Why does this line: 
my %defaults = ref( $_[2+$[] ) ? %{$_[2+$[]} : {};

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get this warning:
Reference found where even-sized list expected at script.pl line 125.
?? The line is the third line of a sub-routine that takes two or three arguments like this: 
sub routine 
{
    my %override = %{$_[$[]};  # reference to a hash.
    my $var      = $_[1+$[];   # scalar
    my %defaults = ref( $_[2+$[] ) ? %{$_[2+$[]} : {}; # optional hash
+ ref.
#blah...

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I only get the warning if there is no third argument. ref returns false when given undef, without any warnings as tested via: 
prompt> perl -we "print ref( undef() ) ? 'y' : 'n'"
n

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In reply to Reference found where even-sized list expected by Adam

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