$ perl -wce 'require foo'
-e syntax OK
$ perl -wce 'package foo'
-e syntax OK
$ perl -wce 'foo -> method'
Unquoted string "foo" may clash with future reserved word at -e line 1.
-e syntax OK
$ perl -wce 'Foo -> method'
-e syntax OK

##</code><code>##

$ perl -wce 'print Foo'
Name "main::Foo" used only once: possible typo at -e line 1.
-e syntax OK
$ perl -wce 'print foo'
Unquoted string "foo" may clash with future reserved word at -e line 1.
Name "main::foo" used only once: possible typo at -e line 1.
-e syntax OK