Simon Peyton Jones pushed to branch wip/T26772 at Glasgow Haskell Compiler / GHC
Commits:
50761451 by Cheng Shao at 2026-01-27T21:51:23-05:00
ci: update darwin boot ghc to 9.10.3
This patch updates darwin boot ghc to 9.10.3, along with other related
updates, and pays off some technical debt here:
- Update `nixpkgs` and use the `nixpkgs-25.05-darwin` channel.
- Update the `niv` template.
- Update LLVM to 21 and update `llvm-targets` to reflect LLVM 21
layout changes for arm64/x86_64 darwin targets.
- Use `stdenvNoCC` to prevent nix packaged apple sdk from being used
by boot ghc, and manually set `DEVELOPER_DIR`/`SDKROOT` to enforce
the usage of system-wide command line sdk for macos.
- When building nix derivation for boot ghc, run `configure` via the
`arch` command so that `configure` and its subprocesses pick up the
manually specified architecture.
- Remove the previous horrible hack that obliterates `configure` to
make autoconf test result in true. `configure` now properly does its
job.
- Remove the now obsolete configure args and post install settings
file patching logic.
- Use `scheme-small` for texlive to avoid build failures in certain
unused texlive packages, especially on x86_64-darwin.
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94dcd15e by Matthew Pickering at 2026-01-27T21:52:05-05:00
Evaluate backtraces for "error" exceptions at the moment they are thrown
See Note [Capturing the backtrace in throw] and
Note [Hiding precise exception signature in throw] which explain the
implementation.
This commit makes `error` and `throw` behave the same with regard to
backtraces. Previously, exceptions raised by `error` would not contain
useful IPE backtraces.
I did try and implement `error` in terms of `throw` but it started to
involve putting diverging functions into hs-boot files, which seemed to
risky if the compiler wouldn't be able to see if applying a function
would diverge.
CLC proposal: https://github.com/haskell/core-libraries-committee/issues/383
Fixes #26751
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ef35e3ea by Teo Camarasu at 2026-01-27T21:52:46-05:00
ghc-internal: move all Data instances to Data.Data
Most instances of Data are defined in GHC.Internal.Data.Data.
Let's move all remaining instance there.
This moves other modules down in the dependency hierarchy allowing for
more parallelism, and it decreases the likelihood that we would need to
load this heavy .hi file if we don't actually need it.
Resolves #26830
Metric Decrease:
T12227
T16875
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5e0ec555 by sheaf at 2026-01-28T06:56:38-05:00
Add test case for #25679
This commit adds the T25679 test case. The test now passes, thanks to
commit 1e53277af36d3f0b6ad5491f70ffc5593a49dcfd.
Fixes #25679
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f1cd1611 by sheaf at 2026-01-28T06:56:38-05:00
Improve defaulting of representational equalities
This commit makes the defaulting of representational equalities, introduced
in 1e53277a, a little bit more robust. Now, instead of calling the eager
unifier, it calls the full-blown constraint solver, which means that it can
handle some subtle situations, e.g. involving functional dependencies and
type-family injectivity annotations, such as:
type family F a = r | r -> a
type instance F Int = Bool
[W] F beta ~R Bool
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25edf516 by sheaf at 2026-01-28T06:56:38-05:00
Improve errors for unsolved representational equalities
This commit adds a new field of CtLoc, CtExplanations, which allows the
typechecker to leave some information about what it has done. For the moment,
it is only used to improve error messages for unsolved representational
equalities. The typechecker will now accumulate, when unifying at
representational role:
- out-of-scope newtype constructors,
- type constructors that have nominal role in a certain argument,
- over-saturated type constructors,
- AppTys, e.g. `c a ~R# c b`, to report that we must assume that 'c' has
nominal role in its parameters,
- data family applications that do not reduce, potentially preventing
newtype unwrapping.
Now, instead of having to re-construct the possible errors after the fact,
we simply consult the CtExplanations field.
Additionally, this commit modifies the typechecker error messages that
concern out-of-scope newtype constructors. The error message now depends
on whether we have an import suggestion to provide to the user:
- If we have an import suggestion for the newtype constructor,
the message will be of the form:
The data constructor MkN of the newtype N is out of scope
Suggested fix: add 'MkN' to the import list in the import of 'M'
- If we don't have any import suggestions, the message will be
of the form:
NB: The type 'N' is an opaque newtype, whose constructor is hidden
Fixes #15850, #20289, #20468, #23731, #25949, #26137
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4d0e6da1 by Simon Peyton Jones at 2026-01-28T06:57:19-05:00
Fix two bugs in short-cut constraint solving
There are two main changes here:
* Use `isSolvedWC` rather than `isEmptyWC` in `tryShortCutSolver`
The residual constraint may have some fully-solved, but
still-there implications, and we don't want them to abort short
cut solving! That bug caused #26805.
* In the short-cut solver, we abandon the fully-solved residual
constraint; but we may thereby lose track of Givens that are
needed, and either report them as redundant or prune evidence
bindings that are in fact needed.
This bug stopped the `constraints` package from compiling;
see the trail in !15389.
The second bug led me to (another) significant refactoring
of the mechanism for tracking needed EvIds. See the new
Note [Tracking needed EvIds] in GHC.Tc.Solver.Solve
It's simpler and much less head-scratchy now.
Some particulars:
* An EvBindsVar now tracks NeededEvIds
* We deal with NeededEvIds for an implication only when it is
fully solved. Much simpler!
* `tryShortCutTcS` now takes a `TcM WantedConstraints` rather than
`TcM Bool`, so that is can plumb the needed EvIds correctly.
* Remove `ic_need` and `ic_need_implic` from Implication (hooray),
and add `ics_dm` and `ics_non_dm` to `IC_Solved`.
Pure refactor
* Shorten data constructor `CoercionHole` to `CH`, following
general practice in GHC.
* Rename `EvBindMap` to `EvBindsMap` for consistency
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662480b7 by Cheng Shao at 2026-01-28T06:58:00-05:00
ci: use debian validate bindists instead of fedora release bindists in testing stage
This patch changes the `abi-test`, `hadrian-multi` and `perf` jobs in
the full-ci pipeline testing stage to use debian validate bindists
instead of fedora release bindists, to increase pipeline level
parallelism and allow full-ci pipelines to complete earlier. Closes #26818.
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39581ec6 by Cheng Shao at 2026-01-28T06:58:40-05:00
ci: run perf test with -j$cores
This patch makes the perf ci job compile Cabal with -j$cores to speed
up the job.
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607b287b by Wolfgang Jeltsch at 2026-01-28T15:41:53+02:00
Remove `GHC.Desugar` from `base`
`GHC.Desugar` was deprecated and should have been removed in GHC 9.14.
However, the removal was forgotten, although there was a code block that
was intended to trigger a compilation error when the GHC version in use
was 9.14 or later. This code sadly didn’t work, because the
`__GLASGOW_HASKELL__` macro was misspelled as `__GLASGOW_HASKELL`.
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e8f5a45d by sterni at 2026-01-29T04:19:18-05:00
users_guide: fix runtime error during build with Sphinx 9.1.0
Appears that pathto is stricter about what it accepts now.
Tested Sphinx 8.2.3 and 9.1.0 on the ghc-9.10 branch.
Resolves #26810.
Co-authored-by: Martin Weinelt