$ perl -Mstrict -Mwarnings -E '
> my @arr = qw{ abc #def ghi };'
Possible attempt to put comments in qw() list at -e line 2.
$ perl -Mstrict -Mwarnings -Mdiagnostics -E '
my @arr = qw{ abc #def ghi };'
Possible attempt to put comments in qw() list at -e line 2 (#1)
    (W qw) qw() lists contain items separated by whitespace; as with literal
    strings, comment characters are not ignored, but are instead treated as
    literal data.  (You may have used different delimiters than the
    parentheses shown here; braces are also frequently used.)
    
    You probably wrote something like this:
    
        @list = qw(
        a # a comment
            b # another comment
        );
    
    when you should have written this:
    
        @list = qw(
        a
            b
        );
    
    If you really want comments, build your list the
    old-fashioned way, with quotes and commas:
    
        @list = (
            'a',    # a comment
            'b',    # another comment
        );
$