==== tests/cases/compiler/assignmentCompatFunctionsWithOptionalArgs.ts (3 errors) ====
    function foo(x: { id: number; name?: string; }): void;
             ~~~
!!! Function implementation is missing or not immediately following the declaration.
    foo({ id: 1234 });                 // Ok
    foo({ id: 1234, name: "hello" });  // Ok
    foo({ id: 1234, name: false });    // Error, name of wrong type
        ~~~~~~~~~~~~~~~~~~~~~~~~~
!!! Argument of type '{ id: number; name: boolean; }' is not assignable to parameter of type '{ id: number; name?: string; }'.
!!!   Types of property 'name' are incompatible:
!!!     Type 'boolean' is not assignable to type 'string'.
    foo({ name: "hello" });            // Error, id required but missing
        ~~~~~~~~~~~~~~~~~
!!! Argument of type '{ name: string; }' is not assignable to parameter of type '{ id: number; name?: string; }'.
!!!   Property 'id' is missing in type '{ name: string; }'.