metrics: compile_time/bytes allocated
------------------------------------------------
CoOpt_Singletons(normal) -1.8%
T15703(normal) -1.2% GOOD
geo. mean -0.1%
minimum -1.8%
maximum +0.0%
Metric Decrease:
CoOpt_Singletons
T15703
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Tracking ticket: #20119
MR: !10129
This converts uses of `mkTcRnUnknownMessage` to newly added constructors
of `TcRnMessage`.
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I observed miscompilations while working on !10088 caused by this.
Fixes #23102.
Metric Decrease:
T10421
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There is no need to run arity analysis and what not if we are not in a
Simplifier phase that eta-expands or if we don't want to eta-expand the
expression in the first place.
Purely a refactoring with the goal of improving compiler perf.
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We should not panic in `add_demands` (now `set_lam_dmds`), because that code
path is legimitely taken for OPAQUE PAP bindings, as in T22997.
Fixes #22997.
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instead of a boolean flag for `CDictCan.cc_pend_sc`.
Pending givens get a fuel of 3 while Wanted and quantified constraints get a fuel of 1.
This helps pending given constraints to keep up with pending wanted constraints in case of
`UndecidableSuperClasses` and superclass expansions while simplifying the infered type.
Adds 3 dynamic flags for controlling the fuels for each type of constraints
`-fgivens-expansion-fuel` for givens `-fwanteds-expansion-fuel` for wanteds and `-fqcs-expansion-fuel` for quantified constraints
Fixes #21909
Added Tests T21909, T21909b
Added Note [Expanding Recursive Superclasses and ExpansionFuel]
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This MR fixes #23022 and #23023. Specifically
* Beef up Note [Type data declarations] in GHC.Rename.Module,
to make invariant (I1) explicit, and to name the several
wrinkles.
And add references to these specific wrinkles.
* Add a Lint check for invariant (I1) above.
See GHC.Core.Lint.checkTypeDataConOcc
* Disable the `caseRules` for dataToTag# for `type data` values.
See Wrinkle (W2c) in the Note above. Fixes #23023.
* Refine the assertion in dataConRepArgTys, so that it does not
complain about the absence of a wrapper for a `type data` constructor
Fixes #23022.
Acked-by: Simon Peyton Jones <simon.peytonjones@gmail.com>
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Fixes #23026
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The first argument is Int64# unconditionally, so we better produce
something of that type. This fixes a core lint error found in the ad
package.
Fixes #23019
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As #23018 showed, in mkRuntimeRepCo we need to account for coercions
between TYPE and COERCION.
See Note [mkRuntimeRepCo] in GHC.Core.Coercion.
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As #22998 showed, we were floating an unlifted binding to top
level, which breaks a Core invariant.
The fix is easy, albeit a little bit conservative. See
Note [Care with unlifted bindings] in GHC.Core.Opt.Specialise
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As #23024 showed, in GHC.Core.Opt.Specialise.specImports, we were
generating specialisations (a locally-define function) for imported
functions; and then generating specialisations for those
locally-defined functions. The RULE for the latter should be
attached to the local Id, not put in the rules-for-imported-ids
set.
Fix is easy; similar to what happens in GHC.HsToCore.addExportFlagsAndRules
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Using incoherent instances, there can be situations where two
occurrences of the same overloaded function at the same type use two
different instances (see #22448). For incoherently resolved instances,
we must mark them with `nospec` to avoid the specialiser rewriting one
to the other. This marking is done during the desugaring of the
`WpEvApp` wrapper.
Fixes #22448
Metric Increase:
T15304
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As #23012 showed, GHC.Core.Opt.Simplify.Utils.prepareAlts was
using an OutType to construct an InAlt. When shadowing is in play,
this is outright wrong.
See Note [Shadowing in prepareAlts].
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Data constructor wrappers only make sense for _value_-level data constructors,
but data constructors for `type data` declarations only exist at the _type_
level. This patch does the following:
* The criteria in `GHC.Types.Id.Make.mkDataConRep` for whether a data
constructor receives a wrapper now consider whether or not its parent data
type was declared with `type data`, omitting a wrapper if this is the case.
* Now that `type data` data constructors no longer receive wrappers, there is a
spot of code in `refineDefaultAlt` that panics when it encounters a value
headed by a `type data` type constructor. I've fixed this with a special case
in `refineDefaultAlt` and expanded `Note [Refine DEFAULT case alternatives]`
to explain why we do this.
Fixes #22948.
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We were failing to expand type synonyms in the function
GHC.Core.RoughMap.typeToRoughMatchLookupTc, even though the
RoughMap infrastructure crucially relies on type synonym expansion
to work.
This patch adds the missing type-synonym expansion.
Fixes #22985
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Following #22924 this patch narrows the test that stops
us decomposing newtypes. The key change is the use of
noGivenNewtypeReprEqs in GHC.Tc.Solver.Canonical.canTyConApp.
We went to and fro on the solution, as you can see in #22924.
The result is carefully documented in
Note [Decomoposing newtype equalities]
On the way I had revert most of
commit 3e827c3f74ef76d90d79ab6c4e71aa954a1a6b90
Author: Richard Eisenberg <rae@cs.brynmawr.edu>
Date: Mon Dec 5 10:14:02 2022 -0500
Do newtype unwrapping in the canonicaliser and rewriter
See Note [Unwrap newtypes first], which has the details.
It turns out that
(a) 3e827c3f makes GHC behave worse on some recursive newtypes
(see one of the tests on this commit)
(b) the finer-grained test (namely noGivenNewtypeReprEqs) renders
3e827c3f unnecessary
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The core change in this commit, which fixes #22761, is that
* In a Core rule, ru_rhs is always occ-analysed.
This means adding a couple of calls to occurAnalyseExpr when
building a Rule, in
* GHC.Core.Rules.mkRule
* GHC.Core.Opt.Simplify.Iteration.simplRules
But diagosing the bug made me stare carefully at the code of the
Simplifier, and I ended up doing some only-loosely-related refactoring.
* I think that RULES could be lost because not every code path
did addBndrRules
* The code around lambdas was very convoluted
It's mainly moving deck chairs around, but I like it more now.
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This reverts commit caced75765472a1a94453f2e5a439dba0d04a265.
It seems the patch "Don't keep exit join points so much" is causing
wide-spread regressions in the bytestring library benchmarks. If I
revert it then the 9.6 numbers are better on average than 9.4.
See https://gitlab.haskell.org/ghc/ghc/-/issues/22893#note_479525
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Metric Decrease:
MultiComponentModules
MultiComponentModulesRecomp
MultiLayerModules
MultiLayerModulesRecomp
MultiLayerModulesTH_Make
T12150
T13386
T13719
T21839c
T3294
parsing001
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Use `Type` instead of star kind (*)
Fix comment with incorrect kind * to have kind `Constraint`
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* Introduce refactorDupsOn f = refactorDups (comparing f)
* Make mkBigTupleCase and coreCaseTuple monadic.
Every call to those functions was preceded by calling newUniqueSupply.
* Use mkUserLocalOrCoVar, which is equivalent to combining
mkLocalIdOrCoVar with mkInternalName.
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Add a CallerCC cost centre flavour for cost centres added by the
CallerCC pass. This avoids potential accidental shadowing between
CCs added by user annotations and ones added by CallerCC.
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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].
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Consider (#22849)
data T a where
MkT :: forall k (t::k->*) (ix::k). t ix -> T @k a
Then dubiousDataConInstArgTys MkT [Type, Foo] should return
[Foo (ix::Type)]
NOT [Foo (ix::k)]
A bit of an obscure case, but it's an outright bug, and the fix is easy.
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This patch fixes a subtle bug in the typechecking of type
applications in patterns, e.g.
f (MkT @Int @a x y) = ...
See Note [Type applications in patterns] in GHC.Tc.Gen.Pat.
This fixes #19847, #22383, #19577, #21501
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Fixes #11270
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This patch fixes #22745 and #15205, which are about GHC's
failure to discard unnecessary superclass selections that
yield coercions. See
GHC.Core.Utils Note [exprOkForSpeculation and type classes]
The main changes are:
* Write new Note [NON-BOTTOM_DICTS invariant] in GHC.Core, and
refer to it
* Define new function isTerminatingType, to identify those
guaranteed-terminating dictionary types.
* exprOkForSpeculation has a new (very simple) case for ClassOpId
* ClassOpId has a new field that says if the return type is
an unlifted type, or a terminating type.
This was surprisingly tricky to get right. In particular note
that unlifted types are not terminating types; you can write an
expression of unlifted type, that diverges. Not so for dictionaries
(or, more precisely, for the dictionaries that GHC constructs).
Metric Decrease:
LargeRecord
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