GHC: Ticket #8555: Simplify given `Coercible` constraints
http://ghc.haskell.org/trac/ghc/ticket/8555
<p>
It would be feasible and possibly useful if
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<pre class="wiki">foo :: Coercible [a] [b] => a -> b
foo = coerce
</pre><p>
would work. This involve simplifying <tt>CtGiven</tt>s similar to how given (nominal) equalities are simplified.
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<p>
I’ll defer working on this, as it is not strictly required, it seems.
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en-usGHChttp://ghc.haskell.org/trac/ghc/chrome/site/ghc_logo.png
http://ghc.haskell.org/trac/ghc/ticket/8555
Trac 1.0.1goldfireFri, 22 Nov 2013 21:54:29 GMT
http://ghc.haskell.org/trac/ghc/ticket/8555#comment:1
http://ghc.haskell.org/trac/ghc/ticket/8555#comment:1
<p>
Certainly nothing blocking this at the Core level... the <tt>Nth</tt> coercion constructor would do the right thing here.
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TicketnomeataTue, 18 Feb 2014 17:22:50 GMTrelated changed
http://ghc.haskell.org/trac/ghc/ticket/8555#comment:2
http://ghc.haskell.org/trac/ghc/ticket/8555#comment:2
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changed from <em>#8503</em> to <em>#8503 #8555</em>
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TicketarchblobMon, 12 May 2014 16:51:37 GMTcc, owner set
http://ghc.haskell.org/trac/ghc/ticket/8555#comment:3
http://ghc.haskell.org/trac/ghc/ticket/8555#comment:3
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<li><strong>cc</strong>
<em>fcsernik@…</em> added
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<li><strong>owner</strong>
set to <em>archblob</em>
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<p>
This looks like a good place to further my understanding of ghc internals so I'll give it a try if no one else is doing it currently, so if someone is, please say so and don't let me waste my time :-P.
</p>
TicketnomeataMon, 12 May 2014 18:02:02 GMT
http://ghc.haskell.org/trac/ghc/ticket/8555#comment:4
http://ghc.haskell.org/trac/ghc/ticket/8555#comment:4
<p>
Nobody is working on it, so if you feel like it, please give it a shot. (But also beware that in the last months, nobody was missing the feature, so it may have a limited impact – don’t let that lessen your motivation!)
</p>
TicketsimonpjMon, 19 May 2014 16:07:12 GMT
http://ghc.haskell.org/trac/ghc/ticket/8555#comment:5
http://ghc.haskell.org/trac/ghc/ticket/8555#comment:5
<p>
I doubt that this is very useful in practice. I think there are plenty of other more directly useful tickets. Eg look at <a class="wiki" href="http://ghc.haskell.org/trac/ghc/wiki/Status/SLPJ-Tickets">Status/SLPJ-Tickets</a>. For example, <a class="closed ticket" href="http://ghc.haskell.org/trac/ghc/ticket/5610" title="feature request: Improve "Unacceptable argument type in foreign declaration" error message (closed: fixed)">#5610</a>/<a class="closed ticket" href="http://ghc.haskell.org/trac/ghc/ticket/7243" title="bug: regression: acceptable foreign result types (closed: fixed)">#7243</a> looks tractable and useful. <a class="new ticket" href="http://ghc.haskell.org/trac/ghc/ticket/8281" title="bug: The impossible happened: primRepToFFIType (new)">#8281</a> looks as if it needs a push. Etc.
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<p>
Simon
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TicketarchblobMon, 19 May 2014 16:42:52 GMT
http://ghc.haskell.org/trac/ghc/ticket/8555#comment:6
http://ghc.haskell.org/trac/ghc/ticket/8555#comment:6
<p>
Yeah, I am more interested in the typechecker part of ghc at the moment, so I just chose something recent. I'll certainly have a lookt at those tickets and see if I can help. :)
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TicketarchblobSat, 24 May 2014 08:11:16 GMTowner deleted
http://ghc.haskell.org/trac/ghc/ticket/8555#comment:7
http://ghc.haskell.org/trac/ghc/ticket/8555#comment:7
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<em>archblob</em> deleted
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