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4df0adf6
by Simon Peyton Jones at 2026-02-11T21:50:13-05:00
Simplify the treatment of static forms
This MR implements GHC proposal 732: simplify static forms,
https://github.com/ghc-proposals/ghc-proposals/pull/732
thereby addressing #26556.
See `Note [Grand plan for static forms]` in GHC.Iface.Tidy.StaticPtrTable
The main changes are:
* There is a new, simple rule for (static e), namely that the free
term variables of `e` must be bound at top level. The check is
done in the `HsStatic` case of `GHC.Rename.Expr.rnExpr`
* That in turn substantially simplifies the info that the typechecker
carries around in its type environment. Hooray.
* The desugarer emits static bindings to top level directly; see the
`HsStatic` case of `dsExpr`.
* There is no longer any special static-related magic in the FloatOut
pass. And the main Simplifier pipeline no longer needs a special case
to run FloatOut even with -O0. Hooray.
All this forced an unexpected change to the pattern match checker. It
recursively invokes the main Hs desugarer when it wants to take a look
at a term to spot some special cases (notably constructor applications).
We don't want to emit any nested (static e) bindings to top level a
second time! Yikes.
That forced a modest refactor in GHC.HsToCore.Pmc:
* The `dsl_nablas` field of `DsLclEnv` now has a `NoPmc` case, which says
"I'm desugaring just for pattern-match checking purposes".
* When that flag is set we don't emit static binds.
That in turn forces a cascade of refactoring, but the net effect is an
improvement; less risk of duplicated (even exponential?) work.
See Note [Desugaring HsExpr during pattern-match checking].
10% metric decrease, on some architectures, of compile-time max-bytes-used on T15304.
Metric Decrease:
T15304
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7922f728
by Teo Camarasu at 2026-02-11T21:50:58-05:00
ghc-internal: avoid depending on GHC.Internal.Exts
This module is mostly just re-exports. It made sense as a user-facing
module, but there's no good reason ghc-internal modules should depend on
it and doing so linearises the module graph
- move considerAccessible to GHC.Internal.Magic
Previously it lived in GHC.Internal.Exts, but it really deserves to live
along with the other magic function, which are already re-exported from .Exts
- move maxTupleSize to GHC.Internal.Tuple
This previously lived in GHC.Internal.Exts but a comment already said it
should be moved to .Tuple
Resolves #26832
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b6a4a29b
by Eric Lee at 2026-02-11T21:51:55-05:00
Remove unused Semigroup imports to fix GHC 9.14 bootstrapping
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99d8c146
by Simon Peyton Jones at 2026-02-12T17:36:59+00:00
Fix subtle bug in cast worker/wrapper
See (CWw4) in Note [Cast worker/wrapper].
The true payload is in the change to the definition of
GHC.Types.Id.Info.hasInlineUnfolding
Everthing else is just documentation.
There is a 2% compile time decrease for T13056;
I'll take the win!
Metric Decrease:
T13056
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c1085eb0
by Simon Peyton Jones at 2026-02-12T14:46:12-05:00
Add regression tests for four StaticPtr bugs
Tickets #26545, #24464, #24773, #16981 are all solved by the
recently-landed MR
commit 318ee13bcffa6aa8df42ba442ccd92aa0f7e210c
Author: Simon Peyton Jones <simon.peytonjones@gmail.com>
Date: Mon Oct 20 23:07:20 2025 +0100
Simplify the treatment of static forms
This MR just adds regression tests for them.