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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.
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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'.
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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.
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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].
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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.
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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
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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.
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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
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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.
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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: <local_reg> = <expr>
node: <local_reg> = <other_expr>
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
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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
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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 <sam.derbyshire@gmail.com>
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64ec82ff
by Andreas Klebinger at 2025-11-11T11:52:48-05:00
Add hpc to release script
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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.
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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 <sam.derbyshire@gmail.com>
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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 <simonpj@microsoft.com>
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 <simon.peytonjones@gmail.com>
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.