Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC Commits: 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 - - - - - 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 - - - - - 3b20030f by Simon Jakobi at 2026-04-15T05:23:04-04:00 Add regression test for #9074 Closes #9074. - - - - - 72809b07 by Sylvain Henry at 2026-04-15T05:23:12-04:00 Add changelog for #15973 - - - - - 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 - - - - - 57 changed files: - + changelog.d/T15973 - + changelog.d/T27121.md - + changelog.d/T27124.md - compiler/GHC/Core/Opt/FloatOut.hs - compiler/GHC/Core/Utils.hs - compiler/GHC/CoreToStg/Prep.hs - compiler/GHC/HsToCore/Pmc/Solver/Types.hs - compiler/GHC/Stg/Debug.hs - compiler/GHC/Tc/Errors.hs - compiler/GHC/Types/Tickish.hs - libraries/base/src/Control/Concurrent.hs - libraries/base/src/GHC/IO/Handle.hs - libraries/base/src/Prelude.hs - libraries/base/src/System/IO.hs - libraries/base/src/Text/Printf.hs - libraries/ghc-heap/tests/tso_and_stack_closures.hs - libraries/ghc-internal/src/GHC/Internal/System/IO.hs - + testsuite/tests/ghci/T9074/Makefile - + testsuite/tests/ghci/T9074/T9074.hs - + testsuite/tests/ghci/T9074/T9074.stdout - + testsuite/tests/ghci/T9074/T9074a.c - + testsuite/tests/ghci/T9074/T9074b.c - + testsuite/tests/ghci/T9074/all.T - testsuite/tests/interface-stability/base-exports.stdout - testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs - testsuite/tests/interface-stability/base-exports.stdout-mingw32 - testsuite/tests/interface-stability/base-exports.stdout-ws-32 - + testsuite/tests/overloadedstrings/should_fail/T25926.hs - + testsuite/tests/overloadedstrings/should_fail/T25926.stderr - + testsuite/tests/overloadedstrings/should_fail/T27124.hs - + testsuite/tests/overloadedstrings/should_fail/T27124.stderr - + testsuite/tests/overloadedstrings/should_fail/all.T - + testsuite/tests/overloadedstrings/should_run/T27124a.hs - testsuite/tests/overloadedstrings/should_run/all.T - + testsuite/tests/profiling/should_compile/T27121.hs - + testsuite/tests/profiling/should_compile/T27121_aux.hs - testsuite/tests/profiling/should_compile/all.T - + testsuite/tests/simplCore/should_compile/T26941.hs - + testsuite/tests/simplCore/should_compile/T26941_aux.hs - testsuite/tests/simplCore/should_compile/all.T - testsuite/tests/typecheck/should_compile/T9497a.stderr - testsuite/tests/typecheck/should_compile/holes.stderr - testsuite/tests/typecheck/should_compile/holes3.stderr - testsuite/tests/typecheck/should_compile/valid_hole_fits.stderr - testsuite/tests/typecheck/should_fail/T9497d.stderr - testsuite/tests/typecheck/should_run/T9497a-run.stderr - testsuite/tests/typecheck/should_run/T9497b-run.stderr - testsuite/tests/typecheck/should_run/T9497c-run.stderr - utils/haddock/html-test/ref/Bug1004.html - utils/haddock/html-test/ref/Bug973.html - utils/haddock/html-test/ref/ConstructorPatternExport.html - utils/haddock/html-test/ref/DefaultSignatures.html - utils/haddock/html-test/ref/Hash.html - utils/haddock/html-test/ref/PatternSyns.html - utils/haddock/html-test/ref/PatternSyns2.html - utils/haddock/html-test/ref/QuasiExpr.html - utils/haddock/html-test/ref/Test.html The diff was not included because it is too large. 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