1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
|
tests/cases/conformance/classes/members/inheritanceAndOverriding/derivedClassTransitivity2.ts(18,1): error TS2322: Type 'E' is not assignable to type 'C'.
Types of property 'foo' are incompatible.
Type '(x: number, y?: string) => void' is not assignable to type '(x: number, y: number) => void'.
Types of parameters 'y' and 'y' are incompatible.
Type 'number' is not assignable to type 'string'.
==== tests/cases/conformance/classes/members/inheritanceAndOverriding/derivedClassTransitivity2.ts (1 errors) ====
// subclassing is not transitive when you can remove required parameters and add optional parameters
class C {
foo(x: number, y: number) { }
}
class D extends C {
foo(x: number) { } // ok to drop parameters
}
class E extends D {
foo(x: number, y?: string) { } // ok to add optional parameters
}
var c: C;
var d: D;
var e: E;
c = e;
~
!!! error TS2322: Type 'E' is not assignable to type 'C'.
!!! error TS2322: Types of property 'foo' are incompatible.
!!! error TS2322: Type '(x: number, y?: string) => void' is not assignable to type '(x: number, y: number) => void'.
!!! error TS2322: Types of parameters 'y' and 'y' are incompatible.
!!! error TS2322: Type 'number' is not assignable to type 'string'.
var r = c.foo(1, 1);
var r2 = e.foo(1, '');
|
