==== tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithParameterInitializers2.ts (4 errors) ====
    // Optional parameters allow initializers only in implementation signatures
    // All the below declarations are errors
    
    function foo(x = 2);
                 ~~~~~
!!! A parameter initializer is only allowed in a function or constructor implementation.
    function foo(x = 1) { }
    
    foo(1);
    foo();
    
    class C {
        foo(x = 2);
            ~~~~~
!!! A parameter initializer is only allowed in a function or constructor implementation.
        foo(x = 1) { }
    }
    
    var c: C;
    c.foo();
    c.foo(1);
    
    var b = {
        foo(x = 1),
                  ~
!!! '{' expected.
        foo(x = 1) { },
        ~~~
!!! Duplicate identifier 'foo'.
    }
    
    b.foo();
    b.foo(1);