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<div class="content">
<h3 style="margin-top: 20px; margin-bottom: 10px;">
Andrei Borzenkov pushed to branch wip/sand-witch/pattern-@a-binders 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: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/9f01d14b5bc1c73828b2b061206c45b84353620e">9f01d14b</a></strong>
<div>
<span> by Matthew Pickering </span> <i> at 2023-06-29T04:13:41-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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 -fpolymorphic-specialisation flag (off by default at all optimisation levels)
Polymorphic specialisation has led to a number of hard to diagnose
incorrect runtime result bugs (see #23469, #23109, #21229, #23445) so
this commit introduces a flag `-fpolymorhphic-specialisation` which
allows users to turn on this experimental optimisation if they are
willing to buy into things going very wrong.
Ticket #23469
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/b1e611d5d7e214cf9286e95936f41566f1235c7f">b1e611d5</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-29T04:14:17-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>Rip out runtime linker/compiler checks
We used to choose flags to pass to the toolchain at runtime based on the
platform running GHC, and in this commit we drop all of those runtime
linker checks
Ultimately, this represents a change in policy: We no longer adapt at
runtime to the toolchain being used, but rather make final decisions
about the toolchain used at /configure time/
(we have deleted Note [Run-time linker info] altogether!).
This works towards the goal of having all toolchain configuration logic
living in the same place, which facilities the work towards a
runtime-retargetable GHC (see #19877).
As of this commit, the runtime linker/compiler logic was moved to
autoconf, but soon it, and the rest of the existing toolchain
configuration logic, will live in the standalone ghc-toolchain program
(see !9263)
In particular, what used to be done at runtime is now as follows:
* The flags -Wl,--no-as-needed for needed shared libs are configured
into settings
* The flag -fstack-check is configured into settings
* The check for broken tables-next-to-code was outdated
* We use the configured c compiler by default as the assembler program
* We drop `asmOpts` because we already configure -Qunused-arguments flag
into settings (see !10589)
Fixes #23562
Co-author: Rodrigo Mesquita (@alt-romes)
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/8b35e8caafeeccbf06b7faa70e807028a3f0ff43">8b35e8ca</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-29T18:46:12-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>Define FFI_GO_CLOSURES
The libffi shipped with Apple's XCode toolchain does not contain a
definition of the FFI_GO_CLOSURES macro, despite containing references
to said macro. Work around this by defining the macro, following the
model of a similar workaround in OpenJDK [1].
[1] https://github.com/openjdk/jdk17u-dev/pull/741/files
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/d7ef1704aeba451bd3e0efbdaaab2638ee1f0bc8">d7ef1704</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-29T18:46:12-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>base: Fix incorrect CPP guard
This was guarded on `darwin_HOST_OS` instead of `defined(darwin_HOST_OS)`.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/7c7d1f66d35f73a2faa898a33aa80cd276159dc2">7c7d1f66</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-29T18:46:48-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>rts/Trace: Ensure that debugTrace arguments are used
As debugTrace is a macro we must take care to ensure that
the fact is clear to the compiler lest we see warnings.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/cb92051e3d85575ff6abd753c9b135930cc50cf8">cb92051e</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-29T18:46:48-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>rts: Various warnings fixes
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/dec81dd1fd0475dde4929baae625d155387300bb">dec81dd1</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-29T18:46:48-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>hadrian: Ignore warnings in unix and semaphore-compat
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/1e5b2642683c660812136b0feb65adb942308b4c">1e5b2642</a></strong>
<div>
<span> by Andrei Borzenkov </span> <i> at 2023-06-30T12:39:32+04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>Draft: Type patterns (22478, 18986)
Improved name resolution and type checking of type patterns in constructors:
1. HsTyPat: a new dedicated data type that represents type patterns in
HsConPatDetails instead of reusing HsPatSigType
2. rnHsTyPat: a new function that renames a type
pattern and collects its binders into three groups:
- explicitly bound type variables, excluding locally bound
variables
- implicitly bound type variables from kind signatures
(only if ScopedTypeVariables are enabled)
- named wildcards (only from kind signatures)
2a. rnHsPatSigTypeBindingVars: removed in favour of rnHsTyPat
2b. rnImplcitTvBndrs: removed because no longer needed
3. collect_pat: updated to collect type variable binders from type patterns
(this means that types and terms use the same infrastructure to detect
conflicting bindings, unused variables and name shadowing)
3a. CollVarTyVarBinders: a new CollectFlag constructor that enables
collection of type variables
4. tcHsTyPat: a new function that typechecks type patterns, capable of
handling polymorphic kinds.
See Note [Type patterns: binders and unifiers]
Examples of code that is now accepted:
f = \(P @a) -> \(P @a) -> ... -- triggers -Wname-shadowing
g :: forall a. Proxy a -> ...
g (P @a) = ... -- also triggers -Wname-shadowing
h (P @($(TH.varT (TH.mkName "t")))) = ...
-- t is bound at splice time
j (P @(a :: (x,x))) = ... -- (x,x) is no longer rejected
data T where
MkT :: forall (f :: forall k. k -> Type).
f Int -> f Maybe -> T
k :: T -> ()
k (MkT @f (x :: f Int) (y :: f Maybe)) = ()
-- f :: forall k. k -> Type
Examples of code that is rejected with better error messages:
f (Left @a @a _) = ...
-- new message:
-- • Conflicting definitions for ‘a’
-- Bound at: Test.hs:1:11
-- Test.hs:1:14
Examples of code that is now rejected:
{-# OPTIONS_GHC -Werror=unused-matches #-}
f (P @a) = ()
-- Defined but not used: type variable ‘a’
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/5956c7bdd7c5114df6bfd57a6c2a22f63e844ea0">5956c7bd</a></strong>
<div>
<span> by Andrei Borzenkov </span> <i> at 2023-06-30T12:39:32+04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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 more notes and comments to the patch
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/9da7d3d5e775392e563b714a00f552bf9cabd887">9da7d3d5</a></strong>
<div>
<span> by Andrei Borzenkov </span> <i> at 2023-06-30T12:39:32+04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>Apply Simon's suggestions about documentation
</pre>
</li>
</ul>
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compiler/GHC/Driver/Session.hs
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compiler/GHC/Hs/Instances.hs
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compiler/GHC/Hs/Type.hs
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compiler/GHC/HsToCore/Quote.hs
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compiler/GHC/Iface/Ext/Ast.hs
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