==== tests/cases/compiler/optionalArgsWithDefaultValues.ts (5 errors) ====
    function foo(x: number, y?:boolean=false, z?=0) {}
                            ~
!!! Parameter cannot have question mark and initializer.
    
    class CCC {
        public foo(x: number, y?:boolean=false, z?=0) {}
                              ~
!!! Parameter cannot have question mark and initializer.
        static foo2(x: number, y?:boolean=false, z?=0) {}
                               ~
!!! Parameter cannot have question mark and initializer.
    }
    
    var a = (x?=0) => { return 1; };
             ~
!!! Parameter cannot have question mark and initializer.
    var b = (x, y?:number = 2) => { x; };
                ~
!!! Parameter cannot have question mark and initializer.