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<h3 style="margin-top: 20px; margin-bottom: 10px;">
Marge Bot pushed to branch master at <a href="https://gitlab.haskell.org/ghc/ghc">Glasgow Haskell Compiler / GHC</a>
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<h4 style="margin-top: 10px; margin-bottom: 10px;">
Commits:
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<ul>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/ffbc2ab0c701ca5e789d1b8d0dc099790e35f820">ffbc2ab0</a></strong>
<div>
<span> by Simon Peyton Jones </span> <i> at 2024-09-10T00:40:37-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>Refactor only newSysLocalDs
* Change newSysLocalDs to take a scaled type
* Add newSysLocalMDs that takes a type and makes a ManyTy local
Lots of files touched, nothing deep.
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/7124e4ad76d98f1fc246ada4fd7bf64413ff2f2e">7124e4ad</a></strong>
<div>
<span> by Simon Peyton Jones </span> <i> at 2024-09-10T00:40:37-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>Don't introduce 'nospec' on the LHS of a RULE
This patch address #25160. The main payload is:
* When desugaring the LHS of a RULE, do not introduce the `nospec` call
for non-canonical evidence. See GHC.Core.InstEnv
Note [Coherence and specialisation: overview]
The `nospec` call usually introdued in `dsHsWrapper`, but we don't want it
on the LHS of a RULE (that's what caused #25160). So now `dsHsWrapper` takes
a flag to say if it's on the LHS of a RULE. See wrinkle (NC1) in
`Note [Desugaring non-canonical evidence]` in GHC.HsToCore.Binds.
But I think this flag will go away again when I have finished with my
(entirely separate) speciaise-on-values patch (#24359).
All this meant I had to re-understand the `nospec` stuff and coherence, and
that in turn made me do some refactoring, and add a lot of new documentation
The big change is that in GHC.Core.InstEnv, I changed
the /type synonym/ `Canonical` into
a /data type/ `CanonicalEvidence`
and documented it a lot better.
That in turn made me realise that CalLStacks were being treated with a
bit of a hack, which I documented in `Note [CallStack and ExecptionContext hack]`.
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/663daf8dfaf878ee5463d56666b6d5e8670f33d8">663daf8d</a></strong>
<div>
<span> by Simon Peyton Jones </span> <i> at 2024-09-10T00:40:37-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>Add defaulting of equalities
This MR adds one new defaulting strategy to the top-level
defaulting story: see Note [Defaulting equalities] in GHC.Tc.Solver.
This resolves #25029 and #25125, which showed that users were
accidentally relying on a GHC bug, which was fixed by
commit 04f5bb85c8109843b9ac2af2a3e26544d05e02f4
Author: Simon Peyton Jones <simon.peytonjones@gmail.com>
Date: Wed Jun 12 17:44:59 2024 +0100
Fix untouchability test
This MR fixes #24938. The underlying problem was tha the test for
"does this implication bring in scope any equalities" was plain wrong.
This fix gave rise to a number of user complaints; but the improved
defaulting story of this MR largely resolves them.
On the way I did a bit of refactoring, of course
* Completely restructure the extremely messy top-level defaulting
code. The new code is in GHC.Tc.Solver.tryDefaulting, and is much,
much, much esaier to grok.
</pre>
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<h4 style="margin-top: 10px; margin-bottom: 10px;">
30 changed files:
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<a href="#5596bb0f228bd2a308c4391df97375ae879430a8">
compiler/GHC/Core/InstEnv.hs
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<a href="#5855ff1d64fcadf28e7984964e69e35ff4de7f0a">
compiler/GHC/HsToCore/Arrows.hs
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<a href="#65e2067fbb7377818b6cadff0531f44029499948">
compiler/GHC/HsToCore/Binds.hs
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<a href="#6bdd5abc649727f2a802bc96ce5c276de19d3726">
compiler/GHC/HsToCore/Expr.hs
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compiler/GHC/HsToCore/Foreign/C.hs
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<a href="#73d2b5c14c6cd4cb2c09087042caf1a69ae51b72">
compiler/GHC/HsToCore/Foreign/Call.hs
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<a href="#db27611d8b29a58e6f2b03a85beb688974be8085">
compiler/GHC/HsToCore/Foreign/JavaScript.hs
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<a href="#204da6b1b12bcfa4ccbef04a1e58b7554a915eac">
compiler/GHC/HsToCore/Foreign/Wasm.hs
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<a href="#912bb8ed70a132c8eb2e037f8c9ecb045d2c229c">
compiler/GHC/HsToCore/ListComp.hs
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compiler/GHC/HsToCore/Monad.hs
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compiler/GHC/HsToCore/Utils.hs
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compiler/GHC/Tc/Errors.hs
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compiler/GHC/Tc/Gen/Splice.hs
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compiler/GHC/Tc/Instance/Class.hs
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compiler/GHC/Tc/Solver.hs
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compiler/GHC/Tc/Solver/Dict.hs
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compiler/GHC/Tc/Solver/Equality.hs
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compiler/GHC/Tc/Solver/Irred.hs
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compiler/GHC/Tc/Solver/Monad.hs
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compiler/GHC/Tc/Solver/Solve.hs
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compiler/GHC/Tc/TyCl/Instance.hs
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compiler/GHC/Tc/Types/Evidence.hs
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compiler/GHC/Tc/Utils/Instantiate.hs
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compiler/GHC/Tc/Utils/Unify.hs
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<a href="#73f41d8898656d3e07220eea9acb4e580214faff">
testsuite/tests/indexed-types/should_compile/Simple14.hs
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testsuite/tests/indexed-types/should_compile/Simple14.stderr
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testsuite/tests/indexed-types/should_compile/all.T
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testsuite/tests/simplCore/should_compile/T25160.hs
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testsuite/tests/simplCore/should_compile/all.T
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The diff was not included because it is too large.
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