Desugaring of ?: operator

In general, it seems like desugared code should never be shown in error messages. Only show code fragments when necessary, and only show code that actually appears in the source files.

Code:

    class A { ?Integer n; }

    void main(String [] args) {
        let a2 = new A(n: new Integer(2));
        Integer n2 = a2.n != null ? a2.n : new Integer(1);
    }

Old message:

    The value if(`!=`(a2.n(), null))
                 a2.n()
              else
                 new Integer(1)
    cannot be assigned to n2 because it might be null.

New message:

    The value a2.n != null ? a2.n : new Integer(1)
    cannot be assigned to n2 because it might be null.

    Attempt to assign a possibly-null value to n2