$ perl -Mstrict -Mdiagnostics -E 'my $a = "3"; say $a->[0];'
Can't use string ("3") as an ARRAY ref while "strict refs" in use at -e line 1 (#1)
    (F) You've told Perl to dereference a string, something which
    use strict blocks to prevent it happening accidentally.  See
    "Symbolic references" in perlref.  This can be triggered by an @ or $
    in a double-quoted string immediately before interpolating a variable,
    for example in "user @$twitter_id", which says to treat the contents
    of $twitter_id as an array reference; use a \ to have a literal @
    symbol followed by the contents of $twitter_id: "user \@$twitter_id".
    
Uncaught exception from user code:
	Can't use string ("3") as an ARRAY ref while "strict refs" in use at -e line 1.