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<h3 style="margin-top: 20px; margin-bottom: 10px;">
Matthew Pickering pushed to branch master at <a href="https://gitlab.haskell.org/ghc/ghc">Glasgow Haskell Compiler / GHC</a>
</h3>
<h4 style="margin-top: 10px; margin-bottom: 10px;">
Commits:
</h4>
<ul>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/9ffd6163c072356f012b6ad8a09bf6e89568e864">9ffd6163</a></strong>
<div>
<span> by Leo </span> <i> at 2024-09-27T16:26:01+05:30 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","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: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Fix typo in Prelude doc for (>>=)

Fix a minor typo ("equivialent" instead of "equivalent") in the documentation for (>>=) in the prelude.
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/5745dbd33ab8dbe9d25f58448bbab506ff7d1ec2">5745dbd3</a></strong>
<div>
<span> by Vladislav Zavialov </span> <i> at 2024-09-27T16:26:52+05:30 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","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: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Wildcard binders in type declarations (#23501)

Add support for wildcard binders in type declarations:

        type Const a b = a   -- BEFORE: the `b` had to be named
                             --         even if unused on the RHS

        type Const a _ = a   -- AFTER: the compiler accepts
                             --        a wildcard binder `_`

The new feature is part of GHC Proposal #425 "Invisible binders
in type declarations", and more specifically its amendment #641.

Just like a named binder, a wildcard binder `_` may be:

        * plain:      _
        * kinded:    (_ :: k -> Type)
        * invisible, plain:  @_
        * invisible, kinded: @(_ :: k -> Type)

Those new forms of binders are allowed to occur on the LHSs of
data, newtype, type, class, and type/data family declarations:

        data D _ = ...
        newtype N _ = ...
        type T _ = ...
        class C _ where ...
        type family F _
        data family DF _

(Test case: testsuite/tests/typecheck/should_compile/T23501a.hs)

However, we choose to reject them in forall telescopes and
type family result variable binders (the latter being part
of the TypeFamilyDependencies extension):

        type family Fd a = _    -- disallowed  (WildcardBndrInTyFamResultVar)
        fn :: forall _. Int     -- disallowed  (WildcardBndrInForallTelescope)

(Test case: testsuite/tests/rename/should_fail/T23501_fail.hs)

See the new Notes:
        * Note [Type variable binders]
        * Note [Wildcard binders in disallowed contexts]

To accommodate the new forms of binders, HsTyVarBndr was changed
as follows (demonstrated without x-fields for clarity)

        -- BEFORE (ignoring x-fields and locations)
        data HsTyVarBndr flag
          = UserTyVar   flag Name
          | KindedTyVar flag Name HsKind

        -- AFTER (ignoring x-fields and locations)
        data HsTyVarBndr flag = HsTvb flag HsBndrVar HsBndrKind
        data HsBndrVar  = HsBndrVar Name | HsBndrWildCard
        data HsBndrKind = HsBndrNoKind | HsBndrKind LHsKind

The rest of the patch is downstream from this change.

To avoid a breaking change to the TH AST, we generate fresh
names to replace wildcard binders instead of adding a dedicated
representation for them (as discussed in #641).

And to put a cherry on top of the cake, we now allow wildcards in
kind-polymorphic type variable binders in constructor patterns,
see Note [Type patterns: binders and unifiers] and the tyPatToBndr
function in GHC.Tc.Gen.HsType; example:

        fn (MkT @(_ :: forall k. k -> Type) _ _) = ...

(Test case: testsuite/tests/typecheck/should_compile/T23501b.hs)
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/ff2bdca222971307363c0af824408d5a98ef1c3c">ff2bdca2</a></strong>
<div>
<span> by Matthew Pickering </span> <i> at 2024-09-27T16:27:08+05:30 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","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: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>ci: Push perf notes from wasm jobs

It was observed in #25299 that we were failing to push performance
numbers from the wasm jobs.

In future we might want to remove this ad-hoc check but for now it's
easier to add another special case.

Towards #25299
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/4c76f75cf6e2afb7bf7d0800dc77d1a935ee444c">4c76f75c</a></strong>
<div>
<span> by Zubin Duggal </span> <i> at 2024-09-27T16:44:00+05:30 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","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: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Bump GHC version to 9.12
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/e4ac1b0d281b85a0144d1ef6f84a1df00e236052">e4ac1b0d</a></strong>
<div>
<span> by Zubin Duggal </span> <i> at 2024-09-27T19:12:24+05:30 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","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: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Bump GHC version to 9.13
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