>perl -le
"use warnings;
 use strict;
 use diagnostics;
 my $list = (2,3,4,5,6);
 print qq{$list \n};
"
Useless use of a constant in void context at -e line 1 (#1)
    (W void) You did something without a side effect in a context that does
    nothing with the return value, such as a statement that doesn't return a
    value from a block, or the left side of a scalar comma operator.      
    ...
    
    Another common error is to use ordinary parentheses to construct a list
    reference when you should be using square or curly brackets, for
    example, if you say

        $array = (1,2);

    when you should have said

        $array = [1,2];

    The square brackets explicitly turn a list value into a scalar value,
    while parentheses do not.  So when a parenthesized list is evaluated in
    a scalar context, the comma is treated like C's comma operator, which
    throws away the left argument, which is not what you want.  See
    perlref for more on this.

    ...

6