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<h3 style="margin-top: 20px; margin-bottom: 10px;">
Simon Peyton Jones pushed to branch wip/T21851 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/92ccb8de9624ea930d66152b2f6a181941a497c9" style="color: #1068bf;">92ccb8de</a></strong>
<div>
<span> by Giles Anderson </span> <i> at 2022-11-09T09:27:52-05:00 </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;'>Use TcRnDiagnostic in GHC.Tc.TyCl.Instance (#20117)

The following `TcRnDiagnostic` messages have been introduced:

TcRnWarnUnsatisfiedMinimalDefinition
TcRnMisplacedInstSig
TcRnBadBootFamInstDeclErr
TcRnIllegalFamilyInstance
TcRnAssocInClassErr
TcRnBadFamInstDecl
TcRnNotOpenFamily
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/90c5abd4581b404f715e72ad55303e18d0c31d68" style="color: #1068bf;">90c5abd4</a></strong>
<div>
<span> by Hécate Moonlight </span> <i> at 2022-11-09T09:28:30-05:00 </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;'>GHCi tags generation phase 2

see #19884
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/f9f17b68b144a7ecb91395c1e987bbf4f91c0180" style="color: #1068bf;">f9f17b68</a></strong>
<div>
<span> by Simon Peyton Jones </span> <i> at 2022-11-10T12:20:03+00:00 </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;'>Fire RULES in the Specialiser

The Specialiser has, for some time, fires class-op RULES in the
specialiser itself: see
   Note [Specialisation modulo dictionary selectors]

This MR beefs it up a bit, so that it fires /all/ RULES in the
specialiser, not just class-op rules.  See
   Note [Fire rules in the specialiser]
The result is a bit more specialisation; see test
   simplCore/should_compile/T21851_2

This pushed me into a bit of refactoring.  I made a new data types
GHC.Core.Rules.RuleEnv, which combines
  - the several source of rules (local, home-package, external)
  - the orphan-module dependencies

in a single record for `getRules` to consult.  That drove a bunch of
follow-on refactoring, including allowing me to remove
cr_visible_orphan_mods from the CoreReader data type.

I moved some of the RuleBase/RuleEnv stuff into GHC.Core.Rule.

The reorganisation in the Simplifier improve compile times a bit
(geom mean -0.1%), but T9961 is an outlier

Metric Decrease:
    T9961
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/2b3d0beec2668963c332b4490328aee256f07766" style="color: #1068bf;">2b3d0bee</a></strong>
<div>
<span> by Simon Peyton Jones </span> <i> at 2022-11-10T12:21:13+00:00 </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;'>Make indexError work better

The problem here is described at some length in
Note [Boxity for bottoming functions] and
Note [Reboxed crud for bottoming calls] in GHC.Core.Opt.DmdAnal.

This patch adds a SPECIALISE pragma for indexError, which
makes it much less vulnerable to the problem described in
these Notes.

(This came up in another line of work, where a small change made
indexError do reboxing (in nofib/spectral/simple/table_sort)
that didn't happen before my change.  I've opened #22404
to document the fagility.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/399e921b05493d79f04e77806c1562806f118d4a" style="color: #1068bf;">399e921b</a></strong>
<div>
<span> by Simon Peyton Jones </span> <i> at 2022-11-10T12:21:14+00:00 </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;'>Fix DsUselessSpecialiseForClassMethodSelector msg

The error message for DsUselessSpecialiseForClassMethodSelector
was just wrong (a typo in some earlier work); trivial fix
</pre>
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