=== tests/cases/conformance/types/objectTypeLiteral/callSignatures/specializedSignatureWithOptional.ts ===
declare function f(x?: "hi"): void;
>f : { (x?: "hi"): void; (x?: string): void; }
>x : "hi"

declare function f(x?: string): void;
>f : { (x?: "hi"): void; (x?: string): void; }
>x : string