==== tests/cases/compiler/optionalParamTypeComparison.ts (2 errors) ====
    var f: (s: string, n?: number) => void;
    var g: (s: string, b?: boolean) => void;
    
    f = g;
    ~
!!! Type '(s: string, b?: boolean) => void' is not assignable to type '(s: string, n?: number) => void':
!!!   Types of parameters 'b' and 'n' are incompatible:
!!!     Type 'boolean' is not assignable to type 'number'.
    g = f;
    ~
!!! Type '(s: string, n?: number) => void' is not assignable to type '(s: string, b?: boolean) => void':
!!!   Types of parameters 'n' and 'b' are incompatible:
!!!     Type 'number' is not assignable to type 'boolean'.