==== tests/cases/compiler/overloadingOnConstantsInImplementation.ts (3 errors) ====
    function foo(a: 'hi', x: string);
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! Specialized overload signature is not assignable to any non-specialized signature.
    function foo(a: 'hi', x: string);
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! Specialized overload signature is not assignable to any non-specialized signature.
    function foo(a: 'hi', x: any) {
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    }
    ~
!!! A signature with an implementation cannot use a string literal type.