perl -MDevel::Peek -le 'my $f = 42; Dump \$f; for $f (2) { Dump \$f } for my $f (2) { Dump \$f }'
SV = RV(0x9d1a678) at 0x9cf1c28
  REFCNT = 1
  FLAGS = (TEMP,ROK)
  RV = 0x9cf1cdc
  SV = IV(0x9d0def8) at 0x9cf1cdc
    REFCNT = 2
    FLAGS = (PADBUSY,PADMY,IOK,pIOK)
    IV = 42
SV = RV(0x9d1a678) at 0x9cf1e2c
  REFCNT = 1
  FLAGS = (TEMP,ROK)
  RV = 0x9cf1c28
  SV = IV(0x9d0defc) at 0x9cf1c28
    REFCNT = 1
    FLAGS = (IOK,pIOK)
    IV = 2
SV = RV(0x9d1a678) at 0x9cf1c28
  REFCNT = 1
  FLAGS = (TEMP,ROK)
  RV = 0x9cf1e2c
  SV = IV(0x9d0defc) at 0x9cf1e2c
    REFCNT = 1
    FLAGS = (IOK,pIOK)
    IV = 2