require with non-sigiled arguments

[vrurg]

Followup to rakudo/rakudo#2983.

Currently require with arguments is supposed to import specified symbols into its lexical scope. The thing which is not specified in the documentation is that the symbols are treated as variables. What happens then is that if a role is requested for import:

require ("module.pm") <a_role>;

rakudo installs a same-name variable a_role. I wonder if its a legit behavior or not? On one hand, we could allow only sigiled entities to import. But this would effectively cut off constants. Though they're not correctly imported now anyway.

Another way is to allow sigilless symbols to be required. But this needs installing a symbol stub which could be resolved at run-time by REQUIRE_IMPORT. So far, I didn't find a way how this could be done.

[vrurg]

This was resolved with several bugfixes in rakudo.