[commit: ghc] master: Comments on oneShot (3a71d78)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/3a71d78156ed9422b7642bfbd665978ea3de7f89/ghc

>---------------------------------------------------------------

commit 3a71d78156ed9422b7642bfbd665978ea3de7f89
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Thu Aug 27 16:23:46 2015 +0100

    Comments on oneShot


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3a71d78156ed9422b7642bfbd665978ea3de7f89
 compiler/basicTypes/MkId.hs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/compiler/basicTypes/MkId.hs b/compiler/basicTypes/MkId.hs
index 36d0794..698c865 100644
--- a/compiler/basicTypes/MkId.hs
+++ b/compiler/basicTypes/MkId.hs
@@ -1326,6 +1326,10 @@ and Note [Left folds via right fold]) it was determined that it would be useful
 if library authors could explicitly tell the compiler that a certain lambda is
 called at most once. The oneShot function allows that.
 
+'oneShot' is open kinded, i.e. the type variables can refer to unlifted
+types as well (Trac #10744); e.g.
+   oneShot (\x:Int# -> x +# 1#)
+
 Like most magic functions it has a compulsary unfolding, so there is no need
 for a real definition somewhere. We have one in GHC.Magic for the convenience
 of putting the documentation there.