$ perl -Mstrict -wE 'sub foo{ my $bar = shift; say $bar } foo("baz");'
baz

$ perl -Mstrict -wE 'sub foo(){ my $bar = shift; say $bar } foo("baz");'
Too many arguments for main::foo at -e line 1, near ""baz")"
Execution of -e aborted due to compilation errors.