safety risk of .fetch/2

[dckc]

<simpson> I feel like we need a space for documenting POLA maybe-not-safe-but-nobody-has-really-shown-a-good-PoC stuff.
<DanC_> PoC = proof of concept?
<simpson> Yeah.
 Stuff like .fetch/2 on Maps.
<DanC_> oh.
<DanC_> yes, the risk around .fetch/2 merits documenting. I'm raising an issue

[erights]

What is the safety risk or POLA violation of .fetch/2 ?

[dckc]

Something about f keeping a reference to k after m.fetch(k, f) I think.

[dckc]

http://wiki.erights.org/wiki/POLA_fetch