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741da00c
by Ben Gamari at 2025-11-12T03:38:20-05:00
template-haskell: Better describe getQ semantics
Clarify that the state is a type-indexed map, as suggested by #26484.
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8b080e04
by ARATA Mizuki at 2025-11-12T03:39:11-05:00
Fix incorrect markups in the User's Guide
* Correct markup for C--: "C-\-" in reST
* Fix internal links
* Fix code highlighting
* Fix inline code: Use ``code`` rather than `code`
* Remove extra backslashes
Fixes #16812
Co-authored-by: sheaf <sam.derbyshire@gmail.com>
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a00840ea
by Simon Peyton Jones at 2025-11-14T15:23:56+00:00
Make TYPE and CONSTRAINT apart again
This patch finally fixes #24279.
* The story started with #11715
* Then #21623 articulated a plan, which made Type and Constraint
not-apart; a horrible hack but it worked. The main patch was
commit 778c6adca2c995cd8a1b84394d4d5ca26b915dac
Author: Simon Peyton Jones <simonpj@microsoft.com>
Date: Wed Nov 9 10:33:22 2022 +0000
Type vs Constraint: finally nailed
* #24279 reported a bug in the above big commit; this small patch fixes it
commit af6932d6c068361c6ae300d52e72fbe13f8e1f18
Author: Simon Peyton Jones <simon.peytonjones@gmail.com>
Date: Mon Jan 8 10:49:49 2024 +0000
Make TYPE and CONSTRAINT not-apart
Issue #24279 showed up a bug in the logic in GHC.Core.Unify.unify_ty
which is supposed to make TYPE and CONSTRAINT be not-apart.
* Then !10479 implemented "unary classes".
* That change in turn allows us to make Type and Constraint apart again,
cleaning up the compiler and allowing a little bit more expressiveness.
It fixes the original hope in #24279, namely that `Type` and `Constraint`
should be distinct throughout.
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c0a1e574
by Georgios Karachalias at 2025-11-15T05:14:31-05:00
Report all missing modules with -M
We now report all missing modules at once in GHC.Driver.Makefile.processDeps,
as opposed to only reporting a single missing module. Fixes #26551.
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c9fa3449
by Sylvain Henry at 2025-11-15T05:15:26-05:00
JS: fix array index for registers
We used to store R32 in h$regs[-1]. While it's correct in JavaScript,
fix this to store R32 in h$regs[0] instead.
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9e469909
by Sylvain Henry at 2025-11-15T05:15:26-05:00
JS: support more than 128 registers (#26558)
The JS backend only supported 128 registers (JS variables/array slots
used to pass function arguments). It failed in T26537 when 129
registers were required.
This commit adds support for more than 128 registers: it is now limited to
maxBound :: Int (compiler's Int). If we ever go above this threshold the
compiler now panics with a more descriptive message.
A few built-in JS functions were assuming 128 registers and have been
rewritten to use loops. Note that loops are only used for "high"
registers that are stored in an array: the 31 "low" registers are still
handled with JS global variables and with explicit switch-cases to
maintain good performance in the most common cases (i.e. few registers
used). Adjusting the number of low registers is now easy: just one
constant to adjust (GHC.StgToJS.Regs.lowRegsCount).
No new test added: T26537 is used as a regression test instead.
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0a64a78b
by Sven Tennie at 2025-11-15T20:31:10-05:00
AArch64: Simplify CmmAssign and CmmStore
The special handling for floats was fake: The general case is always
used. So, the additional code path isn't needed (and only adds
complexity for the reader.)
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15b311be
by sheaf at 2025-11-15T20:32:02-05:00
SimpleOpt: refactor & push coercions into lambdas
This commit improves the simple optimiser (in GHC.Core.SimpleOpt)
in a couple of ways:
- The logic to push coercion lambdas is shored up.
The function 'pushCoercionIntoLambda' used to be called in 'finish_app',
but this meant we could not continue to optimise the program after
performing this transformation.
Now, we call 'pushCoercionIntoLambda' as part of 'simple_app'.
Doing so can be important when dealing with unlifted newtypes,
as explained in Note [Desugaring unlifted newtypes].
- The code is re-structured to avoid duplication and out-of-sync
code paths.
Now, 'simple_opt_expr' defers to 'simple_app' for the 'App', 'Var',
'Cast' and 'Lam' cases. This means all the logic for those is
centralised in a single place (e.g. the 'go_lam' helper function).
To do this, the general structure is brought a bit closer to the
full-blown simplifier, with a notion of 'continuation'
(see 'SimpleContItem').
This commit also modifies GHC.Core.Opt.Arity.pushCoercionIntoLambda to
apply a substitution (a slight generalisation of its existing implementation).
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b33284c7
by sheaf at 2025-11-15T20:32:02-05:00
Improve typechecking of data constructors
This commit changes the way in which we perform typecheck data
constructors, in particular how we make multiplicities line up.
Now, impedance matching occurs as part of the existing subsumption
machinery. See the revamped Note [Typechecking data constructors] in
GHC.Tc.Gen.App, as well as Note [Polymorphisation of linear fields]
in GHC.Core.Multiplicity.
This allows us to get rid of a fair amount of hacky code that was
added with the introduction of LinearTypes; in particular the logic of
GHC.Tc.Gen.Head.tcInferDataCon.
-------------------------
Metric Decrease:
T10421
T14766
T15164
T15703
T19695
T5642
T9630
WWRec
-------------------------
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b6faf5d0
by sheaf at 2025-11-15T20:32:02-05:00
Handle unsaturated rep-poly newtypes
This commit allows GHC to handle unsaturated occurrences of unlifted
newtype constructors. The plan is detailed in
Note [Eta-expanding rep-poly unlifted newtypes]
in GHC.Tc.Utils.Concrete: for unsaturated unlifted newtypes, we perform
the appropriate representation-polymorphism check in tcInstFun.
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682bf979
by Mike Pilgrem at 2025-11-16T16:44:14+00:00
Fix #26293 Valid stack.yaml for hadrian
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acc70c3a
by Simon Peyton Jones at 2025-11-18T16:21:20-05:00
Fix a bug in defaulting
Addresses #26582
Defaulting was doing some unification but then failing to
iterate. Silly.
I discovered that the main solver was unnecessarily iterating even
if there was a unification for an /outer/ unification variable, so
I fixed that too.
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c12fa73e
by Simon Peyton Jones at 2025-11-19T02:55:01-05:00
Make PmLit be in Ord, and use it in Map
This MR addresses #26514, by changing from
data PmAltConSet = PACS !(UniqDSet ConLike) ![PmLit]
to
data PmAltConSet = PACS !(UniqDSet ConLike) !(Map PmLit PmLit)
This matters when doing pattern-match overlap checking, when there
is a very large set of patterns. For most programs it makes
no difference at all.
For the N=5000 case of the repro case in #26514, compiler
mutator time (with `-fno-code`) goes from 1.9s to 0.43s.
All for the price for an Ord instance for PmLit
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41b84f40
by sheaf at 2025-11-19T02:55:52-05:00
Add passing tests for #26311 and #26072
This commit adds two tests cases that now pass since landing the changes
to typechecking of data constructors in b33284c7.
Fixes #26072 #26311
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1faa758a
by sheaf at 2025-11-19T02:55:52-05:00
mkCast: weaken bad cast warning for multiplicity
This commit weakens the warning message emitted when constructing a bad
cast in mkCast to ignore multiplicity.
Justification: since b33284c7, GHC uses sub-multiplicity coercions to
typecheck data constructors. The coercion optimiser is free to discard
these coercions, both for performance reasons, and because GHC's Core
simplifier does not (yet) preserve linearity.
We thus weaken 'mkCast' to use 'eqTypeIgnoringMultiplicity' instead of
'eqType', to avoid getting many spurious warnings about mismatched
multiplicities.
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55eab80d
by Sylvain Henry at 2025-11-20T17:33:13-05:00
Build external interpreter program on demand (#24731)
This patch teaches GHC how to build the external interpreter program
when it is missing. As long as we have the `ghci` library, doing this is
trivial so most of this patch is refactoring for doing it sanely.
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08bbc028
by Rodrigo Mesquita at 2025-11-20T17:33:54-05:00
Add tests for #23973 and #26565
These were fixed by 4af4f0f070f83f948e49ad5d7835fd91b8d3f0e6 in !10417
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6b42232c
by sheaf at 2025-11-20T17:34:35-05:00
Mark T26410_ffi as fragile on Windows
As seen in #26595, this test intermittently fails on Windows.
This commit marks it as fragile, until we get around to fixing it.
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b7b7c049
by Andrew Lelechenko at 2025-11-21T21:04:01+00:00
Add nubOrd / nubOrdBy to Data.List and Data.List.NonEmpty
As per https://github.com/haskell/core-libraries-committee/issues/336
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352d5462
by Marc Scholten at 2025-11-22T10:33:03-05:00
Fix haddock test runner to handle UTF-8 output
xhtml 3000.4.0.0 now produces UTF-8 output instead of escaping non-ASCII characters.
When using --test-accept it previously wrote files in the wrong encoding
because they have not been decoded properly when reading the files.
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a7bab6be
by Matthew Pickering at 2025-11-24T10:26:26+00:00
Add support for building bytecode libraries
A bytecode library is a collection of bytecode files (.gbc) and a
library which combines together additional object files.
A bytecode library is created by invoking GHC with the `-bytecodelib`
flag.
A library can be created from in-memory `ModuleByteCode` linkables or
by passing `.gbc` files as arguments on the command line.
Fixes #26298
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c1584ee5
by Matthew Pickering at 2025-11-24T10:34:16+00:00
Load bytecode libraries to satisfy package dependencies
This commit allows you to use a bytecode library to satisfy a package
dependency when using the interpreter.
If a user enables `-fprefer-byte-code`, then if a package provides a
bytecode library, that will be loaded and used to satisfy the
dependency.
The main change is to separate the relevant parts of the `LoaderState`
into external and home package byte code. Bytecode is loaded into either
the home package or external part (similar to HPT/EPS split), HPT
bytecode can be unloaded. External bytecode is never unloaded.
The unload function has also only been called with an empty list of
"stable linkables" for a long time. It has been modified to directly
implement a complete unloading of the home package bytecode linkables.
At the moment, the bytecode libraries are found in the "library-dirs"
field from the package description. In the future when `Cabal`
implements support for "bytecode-library-dirs" field, we can read the
bytecode libraries from there. No changes to the Cabal submodule are
necessary at the moment.
Four new tests are added in testsuite/tests/cabal, which generate fake
package descriptions and test loading the libraries into GHCi.
Fixes #26298