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<h3 style="margin-top: 20px; margin-bottom: 10px;">
Simon Peyton Jones pushed to branch wip/T25029 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/ff158fcd84f080a3450e09320819ef1d950a2c2d">ff158fcd</a></strong>
<div>
<span> by Tommy Bidne </span> <i> at 2024-08-02T01:14:32+12:00 </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;'>Print exception metadata in default handler
CLC proposals 231 and 261:
- Add exception type metadata to SomeException's displayException.
- Add "Exception" header to default exception handler.
See:
https://github.com/haskell/core-libraries-committee/issues/231
https://github.com/haskell/core-libraries-committee/issues/261
Update stm submodule for test fixes.
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/8b2f70a202ec0913515bf4945de789e959ff8cac">8b2f70a2</a></strong>
<div>
<span> by Andrei Borzenkov </span> <i> at 2024-08-01T23:00:46-04:00 </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;'>Type syntax in expressions (#24159, #24572, #24226)
This patch extends the grammar of expressions with syntax that is
typically found only in types:
* function types (a -> b), (a ->. b), (a %m -> b)
* constrained types (ctx => t)
* forall-quantification (forall tvs. t)
The new forms are guarded behind the RequiredTypeArguments extension,
as specified in GHC Proposal #281. Examples:
{-# LANGUAGE RequiredTypeArguments #-}
e1 = f (Int -> String) -- function type
e2 = f (Int %1 -> String) -- linear function type
e3 = f (forall a. Bounded a => a) -- forall type, constraint
The GHC AST and the TH AST have been extended as follows:
syntax | HsExpr | TH.Exp
---------------+----------+--------------
a -> b | HsFunArr | ConE (->)
a %m -> b | HsFunArr | ConE FUN
ctx => t | HsQual | ConstrainedE
forall a. t | HsForAll | ForallE
forall a -> t | HsForAll | ForallVisE
Additionally, a new warning flag -Wview-pattern-signatures has been
introduced to aid with migration to the new precedence of (e -> p :: t).
Co-authored-by: Vladislav Zavialov <vlad.z.4096@gmail.com>
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/66e7f57d0fa2fdc87f7ab8b14d530eda7111ac19">66e7f57d</a></strong>
<div>
<span> by Brandon Chinn </span> <i> at 2024-08-01T21:50:58-07:00 </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;'>Implement MultilineStrings (#24390)
This commit adds support for multiline strings, proposed at
https://github.com/ghc-proposals/ghc-proposals/pull/569.
Multiline strings can now be written as:
myString =
"""
this is a
multiline string
"""
The multiline string will have leading indentation stripped away.
Full details of this post-processing may be found at the new
GHC.Parser.String module.
In order to cleanly implement this and maximize reusability, I
broke out the lexing logic for strings out of Lexer.x into a
new GHC.Parser.String module, which lexes strings with any
provided "get next character" function. This also gave us the
opportunity to clean up this logic, and even optimize it a bit.
With this change, parsing string literals now takes 25% less
time and 25% less space.
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/cf47b96f8b8100d9f9ad1b8121cbfb65fd7eaf2a">cf47b96f</a></strong>
<div>
<span> by Rodrigo Mesquita </span> <i> at 2024-08-03T05:59:40-04:00 </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;'>hi: Stable sort avails
Sorting the Avails in DocStructures is required to produce fully
deterministic interface files in presence of re-exported modules.
Fixes #25104
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/f3692f6de115746532800e3df5d57c05c1f7b4f1">f3692f6d</a></strong>
<div>
<span> by Simon Peyton Jones </span> <i> at 2024-08-03T23:45:24+01:00 </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/6ce2a69f75dde9c0ebf4e746f015ac7248a1c7b2">6ce2a69f</a></strong>
<div>
<span> by Simon Peyton Jones </span> <i> at 2024-08-03T23:45:24+01:00 </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.
* In GHC.Core.InstEnv, change the type synonym `Canonical` to a data
type `CanonicalEvidence`; and document it 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]`.
* Fix a bug I found when desugaring RULE left hand sides; see (NC1) in
Note [Desugaring non-canonical evidence] in GHC.HsToCore.Binds
This means giving a boolean flag to dsHsWrapper, alas. But I think it
will go away again when I have finished with my (entirely separate)
speciaise-on-values patch.
</pre>
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<h4 style="margin-top: 10px; margin-bottom: 10px;">
30 changed files:
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<a href="#06764eb0158306b83ab1998d18316392a51838c2">
compiler/GHC/Builtin/Names/TH.hs
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<a href="#5596bb0f228bd2a308c4391df97375ae879430a8">
compiler/GHC/Core/InstEnv.hs
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compiler/GHC/Driver/Flags.hs
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compiler/GHC/Driver/Session.hs
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compiler/GHC/Hs/Doc.hs
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compiler/GHC/Hs/Expr.hs
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compiler/GHC/Hs/Instances.hs
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compiler/GHC/Hs/Lit.hs
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compiler/GHC/Hs/Pat.hs
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compiler/GHC/Hs/Syn/Type.hs
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compiler/GHC/Hs/Type.hs
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compiler/GHC/HsToCore/Arrows.hs
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compiler/GHC/HsToCore/Binds.hs
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compiler/GHC/HsToCore/Docs.hs
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compiler/GHC/HsToCore/Expr.hs
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compiler/GHC/HsToCore/Foreign/C.hs
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compiler/GHC/HsToCore/Foreign/JavaScript.hs
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compiler/GHC/HsToCore/Foreign/Wasm.hs
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compiler/GHC/HsToCore/ListComp.hs
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compiler/GHC/HsToCore/Match/Literal.hs
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compiler/GHC/HsToCore/Monad.hs
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compiler/GHC/HsToCore/Quote.hs
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compiler/GHC/HsToCore/Ticks.hs
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compiler/GHC/HsToCore/Utils.hs
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compiler/GHC/Iface/Ext/Ast.hs
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compiler/GHC/Iface/Make.hs
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compiler/GHC/Parser.y
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compiler/GHC/Parser/Annotation.hs
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compiler/GHC/Parser/CharClass.hs
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