Serge S. Gulin pushed to branch wip/T24603 at Glasgow Haskell Compiler / GHC Commits: ce616f49 by Simon Peyton Jones at 2025-04-27T21:10:25+01:00 Fix infelicities in the Specialiser On the way to #23109 (unary classes) I discovered some infelicities (or maybe tiny bugs, I forget) in the type-class specialiser. I also tripped over #25965, an outright bug in the rule matcher Specifically: * Refactor: I enhanced `wantCallsFor`, whih previously always said `True`, to discard calls of class-ops, data constructors etc. This is a bit more efficient; and it means we don't need to worry about filtering them out later. * Fix: I tidied up some tricky logic that eliminated redundant specialisations. It wasn't working correctly. See the expanded Note [Specialisations already covered], and (MP3) in Note [Specialising polymorphic dictionaries]. See also the new top-level `alreadyCovered` function, which now goes via `GHC.Core.Rules.ruleLhsIsMoreSpecific` I also added a useful Note [The (CI-KEY) invariant] * Fix #25965: fixed a tricky bug in the `go_fam_fam` in `GHC.Core.Unify.uVarOrFam`, which allows matching to succeed without binding all type varibles. I enhanced Note [Apartness and type families] some more * #25703. This ticket "just works" with -fpolymorphic-specialisation; but I was surprised that it worked! In this MR I added documentation to Note [Interesting dictionary arguments] to explain; and tests to ensure it stays fixed. - - - - - 22d11fa8 by Simon Peyton Jones at 2025-04-28T18:05:19-04:00 Track rewriter sets more accurately in constraint solving The key change, which fixed #25440, is to call `recordRewriter` in GHC.Tc.Solver.Rewrite.rewrite_exact_fam_app. This missing call meant that we were secretly rewriting a Wanted with a Wanted, but not really noticing; and that led to a very bad error message, as you can see in the ticket. But of course that led me into rabbit hole of other refactoring around the RewriteSet code: * Improve Notes [Wanteds rewrite Wanteds] * Zonk the RewriterSet in `zonkCtEvidence` rather than only in GHC.Tc.Errors. This is tidier anyway (e.g. de-clutters debug output), and helps with the next point. * In GHC.Tc.Solver.Equality.inertsCanDischarge, don't replace a constraint with no rewriters with an equal constraint that has many. See See (CE4) in Note [Combining equalities] * Move zonkRewriterSet and friends from GHC.Tc.Zonk.Type into GHC.Tc.Zonk.TcType, where they properly belong. A handful of tests get better error messages. For some reason T24984 gets 12% less compiler allocation -- good Metric Decrease: T24984 - - - - - 6467d61e by Brandon Chinn at 2025-04-29T18:36:03-04:00 Fix lexing "\^\" (#25937) This broke in the refactor in !13128, where the old code parsed escape codes and collapsed string gaps at the same time, but the new code collapsed gaps first, then resolved escape codes. The new code used a naive heuristic to skip escaped backslashes, but didn't account for "\^\". - - - - - 99868a86 by Jens Petersen at 2025-04-29T18:36:44-04:00 hadrian: default selftest to disabled - - - - - 93fca693 by Serge S. Gulin at 2025-04-30T10:23:06+03:00 Support for ARM64 Windows (LLVM-enabled) (fixes #24603) submodule Co-authored-by: Cheng Shao Co-authored-by: Dmitrii Egorov Co-authored-by: Andrei Borzenkov - - - - - 70 changed files: - .gitlab-ci.yml - .gitlab/ci.sh - .gitlab/generate-ci/gen_ci.hs - .gitlab/hello.hs - .gitlab/jobs.yaml - compiler/CodeGen.Platform.h - compiler/GHC/CmmToAsm/AArch64/CodeGen.hs - compiler/GHC/CmmToAsm/AArch64/Instr.hs - compiler/GHC/CmmToAsm/AArch64/Ppr.hs - compiler/GHC/CmmToAsm/Reg/Linear/AArch64.hs - compiler/GHC/Core/Coercion.hs - compiler/GHC/Core/Opt/Specialise.hs - compiler/GHC/Core/Rules.hs - compiler/GHC/Core/Unify.hs - compiler/GHC/Driver/Session.hs - compiler/GHC/Parser/Errors/Types.hs - compiler/GHC/Parser/String.hs - compiler/GHC/Platform/Regs.hs - compiler/GHC/Tc/Errors.hs - compiler/GHC/Tc/Solver/Default.hs - compiler/GHC/Tc/Solver/Equality.hs - compiler/GHC/Tc/Solver/Monad.hs - compiler/GHC/Tc/Solver/Rewrite.hs - compiler/GHC/Tc/Types/Constraint.hs - compiler/GHC/Tc/Utils/TcMType.hs - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/Tc/Zonk/TcType.hs - compiler/GHC/Tc/Zonk/Type.hs - compiler/GHC/Types/Basic.hs - hadrian/README.md - hadrian/hadrian.cabal - hadrian/src/Oracles/Setting.hs - hadrian/src/Rules/BinaryDist.hs - libraries/Cabal - libraries/Win32 - libraries/base/src/System/CPUTime/Windows.hsc - libraries/base/tests/perf/encodingAllocations.hs - libraries/directory - libraries/ghc-internal/jsbits/errno.js - libraries/ghc-internal/src/GHC/Internal/System/Posix/Internals.hs - libraries/haskeline - libraries/process - libraries/unix - llvm-targets - m4/fp_cc_supports_target.m4 - m4/fptools_set_platform_vars.m4 - m4/ghc_tables_next_to_code.m4 - rts/StgCRun.c - rts/linker/PEi386.c - rts/win32/veh_excn.c - testsuite/tests/ghc-api/fixed-nodes/all.T - testsuite/tests/indexed-types/should_fail/T3330c.stderr - testsuite/tests/indexed-types/should_fail/T4174.stderr - testsuite/tests/indexed-types/should_fail/T8227.stderr - testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs - + testsuite/tests/parser/should_run/T25937.hs - + testsuite/tests/parser/should_run/T25937.stdout - testsuite/tests/parser/should_run/all.T - + testsuite/tests/parser/should_run/parser_unit_tests.hs - + testsuite/tests/simplCore/should_compile/T25703.hs - + testsuite/tests/simplCore/should_compile/T25703.stderr - + testsuite/tests/simplCore/should_compile/T25703a.hs - + testsuite/tests/simplCore/should_compile/T25703a.stderr - + testsuite/tests/simplCore/should_compile/T25965.hs - testsuite/tests/simplCore/should_compile/all.T - testsuite/tests/typecheck/should_compile/T25266a.stderr - testsuite/tests/typecheck/should_fail/T18851.stderr - utils/ghc-toolchain/exe/Main.hs - utils/hsc2hs - utils/llvm-targets/gen-data-layout.sh The diff was not included because it is too large. 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