# New Ticket Created by Zoffix Znet
# Please include the string: [perl #132352]
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# <URL: https://rt.perl.org/Ticket/Display.html?id=132352 >
Set operators are a lot less useful with mutable types, like SetHash, because
even when one of the operands is a SetHash, they still return a Set, making
constructs like `∖=` or `∪=` entirely unusable:
my $days = SetHash.new: Date.today … Date.new: '2014-04-02';
$days ∖= $days.grep: *.key.day-of-week > 5;
dd $days.^name; # "Set"
$days{Date.today}:delete; # Cannot call 'DELETE-KEY' on an immutable 'Set'