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2dadf3b0
by sheaf at 2026-04-16T13:28:39-04:00
Simplify mkTick
This commit simplifies 'GHC.Core.Utils.mkTick', removing the
accumulating parameter 'rest' which was suspiciously treating a bunch of
different ticks as a group, and moving the group as a whole around the
AST, ignoring that the ticks in the group might have different placement
properties.
The most important change is that we revert the logic (added in 85b0aae2)
that allowed ticks to be placed around coercions, which caused serious
issues (e.g. #27121). It was just a mistake, as it doesn't make sense
to put a tick around a coercion.
Also adds Note [Pushing SCCs inwards] which clarifies the logic for
pushing SCCs into lambdas, constructor applications, and dropping SCCs
around non-function variables (in particular the treatment of splittable
ticks).
A few other changes are also implemented:
- simplify 'can_split' predicate (no functional change)
- combine profiling ticks into one when possible
Fixes #26878, #26941 and #27121
Co-authored-by: simonpj <simon.peytonjones@gmail.com>
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a0d6f1f4
by Simon Jakobi at 2026-04-16T13:29:28-04:00
Add regression test for #9074
Closes #9074.
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d178ee89
by Sylvain Henry at 2026-04-16T13:30:25-04:00
Add changelog for #15973
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e8a196c6
by sheaf at 2026-04-16T13:31:19-04:00
Deal with 'noSpec' in 'coreExprToPmLit'
This commit makes two separate changes relating to
'GHC.HsToCore.Pmc.Solver.Types.coreExprAsPmLit':
1. Commit 7124e4ad mistakenly marked deferred errors as non-canonical,
which led to the introduction of 'nospec' wrappers in the
generated Core. This reverts that accident by declaring deferred
errors as being canonical, avoiding spurious 'nospec' wrapping.
2. Look through magic identity-like Ids such as 'nospec', 'inline' and
'lazy' in 'coreExprAsPmLit', just like Core Prep does.
There might genuinely be incoherent evidence, but that shouldn't
obstruct the pattern match checker. See test T27124a.
Fixes #25926 #27124
-------------------------
Metric Decrease:
T3294
-------------------------
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8cb99552
by Sylvain Henry at 2026-04-16T19:22:43-04:00
hadrian: warn when package index is missing (#16484)
Since cabal-install 3.0 we can query the path of remote-repo-cache and
check if hackage package index is present.
Fixes #16484
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d6ce7477
by Richard Eisenberg at 2026-04-16T19:23:25-04:00
Teach hadrian to --skip-test.
Fixes #27188.
This adds the --skip-test flag to `hadrian build`, as documented in the
patch.
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7666f4a9
by Fendor at 2026-04-17T22:29:51-04:00
Migrate `ghc-pkg` to use `OsPath` and `file-io`
`ghc-pkg` should use UNC paths as much as possible to avoid MAX_PATH
issues on windows.
`file-io` uses UNC Paths by default on windows, ensuring we use the
correct APIs and that we finally are no longer plagued by MAX_PATH
issues in CI and private machines.
On top of it, the higher correctness of `OsPath` is appreciated in this
small codebase. Also, we improve memory usage very slightly, due to the
more efficient memory representation of `OsPath` over `FilePath`
Adds `ghc-pkg` regression test for MAX_PATH on windows
Make sure `ghc-pkg` behaves as expected when long paths (> 255) are
involved on windows.
Let's generate a testcase where we can actually observe that `ghc-pkg`
behaves as epxected.
See the documentation for windows on Maximum Path Length Limitation:
* `https://learn.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation`
Adds changelog entry for long path support in ghc-pkg.
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78434e8c
by Simon Peyton Jones at 2026-04-17T22:30:38-04:00
Kill off the substitution in Lint
Now that we have invariant (NoTypeShadowing) we no longer
need Lint to carry an ambient substitution. This makes it
simpler and faster. A really worthwhile refactor.
There are some knock-on effects
* Linting join points after worker/wrapper. See
Note [Join points and beta redexes]
* Running a type substitution after the desugarer.
See Note [Substituting type-lets] in
the new module GHC.Core.SubstTypeLets
Implements #27078
Most perf tests don't use Lint so we won't see a perf incresae.
But T1969, which uses -O0 and Lint, gets 1.3% worse because it has
to run the SubstTypeLets pass which is a somewhat expensive no-op
Overall though compile-time allocations are down 0.1%.
Metric Increase:
T1969
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86ca6c2c
by mangoiv at 2026-04-17T22:31:22-04:00
testsuite: inline elemCoreTest
Some weird (probably python scoping) rule caused elemCoreTest, a regex
being out of scope on ubuntu, presumably because of a newer python version.
This patch just inlines the regex, which fixes the issue.
Fixes #27193
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029a9139
by Simon Jakobi at 2026-04-18T14:00:25+02:00
Implement List.elem via foldr
...in order to allow specialization to Eq instances.
The implementation of notElem is updated for consistency.`
Addresses #27096.