Apoorv Ingle pushed to branch wip/spj-apporv-Oct24 at Glasgow Haskell Compiler / GHC Commits: fcf6331e by Richard Eisenberg at 2025-11-03T08:33:05+00:00 Refactor fundep solving This commit is a large-scale refactor of the increasingly-messy code that handles functional dependencies. It has virtually no effect on what compiles but improves error messages a bit. And it does the groundwork for #23162. The big picture is described in Note [Overview of functional dependencies in type inference] in GHC.Tc.Solver.FunDeps * New module GHC.Tc.Solver.FunDeps contains all the fundep-handling code for the constraint solver. * Fundep-equalities are solved in a nested scope; they may generate unifications but otherwise have no other effect. See GHC.Tc.Solver.FunDeps.solveFunDeps The nested needs to start from the Givens in the inert set, but not the Wanteds; hence a new function `resetInertCans`, used in `nestFunDepsTcS`. * That in turn means that fundep equalities never show up in error messages, so the complicated FunDepOrigin tracking can all disappear. * We need to be careful about tracking unifications, so we kick out constraints from the inert set after doing unifications. Unification tracking has been majorly reformed: see Note [WhatUnifications] in GHC.Tc.Utils.Unify. A good consequence is that the hard-to-grok `resetUnificationFlag` has been replaced with a simpler use of `reportCoarseGrainUnifications` Smaller things: * Rename `FunDepEqn` to `FunDepEqns` since it contains multiple type equalities. Some compile time improvement Metrics: compile_time/bytes allocated Baseline Test value New value Change ---------------------- -------------------------------------- T5030(normal) 173,839,232 148,115,248 -14.8% GOOD hard_hole_fits(normal) 286,768,048 284,015,416 -1.0% geo. mean -0.2% minimum -14.8% maximum +0.3% Metric Decrease: T5030 - - - - - 231adc30 by Simon Peyton Jones at 2025-11-03T08:33:05+00:00 QuickLook's tcInstFun should make instantiation variables directly tcInstFun must make "instantiation variables", not regular unification variables, when instantiating function types. That was previously implemented by a hack: set the /ambient/ level to QLInstTyVar. But the hack finally bit me, when I was refactoring WhatUnifications. And it was always wrong: see the now-expunged (TCAPP2) note. This commit does it right, by making tcInstFun call its own instantiation functions. That entails a small bit of duplication, but the result is much, much cleaner. - - - - - 39d4a24b by Simon Peyton Jones at 2025-11-03T08:33:05+00:00 Build implication for constraints from (static e) This commit addresses #26466, by buiding an implication for the constraints arising from a (static e) form. The implication has a special ic_info field of StaticFormSkol, which tells the constraint solver to use an empty set of Givens. See (SF3) in Note [Grand plan for static forms] in GHC.Iface.Tidy.StaticPtrTable This commit also reinstates an `assert` in GHC.Tc.Solver.Equality. The test `StaticPtrTypeFamily` was failing with an assertion failure, but it now works. - - - - - 2e2aec1e by Simon Peyton Jones at 2025-11-03T08:33:05+00:00 Comments about defaulting representation equalities - - - - - 52a4d1da by Simon Peyton Jones at 2025-11-03T08:33:05+00:00 Improve tracking of rewriter-sets This refactor substantially improves the treatment of so-called "rewriter-sets" in the constraint solver. The story is described in the rewritten Note [Wanteds rewrite Wanteds: rewriter-sets] in GHC.Tc.Types.Constraint Some highlights * Trace the free coercion holes of a filled CoercionHole, in CoercionPlusHoles. See Note [Coercion holes] (COH5) This avoids taking having to take the free coercion variables of a coercion when zonking a rewrriter-set * Many knock on changes * Make fillCoercionHole take CoercionPlusHoles as its argument rather than to separate arguments. * Similarly setEqIfWanted, setWantedE, wrapUnifierAndEmit. * Be more careful about passing the correct CoHoleSet to `rewriteEqEvidence` and friends * Make kickOurAfterFillingCoercionHole more clever. See new Note [Kick out after filling a coercion hole] Smaller matters * Rename RewriterSet to CoHoleSet * Add special-case helper `rewriteEqEvidenceSwapOnly` - - - - - 3e78e1ba by Simon Peyton Jones at 2025-11-03T08:33:05+00:00 Tidy up constraint solving for foralls * In `can_eq_nc_forall` make sure to track Givens that are used in the nested solve step. * Tiny missing-swap bug-fix in `lookup_eq_in_qcis` * Fix some leftover mess from commit 14123ee646f2b9738a917b7cec30f9d3941c13de Author: Simon Peyton Jones Date: Wed Aug 20 00:35:48 2025 +0100 Solve forall-constraints via an implication, again Specifically, trySolveImplication is now dead. - - - - - 973f2c25 by Simon Peyton Jones at 2025-11-03T08:33:05+00:00 Do not treat CoercionHoles as free variables in coercions This fixes a long-standing wart in the free-variable finder; now CoercionHoles are no longer treated as a "free variable" of a coercion. I got big and unexpected performance regressions when making this change. Turned out that CallArity didn't discover that the free variable finder could be eta-expanded, which gave very poor code. So I re-used Note [The one-shot state monad trick] for Endo, resulting in GHC.Utils.EndoOS. Very simple, big win. - - - - - c2b8a0f9 by Simon Peyton Jones at 2025-11-03T08:33:05+00:00 Update debug-tracing in CallArity No effect on behaviour, and commented out anyway - - - - - 9aa5ee99 by Simon Peyton Jones at 2025-11-03T08:33:28+00:00 Comments only -- remove dangling Note references - - - - - 6683f183 by Simon Peyton Jones at 2025-11-03T08:33:28+00:00 Accept error message wibbles - - - - - 3ba3d9f9 by Luite Stegeman at 2025-11-04T00:59:41-05:00 rts: fix eager black holes: record mutated closure and fix assertion This fixes two problems with handling eager black holes, introduced by a1de535f762bc23d4cf23a5b1853591dda12cdc9. - the closure mutation must be recorded even for eager black holes, since the mutator has mutated it before calling threadPaused - The assertion that an unmarked eager black hole must be owned by the TSO calling threadPaused is incorrect, since multiple threads can race to claim the black hole. fixes #26495 - - - - - b5508f2c by Rodrigo Mesquita at 2025-11-04T14:10:56+00:00 build: Relax ghc/ghc-boot Cabal bound to 3.16 Fixes #26202 - - - - - c5b3541f by Rodrigo Mesquita at 2025-11-04T14:10:56+00:00 cabal-reinstall: Use haddock-api +in-tree-ghc Fixes #26202 - - - - - c6d4b945 by Rodrigo Mesquita at 2025-11-04T14:10:56+00:00 cabal-reinstall: Pass --strict to Happy This is necessary to make the generated Parser build successfully This mimics Hadrian, which always passes --strict to happy. Fixes #26202 - - - - - 79df1e0e by Rodrigo Mesquita at 2025-11-04T14:10:56+00:00 genprimopcode: Require higher happy version I've bumped the happy version to forbid deprecated Happy versions which don't successfully compile. - - - - - fa5d33de by Simon Peyton Jones at 2025-11-05T08:35:40-05:00 Add a HsWrapper optimiser This MR addresses #26349, by introduceing optSubTypeHsWrapper. There is a long Note [Deep subsumption and WpSubType] in GHC.Tc.Types.Evidence that explains what is going on. - - - - - ea58cae5 by Simon Peyton Jones at 2025-11-05T08:35:40-05:00 Improve mkWpFun_FRR This commit ensures that `mkWpFun_FRR` directly produces a `FunCo` in the cases where it can. (Previously called `mkWpFun` which in turn optimised to a `FunCo`, but that made the smarts in `mkWpFun` /essential/ rather than (as they should be) optional. - - - - - 5cdcfaed by Ben Gamari at 2025-11-06T09:01:36-05:00 compiler: Exclude units with no exposed modules from unused package check Such packages cannot be "used" in the Haskell sense of the word yet are nevertheless necessary as they may provide, e.g., C object code or link flags. Fixes #24120. - - - - - 74b8397a by Brandon Chinn at 2025-11-06T09:02:19-05:00 Replace deprecated argparse.FileType - - - - - 36ddf988 by Ben Gamari at 2025-11-06T09:03:01-05:00 Bump unix submodule to 2.8.8.0 Closes #26474. - - - - - c32b3a29 by fendor at 2025-11-06T09:03:43-05:00 Fix assertion in `postStringLen` to account for \0 byte We fix the assertion to handle trailing \0 bytes in `postStringLen`. Before this change, the assertion looked like this: ASSERT(eb->begin + eb->size > eb->pos + len + 1); Let's assume some values to see why this is actually off by one: eb->begin = 0 eb->size = 1 eb->pos = 0 len = 1 then the assertion would trigger correctly: 0 + 1 > 0 + 1 + 1 => 1 > 2 => false as there is not enough space for the \0 byte (which is the trailing +1). However, if we change `eb->size = 2`, then we do have enough space for a string of length 1, but the assertion still fails: 0 + 2 > 0 + 1 + 1 => 2 > 2 => false Which causes the assertion to fail if there is exactly enough space for the string with a trailing \0 byte. Clearly, the assertion should be `>=`! If we switch around the operand, it should become more obvious that `<=` is the correct comparison: ASSERT(eb->pos + len + 1 <= eb->begin + eb->size); This is expresses more naturally that the current position plus the length of the string (and the null byte) must be smaller or equal to the overall size of the buffer. This change also is in line with the implementation in `hasRoomForEvent` and `hasRoomForVariableEvent`: ``` StgBool hasRoomForEvent(EventsBuf *eb, EventTypeNum eNum) { uint32_t size = ...; if (eb->pos + size > eb->begin + eb->size) ... ``` the check `eb->pos + size > eb->begin + eb->size` is identical to `eb->pos + size <= eb->begin + eb->size` plus a negation. - - - - - 3034a6f2 by Ben Gamari at 2025-11-06T09:04:24-05:00 Bump os-string submodule to 2.0.8 - - - - - 39567e85 by Cheng Shao at 2025-11-06T09:05:06-05:00 rts: use computed goto for instruction dispatch in the bytecode interpreter This patch uses computed goto for instruction dispatch in the bytecode interpreter. Previously instruction dispatch is done by a classic switch loop, so executing the next instruction requires two jumps: one to the start of the switch loop and another to the case block based on the instruction tag. By using computed goto, we can build a jump table consisted of code addresses indexed by the instruction tags themselves, so executing the next instruction requires only one jump, to the destination directly fetched from the jump table. Closes #12953. - - - - - 93fc7265 by sheaf at 2025-11-06T21:33:24-05:00 Correct hasFixedRuntimeRep in matchExpectedFunTys This commit fixes a bug in the representation-polymormorphism check in GHC.Tc.Utils.Unify.matchExpectedFunTys. The problem was that we put the coercion resulting from hasFixedRuntimeRep in the wrong place, leading to the Core Lint error reported in #26528. The change is that we have to be careful when using 'mkWpFun': it expects **both** the expected and actual argument types to have a syntactically fixed RuntimeRep, as explained in Note [WpFun-FRR-INVARIANT] in GHC.Tc.Types.Evidence. On the way, this patch improves some of the commentary relating to other usages of 'mkWpFun' in the compiler, in particular in the view pattern case of 'tc_pat'. No functional changes, but some stylistic changes to make the code more readable, and make it easier to understand how we are upholding the WpFun-FRR-INVARIANT. Fixes #26528 - - - - - c052c724 by Simon Peyton Jones at 2025-11-06T21:34:06-05:00 Fix a horrible shadowing bug in implicit parameters Fixes #26451. The change is in GHC.Tc.Solver.Monad.updInertDicts where we now do /not/ delete /Wanted/ implicit-parameeter constraints. This bug has been in GHC since 9.8! But it's quite hard to provoke; I contructed a tests in T26451, but it was hard to do so. - - - - - b253013e by Georgios Karachalias at 2025-11-07T17:21:57-05:00 Remove the `CoreBindings` constructor from `LinkablePart` Adjust HscRecompStatus to disallow unhydrated WholeCoreBindings from being passed as input to getLinkDeps (which would previously panic in this case). Fixes #26497 - - - - - ac7b737e by Sylvain Henry at 2025-11-07T17:22:51-05:00 Testsuite: pass ext-interp test way (#26552) Note that some tests are still marked as broken with the ext-interp way (see #26552 and #14335) - - - - - 3c2f4bb4 by sheaf at 2025-11-11T11:47:28-05:00 Preserve user-written kinds in data declarations This commit ensures that we preserve the user-written kind for data declarations, e.g. in type T2T = Type -> Type type D :: T2T data D a where { .. } that we preserve the user-written kind of D as 'T2T', instead of expanding the type synonym 'T2T' during kind checking. We do this by storing 'tyConKind' separately from 'tyConResKind'. This means that 'tyConKind' is not necessarily equal to 'mkTyConKind binders res_kind', as e.g. in the above example the former is 'T2T' while the latter is 'Type -> Type'. This is explained in Note [Preserve user-written TyCon kind] in GHC.Core.TyCon. This is particularly important for Haddock, as the kinds stored in interface files affect the generated documentation, and we want to preserve the user-written types as much as possible. - - - - - 19859584 by sheaf at 2025-11-11T11:47:28-05:00 Store user-written datacon tvs in interface files This commit ensures we store the user-written quantified type variables of data constructors in interface files, e.g. in data D a where MkD1 :: forall x. x -> D x MkD2 :: forall u v. u -> v -> D v The previous behaviour was to rename the universal variables to match the universal variables of the data constructor. This was undesirable because the names that end up in interface files end up mattering for generated Haddock documentation; it's better to preserve the user-written type variables. Moreover, the universal variables may not have been user-written at all, e.g. in an example such as: type T2T = Type -> Type data G :: T2T where MkG :: forall x. D x Here GHC will invent the type variable name 'a' for the first binder of the TyCon G. We really don't want to then rename the user-written 'x' into the generated 'a'. - - - - - 034b2056 by sheaf at 2025-11-11T11:47:28-05:00 DataCon univ_tvs names: pick TyCon over inferred This commit changes how we compute the names of universal type variables in GADT data constructors. This augments the existing logic that chose which type variable name to use, in GHC.Tc.TyCl.mkGADTVars. We continue to prefer DataCon tv names for user-written binders, but we now prefer TyCon tv names for inferred (non-user-written) DataCon binders. This makes a difference in examples such as: type (:~~:) :: k1 -> k2 -> Type data a :~~: b where HRefl :: a :~~: a Before this patch, we ended up giving HRefl the type: forall {k2}. forall (a :: k2). a :~~: a whereas we now give it the type: forall {k1}. forall (a :: k1). a :~~: a The important part isn't really 'k1' or 'k2', but more that the inferred type variable names of the DataCon can be arbitrary/unpredictable (as they are chosen by GHC and depend on how unification proceeds), so it's much better to use the more predictable TyCon type variable names. - - - - - 95078d00 by sheaf at 2025-11-11T11:47:28-05:00 Backpack Rename: use explicit record construction This commit updates the Backpack boilerplate in GHC.Iface.Rename to use explicit record construction rather than record update. This makes sure that the code stays up to date when the underlying constructors change (e.g. new fields are added). The rationale is further explained in Note [Prefer explicit record construction]. - - - - - 2bf36263 by sheaf at 2025-11-11T11:47:28-05:00 Store # eta binders in TyCon and use for Haddock This commit stores the number of TyCon binders that were introduced by eta-expansion (by the function GHC.Tc.Gen.HsType.splitTyConKind). This is then used to pretty-print the TyCon as the user wrote it, e.g. for type Effect :: (Type -> Type) -> Type -> Type data State s :: Effect where {..} -- arity 3 GHC will eta-expand the data declaration to data State s a b where {..} but also store in the 'TyCon' that the number of binders introduced by this eta expansion is 2. This allows us, in 'Haddock.Convert.synifyTyConKindSig', to recover the original user-written syntax, preserving the user's intent in Haddock documentation. See Note [Inline kind signatures with GADTSyntax] in Haddock.Convert. - - - - - 6c91582f by Matthew Pickering at 2025-11-11T11:48:12-05:00 driver: Properly handle errors during LinkNode steps Previously we were not properly catching errors during the LinkNode step (see T9930fail test). This is fixed by wrapping the `LinkNode` action in `wrapAction`, the same handler which is used for module compilation. Fixes #26496 - - - - - e1e1eb32 by Matthew Pickering at 2025-11-11T11:48:54-05:00 driver: Remove unecessary call to hscInsertHPT This call was left-over from e9445c013fbccf9318739ca3d095a3e0a2e1be8a If you follow the functions which call `upsweep_mod`, they immediately add the interface to the HomePackageTable when `upsweep_mod` returns. - - - - - b22777d4 by ARATA Mizuki at 2025-11-11T11:49:44-05:00 LLVM backend: Pass the +evex512 attribute to LLVM 18+ if -mavx512f is set The newer LLVM requires the +evex512 attribute to enable use of ZMM registers. LLVM exhibits a backward-compatible behavior if the cpu is `x86-64`, but not if `penryn`. Therefore, on macOS, where the cpu is set to `penryn`, we need to explicitly pass +evex512. Fixes #26410 - - - - - 6ead7d06 by Vladislav Zavialov at 2025-11-11T11:50:26-05:00 Comments only in GHC.Parser.PostProcess.Haddock Remove outdated Note [Register keyword location], as the issue it describes was addressed by commit 05eb50dff2fcc78d025e77b9418ddb369db49b9f. - - - - - 43fa8be8 by sheaf at 2025-11-11T11:51:18-05:00 localRegistersConflict: account for assignment LHS This commit fixes a serious oversight in GHC.Cmm.Sink.conflicts, specifically the code that computes which local registers conflict between an assignment and a Cmm statement. If we have: assignment: = <expr> node: = then clearly the two conflict, because we cannot move one statement past the other, as they assign two different values to the same local register. (Recall that 'conflicts (local_reg,expr) node' is False if and only if the assignment 'local_reg = expr' can be safely commuted past the statement 'node'.) The fix is to update 'GHC.Cmm.Sink.localRegistersConflict' to take into account the following two situations: (1) 'node' defines the LHS local register of the assignment, (2) 'node' defines a local register used in the RHS of the assignment. The bug is precisely that we were previously missing condition (1). Fixes #26550 - - - - - 79dfcfe0 by sheaf at 2025-11-11T11:51:18-05:00 Update assigned register format when spilling When we come to spilling a register to put new data into it, in GHC.CmmToAsm.Reg.Linear.allocRegsAndSpill_spill, we need to: 1. Spill the data currently in the register. That is, do a spill with a format that matches what's currently in the register. 2. Update the register assignment, allocating a virtual register to this real register, but crucially **updating the format** of this assignment. Due to shadowing in the Haskell code for allocRegsAndSpill_spill, we were mistakenly re-using the old format. This could lead to a situation where: a. We were using xmm6 to store a Double#. b. We want to store a DoubleX2# into xmm6, so we spill the current content of xmm6 to the stack using a scalar move (correct). c. We update the register assignment, but we fail to update the format of the assignment, so we continue to think that xmm6 stores a Double# and not a DoubleX2#. d. Later on, we need to spill xmm6 because it is getting clobbered by another instruction. We then decide to only spill the lower 64 bits of the register, because we still think that xmm6 only stores a Double# and not a DoubleX2#. Fixes #26542 - - - - - aada5db9 by ARATA Mizuki at 2025-11-11T11:52:07-05:00 Fix the order of spill/reload instructions The AArch64 NCG could emit multiple instructions for a single spill/reload, but their order was not consistent between the definition and a use. Fixes #26537 Co-authored-by: sheaf - - - - - 64ec82ff by Andreas Klebinger at 2025-11-11T11:52:48-05:00 Add hpc to release script - - - - - 741da00c by Ben Gamari at 2025-11-12T03:38:20-05:00 template-haskell: Better describe getQ semantics Clarify that the state is a type-indexed map, as suggested by #26484. - - - - - 8b080e04 by ARATA Mizuki at 2025-11-12T03:39:11-05:00 Fix incorrect markups in the User's Guide * Correct markup for C--: "C-\-" in reST * Fix internal links * Fix code highlighting * Fix inline code: Use ``code`` rather than `code` * Remove extra backslashes Fixes #16812 Co-authored-by: sheaf - - - - - a00840ea by Simon Peyton Jones at 2025-11-14T15:23:56+00:00 Make TYPE and CONSTRAINT apart again This patch finally fixes #24279. * The story started with #11715 * Then #21623 articulated a plan, which made Type and Constraint not-apart; a horrible hack but it worked. The main patch was commit 778c6adca2c995cd8a1b84394d4d5ca26b915dac Author: Simon Peyton Jones Date: Wed Nov 9 10:33:22 2022 +0000 Type vs Constraint: finally nailed * #24279 reported a bug in the above big commit; this small patch fixes it commit af6932d6c068361c6ae300d52e72fbe13f8e1f18 Author: Simon Peyton Jones Date: Mon Jan 8 10:49:49 2024 +0000 Make TYPE and CONSTRAINT not-apart Issue #24279 showed up a bug in the logic in GHC.Core.Unify.unify_ty which is supposed to make TYPE and CONSTRAINT be not-apart. * Then !10479 implemented "unary classes". * That change in turn allows us to make Type and Constraint apart again, cleaning up the compiler and allowing a little bit more expressiveness. It fixes the original hope in #24279, namely that `Type` and `Constraint` should be distinct throughout. - - - - - c0a1e574 by Georgios Karachalias at 2025-11-15T05:14:31-05:00 Report all missing modules with -M We now report all missing modules at once in GHC.Driver.Makefile.processDeps, as opposed to only reporting a single missing module. Fixes #26551. - - - - - c9fa3449 by Sylvain Henry at 2025-11-15T05:15:26-05:00 JS: fix array index for registers We used to store R32 in h$regs[-1]. While it's correct in JavaScript, fix this to store R32 in h$regs[0] instead. - - - - - 9e469909 by Sylvain Henry at 2025-11-15T05:15:26-05:00 JS: support more than 128 registers (#26558) The JS backend only supported 128 registers (JS variables/array slots used to pass function arguments). It failed in T26537 when 129 registers were required. This commit adds support for more than 128 registers: it is now limited to maxBound :: Int (compiler's Int). If we ever go above this threshold the compiler now panics with a more descriptive message. A few built-in JS functions were assuming 128 registers and have been rewritten to use loops. Note that loops are only used for "high" registers that are stored in an array: the 31 "low" registers are still handled with JS global variables and with explicit switch-cases to maintain good performance in the most common cases (i.e. few registers used). Adjusting the number of low registers is now easy: just one constant to adjust (GHC.StgToJS.Regs.lowRegsCount). No new test added: T26537 is used as a regression test instead. - - - - - 0a64a78b by Sven Tennie at 2025-11-15T20:31:10-05:00 AArch64: Simplify CmmAssign and CmmStore The special handling for floats was fake: The general case is always used. So, the additional code path isn't needed (and only adds complexity for the reader.) - - - - - 15b311be by sheaf at 2025-11-15T20:32:02-05:00 SimpleOpt: refactor & push coercions into lambdas This commit improves the simple optimiser (in GHC.Core.SimpleOpt) in a couple of ways: - The logic to push coercion lambdas is shored up. The function 'pushCoercionIntoLambda' used to be called in 'finish_app', but this meant we could not continue to optimise the program after performing this transformation. Now, we call 'pushCoercionIntoLambda' as part of 'simple_app'. Doing so can be important when dealing with unlifted newtypes, as explained in Note [Desugaring unlifted newtypes]. - The code is re-structured to avoid duplication and out-of-sync code paths. Now, 'simple_opt_expr' defers to 'simple_app' for the 'App', 'Var', 'Cast' and 'Lam' cases. This means all the logic for those is centralised in a single place (e.g. the 'go_lam' helper function). To do this, the general structure is brought a bit closer to the full-blown simplifier, with a notion of 'continuation' (see 'SimpleContItem'). This commit also modifies GHC.Core.Opt.Arity.pushCoercionIntoLambda to apply a substitution (a slight generalisation of its existing implementation). - - - - - b33284c7 by sheaf at 2025-11-15T20:32:02-05:00 Improve typechecking of data constructors This commit changes the way in which we perform typecheck data constructors, in particular how we make multiplicities line up. Now, impedance matching occurs as part of the existing subsumption machinery. See the revamped Note [Typechecking data constructors] in GHC.Tc.Gen.App, as well as Note [Polymorphisation of linear fields] in GHC.Core.Multiplicity. This allows us to get rid of a fair amount of hacky code that was added with the introduction of LinearTypes; in particular the logic of GHC.Tc.Gen.Head.tcInferDataCon. ------------------------- Metric Decrease: T10421 T14766 T15164 T15703 T19695 T5642 T9630 WWRec ------------------------- - - - - - b6faf5d0 by sheaf at 2025-11-15T20:32:02-05:00 Handle unsaturated rep-poly newtypes This commit allows GHC to handle unsaturated occurrences of unlifted newtype constructors. The plan is detailed in Note [Eta-expanding rep-poly unlifted newtypes] in GHC.Tc.Utils.Concrete: for unsaturated unlifted newtypes, we perform the appropriate representation-polymorphism check in tcInstFun. - - - - - b9294468 by Apoorv Ingle at 2025-11-16T20:58:12-06:00 This commit: - Streamlines implementations of `tcExpr` and `tcXExpr` to work on `XExpr` Calls `setInGeneratedCode` everytime the typechecker goes over an `XExpr` - Kills `VACtxt` (and its associated VAExpansion and VACall) datatype, it is subsumed by simply a SrcSpan. - Kills the function `addHeadCtxt` as it is now mearly setting a location - The function `tcValArgs` does its own argument number management - Makes `splitHsApps` not look through `XExpr` - `tcExprSigma` is called if the head of the expression after calling `splitHsApps` turns out to be an `XExpr` - Removes location information from `OrigPat` payload - Removes special case of tcBody from `tcLambdaMatches` - Removes special case of `dsExpr` for `ExpandedThingTc` - Moves `setQLInstLevel` inside `tcInstFun` - Rename `HsThingRn` to `SrcCodeCtxt` - Kills `tcl_in_gen_code` and `tcl_err_ctxt`. It is subsumed by `ErrCtxtStack` - Kills `ExpectedFunTyOrig`. It is subsumed by `CtOrigin` - Fixes `CtOrigin` for `HsProjection` case in `exprCtOrigin`. It was previously assigned to be `SectionOrigin`. It is now just the expression - Adds a new `CtOrigin.ExpansionOrigin` for storing the original syntax - Adds a new `CtOrigin.ExpectedTySyntax` as a replacement for `ExpectedTySyntaxOp`. Cannot kill the former yet because of `ApplicativeDo` - Renames `tcMonoExpr` -> `tcMonoLExpr`, `tcMonoExprNC` -> `tcMonoLExpr` - Renames `EValArg`, `EValArgQL` fields: `ea_ctxt` -> `ea_loc_span` and `eaql_ctx` -> `eaql_loc_span` Notes added [Error Context Stack] Notes updated Note [Expanding HsDo with XXExprGhcRn] ------------------------- Metric Decrease: T9020 ------------------------- - - - - - e739d09b by Apoorv Ingle at 2025-11-16T21:04:51-06:00 - Move `PopErrCtxt` into `SrcCodeOrigin` - Pass in the location of the head of the application chain to `addArgCtxt` to print better error messages. Make `addArgCtxt` print in the nth argument if the head of the application chain is user located. - match context with record updates dont get added in error context - - - - - 93323c63 by Apoorv Ingle at 2025-11-16T21:05:34-06:00 accept new test output - - - - - 522dc613 by Apoorv Ingle at 2025-11-16T21:05:41-06:00 Do not use HsPar in Last statement - - - - - 4a1f55eb by Apoorv Ingle at 2025-11-16T21:06:22-06:00 accept test cases - - - - - af68cc2c by Apoorv Ingle at 2025-11-16T21:08:21-06:00 simplify addArgCtxt and push setSrcSpan inside addLExprCtxt. Make sure addExprCtxt is not called by itself - - - - - eb4b3399 by Apoorv Ingle at 2025-11-16T21:08:31-06:00 fun_orig in tcApp depends on the SrcSpan of the head of the application chain (similar to addArgCtxt) - - - - - 1ce51810 by Apoorv Ingle at 2025-11-16T21:08:31-06:00 rename fun_ctxt to fun_lspan, fun_orig passed in tcInstFun to default to app chain head if its user located, fall back to srcCodeOrigin if it's a generated location - - - - - 917643a4 by Apoorv Ingle at 2025-11-16T21:08:31-06:00 kill PopErrCtxt - - - - - 33ef76cf by Apoorv Ingle at 2025-11-16T21:08:31-06:00 make sure only expression wrapped around generated src span are ignored while adding them to the error context stack - - - - - b940976d by Apoorv Ingle at 2025-11-16T21:08:31-06:00 In `addArgCtxt` the nth argument's err ctxt adds a generated error ctxt if the argument is XExpr - - - - - 055b893d by Apoorv Ingle at 2025-11-16T21:49:47-06:00 rebase fixes - - - - - a5ca25c6 by Apoorv Ingle at 2025-11-17T09:06:59-06:00 deepsubsumption wibbles - - - - - 354 changed files: - .gitlab/rel_eng/upload_ghc_libs.py - cabal.project-reinstall - compiler/GHC/Builtin/Types.hs - compiler/GHC/Builtin/Types/Literals.hs - compiler/GHC/Builtin/Types/Prim.hs - compiler/GHC/Cmm/Sink.hs - compiler/GHC/CmmToAsm.hs - compiler/GHC/CmmToAsm/AArch64/CodeGen.hs - compiler/GHC/CmmToAsm/Reg/Linear.hs - compiler/GHC/CmmToAsm/Reg/Liveness.hs - compiler/GHC/Core.hs - compiler/GHC/Core/Coercion.hs - compiler/GHC/Core/Coercion/Opt.hs - compiler/GHC/Core/DataCon.hs - compiler/GHC/Core/Lint.hs - compiler/GHC/Core/Multiplicity.hs - compiler/GHC/Core/Opt/Arity.hs - compiler/GHC/Core/Opt/CallArity.hs - compiler/GHC/Core/Opt/Simplify/Iteration.hs - compiler/GHC/Core/Opt/Simplify/Utils.hs - compiler/GHC/Core/RoughMap.hs - compiler/GHC/Core/SimpleOpt.hs - compiler/GHC/Core/TyCo/FVs.hs - compiler/GHC/Core/TyCo/Rep.hs - compiler/GHC/Core/TyCon.hs - compiler/GHC/Core/Type.hs - compiler/GHC/Core/Unify.hs - compiler/GHC/Driver/Config/Core/Lint.hs - compiler/GHC/Driver/Downsweep.hs - 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