/a.js(1,12): error TS8030: A JSDoc '@type' tag on a function must have a signature with the correct number of arguments.
/a.js(1,20): error TS1005: '}' expected.


==== /a.js (2 errors) ====
    /** @type {function(): number} */
               ~~~~~~~~
!!! error TS8030: A JSDoc '@type' tag on a function must have a signature with the correct number of arguments.
                       ~
!!! error TS1005: '}' expected.
    function f() {}
    