==== tests/cases/compiler/objectTypesIdentityWithGenericCallSignaturesOptionalParams.ts (10 errors) ====
    // Two call or construct signatures are considered identical when they have the same number of type parameters and, considering those 
    // parameters pairwise identical, have identical type parameter constraints, identical number of parameters with identical kind(required, 
    // optional or rest) and types, and identical return types.
    
    class A {
        foo<T>(x: T, y?: T): T { return null; }
    }
    
    class B<T> {
        foo(x: T, y?: T): T { return null; }
    }
    
    class C<T> {
        foo(x: T, y?: T): T { return null; }
    }
    
    interface I<T> {
        foo(x: T, y?: T): T;
    }
    
    interface I2 {
        foo<T>(x: T, y?: T): T;
    }
    
    var a: { foo<T>(x: T, y?: T): T }
    var b = { foo<T>(x: T, y?: T) { return x; } };
    
    function foo1(x: A);
    function foo1(x: A); // error
    ~~~~~~~~~~~~~~~~~~~~
!!! objectTypesIdentityWithGenericCallSignaturesOptionalParams.ts(29,1): error TS2144: Duplicate overload signature for 'foo1'.
    function foo1(x: any) { }
    
    function foo1b(x: B<string>);
    function foo1b(x: B<string>); // error
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! objectTypesIdentityWithGenericCallSignaturesOptionalParams.ts(33,1): error TS2144: Duplicate overload signature for 'foo1b'.
    function foo1b(x: any) { }
    
    function foo1c(x: C<string>);
    function foo1c(x: C<string>); // error
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! objectTypesIdentityWithGenericCallSignaturesOptionalParams.ts(37,1): error TS2144: Duplicate overload signature for 'foo1c'.
    function foo1c(x: any) { }
    
    function foo2(x: I<string>);
    function foo2(x: I<string>); // error
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! objectTypesIdentityWithGenericCallSignaturesOptionalParams.ts(41,1): error TS2144: Duplicate overload signature for 'foo2'.
    function foo2(x: any) { }
    
    function foo3(x: typeof a);
    function foo3(x: typeof a); // error
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! objectTypesIdentityWithGenericCallSignaturesOptionalParams.ts(45,1): error TS2144: Duplicate overload signature for 'foo3'.
    function foo3(x: any) { }
    
    function foo4(x: typeof b);
    function foo4(x: typeof b); // error
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! objectTypesIdentityWithGenericCallSignaturesOptionalParams.ts(49,1): error TS2144: Duplicate overload signature for 'foo4'.
    function foo4(x: any) { }
    
    function foo5(x: A);
    function foo5(x: B<string>); // ok
    function foo5(x: any) { }
    
    function foo5b(x: A);
    function foo5b(x: C<string>); // ok
    function foo5b(x: any) { }
    
    function foo6(x: A);
    function foo6(x: I<string>); // ok
    function foo6(x: any) { }
    
    function foo7(x: A);
    function foo7(x: typeof a); // no error, bug?
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! objectTypesIdentityWithGenericCallSignaturesOptionalParams.ts(65,1): error TS2144: Duplicate overload signature for 'foo7'.
    function foo7(x: any) { }
    
    function foo8(x: B<string>);
    function foo8(x: I<string>); // error
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! objectTypesIdentityWithGenericCallSignaturesOptionalParams.ts(69,1): error TS2144: Duplicate overload signature for 'foo8'.
    function foo8(x: any) { }
    
    function foo9(x: B<string>);
    function foo9(x: C<string>); // error
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! objectTypesIdentityWithGenericCallSignaturesOptionalParams.ts(73,1): error TS2144: Duplicate overload signature for 'foo9'.
    function foo9(x: any) { }
    
    function foo10(x: B<string>);
    function foo10(x: typeof a); // ok
    function foo10(x: any) { }
    
    function foo11(x: B<string>);
    function foo11(x: typeof b); // ok
    function foo11(x: any) { }
    
    function foo12(x: I<string>);
    function foo12(x: C<string>); // error
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! objectTypesIdentityWithGenericCallSignaturesOptionalParams.ts(85,1): error TS2144: Duplicate overload signature for 'foo12'.
    function foo12(x: any) { }
    
    function foo12b(x: I2);
    function foo12b(x: C<string>); // ok
    function foo12b(x: any) { }
    
    function foo13(x: I<string>);
    function foo13(x: typeof a); // ok
    function foo13(x: any) { }
    
    function foo14(x: I<string>);
    function foo14(x: typeof b); // ok
    function foo14(x: any) { }
    
    function foo15(x: I2);
    function foo15(x: C<number>); // ok
    function foo15(x: any) { }