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[Git][ghc/ghc][master] wasm: use import.meta.main for proper distinction of nodejs main modules
by Marge Bot (＠marge-bot) 13 Feb '26

13 Feb '26

Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC Commits: 039f1977 by Cheng Shao at 2026-02-13T06:27:47-05:00 wasm: use import.meta.main for proper distinction of nodejs main modules This patch uses `import.meta.main` for proper distinction of nodejs main modules, especially when the main module might be installed as a symlink. Fixes #26916. - - - - - 2 changed files: - utils/jsffi/dyld.mjs - utils/jsffi/post-link.mjs Changes: ===================================== utils/jsffi/dyld.mjs ===================================== @@ -1470,7 +1470,7 @@ async function nodeMain({ searchDirs, mainSoPath, outFd, inFd, args }) { ); } -const isNodeMain = isNode && import.meta.filename === process.argv[1]; +const isNodeMain = isNode && import.meta.main; // node iserv as invoked by // GHC.Runtime.Interpreter.Wasm.spawnWasmInterp ===================================== utils/jsffi/post-link.mjs ===================================== @@ -119,7 +119,7 @@ function isMain() { return false; } - return import.meta.filename === process.argv[1]; + return import.meta.main; } async function main() { View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/039f19778e35b193af0de2a2c6ed895… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/039f19778e35b193af0de2a2c6ed895… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][master] ci: remove unused hlint-ghc-and-base job definition
by Marge Bot (＠marge-bot) 13 Feb '26

13 Feb '26

Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC Commits: 4157160f by Cheng Shao at 2026-02-13T06:27:04-05:00 ci: remove unused hlint-ghc-and-base job definition This patch removes the unused `hlint-ghc-and-base` job definition, it's never run since !9806. Note that hadrian lint rules still work locally, so anyone that wishes to run hlint on the codebase can continue to do so in their local worktree. - - - - - 1 changed file: - .gitlab-ci.yml Changes: ===================================== .gitlab-ci.yml ===================================== @@ -387,20 +387,6 @@ lint-submods-branch: paths: - cabal-cache -# Disabled due to #22830 -.hlint-ghc-and-base: - extends: .lint-params - image: "registry.gitlab.haskell.org/ghc/ci-images/linters:$DOCKER_REV" - variables: - BUILD_FLAVOUR: default - script: - - .gitlab/ci.sh setup - - .gitlab/ci.sh configure - - .gitlab/ci.sh run_hadrian lint:ghc-internal - - .gitlab/ci.sh run_hadrian lint:ghc-experimental - - .gitlab/ci.sh run_hadrian lint:base - - .gitlab/ci.sh run_hadrian lint:compiler - ############################################################ # GHC-in-GHCi (Hadrian) ############################################################ View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/4157160ffb3c692c0ff3fe4c2db5f5a… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/4157160ffb3c692c0ff3fe4c2db5f5a… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/T26831] Never eta-expand a naked variable!
by Simon Peyton Jones (＠simonpj) 13 Feb '26

13 Feb '26

Simon Peyton Jones pushed to branch wip/T26831 at Glasgow Haskell Compiler / GHC Commits: c49c255a by Simon Peyton Jones at 2026-02-13T11:03:20+00:00 Never eta-expand a naked variable! - - - - - 1 changed file: - compiler/GHC/CoreToStg/Prep.hs Changes: ===================================== compiler/GHC/CoreToStg/Prep.hs ===================================== @@ -1584,8 +1584,11 @@ eta_would_wreck_join _ = False maybeSaturate :: Id -> CpeApp -> Int -> [CoreTickish] -> UniqSM CpeRhs maybeSaturate fn expr n_args unsat_ticks | isJoinId fn -- Never eta-expand a call to a join point + -- See Note [Do not eta-expand join points] = return expr - | hasNoBinding fn || excess_arity > 0 + | hasNoBinding fn || (n_args > 0 && excess_arity > 0) + -- n_args > 0: do not eta-expand a naked variable! + -- excess_arity > 0: eta-expansion would be a no-op = return $ wrapLamBody (mkTicks unsat_ticks) sat_expr | otherwise = return expr View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/c49c255a82ca89864270bd9adaa83f6… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/c49c255a82ca89864270bd9adaa83f6… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/fendor/ghci-load-all-targets] Introduce `-fimport-loaded-targets` GHCi flag
by Hannes Siebenhandl (＠fendor) 13 Feb '26

13 Feb '26

Hannes Siebenhandl pushed to branch wip/fendor/ghci-load-all-targets at Glasgow Haskell Compiler / GHC Commits: 6da11434 by fendor at 2026-02-13T10:18:32+01:00 Introduce `-fimport-loaded-targets` GHCi flag This new flag automatically adds all loaded targets to the GHCi session by adding an `InteractiveImport` for the loaded targets. By default, this flag is disabled, as it potentially increases memory-usage. Fixes #26866 by rendering the use of a `-ghci-script` to achieve the same thing redundant. - - - - - 31 changed files: - compiler/GHC/Driver/Flags.hs - compiler/GHC/Driver/Session.hs - docs/users_guide/ghci.rst - ghc/GHCi/UI.hs - testsuite/tests/ghci/prog-mhu005/Makefile - testsuite/tests/ghci/prog-mhu005/all.T - + testsuite/tests/ghci/prog-mhu005/prog-mhu005b.script - + testsuite/tests/ghci/prog-mhu005/prog-mhu005b.stdout - + testsuite/tests/ghci/prog-mhu005/prog-mhu005c.script - + testsuite/tests/ghci/prog-mhu005/prog-mhu005c.stderr - + testsuite/tests/ghci/prog-mhu005/prog-mhu005c.stdout - + testsuite/tests/ghci/prog-mhu005/prog-mhu005d.script - + testsuite/tests/ghci/prog-mhu005/prog-mhu005d.stderr - + testsuite/tests/ghci/prog-mhu005/prog-mhu005d.stdout - + testsuite/tests/ghci/prog-mhu005/prog-mhu005e.script - + testsuite/tests/ghci/prog-mhu005/prog-mhu005e.stderr - + testsuite/tests/ghci/prog-mhu005/prog-mhu005e.stdout - + testsuite/tests/ghci/prog-mhu005/prog-mhu005f.script - + testsuite/tests/ghci/prog-mhu005/prog-mhu005f.stderr - + testsuite/tests/ghci/prog-mhu005/prog-mhu005f.stdout - testsuite/tests/ghci/prog022/Makefile - testsuite/tests/ghci/prog022/all.T - + testsuite/tests/ghci/prog022/ghci.prog022c.script - + testsuite/tests/ghci/prog022/ghci.prog022c.stderr - + testsuite/tests/ghci/prog022/ghci.prog022c.stdout - + testsuite/tests/ghci/prog022/ghci.prog022d.script - + testsuite/tests/ghci/prog022/ghci.prog022d.stderr - + testsuite/tests/ghci/prog022/ghci.prog022d.stdout - + testsuite/tests/ghci/prog022/ghci.prog022e.script - + testsuite/tests/ghci/prog022/ghci.prog022e.stderr - + testsuite/tests/ghci/prog022/ghci.prog022e.stdout The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/6da114341b115d8f842d18f3900a142… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/6da114341b115d8f842d18f3900a142… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/T26831] Never eta-expand join points
by Simon Peyton Jones (＠simonpj) 13 Feb '26

13 Feb '26

Simon Peyton Jones pushed to branch wip/T26831 at Glasgow Haskell Compiler / GHC Commits: d6e6ec76 by Simon Peyton Jones at 2026-02-13T09:11:29+00:00 Never eta-expand join points - - - - - 1 changed file: - compiler/GHC/CoreToStg/Prep.hs Changes: ===================================== compiler/GHC/CoreToStg/Prep.hs ===================================== @@ -1583,6 +1583,8 @@ eta_would_wreck_join _ = False maybeSaturate :: Id -> CpeApp -> Int -> [CoreTickish] -> UniqSM CpeRhs maybeSaturate fn expr n_args unsat_ticks + | isJoinId fn -- Never eta-expand a call to a join point + = return expr | hasNoBinding fn || excess_arity > 0 = return $ wrapLamBody (mkTicks unsat_ticks) sat_expr | otherwise View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/d6e6ec76152aaf59175b63624ff43e5… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/d6e6ec76152aaf59175b63624ff43e5… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/T26831] Comment out dead code
by Simon Peyton Jones (＠simonpj) 13 Feb '26

13 Feb '26

Simon Peyton Jones pushed to branch wip/T26831 at Glasgow Haskell Compiler / GHC Commits: 2df0ec18 by Simon Peyton Jones at 2026-02-13T09:08:55+00:00 Comment out dead code - - - - - 1 changed file: - compiler/GHC/CoreToStg/Prep.hs Changes: ===================================== compiler/GHC/CoreToStg/Prep.hs ===================================== @@ -1622,8 +1622,8 @@ maybeSaturate fn expr n_args unsat_ticks fn_arity = idArity fn excess_arity = (max fn_arity mark_arity) - n_args sat_expr = cpeEtaExpand excess_arity expr - applied_marks = n_args >= (length . dropWhile (not . isMarkedCbv) . - reverse . expectJust $ (idCbvMarks_maybe fn)) +-- applied_marks = n_args >= (length . dropWhile (not . isMarkedCbv) . +-- reverse . expectJust $ (idCbvMarks_maybe fn)) -- For join points we never eta-expand (See Note [Do not eta-expand join points]) -- so we assert all arguments that need to be passed cbv are visible so that the -- backend can evalaute them if required.. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/2df0ec18e729a5ed4115e5a050d3a9f… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/2df0ec18e729a5ed4115e5a050d3a9f… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/marge_bot_batch_merge_job] 2 commits: ci: remove unused hlint-ghc-and-base job definition
by Marge Bot (＠marge-bot) 13 Feb '26

13 Feb '26

Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC Commits: 772c0d0e by Cheng Shao at 2026-02-13T00:16:22-05:00 ci: remove unused hlint-ghc-and-base job definition This patch removes the unused `hlint-ghc-and-base` job definition, it's never run since !9806. Note that hadrian lint rules still work locally, so anyone that wishes to run hlint on the codebase can continue to do so in their local worktree. - - - - - 12f48505 by Cheng Shao at 2026-02-13T00:16:23-05:00 wasm: use import.meta.main for proper distinction of nodejs main modules This patch uses `import.meta.main` for proper distinction of nodejs main modules, especially when the main module might be installed as a symlink. Fixes #26916. - - - - - 3 changed files: - .gitlab-ci.yml - utils/jsffi/dyld.mjs - utils/jsffi/post-link.mjs Changes: ===================================== .gitlab-ci.yml ===================================== @@ -387,20 +387,6 @@ lint-submods-branch: paths: - cabal-cache -# Disabled due to #22830 -.hlint-ghc-and-base: - extends: .lint-params - image: "registry.gitlab.haskell.org/ghc/ci-images/linters:$DOCKER_REV" - variables: - BUILD_FLAVOUR: default - script: - - .gitlab/ci.sh setup - - .gitlab/ci.sh configure - - .gitlab/ci.sh run_hadrian lint:ghc-internal - - .gitlab/ci.sh run_hadrian lint:ghc-experimental - - .gitlab/ci.sh run_hadrian lint:base - - .gitlab/ci.sh run_hadrian lint:compiler - ############################################################ # GHC-in-GHCi (Hadrian) ############################################################ ===================================== utils/jsffi/dyld.mjs ===================================== @@ -1470,7 +1470,7 @@ async function nodeMain({ searchDirs, mainSoPath, outFd, inFd, args }) { ); } -const isNodeMain = isNode && import.meta.filename === process.argv[1]; +const isNodeMain = isNode && import.meta.main; // node iserv as invoked by // GHC.Runtime.Interpreter.Wasm.spawnWasmInterp ===================================== utils/jsffi/post-link.mjs ===================================== @@ -119,7 +119,7 @@ function isMain() { return false; } - return import.meta.filename === process.argv[1]; + return import.meta.main; } async function main() { View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/d93ce70317093737d03b84907137bd… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/d93ce70317093737d03b84907137bd… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/marge_bot_batch_merge_job] 3 commits: Add regression tests for four StaticPtr bugs
by Marge Bot (＠marge-bot) 13 Feb '26

13 Feb '26

Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC Commits: 530e8e58 by Simon Peyton Jones at 2026-02-12T20:17:23-05:00 Add regression tests for four StaticPtr bugs Tickets #26545, #24464, #24773, #16981 are all solved by the recently-landed MR commit 318ee13bcffa6aa8df42ba442ccd92aa0f7e210c Author: Simon Peyton Jones <simon.peytonjones(a)gmail.com> Date: Mon Oct 20 23:07:20 2025 +0100 Simplify the treatment of static forms This MR just adds regression tests for them. - - - - - e594aa0f by Cheng Shao at 2026-02-12T20:50:17-05:00 ci: remove unused hlint-ghc-and-base job definition This patch removes the unused `hlint-ghc-and-base` job definition, it's never run since !9806. Note that hadrian lint rules still work locally, so anyone that wishes to run hlint on the codebase can continue to do so in their local worktree. - - - - - d93ce703 by Cheng Shao at 2026-02-12T20:50:18-05:00 wasm: use import.meta.main for proper distinction of nodejs main modules This patch uses `import.meta.main` for proper distinction of nodejs main modules, especially when the main module might be installed as a symlink. Fixes #26916. - - - - - 13 changed files: - .gitlab-ci.yml - + testsuite/tests/rename/should_fail/T26545.hs - + testsuite/tests/rename/should_fail/T26545.stderr - testsuite/tests/rename/should_fail/all.T - + testsuite/tests/typecheck/should_compile/T24464.hs - testsuite/tests/typecheck/should_compile/all.T - + testsuite/tests/typecheck/should_run/T16981.hs - + testsuite/tests/typecheck/should_run/T16981.stdout - + testsuite/tests/typecheck/should_run/T24773.hs - + testsuite/tests/typecheck/should_run/T24773.stdout - testsuite/tests/typecheck/should_run/all.T - utils/jsffi/dyld.mjs - utils/jsffi/post-link.mjs Changes: ===================================== .gitlab-ci.yml ===================================== @@ -387,20 +387,6 @@ lint-submods-branch: paths: - cabal-cache -# Disabled due to #22830 -.hlint-ghc-and-base: - extends: .lint-params - image: "registry.gitlab.haskell.org/ghc/ci-images/linters:$DOCKER_REV" - variables: - BUILD_FLAVOUR: default - script: - - .gitlab/ci.sh setup - - .gitlab/ci.sh configure - - .gitlab/ci.sh run_hadrian lint:ghc-internal - - .gitlab/ci.sh run_hadrian lint:ghc-experimental - - .gitlab/ci.sh run_hadrian lint:base - - .gitlab/ci.sh run_hadrian lint:compiler - ############################################################ # GHC-in-GHCi (Hadrian) ############################################################ ===================================== testsuite/tests/rename/should_fail/T26545.hs ===================================== @@ -0,0 +1,12 @@ +{-# LANGUAGE MagicHash #-} +{-# LANGUAGE StaticPointers #-} + +module Foo where + +import GHC.Exts + +f :: Int# -> Int# +f 0# = 0# +f n# = f (n# -# 1#) + +h x = let v = f 3# in static (I# (v +# 1#)) ===================================== testsuite/tests/rename/should_fail/T26545.stderr ===================================== @@ -0,0 +1,3 @@ +T26545.hs:12:23: error: [GHC-88431] + ‘v’ is used in a static form but it is not defined at top level + ===================================== testsuite/tests/rename/should_fail/all.T ===================================== @@ -263,3 +263,4 @@ test('T25901_sub_b', normal, compile_fail, ['']) test('T25901_sub_c', [extra_files(['T25901_sub_c_helper.hs'])], multimod_compile_fail, ['T25901_sub_c', '-v0']) test('T25901_sub_d', [extra_files(['T25901_sub_d_helper.hs'])], multimod_compile_fail, ['T25901_sub_d', '-v0']) test('T25901_sub_w', normal, compile_fail, ['']) +test('T26545', normal, compile_fail, ['']) ===================================== testsuite/tests/typecheck/should_compile/T24464.hs ===================================== @@ -0,0 +1,8 @@ +{-# LANGUAGE StaticPointers #-} +module T24464 where + +import GHC.StaticPtr + +class C a where + f :: a -> StaticPtr () + f _ = static () ===================================== testsuite/tests/typecheck/should_compile/all.T ===================================== @@ -960,4 +960,5 @@ test('T26582', normal, compile, ['']) test('T26746', normal, compile, ['']) test('T26737', normal, compile, ['']) test('T26805a', normal, compile, ['']) +test('T24464', normal, compile, ['']) ===================================== testsuite/tests/typecheck/should_run/T16981.hs ===================================== @@ -0,0 +1,31 @@ +{-# LANGUAGE StaticPointers #-} +-- Main.hs +module Main where + +import GHC.StaticPtr + +class UniqueHash a where + hash :: a -> String + +{-# NOINLINE unCacheable #-} +unCacheable :: Cacheable a -> a +unCacheable (CExplicit _ a) = a + +data Cacheable a = CExplicit String a + +instance UniqueHash (StaticPtr a) where + hash ptr = show $ staticKey ptr + +instance IsStatic Cacheable where + fromStaticPtr ptr = CExplicit h a where + h = hash ptr + a = deRefStaticPtr ptr + +{-# NOINLINE splitInjectedAsWindowed #-} +splitInjectedAsWindowed :: Int +-- WindowedDataset +splitInjectedAsWindowed = unCacheable $ static 1 + + +main :: IO () +main = print splitInjectedAsWindowed ===================================== testsuite/tests/typecheck/should_run/T16981.stdout ===================================== @@ -0,0 +1 @@ +1 ===================================== testsuite/tests/typecheck/should_run/T24773.hs ===================================== @@ -0,0 +1,16 @@ +{-# LANGUAGE StaticPointers #-} +{-# OPTIONS_GHC -O1 #-} + +module Main where + +import GHC.StaticPtr ( StaticPtr ) + +{-# NOINLINE uhoh #-} +uhoh :: () -> StaticPtr () +uhoh = + let ptr :: StaticPtr () + ptr = static () + in \_ -> ptr + +main :: IO () +main = putStrLn "Hello, Haskell!" ===================================== testsuite/tests/typecheck/should_run/T24773.stdout ===================================== @@ -0,0 +1 @@ +Hello, Haskell! ===================================== testsuite/tests/typecheck/should_run/all.T ===================================== @@ -181,3 +181,5 @@ test('T15598', normal, compile_and_run, ['']) test('T22086', normal, compile_and_run, ['']) test('T24411', normal, compile_and_run, ['']) test('DefaultExceptionContext', normal, compile_and_run, ['']) +test('T24773', normal, compile_and_run, ['']) +test('T16981', normal, compile_and_run, ['']) ===================================== utils/jsffi/dyld.mjs ===================================== @@ -1470,7 +1470,7 @@ async function nodeMain({ searchDirs, mainSoPath, outFd, inFd, args }) { ); } -const isNodeMain = isNode && import.meta.filename === process.argv[1]; +const isNodeMain = isNode && import.meta.main; // node iserv as invoked by // GHC.Runtime.Interpreter.Wasm.spawnWasmInterp ===================================== utils/jsffi/post-link.mjs ===================================== @@ -119,7 +119,7 @@ function isMain() { return false; } - return import.meta.filename === process.argv[1]; + return import.meta.main; } async function main() { View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/c1085eb00c38d964e9ae6e3066c992… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/c1085eb00c38d964e9ae6e3066c992… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][master] Add regression tests for four StaticPtr bugs
by Marge Bot (＠marge-bot) 13 Feb '26

13 Feb '26

Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC Commits: 530e8e58 by Simon Peyton Jones at 2026-02-12T20:17:23-05:00 Add regression tests for four StaticPtr bugs Tickets #26545, #24464, #24773, #16981 are all solved by the recently-landed MR commit 318ee13bcffa6aa8df42ba442ccd92aa0f7e210c Author: Simon Peyton Jones <simon.peytonjones(a)gmail.com> Date: Mon Oct 20 23:07:20 2025 +0100 Simplify the treatment of static forms This MR just adds regression tests for them. - - - - - 10 changed files: - + testsuite/tests/rename/should_fail/T26545.hs - + testsuite/tests/rename/should_fail/T26545.stderr - testsuite/tests/rename/should_fail/all.T - + testsuite/tests/typecheck/should_compile/T24464.hs - testsuite/tests/typecheck/should_compile/all.T - + testsuite/tests/typecheck/should_run/T16981.hs - + testsuite/tests/typecheck/should_run/T16981.stdout - + testsuite/tests/typecheck/should_run/T24773.hs - + testsuite/tests/typecheck/should_run/T24773.stdout - testsuite/tests/typecheck/should_run/all.T Changes: ===================================== testsuite/tests/rename/should_fail/T26545.hs ===================================== @@ -0,0 +1,12 @@ +{-# LANGUAGE MagicHash #-} +{-# LANGUAGE StaticPointers #-} + +module Foo where + +import GHC.Exts + +f :: Int# -> Int# +f 0# = 0# +f n# = f (n# -# 1#) + +h x = let v = f 3# in static (I# (v +# 1#)) ===================================== testsuite/tests/rename/should_fail/T26545.stderr ===================================== @@ -0,0 +1,3 @@ +T26545.hs:12:23: error: [GHC-88431] + ‘v’ is used in a static form but it is not defined at top level + ===================================== testsuite/tests/rename/should_fail/all.T ===================================== @@ -263,3 +263,4 @@ test('T25901_sub_b', normal, compile_fail, ['']) test('T25901_sub_c', [extra_files(['T25901_sub_c_helper.hs'])], multimod_compile_fail, ['T25901_sub_c', '-v0']) test('T25901_sub_d', [extra_files(['T25901_sub_d_helper.hs'])], multimod_compile_fail, ['T25901_sub_d', '-v0']) test('T25901_sub_w', normal, compile_fail, ['']) +test('T26545', normal, compile_fail, ['']) ===================================== testsuite/tests/typecheck/should_compile/T24464.hs ===================================== @@ -0,0 +1,8 @@ +{-# LANGUAGE StaticPointers #-} +module T24464 where + +import GHC.StaticPtr + +class C a where + f :: a -> StaticPtr () + f _ = static () ===================================== testsuite/tests/typecheck/should_compile/all.T ===================================== @@ -960,4 +960,5 @@ test('T26582', normal, compile, ['']) test('T26746', normal, compile, ['']) test('T26737', normal, compile, ['']) test('T26805a', normal, compile, ['']) +test('T24464', normal, compile, ['']) ===================================== testsuite/tests/typecheck/should_run/T16981.hs ===================================== @@ -0,0 +1,31 @@ +{-# LANGUAGE StaticPointers #-} +-- Main.hs +module Main where + +import GHC.StaticPtr + +class UniqueHash a where + hash :: a -> String + +{-# NOINLINE unCacheable #-} +unCacheable :: Cacheable a -> a +unCacheable (CExplicit _ a) = a + +data Cacheable a = CExplicit String a + +instance UniqueHash (StaticPtr a) where + hash ptr = show $ staticKey ptr + +instance IsStatic Cacheable where + fromStaticPtr ptr = CExplicit h a where + h = hash ptr + a = deRefStaticPtr ptr + +{-# NOINLINE splitInjectedAsWindowed #-} +splitInjectedAsWindowed :: Int +-- WindowedDataset +splitInjectedAsWindowed = unCacheable $ static 1 + + +main :: IO () +main = print splitInjectedAsWindowed ===================================== testsuite/tests/typecheck/should_run/T16981.stdout ===================================== @@ -0,0 +1 @@ +1 ===================================== testsuite/tests/typecheck/should_run/T24773.hs ===================================== @@ -0,0 +1,16 @@ +{-# LANGUAGE StaticPointers #-} +{-# OPTIONS_GHC -O1 #-} + +module Main where + +import GHC.StaticPtr ( StaticPtr ) + +{-# NOINLINE uhoh #-} +uhoh :: () -> StaticPtr () +uhoh = + let ptr :: StaticPtr () + ptr = static () + in \_ -> ptr + +main :: IO () +main = putStrLn "Hello, Haskell!" ===================================== testsuite/tests/typecheck/should_run/T24773.stdout ===================================== @@ -0,0 +1 @@ +Hello, Haskell! ===================================== testsuite/tests/typecheck/should_run/all.T ===================================== @@ -181,3 +181,5 @@ test('T15598', normal, compile_and_run, ['']) test('T22086', normal, compile_and_run, ['']) test('T24411', normal, compile_and_run, ['']) test('DefaultExceptionContext', normal, compile_and_run, ['']) +test('T24773', normal, compile_and_run, ['']) +test('T16981', normal, compile_and_run, ['']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/530e8e580734b42740ae6d7145c999a… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/530e8e580734b42740ae6d7145c999a… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][master] Fix subtle bug in cast worker/wrapper
by Marge Bot (＠marge-bot) 13 Feb '26

13 Feb '26

Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC Commits: 99d8c146 by Simon Peyton Jones at 2026-02-12T17:36:59+00:00 Fix subtle bug in cast worker/wrapper See (CWw4) in Note [Cast worker/wrapper]. The true payload is in the change to the definition of GHC.Types.Id.Info.hasInlineUnfolding Everthing else is just documentation. There is a 2% compile time decrease for T13056; I'll take the win! Metric Decrease: T13056 - - - - - 8 changed files: - compiler/GHC/Core/Opt/Simplify/Iteration.hs - compiler/GHC/Core/Opt/WorkWrap.hs - compiler/GHC/Driver/Config/Core/Lint.hs - compiler/GHC/Types/Id/Info.hs - + testsuite/tests/simplCore/should_compile/T26903.hs - + testsuite/tests/simplCore/should_compile/T26903.stderr - testsuite/tests/simplCore/should_compile/T8331.stderr - testsuite/tests/simplCore/should_compile/all.T Changes: ===================================== compiler/GHC/Core/Opt/Simplify/Iteration.hs ===================================== @@ -474,14 +474,14 @@ leaving a simpler job for demand-analysis worker/wrapper. See #19874. Wrinkles -1. We must /not/ do cast w/w on +(CWW1) We must /not/ do cast w/w on f = g |> co otherwise it'll just keep repeating forever! You might think this is avoided because the call to tryCastWorkerWrapper is guarded by - preInlineUnconditinally, but I'm worried that a loop-breaker or an - exported Id might say False to preInlineUnonditionally. + preInlineUnconditionally, but I'm worried that a loop-breaker or an + exported Id might say False to preInlineUnconditionally. -2. We need to be careful with inline/noinline pragmas: +(CWW2) We need to be careful with inline/noinline pragmas: rec { {-# NOINLINE f #-} f = (...g...) |> co ; g = ...f... } @@ -496,15 +496,15 @@ Wrinkles f = $wf |> co ; g = ...f... } and that is bad: the whole point is that we want to inline that - cast! We want to transfer the pagma to $wf: + cast! We want to transfer the pragma to $wf: rec { {-# NOINLINE $wf #-} $wf = ...g... ; f = $wf |> co ; g = ...f... } c.f. Note [Worker/wrapper for NOINLINE functions] in GHC.Core.Opt.WorkWrap. -3. We should still do cast w/w even if `f` is INLINEABLE. E.g. - {- f: Stable unfolding = <stable-big> -} +(CWW3) We should still do cast w/w even if `f` is INLINEABLE. E.g. + {- f: Stable unfolding (arity 2) = <stable-big> -} f = (\xy. <big-body>) |> co Then we want to w/w to {- $wf: Stable unfolding = <stable-big> |> sym co -} @@ -513,15 +513,43 @@ Wrinkles Notice that the stable unfolding moves to the worker! Now demand analysis will work fine on $wf, whereas it has trouble with the original f. c.f. Note [Worker/wrapper for INLINABLE functions] in GHC.Core.Opt.WorkWrap. - This point also applies to strong loopbreakers with INLINE pragmas, see - wrinkle (4). -4. We should /not/ do cast w/w for non-loop-breaker INLINE functions (hence - hasInlineUnfolding in tryCastWorkerWrapper, which responds False to - loop-breakers) because they'll definitely be inlined anyway, cast and - all. And if we do cast w/w for an INLINE function with arity zero, we get +(CWW4) We should /not/ do cast w/w for INLINE functions (hence `hasInlineUnfolding` + in `tryCastWorkerWrapper`) because they'll definitely be inlined anyway, cast + and all. + + Moreover, if we do cast w/w for an INLINE function with arity zero, we get something really silly: we inline that "worker" right back into the wrapper! - Worse than a no-op, because we have then lost the stable unfolding. + In fact it is Much Worse than a no-op, because we have then lost the stable + unfolding --- aargh (see #26903). E.g. similar example to (CWW3) + {- g: Stable unfolding (arity 0) = <stable-big> -} NB arity 0! + g = (\xy. <big-body>) |> co + If we w/w to this: + {- $wg: Stable unfolding (arity 0) = <stable-big> |> sym co -} + $wg = \xy. <big-body> + g = $wg |> co + then we'll inline $wg at the call site in `g` giving + {- $wg: Stable unfolding (arity 0) = <stable-big> |> sym co -} + $wg = \xy. <big-body> + g = (<stable-big> |> sym co) |> co + and now we'll drop `$wg` as dead and we have lost the unfolding on `g`. + (We could /also/ give the binding `g = $wf |> co` a stable unfolding. Then + things would work right; but there is also no point in doing the cast + worker/wrapper in the first place.) + + NB: you might wonder about a loop-breaker with an INLINE pragma; after all, a + loop breaker won't "definitely be inlined anyway", so arguably we should not + disable cast w/w/ for it. But a Rec group can /look/ recursive at an early + stage, and subsequently /become/ non-recursive after some simplification. + (This is common in instance decls; see Note [Checking for INLINE loop breakers] + in GHC.Core.Lint.) So the danger is that we'll permanently lose that stable + unfolding that we specifically wanted (#26903). Simple solution: disable cast + w/w for /any/ INLINE function. See the defn + of `GHC.Types.Id.Info.hasInlineUnfolding`. + + The danger is that an INLINE pragma on a genuninely-recursive function + will kill worker-wrapper. Well, so be it. They are pretty suspicious anyway; + see Note [Checking for INLINE loop breakers]. All these wrinkles are exactly like worker/wrapper for strictness analysis: f is the wrapper and must inline like crazy @@ -586,11 +614,11 @@ tryCastWorkerWrapper env bind_cxt old_bndr bndr (Cast rhs co) | BC_Let top_lvl is_rec <- bind_cxt -- Not join points , not (isDFunId bndr) -- nor DFuns; cast w/w is no help, and we can't transform -- a DFunUnfolding in mk_worker_unfolding - , not (exprIsTrivial rhs) -- Not x = y |> co; Wrinkle 1 - , not (hasInlineUnfolding info) -- Not INLINE things: Wrinkle 4 - , typeHasFixedRuntimeRep work_ty -- Don't peel off a cast if doing so would - -- lose the underlying runtime representation. - -- See Note [Preserve RuntimeRep info in cast w/w] + , not (exprIsTrivial rhs) -- Not x = y |> co; see (CWW1) + , not (hasInlineUnfolding info) -- Not INLINE things: see (CWW4) + , typeHasFixedRuntimeRep work_ty -- Don't peel off a cast if doing so would + -- lose the underlying runtime representation. + -- See Note [Preserve RuntimeRep info in cast w/w] , not (isOpaquePragma (idInlinePragma old_bndr)) -- Not for OPAQUE bindings -- See Note [OPAQUE pragma] = do { uniq <- getUniqueM @@ -637,13 +665,13 @@ tryCastWorkerWrapper env bind_cxt old_bndr bndr (Cast rhs co) `setArityInfo` work_arity -- We do /not/ want to transfer OccInfo, Rules -- Note [Preserve strictness in cast w/w] - -- and Wrinkle 2 of Note [Cast worker/wrapper] + -- and (CWW2) of Note [Cast worker/wrapper] ----------- Worker unfolding ----------- -- Stable case: if there is a stable unfolding we have to compose with (Sym co); -- the next round of simplification will do the job -- Non-stable case: use work_rhs - -- Wrinkle 3 of Note [Cast worker/wrapper] + -- See (CWW4) of Note [Cast worker/wrapper] mk_worker_unfolding top_lvl work_id work_rhs = case realUnfoldingInfo info of -- NB: the real one, even for loop-breakers unf@(CoreUnfolding { uf_tmpl = unf_rhs, uf_src = src }) ===================================== compiler/GHC/Core/Opt/WorkWrap.hs ===================================== @@ -179,8 +179,9 @@ several liked-named Ids bouncing around at the same time---absolute mischief.) Notice that we refrain from w/w'ing an INLINE function even if it is -in a recursive group. It might not be the loop breaker. (We could -test for loop-breaker-hood, but I'm not sure that ever matters.) +in a recursive group. It might not be the loop breaker. (We used to +test for loop-breaker-hood, but see (CWW4) in Note [Cast worker/wrapper] +in GHC.Core.Opt.Simplify.Iteration.) Note [Worker/wrapper for INLINABLE functions] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ===================================== compiler/GHC/Driver/Config/Core/Lint.hs ===================================== @@ -132,8 +132,6 @@ perPassFlags dflags pass -- there may be some INLINE knots still tied, which is tiresomely noisy CoreDoSimplify cfg | SimplPhase InitialPhase <- sm_phase (so_mode cfg) - -> True - | otherwise -> False _ -> True ===================================== compiler/GHC/Types/Id/Info.hs ===================================== @@ -610,7 +610,12 @@ hasInlineUnfolding :: IdInfo -> Bool -- ^ True of a /non-loop-breaker/ Id that has a /stable/ unfolding that is -- (a) always inlined; that is, with an `UnfWhen` guidance, or -- (b) a DFunUnfolding which never needs to be inlined -hasInlineUnfolding info = isInlineUnfolding (unfoldingInfo info) +-- +-- Very important that this work with `realUnfoldingInfo` and so returns +-- True even for a loop-breaker that has an INLINE pragma. +-- See (CWW4) in Note [Cast worker/wrapper] in GHC.Core.Opt.Simplify.Iteration +-- for discussion, and #26903 for the dire consequences of getting this wrong. +hasInlineUnfolding info = isInlineUnfolding (realUnfoldingInfo info) setArityInfo :: IdInfo -> ArityInfo -> IdInfo setArityInfo info ar = ===================================== testsuite/tests/simplCore/should_compile/T26903.hs ===================================== @@ -0,0 +1,23 @@ +{-# LANGUAGE DefaultSignatures #-} +module T26903 where + +newtype T a = MkT [a] + +class C a where + op :: [a] -> [a] -> T a + + -- This default method + -- * Has an INLINE pragma + -- * Is too big to inline without a pragma + -- * Has arity zero + {-# INLINE[1] op #-} + default op :: Ord a => [a] -> [a] -> T a + op = \xs ys -> MkT $ if xs>ys then reverse (reverse (reverse (reverse xs))) + else reverse (reverse (reverse (reverse (xs ++ ys)))) + +instance C Int where {} + +test :: [Int] -> T Int +test xs = op [] xs + -- We expect to see `op` inlined into the RHS of `test` + ===================================== testsuite/tests/simplCore/should_compile/T26903.stderr ===================================== @@ -0,0 +1,52 @@ + +==================== Tidy Core ==================== +Result size of Tidy Core + = {terms: 127, types: 130, coercions: 48, joins: 0/0} + +$dmop + = (\ @a _ $dOrd xs ys -> + case $fOrdList_$ccompare $dOrd xs ys of { + __DEFAULT -> + reverse1 (reverse1 (reverse1 (reverse1 (++ xs ys) []) []) []) []; + GT -> reverse1 (reverse1 (reverse1 (reverse xs) []) []) [] + }) + `cast` <Co:20> :: ... + +$fCInt_$cop + = (\ xs ys -> + case $fOrdList_$s$ccompare xs ys of { + __DEFAULT -> + reverse1 (reverse1 (reverse1 (reverse1 (++ xs ys) []) []) []) []; + GT -> reverse1 (reverse1 (reverse1 (reverse xs) []) []) [] + }) + `cast` <Co:11> :: ... + +$fCInt1 + = \ xs ys -> + case $fOrdList_$s$ccompare xs ys of { + __DEFAULT -> + reverse1 (reverse1 (reverse1 (reverse1 (++ xs ys) []) []) []) []; + GT -> reverse1 (reverse1 (reverse1 (reverse xs) []) []) [] + } + +$fCInt = C:C ($fCInt1 `cast` <Co:11> :: ...) + +test4 = reverse1 [] [] + +test3 = reverse1 test4 [] + +test2 = reverse1 test3 [] + +test1 = reverse1 test2 [] + +test + = \ xs -> + case $fOrdList_$s$ccompare [] xs of { + __DEFAULT -> + (reverse1 (reverse1 (reverse1 (reverse1 (++ [] xs) []) []) []) []) + `cast` <Co:3> :: ...; + GT -> test1 `cast` <Co:3> :: ... + } + + + ===================================== testsuite/tests/simplCore/should_compile/T8331.stderr ===================================== @@ -56,11 +56,11 @@ ReaderT r (ST s) (a -> b) -> ReaderT r (ST s) a -> r -> ST s b)) "SPEC $c>> @(ST s) @_" forall (@s) (@r) ($dMonad :: Monad (ST s)). - $fMonadReaderT1 @(ST s) @r $dMonad + $fMonadReaderT_$c>> @(ST s) @r $dMonad = $fMonadAbstractIOSTReaderT_$s$c>> @s @r "SPEC $c>>= @(ST s) @_" forall (@s) (@r) ($dMonad :: Monad (ST s)). - $fMonadReaderT2 @(ST s) @r $dMonad + $fMonadReaderT1 @(ST s) @r $dMonad = ($fMonadAbstractIOSTReaderT2 @s @r) `cast` (forall (a ::~ <*>_N) (b ::~ <*>_N). <ReaderT r (ST s) a>_R ===================================== testsuite/tests/simplCore/should_compile/all.T ===================================== @@ -581,3 +581,4 @@ test('T26722', [grep_errmsg(r'SPEC')], compile, ['-O -dno-typeable-binds']) test('T26805', [grep_errmsg(r'fromInteger')], compile, ['-O -dno-typeable-binds -ddump-simpl -dsuppress-uniques']) test('T26826', normal, compile, ['-O']) +test('T26903', [grep_errmsg(r'reverse')], compile, ['-O -dno-typeable-binds -ddump-simpl -dsuppress-uniques -dsuppress-all']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/99d8c146c12146e1e21b1f2d3180984… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/99d8c146c12146e1e21b1f2d3180984… You're receiving this email because of your account on gitlab.haskell.org.

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