You put the emphasis on the wrong part of the quoted documentation. The essential part is has ever been used in a numeric context. Either side of binary + is classifies as numeric context.

The more technical reason is "you get normal increment if the SV isn't a PV". 

perl -MDevel::Peek -e '$n = "z"; Dump($n); $f = 3 + $n; Dump($n)'
SV = PV(0x804def8) at 0x8063ad0
  REFCNT = 1
  FLAGS = (POK,pPOK)
  PV = 0x805cce8 "z"\0
  CUR = 1
  LEN = 2
SV = PVNV(0x8080dc0) at 0x8063ad0
  REFCNT = 1
  FLAGS = (IOK,NOK,POK,pIOK,pNOK,pPOK)
  IV = 0
  NV = 0
  PV = 0x805cce8 "z"\0
  CUR = 1
  LEN = 2

[download]
As you can see, the variable does change by just looking at it.

In reply to Re: A somewhat unexpected side effect... by Anonymous Monk
in thread A somewhat unexpected side effect... by blazar

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