Are there other dualvars in perl core?

$ perl -MScalar::Util=isdual -E'
   $x=1; say isdual($x)?1:0;
   "$x"; say isdual($x)?1:0;
'
0
1

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The stringification is cached.

In reply to Re: Dualvars besides $! by ikegami
in thread Dualvars besides $! by szabgab

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