| Commit message (Collapse) | Author | Age | Files | Lines |
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Ryan Scott offered a cut-down repro case
(60 lines instead of more than 700 lines)
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Ticket #22379 revealed that skolemiseQuantifiedTyVar was
dropping the passed-in skol_info on the floor when it encountered
a SkolemTv. Bad! Several TyCons thereby share a single SkolemInfo
on their binders, which lead to bogus error reports.
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Before this patch, when converting from TH.Exp to LHsExpr GhcPs,
the compiler inserted more parentheses than required:
((f a) (b + c)) d
This was happening because the LHS of the function application was
parenthesized as if it was the RHS.
Now we use funPrec and appPrec appropriately and produce sensibly
parenthesized expressions:
f a (b + c) d
I also took the opportunity to remove the special case for LamE,
which was not special at all and simply duplicated code.
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I had forgotten to add the auxiliary dict bindings to the
/unfolding/ of a specialised function. This caused #22358,
which reports failures when compiling Hackage packages
fixed-vector
indexed-traversable
Regression test T22357 is snarfed from indexed-traversable
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When faced with VDQ in the type of a term, GHC generates the following
error message:
Illegal visible, dependent quantification in the type of a term
(GHC does not yet support this)
Prior to this patch, there were two ways this message could have been
generated and represented:
1. with the dedicated constructor TcRnVDQInTermType
(see check_type in GHC.Tc.Validity)
2. with the transitional constructor TcRnUnknownMessage
(see noNestedForallsContextsErr in GHC.Rename.Utils)
Not only this led to duplication of code generating the final SDoc,
it also made it tricky to track the origin of the error message.
This patch fixes the problem by using TcRnVDQInTermType exclusively.
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Necessary for newer cross-compiling backends (JS, Wasm) that don't
support TH yet.
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Before this patch, GHC used withHsDocContext to attach an HsDocContext
to an error message:
addErr $ mkTcRnUnknownMessage $ mkPlainError noHints (withHsDocContext ctxt msg)
The problem with this approach is that it only works with
TcRnUnknownMessage. But could we attach an HsDocContext to a
structured error message in a generic way? This patch solves
the problem by introducing a new constructor to TcRnMessage:
data TcRnMessage where
...
TcRnWithHsDocContext :: !HsDocContext -> !TcRnMessage -> TcRnMessage
...
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This patch fixes two distinct (but closely related) buglets that were uncovered
in #22235:
* `liftEnvSubst` used an empty in-scope set, which was not wide enough to cover
the variables in the range of the substitution. This patch fixes this by
populating the in-scope set from the free variables in the range of the
substitution.
* `composeTCvSubst` applied the first substitution argument to the range of the
second substitution argument, but the first substitution's in-scope set was
not wide enough to cover the range of the second substutition. We similarly
fix this issue in this patch by widening the first substitution's in-scope set
before applying it.
Fixes #22235.
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Ticket #13873 unexpectedly showed that a SPECIALISE pragma made a
program run (a lot) slower, because less specialisation took place
overall. It turned out that the specialiser was missing opportunities
because of quantified type variables.
It was quite easy to fix. The story is given in
Note [Specialising polymorphic dictionaries]
Two other minor fixes in the specialiser
* There is no benefit in specialising data constructor /wrappers/.
(They can appear overloaded because they are given a dictionary
to store in the constructor.) Small guard in canSpecImport.
* There was a buglet in the UnspecArg case of specHeader, in the
case where there is a dead binder. We need a LitRubbish filler
for the specUnfolding stuff. I expanded
Note [Drop dead args from specialisations] to explain.
There is a 4% increase in compile time for T15164, because we generate
more specialised code. This seems OK.
Metric Increase:
T15164
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This patch fixes #21229 properly, by avoiding doing a
binder-swap on dictionary Ids. This is pretty subtle, and explained
in Note [Care with binder-swap on dictionaries].
Test is already in simplCore/should_run/T21229
This allows us to restore a feature to the specialiser that we had
to revert: see Note [Specialising polymorphic dictionaries].
(This is done in a separate patch.)
I also modularised things, using a new function scrutBinderSwap_maybe
in all the places where we are (effectively) doing a binder-swap,
notably
* Simplify.Iteration.addAltUnfoldings
* SpecConstr.extendCaseBndrs
In Simplify.Iteration.addAltUnfoldings I also eliminated a guard
Many <- idMult case_bndr
because we concluded, in #22123, that it was doing no good.
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Replaces uses of `TcRnUnknownMessage` in `GHC.Tc.Gen.Splice` with
structured diagnostics.
closes #20116
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cloneMyStack checks the order of closures on the cloned stack. This may
change for different ways. Thus we limit this test to one way (normal).
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Updates the haddock submodule.
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For some reason I implemented this as a makefile test rather than a
ghci_script test. Hopefully making it a ghci_script test makes it more
robust.
Fixes #22313
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The assertion that checked TyEq:N in canEqCanLHSFinish incorrectly
triggered in the case of an unsaturated newtype TyCon heading the RHS,
even though we can't unwrap such an application. Now, we only trigger
an assertion failure in case of a saturated application of a newtype
TyCon.
Fixes #22310
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This test checks that typed splices and quotes get the right type
information when used in hiefiles.
See #21619
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As noted in #22297, SIMD vector registers can be used
to store different kinds of values, e.g. xmm1 can be used
both to store integer and floating point values.
The Cmm type system doesn't properly account for this, so
we weaken the Cmm register assignment lint check to only
compare widths when comparing a vector type with its
allocated vector register.
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This patch makes it so that packing/unpacking SIMD
vectors always uses the right sized types, e.g.
unpacking a Word16X4# will give a tuple of Word16#s.
As a result, we can get rid of the conversion instructions
that were previously required.
Fixes #22296
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This patch adds the missing `VecRep` case to `primRepSlot` function and
all the necessary machinery to carry this new `VecSlot` through code
generation. This allows programs involving unboxed sums of SIMD vectors
to be written and compiled.
Fixes #22187
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In many development environments, the source span is the primary means
of seeing what an error message relates to, and the In the expression:
and In an equation for: clauses are not particularly relevant. However,
they can grow to be quite long, which can make the message itself both
feel overwhelming and interact badly with limited-space areas.
It's simple to implement this flag so we might as well do it and give
the user control about how they see their messages.
Fixes #21722
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This MR implements the idea of #21731 that the printing of a diagnostic
method should be configurable at the printing time.
The interface of the `Diagnostic` class is modified from:
```
class Diagnostic a where
diagnosticMessage :: a -> DecoratedSDoc
diagnosticReason :: a -> DiagnosticReason
diagnosticHints :: a -> [GhcHint]
```
to
```
class Diagnostic a where
type DiagnosticOpts a
defaultDiagnosticOpts :: DiagnosticOpts a
diagnosticMessage :: DiagnosticOpts a -> a -> DecoratedSDoc
diagnosticReason :: a -> DiagnosticReason
diagnosticHints :: a -> [GhcHint]
```
and so each `Diagnostic` can implement their own configuration record
which can then be supplied by a client in order to dictate how to print
out the error message.
At the moment this only allows us to implement #21722 nicely but in
future it is more natural to separate the configuration of how much
information we put into an error message and how much we decide to print
out of it.
Updates Haddock submodule
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I had assumed that wrappers were not inlined in interactive mode.
Meaning we would always execute the compiled wrapper which properly
takes care of upholding the strict field invariant.
This turned out to be wrong. So instead we now run tag inference even
when we generate bytecode. In that case only for correctness not
performance reasons although it will be still beneficial for runtime
in some cases.
I further fixed a bug where GHCi didn't tag nullary constructors
properly when used as arguments. Which caused segfaults when calling
into compiled functions which expect the strict field invariant to
be upheld.
Fixes #22042 and #21083
-------------------------
Metric Increase:
T4801
Metric Decrease:
T13035
-------------------------
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And use it to avoid T21710a failing on non-tntc archs.
Fixes #22169
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GHC tests the exact print annotations using the contents of
utils/check-exact.
The same functionality is provided via
https://github.com/alanz/ghc-exactprint
The latter was updated to ensure it works with all of the files on
hackage when 9.2 was released, as well as updated to ensure users of
the library could work properly (apply-refact, retrie, etc).
This commit brings the changes from ghc-exactprint into
GHC/utils/check-exact, adapting for the changes to master.
Once it lands, it will form the basis for the 9.4 version of
ghc-exactprint.
See also discussion around this process at #21355
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Previously, the demand signature we computed upfront for a DataCon wrapper
lacked boxity information and was much less precise than the demand transformer
for the DataCon worker.
In this patch we adopt the solution to look through unfoldings of DataCon
wrappers during Demand Analysis, but still attach a demand signature for other
passes such as the Simplifier.
See `Note [DmdAnal for DataCon wrappers]` for more details.
Fixes #22241.
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This will complement mpickering's more general port of foundation's
numerical testsuite, providing a test for the specific case found
in #22282.
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When a newtype introduces GADT eq_specs due to a defaulted
RuntimeRep, we detect this and print the error message with
explicit kinds.
This also refactors newtype type checking to use the new
diagnostic infra.
Fixes #21447
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This code showed a strong shift between compile time (got worse) and
run time (got a lot better) recently which is perfectly acceptable.
However it wasn't clear why the compile time regression was happening
initially so I'm adding this test to make it easier to track such changes
in the future.
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Implements GHC proposal:
https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0170-unrestricted-overloadedlabels.rst
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On x86_64-linux, T7919 timed out ~30 times during July 2022.
And again ~30 times in September 2022.
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The source file name can very often be shared across many IPE entries
whereas the source coordinates are generally unique. Separate the two to
exploit sharing of the former.
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Here we refactor the representation of info table provenance information
in object code to significantly reduce its size and link-time impact.
Specifically, we deduplicate strings and represent them as 32-bit
offsets into a common string table.
In addition, we rework the registration logic to eliminate allocation
from the registration path, which is run from a static initializer where
things like allocation are technically undefined behavior (although it
did previously seem to work). For similar reasons we eliminate lock
usage from registration path, instead relying on atomic CAS.
Closes #22077.
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We were religiously keeping exit join points throughout, which
had some bad effects (#21148, #22084).
This MR does two things:
* Arranges that exit join points are inhibited from inlining
only in /one/ Simplifier pass (right after Exitification).
See Note [Be selective about not-inlining exit join points]
in GHC.Core.Opt.Exitify
It's not a big deal, but it shaves 0.1% off compile times.
* Inline used-once non-recursive join points very aggressively
Given join j x = rhs in
joinrec k y = ....j x....
where this is the only occurrence of `j`, we want to inline `j`.
(Unless sm_keep_exits is on.)
See Note [Inline used-once non-recursive join points] in
GHC.Core.Opt.Simplify.Utils
This is just a tidy-up really. It doesn't change allocation, but
getting rid of a binding is always good.
Very effect on nofib -- some up and down.
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This patch teachs the code generation logic of -fno-code about
-fprefer-byte-code, so that if we need to generate code for a module
which prefers byte code, then we generate byte code rather than object
code.
We keep track separately which modules need object code and which byte
code and then enable the relevant code generation for each. Typically
the option will be enabled globally so one of these sets should be empty
and we will just turn on byte code or object code generation.
We also fix the bug where we would generate code for a module which
enables Template Haskell despite the fact it was unecessary.
Fixes #22016
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This commit adds three new flags
* -fwrite-if-simplified-core: Writes the whole core program into an interface
file
* -fbyte-code-and-object-code: Generate both byte code and object code
when compiling a file
* -fprefer-byte-code: Prefer to use byte-code if it's available when
running TH splices.
The goal for including the core bindings in an interface file is to be able to restart the compiler pipeline
at the point just after simplification and before code generation. Once compilation is
restarted then code can be created for the byte code backend.
This can significantly speed up
start-times for projects in GHCi. HLS already implements its own version of these extended interface
files for this reason.
Preferring to use byte-code means that we can avoid some potentially
expensive code generation steps (see #21700)
* Producing object code is much slower than producing bytecode, and normally you
need to compile with `-dynamic-too` to produce code in the static and dynamic way, the
dynamic way just for Template Haskell execution when using a dynamically linked compiler.
* Linking many large object files, which happens once per splice, can be quite
expensive compared to linking bytecode.
And you can get GHC to compile the necessary byte code so
`-fprefer-byte-code` has access to it by using
`-fbyte-code-and-object-code`.
Fixes #21067
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We want to put implicit binds into fat interface files, so the easiest
thing to do seems to be to treat them uniformly with other binders.
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If a rewrite rule and a rewrite rule compete in the simplifier, this
patch makes sure that the rewrite rule "win". That is, in general
a bit fragile, but it's a huge help when making specialisation work
reliably, as #21851 and #22097 showed.
The change is fairly straightforwad, and documented in
Note [Rewrite rules and inlining]
in GHC.Core.Opt.Simplify.Iteration.
Compile-times change, up and down a bit -- in some cases because
we get better specialisation. But the payoff (more reliable
specialisation) is large.
Metrics: compile_time/bytes allocated
-----------------------------------------------
T10421(normal) +3.7% BAD
T10421a(normal) +5.5%
T13253(normal) +1.3%
T14052(ghci) +1.8%
T15304(normal) -1.4%
T16577(normal) +3.1% BAD
T17516(normal) +2.3%
T17836(normal) -1.9%
T18223(normal) -1.8%
T8095(normal) -1.3%
T9961(normal) +2.5% BAD
geo. mean +0.0%
minimum -1.9%
maximum +5.5%
Nofib results are (bytes allocated)
+-------------------------------++----------+
| ||tsv (rel) |
+===============================++==========+
| imaginary/paraffins || +0.27% |
| imaginary/rfib || -0.04% |
| real/anna || +0.02% |
| real/fem || -0.04% |
| real/fluid || +1.68% |
| real/gamteb || -0.34% |
| real/gg || +1.54% |
| real/hidden || -0.01% |
| real/hpg || -0.03% |
| real/infer || -0.03% |
| real/prolog || +0.02% |
| real/veritas || -0.47% |
| shootout/fannkuch-redux || -0.03% |
| shootout/k-nucleotide || -0.02% |
| shootout/n-body || -0.06% |
| shootout/spectral-norm || -0.01% |
| spectral/cryptarithm2 || +1.25% |
| spectral/fibheaps || +18.33% |
| spectral/last-piece || -0.34% |
+===============================++==========+
| geom mean || +0.17% |
There are extensive notes in !8897 about the regressions.
Briefly
* fibheaps: there was a very delicately balanced inlining that
tipped over the wrong way after this change.
* cryptarithm2 and paraffins are caused by #22274, which is
a separate issue really. (I.e. the right fix is *not* to
make inlining "win" over rules.)
So I'm accepting these changes
Metric Increase:
T10421
T16577
T9961
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This implements this Core Libraries Proposal:
https://github.com/haskell/core-libraries-committee/issues/85
In particular, it:
1. Exposes the `symbolSing` method of `KnownSymbol`,
2. Exports the abstract `SSymbol` type used in `symbolSing`, and
3. Defines an API for interacting with `SSymbol`.
This also makes corresponding changes for `natSing`/`KnownNat`/`SNat` and
`charSing`/`KnownChar`/`SChar`. This fixes #15183 and addresses part (2)
of #21568.
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A small refactoring in our Core Opt pipeline and some new functions for
transfering argument boxities from one signature to another to facilitate
`Note [Don't change boxity without worker/wrapper]`.
Fixes #21754.
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Justification in #22231. Short form: In a demand like `1C1(C1(L))`
it was too easy to confuse which `1` belongs to which `C`. Now
that should be more obvious.
Fixes #22231
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This allows to avoid further partiality, e. g., map head . group is
replaced by map NE.head . NE.group, and there are less panic calls.
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I finally got tired of the way that IfaceUnfolding reflected
a previous structure of unfoldings, not the current one. This
MR refactors UnfoldingSource and IfaceUnfolding to be simpler
and more consistent.
It's largely just a refactor, but in UnfoldingSource (which moves
to GHC.Types.Basic, since it is now used in IfaceSyn too), I
distinguish between /user-specified/ and /system-generated/ stable
unfoldings.
data UnfoldingSource
= VanillaSrc
| StableUserSrc -- From a user-specified pragma
| StableSystemSrc -- From a system-generated unfolding
| CompulsorySrc
This has a minor effect in CSE (see the use of isisStableUserUnfolding
in GHC.Core.Opt.CSE), which I tripped over when working on
specialisation, but it seems like a Good Thing to know anyway.
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This patch fixes #21286, by not unboxing dictionaries in
worker/wrapper (ever). The main payload is tiny:
* In `GHC.Core.Opt.DmdAnal.finaliseArgBoxities`, do not unbox
dictionaries in `get_dmd`. See Note [Do not unbox class dictionaries]
in that module
* I also found that imported wrappers were being fruitlessly
specialised, so I fixed that too, in canSpecImport.
See Note [Specialising imported functions] point (2).
In doing due diligence in the testsuite I fixed a number of
other things:
* Improve Note [Specialising unfoldings] in GHC.Core.Unfold.Make,
and Note [Inline specialisations] in GHC.Core.Opt.Specialise,
and remove duplication between the two. The new Note describes
how we specialise functions with an INLINABLE pragma.
And simplify the defn of `spec_unf` in `GHC.Core.Opt.Specialise.specCalls`.
* Improve Note [Worker/wrapper for INLINABLE functions] in
GHC.Core.Opt.WorkWrap.
And (critially) make an actual change which is to propagate the
user-written pragma from the original function to the wrapper; see
`mkStrWrapperInlinePrag`.
* Write new Note [Specialising imported functions] in
GHC.Core.Opt.Specialise
All this has a big effect on some compile times. This is
compiler/perf, showing only changes over 1%:
Metrics: compile_time/bytes allocated
-------------------------------------
LargeRecord(normal) -50.2% GOOD
ManyConstructors(normal) +1.0%
MultiLayerModulesTH_OneShot(normal) +2.6%
PmSeriesG(normal) -1.1%
T10547(normal) -1.2%
T11195(normal) -1.2%
T11276(normal) -1.0%
T11303b(normal) -1.6%
T11545(normal) -1.4%
T11822(normal) -1.3%
T12150(optasm) -1.0%
T12234(optasm) -1.2%
T13056(optasm) -9.3% GOOD
T13253(normal) -3.8% GOOD
T15164(normal) -3.6% GOOD
T16190(normal) -2.1%
T16577(normal) -2.8% GOOD
T16875(normal) -1.6%
T17836(normal) +2.2%
T17977b(normal) -1.0%
T18223(normal) -33.3% GOOD
T18282(normal) -3.4% GOOD
T18304(normal) -1.4%
T18698a(normal) -1.4% GOOD
T18698b(normal) -1.3% GOOD
T19695(normal) -2.5% GOOD
T5837(normal) -2.3%
T9630(normal) -33.0% GOOD
WWRec(normal) -9.7% GOOD
hard_hole_fits(normal) -2.1% GOOD
hie002(normal) +1.6%
geo. mean -2.2%
minimum -50.2%
maximum +2.6%
I diligently investigated some of the big drops.
* Caused by not doing w/w for dictionaries:
T13056, T15164, WWRec, T18223
* Caused by not fruitlessly specialising wrappers
LargeRecord, T9630
For runtimes, here is perf/should+_run:
Metrics: runtime/bytes allocated
--------------------------------
T12990(normal) -3.8%
T5205(normal) -1.3%
T9203(normal) -10.7% GOOD
haddock.Cabal(normal) +0.1%
haddock.base(normal) -1.1%
haddock.compiler(normal) -0.3%
lazy-bs-alloc(normal) -0.2%
------------------------------------------
geo. mean -0.3%
minimum -10.7%
maximum +0.1%
I did not investigate exactly what happens in T9203.
Nofib is a wash:
+-------------------------------++--+-----------+-----------+
| || | tsv (rel) | std. err. |
+===============================++==+===========+===========+
| real/anna || | -0.13% | 0.0% |
| real/fem || | +0.13% | 0.0% |
| real/fulsom || | -0.16% | 0.0% |
| real/lift || | -1.55% | 0.0% |
| real/reptile || | -0.11% | 0.0% |
| real/smallpt || | +0.51% | 0.0% |
| spectral/constraints || | +0.20% | 0.0% |
| spectral/dom-lt || | +1.80% | 0.0% |
| spectral/expert || | +0.33% | 0.0% |
+===============================++==+===========+===========+
| geom mean || | | |
+-------------------------------++--+-----------+-----------+
I spent quite some time investigating dom-lt, but it's pretty
complicated. See my note on !7847. Conclusion: it's just a delicate
inlining interaction, and we have plenty of those.
Metric Decrease:
LargeRecord
T13056
T13253
T15164
T16577
T18223
T18282
T18698a
T18698b
T19695
T9630
WWRec
hard_hole_fits
T9203
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When multiple Given quantified constraints match a Wanted, and there is
a quantified constraint that dominates all others, we now pick it
to solve the Wanted.
See Note [Use only the best matching quantified constraint].
For example:
[G] d1: forall a b. ( Eq a, Num b, C a b ) => D a b
[G] d2: forall a . C a Int => D a Int
[W] {w}: D a Int
When solving the Wanted, we find that both Givens match, but we pick
the second, because it has a weaker precondition, C a Int, compared
to (Eq a, Num Int, C a Int). We thus say that d2 dominates d1;
see Note [When does a quantified instance dominate another?].
This domination test is done purely in terms of superclass expansion,
in the function GHC.Tc.Solver.Interact.impliedBySCs. We don't attempt
to do a full round of constraint solving; this simple check suffices
for now.
Fixes #22216 and #22223
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