[commit: ghc] master: Coments only (75f5f23)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/75f5f23b810f74376c71bdf0db51f3ffca6de015/ghc

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

commit 75f5f23b810f74376c71bdf0db51f3ffca6de015
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Thu Aug 6 13:40:07 2015 +0100

    Coments only


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

75f5f23b810f74376c71bdf0db51f3ffca6de015
 compiler/simplCore/SimplUtils.hs | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/compiler/simplCore/SimplUtils.hs b/compiler/simplCore/SimplUtils.hs
index d297be3..db74855 100644
--- a/compiler/simplCore/SimplUtils.hs
+++ b/compiler/simplCore/SimplUtils.hs
@@ -702,20 +702,24 @@ updModeForStableUnfoldings inline_rule_act current_mode
     phaseFromActivation _               = InitialPhase
 
 updModeForRuleLHS :: SimplifierMode -> SimplifierMode
--- See Note [Simplifying RULE LHSs]
+-- See Note [Simplifying rule LHSs]
 updModeForRuleLHS current_mode
   = current_mode { sm_phase  = InitialPhase
                  , sm_inline = False
                  , sm_rules  = False
                  , sm_eta_expand = False }
 
-{- Note [Simplifying RULE LHSs]
+{- Note [Simplifying rule LHSs]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 When simplifying on the LHS of a rule, refrain from all inlining and
 all RULES.  Doing anything to the LHS is plain confusing, because it
 means that what the rule matches is not what the user wrote.
 c.f. Trac #10595, and #10528.
 
+Moreover, inlining (or applying rules) on rule LHSs risks introducing
+Ticks into the LHS, which makes matching trickier. Trac #10665, #10745.
+
+
 Note [Inlining in gentle mode]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Something is inlined if