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2b122956
by sheaf at 2026-04-15T05:23:00-04:00
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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c2b49fed
by Wolfgang Jeltsch at 2026-04-15T05:23:01-04:00
Move most of the `System.IO` implementation into `base`
This involves a rewrite of the `combine` helper function to avoid the
use of `last`, which would now be flagged as an error.
Metric Increase:
T12227
T12707
T5642
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3b20030f
by Simon Jakobi at 2026-04-15T05:23:04-04:00
Add regression test for #9074
Closes #9074.
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72809b07
by Sylvain Henry at 2026-04-15T05:23:12-04:00
Add changelog for #15973
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46037ee9
by sheaf at 2026-04-15T05:23:17-04:00
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