I'm currently looking for a solution and if I find anything I will create a pull request

Works without @noSelf attribute
Same issue with @noSelfInFile

https://typescripttolua.github.io/play#code/PQKhAIAEDsHsGUCmAbAZuEwBQATRBjZAQwCdFxoiBbRAZwAcj9yBzaugFyI-IG8twg8KAiR8AV1odYVAHLtwjWrQzYh4VOOj4OAS1jQNRXcgAUASgBc4AG6xdOLAF8sWNjSndEAOlTGz5gDcQA

/** @noSelf */
declare namespace gamestate {
    /** @customName pass */
    function fail(): void
}

gamestate.fail();

Expected:

gamestate.pass()

Got:

gamestate.fail()