foo(@foo_bar);                 : 2
Argument "" isn't numeric in array element at (eval 2) line 1.
foo($foo_bar[0..$#foo_bar]);   : foo
foo(@foo_bar[0,$#foo_bar]);    : bar
foo("foo","bar");              : # Too many arguments for main::foo at (eval 4) line 1, near ""bar")"

foo(map{$_}"foo","bar");       : 2
Useless use of a constant in void context at (eval 6) line 1.
foo(qw[ foo bar ]);            : bar
foo(@{[qw[ foo bar ]]});       : 2
foo(${[qw[ foo bar ]]}[0,1]);  : bar
foo(map{$_}qw[ foo bar ]);     : 2
foo(reverse @foo_bar);         : raboof
foo(returns_two());            : bar
foo(returns_two_2());          : bar
foo(returns_array());          : 2