<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
<html lang="en">
<head>
<meta content="text/html; charset=US-ASCII" http-equiv="Content-Type">
<title>
GitLab
</title>
<style data-premailer="ignore" type="text/css">
a { color: #1068bf; }
</style>
<style>img {
max-width: 100%; height: auto;
}
body {
font-size: 0.875rem;
}
body {
-webkit-text-shadow: rgba(255,255,255,0.01) 0 0 1px;
}
body {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Noto Sans", Ubuntu, Cantarell, "Helvetica Neue", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji"; font-size: inherit;
}
</style>
</head>
<body style='font-size: inherit; -webkit-text-shadow: rgba(255,255,255,0.01) 0 0 1px; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Noto Sans", Ubuntu, Cantarell, "Helvetica Neue", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";'>
<div class="content">
<h3 style="margin-top: 20px; margin-bottom: 10px;">
Marge Bot pushed to branch wip/marge_bot_batch_merge_job
at <a href="https://gitlab.haskell.org/ghc/ghc" style="color: #1068bf;">Glasgow Haskell Compiler / GHC</a>
</h3>
<h4 style="margin-top: 10px; margin-bottom: 10px;">
Commits:
</h4>
<ul>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/c9afe2216ccabd36e3083ec3b508310fcdb5eae3" style="color: #1068bf;">c9afe221</a></strong>
<div>
<span>by M Farkas-Dyck</span>
<i>at 2022-09-17T06:44:47-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Clean up some. In particular:
• Delete some dead code, largely under `GHC.Utils`.
• Clean up a few definitions in `GHC.Utils.(Misc, Monad)`.
• Clean up `GHC.Types.SrcLoc`.
• Derive stock `Functor, Foldable, Traversable` for more types.
• Derive more instances for newtypes.
Bump haddock submodule.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/85431ac363e77dd0f93d46ff1ed450b4833c2a40" style="color: #1068bf;">85431ac3</a></strong>
<div>
<span>by Cheng Shao</span>
<i>at 2022-09-17T06:45:25-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>driver: pass original Cmm filename in ModLocation
When compiling Cmm, the ml_hs_file field is used to indicate Cmm
filename when later generating DWARF information. We should pass the
original filename here, otherwise for preprocessed Cmm files, the
filename will be a temporary filename which is confusing.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/63aa006939a8b5284b0f6f6a1c26d52aa3ae47da" style="color: #1068bf;">63aa0069</a></strong>
<div>
<span>by Cheng Shao</span>
<i>at 2022-09-17T06:46:04-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>rts: remove legacy logging cabal flag
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/bd0f418422a3ace8d05c8ce93850190e57321465" style="color: #1068bf;">bd0f4184</a></strong>
<div>
<span>by Cheng Shao</span>
<i>at 2022-09-17T06:46:04-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>rts: make threaded ways optional
For certain targets (e.g. wasm32-wasi), the threaded rts is known not to
work. This patch adds a "threaded" cabal flag to rts to make threaded
rts ways optional. Hadrian enables this flag iff the flavour rtsWays
contains threaded ways.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/08280089b080c90bd25e2261d1b337931d242013" style="color: #1068bf;">08280089</a></strong>
<div>
<span>by John Ericson</span>
<i>at 2022-09-17T13:44:00-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Add `Eq` and `Ord` instances for `Generically1`
These are needed so the subsequent commit overhauling the `*1` classes
type-checks.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/08eca4ec4025bb42666a318cca73ca73f1beac75" style="color: #1068bf;">08eca4ec</a></strong>
<div>
<span>by John Ericson</span>
<i>at 2022-09-17T13:44:53-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Relax instances for Functor combinators; put superclass on Class1 and Class2 to make non-breaking
This change is approved by the Core Libraries commitee in
https://github.com/haskell/core-libraries-committee/issues/10
The first change makes the `Eq`, `Ord`, `Show`, and `Read` instances for
`Sum`, `Product`, and `Compose` match those for `:+:`, `:*:`, and `:.:`.
These have the proper flexible contexts that are exactly what the
instance needs:
For example, instead of
```haskell
instance (Eq1 f, Eq1 g, Eq a) => Eq (Compose f g a) where
(==) = eq1
```
we do
```haskell
deriving instance Eq (f (g a)) => Eq (Compose f g a)
```
But, that change alone is rather breaking, because until now `Eq (f a)`
and `Eq1 f` (and respectively the other classes and their `*1`
equivalents too) are *incomparable* constraints. This has always been an
annoyance of working with the `*1` classes, and now it would rear it's
head one last time as an pesky migration.
Instead, we give the `*1` classes superclasses, like so:
```haskell
(forall a. Eq a => Eq (f a)) => Eq1 f
```
along with some laws that canonicity is preserved, like:
```haskell
liftEq (==) = (==)
```
and likewise for `*2` classes:
```haskell
(forall a. Eq a => Eq1 (f a)) => Eq2 f
```
and laws:
```haskell
liftEq2 (==) = liftEq1
```
The `*1` classes also have default methods using the `*2` classes where
possible.
What this means, as explained in the docs, is that `*1` classes really
are generations of the regular classes, indicating that the methods can
be split into a canonical lifting combined with a canonical inner, with
the super class "witnessing" the laws[1] in a fashion.
Circling back to the pragmatics of migrating, note that the superclass
means evidence for the old `Sum`, `Product`, and `Compose` instances is
(more than) sufficient, so breakage is less likely --- as long no
instances are "missing", existing polymorphic code will continue to
work.
Breakage can occur when a datatype implements the `*1` class but not the
corresponding regular class, but this is almost certainly an oversight.
For example, containers made that mistake for `Tree` and `Ord`, which I
fixed in https://github.com/haskell/containers/pull/761, but fixing the
issue by adding `Ord1` was extremely *un*controversial.
`Generically1` was also missing `Eq`, `Ord`, `Read,` and `Show`
instances. It is unlikely this would have been caught without
implementing this change.
-----
[1]: In fact, someday, when the laws are part of the language and not
only documentation, we might be able to drop the superclass field of the
dictionary by using the laws to recover the superclass in an
instance-agnostic manner, e.g. with a *non*-overloaded function with
type:
```haskell
DictEq1 f -> DictEq a -> DictEq (f a)
```
But I don't wish to get into optomizations now, just demonstrate the
close relationship between the law and the superclass.
Bump haddock submodule because of test output changing.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/b62d7c1d8e25fc254c68f1416070701d7c64fc17" style="color: #1068bf;">b62d7c1d</a></strong>
<div>
<span>by Ryan Scott</span>
<i>at 2022-09-17T16:48:42-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>DeriveFunctor: Check for last type variables using dataConUnivTyVars
Previously, derived instances of `Functor` (as well as the related classes
`Foldable`, `Traversable`, and `Generic1`) would determine which constraints to
infer by checking for fields that contain the last type variable. The problem
was that this last type variable was taken from `tyConTyVars`. For GADTs, the
type variables in each data constructor are _not_ the same type variables as
in `tyConTyVars`, leading to #22167.
This fixes the issue by instead checking for the last type variable using
`dataConUnivTyVars`. (This is very similar in spirit to the fix for #21185,
which also replaced an errant use of `tyConTyVars` with type variables from
each data constructor.)
Fixes #22167.
</pre>
</li>
</ul>
<h4 style="margin-top: 10px; margin-bottom: 10px;">30 changed files:</h4>
<ul>
<li class="file-stats">
<a href="#db697f6aea9f93f1583f1d5c62d25570a1e07f73" style="color: #1068bf;">
compiler/GHC/Cmm/CLabel.hs
</a>
</li>
<li class="file-stats">
<a href="#806448db91cc2906ebcc088107220a663d3d43eb" style="color: #1068bf;">
compiler/GHC/Cmm/CommonBlockElim.hs
</a>
</li>
<li class="file-stats">
<a href="#cf82b82d6e47b3c81686a3340668a31ce028e2a1" style="color: #1068bf;">
compiler/GHC/Cmm/Lint.hs
</a>
</li>
<li class="file-stats">
<a href="#90378e83c3a00a78bc0b3c01da111e0a787de451" style="color: #1068bf;">
compiler/GHC/Cmm/Node.hs
</a>
</li>
<li class="file-stats">
<a href="#dafe0c717051bfbe491ee2662d7c0e72cf3c0034" style="color: #1068bf;">
compiler/GHC/CmmToAsm/CFG/Dominators.hs
</a>
</li>
<li class="file-stats">
<a href="#ea29061dab1b843e0ea9294afc614998f3a8d08f" style="color: #1068bf;">
compiler/GHC/CmmToAsm/Monad.hs
</a>
</li>
<li class="file-stats">
<a href="#76664ab267df4fc0bec2465efd78bf0afacfe3a7" style="color: #1068bf;">
compiler/GHC/CmmToC.hs
</a>
</li>
<li class="file-stats">
<a href="#b5ac041c7f79084a7a7626eda4cdadda3457d235" style="color: #1068bf;">
compiler/GHC/CmmToLlvm/Base.hs
</a>
</li>
<li class="file-stats">
<a href="#783e5dae6e86931f06700fc088fb7d48c8a07386" style="color: #1068bf;">
compiler/GHC/Core/Coercion.hs
</a>
</li>
<li class="file-stats">
<a href="#91648438362e5a35363d2bb7abb04016dedd7d7e" style="color: #1068bf;">
compiler/GHC/Core/FamInstEnv.hs
</a>
</li>
<li class="file-stats">
<a href="#84c9d3ba34173297e7d7747e02caa2e004b164fc" style="color: #1068bf;">
compiler/GHC/Core/Type.hs
</a>
</li>
<li class="file-stats">
<a href="#2fefe3125c649bc5377b06a7cca18e785855b79c" style="color: #1068bf;">
compiler/GHC/Data/Bag.hs
</a>
</li>
<li class="file-stats">
<a href="#f4ae6618b39d5ee4af8302b821aa7e38097a84b7" style="color: #1068bf;">
compiler/GHC/Data/Maybe.hs
</a>
</li>
<li class="file-stats">
<a href="#b7b115d3575360d6e09fca92d3acd66eeb7b9560" style="color: #1068bf;">
compiler/GHC/Data/Pair.hs
</a>
</li>
<li class="file-stats">
<a href="#cb60c43d987aedeac6767618d9c910aefe1b2aa5" style="color: #1068bf;">
compiler/GHC/Data/Stream.hs
</a>
</li>
<li class="file-stats">
<a href="#5240ba4d079cfeb9884babd8ec4e134730308b54" style="color: #1068bf;">
compiler/GHC/Driver/CmdLine.hs
</a>
</li>
<li class="file-stats">
<a href="#9a679a2680ef6061397f1987091ea9f96ffe095d" style="color: #1068bf;">
compiler/GHC/Driver/Main.hs
</a>
</li>
<li class="file-stats">
<a href="#1dab250036d04cfcf3530f6ff27889f723cc2dda" style="color: #1068bf;">
compiler/GHC/Driver/Make.hs
</a>
</li>
<li class="file-stats">
<a href="#50938348a9ded102cf1615f77db63c178b7fd1d8" style="color: #1068bf;">
compiler/GHC/Driver/Monad.hs
</a>
</li>
<li class="file-stats">
<a href="#774d88050336ef660c7a219fb06c480c2fc639bc" style="color: #1068bf;">
compiler/GHC/Driver/Session.hs
</a>
</li>
<li class="file-stats">
<a href="#dd79b5199bc3b425c4536c633b39006df111a7ef" style="color: #1068bf;">
compiler/GHC/HsToCore.hs
</a>
</li>
<li class="file-stats">
<a href="#ea46b374e004d4416e29a563ee063542f98e48c5" style="color: #1068bf;">
compiler/GHC/HsToCore/Docs.hs
</a>
</li>
<li class="file-stats">
<a href="#aa160d2e15ce4b9872864040e449a60d09ad648f" style="color: #1068bf;">
compiler/GHC/HsToCore/Ticks.hs
</a>
</li>
<li class="file-stats">
<a href="#649144a78135a23cabfc90dd83c4aabf448eb6ab" style="color: #1068bf;">
compiler/GHC/Iface/Ext/Ast.hs
</a>
</li>
<li class="file-stats">
<a href="#ea70f9cf0a00327d944951cb4a4dfa9fe4194b2d" style="color: #1068bf;">
compiler/GHC/Iface/Ext/Types.hs
</a>
</li>
<li class="file-stats">
<a href="#4ed0dc87b8bdd9324e8a181cff15caa104b9e58c" style="color: #1068bf;">
compiler/GHC/Iface/Make.hs
</a>
</li>
<li class="file-stats">
<a href="#a8e6b17fc507589522323d8dd20d9713e8c06760" style="color: #1068bf;">
compiler/GHC/Iface/Recomp.hs
</a>
</li>
<li class="file-stats">
<a href="#06ff7bac58fd8cfe0c17b81963b03f4cce86a065" style="color: #1068bf;">
compiler/GHC/IfaceToCore.hs
</a>
</li>
<li class="file-stats">
<a href="#bf951467d4a9aa443cb109cb4c84a2891945649b" style="color: #1068bf;">
compiler/GHC/Parser.y
</a>
</li>
<li class="file-stats">
<a href="#446cb12ca6cefaf1c6eb79b7db643632744263c7" style="color: #1068bf;">
compiler/GHC/Parser/PostProcess.hs
</a>
</li>
</ul>
<h5 style="margin-top: 10px; margin-bottom: 10px; font-size: 0.875rem;">The diff was not included because it is too large.</h5>
</div>
<div class="footer" style="margin-top: 10px;">
<p style="font-size: small; color: #666;">
—
<br>
<a href="https://gitlab.haskell.org/ghc/ghc/-/compare/bb74d46edf49a8ab8739245a5711d8984f2d9eac...b62d7c1d8e25fc254c68f1416070701d7c64fc17" style="color: #1068bf;">View it on GitLab</a>.
<br>
You're receiving this email because of your account on <a target="_blank" rel="noopener noreferrer" href="https://gitlab.haskell.org" style="color: #1068bf;">gitlab.haskell.org</a>. <a href="https://gitlab.haskell.org/-/profile/notifications" target="_blank" rel="noopener noreferrer" class="mng-notif-link" style="color: #1068bf;">Manage all notifications</a> · <a href="https://gitlab.haskell.org/help" target="_blank" rel="noopener noreferrer" class="help-link" style="color: #1068bf;">Help</a>
</p>
</div>
</body>
</html>