Occurrence analysis and RULES

Something is wrong with the occurrence analysis of rules.

module Foo where

f :: Int -> Int
{-# NOINLINE [1] f #-}
f x = x+1

{-# RULES
   "map/f" map f = map (f . f)
#-}

At least with -DDEBUG you'll see

WARNING: file compiler/simplCore/OccurAnal.hs, line 73
  Glomming in Foo: [rgg :->]
  Call stack:
      CallStack (from HasCallStack):
        callStackDoc, called at compiler/utils/Outputable.hs:1237:29 in ghc:Outputable
        warnPprTrace, called at compiler/simplCore/OccurAnal.hs:72:6 in ghc:OccurAnal
WARNING: file compiler/simplCore/OccurAnal.hs, line 73
  Glomming in Foo: [rgg :->]
  Call stack:
      CallStack (from HasCallStack):
        callStackDoc, called at compiler/utils/Outputable.hs:1237:29 in ghc:Outputable
        warnPprTrace, called at compiler/simplCore/OccurAnal.hs:72:6 in ghc:OccurAnal
WARNING: file compiler/simplCore/OccurAnal.hs, line 73
  Glomming in Foo: [rgg :->]
  Call stack:
      CallStack (from HasCallStack):
        callStackDoc, called at compiler/utils/Outputable.hs:1237:29 in ghc:Outputable
        warnPprTrace, called at compiler/simplCore/OccurAnal.hs:72:6 in ghc:OccurAnal

Etc. We glom in every simplifier run. This is silly.

It happens because of Note [Preventing loops due to imported functions rules], but it's clearly wrong to do repeated glomming.

Maybe not urgent, but it'd be good to attend to this.