No warning when using unary +/- operators on functions and objects?

TypeScript Version: 2.6.1

Code

let func = () => "func";
+func; // no error
-func; // no error

let obj = { foo: "bar" };
+obj; // no error
-obj; // no error

Expected behavior:
Unary + or - is only applicable to a number or maybe a string. I would expect the lines listed as // no error to be errors.

Actual behavior:
Unary + and - never generates a warning no matter what crazy stuff I try to apply it to.

I was made aware of this behavior by a recent Stack Overflow question. I see from #7019 that unary + and - on strings is supported, and I guess I can understand that as a way to parse a string into a number (for +, anyway. Is - really used like this in practice?). But functions? objects? Seems more likely to be an error than intentional to me. Thoughts?

Reproduisez l’exemple TypeScript 2.6.1 et comparez les diagnostics pour + et - unaires sur des fonctions, des objets et des chaînes. Examinez le comportement existant de vérification de type des opérateurs unaires ; le travail est considéré comme terminé lorsque les opérandes invalides attendus produisent des erreurs, tandis que le comportement pris en charge pour les chaînes reste délibéré et est couvert par des tests.