These work: $hash{'test'} = $hash{'test'} + 3;

Yeah, because you overload "+" but not "+=". You need to overload "+=" too.

Update: While the above it true, there is a bug cause the overload handler for '+=' not to get called. Filed a ticket: RT#84786

In reply to Re: Mixing tie %hash and overload results in strange behavior by ikegami
in thread Mixing tie %hash and overload results in strange behavior by robhoelz

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