CORE notes break optimisation

I think at some point we decided that Core notes shouldn't affect optimisation. Here is a case where they do:

module Foo where

foo :: Int -> Int
{-# INLINE [1] foo #-}
foo x = x+1

{-# RULES "foo/foo" forall x. foo (foo x) = x #-}

module Bar where

import Foo

bar :: Int -> Int -> Int
bar x y = foo ({-# CORE "note" #-} x `seq` foo y)

When compiled with -O2, the rule doesn't fire with the note but does fire without it. This is the Core with the note:

Bar.bar =
  \ (x_aaw :: GHC.Types.Int) (y_aax :: GHC.Types.Int) ->
    Foo.foo
      (__core_note "note"
       (case x_aaw of _ { GHC.Types.I# _ -> Foo.foo y_aax }))

For the rule to fire, GHC must move the seq to the outside but because of the note, it doesn't.

Trac metadata

Trac field	Value
Version	7.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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