That comes from the high precedence of '+' over '=>'.

If stringification came first there would be no error; you'd wind up with the string '3+5' as a key, which is perfectly all right. Fat comma stringifies like qw, breaking on whitespace.

$ perl -e'%foo = ("3+5", "something");print keys(%foo),$/'
3+5
$

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After Compline,
Zaxo

In reply to Re^3: Use of the => operator by Zaxo
in thread Use of the => operator by roju

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