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?

Reproduce el ejemplo de TypeScript 2.6.1 y compara los diagnósticos para + y - unarios en funciones, objetos y cadenas. Revisa el comportamiento existente de comprobación de tipos de los operadores unarios; se considera terminado cuando los operandos no válidos previstos producen errores, mientras que el comportamiento compatible con cadenas sigue siendo deliberado y está cubierto por pruebas.