[ ghc-Bugs-1019758 ] SPECIALIZE pragma and polymorphic instances

Bugs item #1019758, was opened at 2004-08-31 15:14
Message generated for change (Comment added) made by simonpj
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Category: Compiler
Group: 6.2.1
Status: Open
Resolution: None
>Priority: 5
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Nobody/Anonymous (nobody)
Summary: SPECIALIZE pragma and polymorphic instances

Initial Comment:
Given a polymorphic specialization like

        f :: (Storable a, Eq a) => T a
        {-# SPECIALIZE f :: T (Ptr a) #-}

GHC does not produce the requested polymorphic
specialization, but if we use f at the ground types T
(Ptr Foo) and T (Ptr Bar), we get a specialization for
each, and these are essentially the same.

ross@xxxxxxxxxxxxxx

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>Comment By: Simon Peyton Jones (simonpj)
Date: 2005-07-07 12:34

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Upping the priority. It's not trivial to do this, but it's still very 
much on my radar

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Comment By: Remi Turk (remit)
Date: 2005-07-06 17:28

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A few more links to messages about this:

SPJ explains (a.o. why he won't solve it before the POPL
deadline ;)
http://www.haskell.org/pipermail/glasgow-haskell-users/2004-June/006874.html

SPJ hints that the patch will appear soon, or perhaps even
already exists:
http://www.haskell.org/pipermail/glasgow-haskell-users/2005-May/008503.html

My own I-hadn't-seen-this-yet bugreport, explaining why it
is, ahum, Vitally Important(TM) to tackle this bug:
http://www.haskell.org/pipermail/glasgow-haskell-bugs/2005-March/004765.html

Simon Marlow implies this one (Priority 4) won't be solved
anytime soon.
http://haskell.org/pipermail/glasgow-haskell-users/2005-July/008738.html

Now, whether this counts as a "yell if you disagree [about
not solving priority < 5]." or as "if you know of a specific
perf problem, please submit it as a bug" I'll leave to the
ones who actually do the work :)

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