-
ffa56ae4
by sheaf at 2026-10-09T17:15:59+02:00
Preserve sign of zero when parsing -0.0#
This commit leverages the recently added GHC.Types.Literal.Floating
module in order to preserve the sign of negative zero from
source-written floating-point literals.
Fixes #27545
-
d538cac9
by Facundo Domínguez at 2026-10-09T20:26:38-04:00
Propagate annotations to simple interfaces
This allows annotations to be visible to plugins when run by
haddock. The LiquidHaskell plugin needs the annotations, in particular.
Fixes #26761
-
32c4f4ab
by meooow25 at 2026-10-09T20:27:28-04:00
Bump containers submodule to 0.8.1
And fix affected tests.
* T4086a: containers depends on template-haskell-lift now instead of
template-haskell.
* T22611: Updated to be less dependent on containers internals.
-
c786065e
by sheaf at 2026-10-09T20:28:20-04:00
Use an explicit pattern match in toIfaceIdDetails
The old wildcard pattern let this code bit rot: it did not properly account
for recently added 'IdDetails' such as 'RepPolyId', which resulted in
spurious 'pprTrace' messages that could even pollute HLS sessions.
Fixes #23785
-
e7cacf59
by sheaf at 2026-10-09T20:29:09-04:00
Take into account ifKind in freeNamesIfDecl
Commit 3c2f4bb4 added the 'ifKind' field to various constructors
of 'IfaceDecl', which preserves the original kind (before type synonym
expansion) for better error messages.
However, that commit forgot to update 'freeNamesIfDecl' correspondingly.
This could result in a "urk! lookup local fingerpring" crash when e.g.
a type's kind uses a type synonym defined later, as we failed to add a
dependency on the type synonym during dependency analysis.
Fixes #27916
-
8e606440
by Simon Peyton Jones at 2026-10-10T16:14:47+01:00
Remove the Eq and Ord instances for ForAllTyFlag
In Note [Comparing visibility] in GHC.Core.TyCo.Compare we read that
"we always compare ForAllTyFlags with `eqForAllVis` or `cmpForAllVis`"
But alas there was an Eq and Ord instance for ForAllTyFlag, which made it
impossible to check this claim. So I made these changes:
* Move the definition of ForAllTyFlag and its related functions from
L.H.S.Specificity (where it did not belong, since L.H.S didn't use it)
into GHC.Types.Var.
* Remove the Eq and Ord instances for ForAllTyFlag
* Deal with the fallout, by using `eqForAllVis` or related functions.
* In interface files we use IfaceType as a key for a de-deduplication map
See Note [Deduplication during iface binary serialisation]
in GHC.Iface.Binary. For this we need /exact/ comparison, so we use a
newtype wrapper for IfaceForAllTyFlag, and give use `cmpForAllTyFlagExactly`
to implement its Ord instance. Tiresome but easy.
* Rename `toIfaceForAllBndrs` to `toIfaceForAllTyBndrs`
-
d91d6dfb
by Simon Peyton Jones at 2026-10-10T16:14:47+01:00
Refactor type and coercion substitution
This MR refactors type and coercion substitution so that they use
TyCoMapper, rather than hand-rolled code. Fundamentally it's a simple
idea, but I had to do quite a bit of refactoring to make it fly.
I got Claude to help me this this refactoring, but I paid careful
attention to every line of code.
Main changes:
* New module GHC.Core.TyCo.Make which defines TyCoMapper, and a bunch of other
simple "smart constructors" for types and coercions. See
GHC.Core.TyCo.Rep Note [The Type-related module hierarchy], esp (TRM1)
* The new TyCoMapper has new fields `tcm_tcapp_ty` and `tcm_tcapp_co` to handle
type-constructor applications. These replace `tcm_tycon`.
* Rewrite GHC.Core.TyCo.Subst to use TyCoMapper
* Rewrite GHC.Core.Type.expandTypeSynonyms to use TyCoMapper.
* Implement `seqType` and `seqCo` with TyCoFolder. To to this I had to add
a `tcf_lit` field to TyCoFolder.
* A new module GHC.Utils.StrictIdentity to define a strict identity monad,
which itself is used for
substTyCoMapper :: TyCoMapper Subst StrictIdentity
Refactoring `seq` functions
* In GHC.Core.Seq, redefine `seqOneShot`, `seqRuleInfo`, and friends to return
`SeqResult`, a new type defined in GHC.Types.Baseic, rather than `()`. We
can define a Monoid instance for `SeqResult` that does the right thing.
* This has knock-on effects across the compiler.
-
24a92554
by Simon Peyton Jones at 2026-10-10T16:14:47+01:00
Refactor TyCoMapper to take a single monad; add StrictReaderT
TyCoMapper used to be parameterised over both an environment and a
monad, with fields like
tcm_tyvar :: env -> TyVar -> m Type
Now it is parameterised over just the monad:
tcm_tyvar :: TyVar -> m Type
If the mapping needs an environment, `m` is a reader monad over that
environment. Many uses (e.g. zonkTcTypeMapper, swizzleMapper) need no
environment at all, and used to pass a dummy (). The binder field
becomes
tcm_tycobinder :: forall r. TyCoVar -> ForAllTyFlag
-> (TyCoVar -> m r) -> m r
and runs the continuation in the extended environment. mapTyCoX is gone;
only mapTyCo remains.
To make this efficient, the reader monad must use the one-shot trick and
be strict in the environment. So:
* New module GHC.Utils.Monad.StrictReader defines
newtype StrictReaderT r m a
with hand-written instances. The builder of the pattern synonym
`StrictReaderT` is a smart constructor that adds both `oneShot` and a
bang on the environment, so every StrictReaderT computation is strict
in the environment. See Note [Instances for StrictReaderT].
* ZonkT becomes type ZonkT = StrictReaderT ZonkEnv
ZonkM becomes type ZonkM = StrictReaderT ZonkGblEnv IO
replacing their own hand-written instances.
* Substitution uses
type SubstM = StrictReaderT Subst StrictIdentity
substTyCoMapper :: TyCoMapper SubstM
and similarly expandTypeSynonymMapper.
* zonk_tycomapper :: TyCoMapper (ZonkT TcM) is now much simpler.
* swizzleMapper uses StrictIdentity rather than Identity.
* Module renaming, so that the strict monads are all peers in GHC.Utils.Monad:
GHC.Utils.StrictIdentity ==> GHC.Utils.Monad.StrictIdentity
GHC.Utils.Monad.State.Strict ==> GHC.Utils.Monad.StrictState
alongside the new GHC.Utils.Monad.StrictReader.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>