Proposal: Export Any from Unsafe.Coerce

David Feuer

14 Sep 2015 14 Sep '15

1:44 p.m.

Any is the sanctioned intermediary for unsafeCoerce. GHC claims to guarantee that any lifted type can be coerced to and from Any without harm. Yet Any seems to be available only from the deeply mystical GHC.Prim, which users outside the GHC source tree are never supposed to import. While GHC.Exts would be an acceptable place, I think Unsafe.Coerce is more appropriate, and will make it easier for users to find this type.

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Richard Eisenberg

15 Sep 15 Sep

10:10 a.m.

Sounds reasonable to me. Also, see #10886, which this request prompted me to make. Richard On Sep 14, 2015, at 1:44 PM, David Feuer wrote:

...

Any is the sanctioned intermediary for unsafeCoerce. GHC claims to guarantee that any lifted type can be coerced to and from Any without harm. Yet Any seems to be available only from the deeply mystical GHC.Prim, which users outside the GHC source tree are never supposed to import. While GHC.Exts would be an acceptable place, I think Unsafe.Coerce is more appropriate, and will make it easier for users to find this type.

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Carter Schonwald

10:23 a.m.

Sounds like a good idea to me, granted I don't use Any myself, but it and unsafeCoerce require similar levels of care and compiler understanding afaik On Tuesday, September 15, 2015, Richard Eisenberg wrote:

...

Sounds reasonable to me. Also, see #10886, which this request prompted me to make.

Richard

On Sep 14, 2015, at 1:44 PM, David Feuer javascript:_e(%7B%7D,'cvml','david.feuer@gmail.com');> wrote:

Any is the sanctioned intermediary for unsafeCoerce. GHC claims to guarantee that any lifted type can be coerced to and from Any without harm. Yet Any seems to be available only from the deeply mystical GHC.Prim, which users outside the GHC source tree are never supposed to import. While GHC.Exts would be an acceptable place, I think Unsafe.Coerce is more appropriate, and will make it easier for users to find this type. _______________________________________________ Libraries mailing list Libraries@haskell.org javascript:_e(%7B%7D,'cvml','Libraries@haskell.org'); http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

Simon Peyton Jones

5:41 p.m.

Certainly OK with me too. GHC.Exts is the right place. Simon From: Libraries [mailto:libraries-bounces@haskell.org] On Behalf Of Richard Eisenberg Sent: 15 September 2015 15:10 To: David Feuer Cc: Haskell Libraries Subject: Re: Proposal: Export Any from Unsafe.Coerce Sounds reasonable to me. Also, see #10886, which this request prompted me to make. Richard On Sep 14, 2015, at 1:44 PM, David Feuer mailto:david.feuer@gmail.com> wrote: Any is the sanctioned intermediary for unsafeCoerce. GHC claims to guarantee that any lifted type can be coerced to and from Any without harm. Yet Any seems to be available only from the deeply mystical GHC.Prim, which users outside the GHC source tree are never supposed to import. While GHC.Exts would be an acceptable place, I think Unsafe.Coerce is more appropriate, and will make it easier for users to find this type. _______________________________________________ Libraries mailing list Libraries@haskell.orgmailto:Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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participants (4)

Carter Schonwald
David Feuer
Richard Eisenberg
Simon Peyton Jones