[commit: ghc] master: Add specialization rules for realToFrac on Complex (5800b02)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/5800b02a1910a468485b272a2063377e8b06ee1d/ghc

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

commit 5800b02a1910a468485b272a2063377e8b06ee1d
Author: Takano Akio <tak at anoak.io>
Date:   Tue Jan 3 00:20:24 2017 -0500

    Add specialization rules for realToFrac on Complex
    
    This patch implements RULES that specialize realToFrac at these 2 types:
    
    `(Real a) => a -> Complex Double`
    `(Real a) => a -> Complex Float`
    
    Test Plan: ./validate
    
    Reviewers: austin, hvr, bgamari
    
    Reviewed By: bgamari
    
    Subscribers: thomie
    
    Differential Revision: https://phabricator.haskell.org/D2901
    
    GHC Trac Issues: #13040


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

5800b02a1910a468485b272a2063377e8b06ee1d
 libraries/base/Data/Complex.hs | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/libraries/base/Data/Complex.hs b/libraries/base/Data/Complex.hs
index 17ef805..efdc1c5 100644
--- a/libraries/base/Data/Complex.hs
+++ b/libraries/base/Data/Complex.hs
@@ -235,3 +235,16 @@ instance Applicative Complex where
 -- | @since 4.9.0.0
 instance Monad Complex where
   a :+ b >>= f = realPart (f a) :+ imagPart (f b)
+
+-- -----------------------------------------------------------------------------
+-- Rules on Complex
+
+{-# RULES
+
+"realToFrac/a->Complex Double"
+  realToFrac = \x -> realToFrac x :+ (0 :: Double)
+
+"realToFrac/a->Complex Float"
+  realToFrac = \x -> realToFrac x :+ (0 :: Float)
+
+  #-}