Hi,
I was a little surprised that 
my @test = ( 0 );
if ( defined @{ $test[1] }[1] ){}
my $l = @test;
print $l;

[download]
produced a "2".
Sure it is easy to extend the if clause as 
my @test = ( 0 );
if ( defined $test[1] && defined @{ $test[1] }[1] ){}
my $l = @test;
print $l;

[download]
and all is fine again, but where can I find any documentation of this behaviour? It was unexpected to me and I would like to read more about it. Neither perlref nor the perlreftut seemed to document that an element is appended to @test as soon as it is accessed.
Cheers,
Hans

In reply to defined of a matrix by PerlingTheUK

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