Simon Peyton Jones pushed to branch wip/T26315 at Glasgow Haskell Compiler / GHC Commits: 9e50a25d by Simon Peyton Jones at 2025-09-05T17:11:33+01:00 Solve forall-constraints via an implication, again In this earlier commit: commit 953fd8f1dc080f1c56e3a60b4b7157456949be29 Author: Simon Peyton Jones Date: Mon Jul 21 10:06:43 2025 +0100 Solve forall-constraints immediately, or not at all I used a all-or-nothing strategy for quantified constraints (aka forall-constraints). But alas that fell foul of #26315, and #26376. So this MR goes back to solving a quantified constraint by turning it into an implication; UNLESS we are simplifying constraints from a SPECIALISE pragma, in which case the all-or-nothing strategy is great. See: Note [Solving a Wanted forall-constraint] Other stuff in this MR: * TcSMode becomes a record of flags, rather than an enumeration type; much nicer. * Some fancy footwork to avoid error messages worsening again (The above MR made them better; we want to retain that.) See `GHC.Tc.Errors.Ppr.pprQCOriginExtra`. - - - - - 44 changed files: - compiler/GHC/HsToCore/Binds.hs - compiler/GHC/Tc/Deriv/Utils.hs - compiler/GHC/Tc/Errors/Ppr.hs - compiler/GHC/Tc/Gen/Sig.hs - compiler/GHC/Tc/Solver.hs - compiler/GHC/Tc/Solver/Default.hs - compiler/GHC/Tc/Solver/Dict.hs - compiler/GHC/Tc/Solver/Equality.hs - compiler/GHC/Tc/Solver/InertSet.hs - compiler/GHC/Tc/Solver/Monad.hs - compiler/GHC/Tc/Solver/Solve.hs - compiler/GHC/Tc/Solver/Solve.hs-boot - compiler/GHC/Tc/Types/Constraint.hs - compiler/GHC/Tc/Types/Evidence.hs - compiler/GHC/Tc/Types/Origin.hs - compiler/GHC/Tc/Utils/Monad.hs - compiler/GHC/Tc/Zonk/TcType.hs - compiler/GHC/Tc/Zonk/Type.hs - testsuite/tests/backpack/should_fail/bkpfail11.stderr - testsuite/tests/backpack/should_fail/bkpfail43.stderr - testsuite/tests/deriving/should_fail/T12768.stderr - testsuite/tests/deriving/should_fail/T1496.stderr - testsuite/tests/deriving/should_fail/T21302.stderr - testsuite/tests/deriving/should_fail/T22696b.stderr - testsuite/tests/deriving/should_fail/T5498.stderr - testsuite/tests/deriving/should_fail/T7148.stderr - testsuite/tests/deriving/should_fail/T7148a.stderr - testsuite/tests/impredicative/T17332.stderr - testsuite/tests/quantified-constraints/T19690.stderr - testsuite/tests/quantified-constraints/T19921.stderr - testsuite/tests/quantified-constraints/T21006.stderr - testsuite/tests/roles/should_fail/RolesIArray.stderr - testsuite/tests/simplCore/should_compile/DsSpecPragmas.hs - testsuite/tests/simplCore/should_compile/DsSpecPragmas.stderr - testsuite/tests/typecheck/should_compile/T14434.hs - + testsuite/tests/typecheck/should_compile/T26376.hs - testsuite/tests/typecheck/should_compile/all.T - testsuite/tests/typecheck/should_fail/T15801.stderr - testsuite/tests/typecheck/should_fail/T19627.stderr - testsuite/tests/typecheck/should_fail/T20666.stderr - testsuite/tests/typecheck/should_fail/T20666a.stderr - testsuite/tests/typecheck/should_fail/T20666b.stderr - testsuite/tests/typecheck/should_fail/T22912.stderr - testsuite/tests/typecheck/should_fail/T23427.stderr The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/9e50a25df9dc8e52d8c0da621756d7f4... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/9e50a25df9dc8e52d8c0da621756d7f4... You're receiving this email because of your account on gitlab.haskell.org.