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
35
36
37
38
39
40
41
42
43
|
tests/cases/compiler/implementGenericWithMismatchedTypes.ts(7,7): error TS2420: Class 'C<T>' incorrectly implements interface 'IFoo<T>'.
Types of property 'foo' are incompatible.
Type '(x: string) => number' is not assignable to type '(x: T) => T'.
Types of parameters 'x' and 'x' are incompatible.
Type 'T' is not assignable to type 'string'.
tests/cases/compiler/implementGenericWithMismatchedTypes.ts(16,7): error TS2420: Class 'C2<T>' incorrectly implements interface 'IFoo2<T>'.
Types of property 'foo' are incompatible.
Type '<Tstring>(x: Tstring) => number' is not assignable to type '(x: T) => T'.
Type 'number' is not assignable to type 'T'.
==== tests/cases/compiler/implementGenericWithMismatchedTypes.ts (2 errors) ====
// no errors because in the derived types the best common type for T's value is Object
// and that matches the original signature for assignability since we treat its T's as Object
interface IFoo<T> {
foo(x: T): T;
}
class C<T> implements IFoo<T> { // error
~
!!! error TS2420: Class 'C<T>' incorrectly implements interface 'IFoo<T>'.
!!! error TS2420: Types of property 'foo' are incompatible.
!!! error TS2420: Type '(x: string) => number' is not assignable to type '(x: T) => T'.
!!! error TS2420: Types of parameters 'x' and 'x' are incompatible.
!!! error TS2420: Type 'T' is not assignable to type 'string'.
foo(x: string): number {
return null;
}
}
interface IFoo2<T> {
foo(x: T): T;
}
class C2<T> implements IFoo2<T> { // error
~~
!!! error TS2420: Class 'C2<T>' incorrectly implements interface 'IFoo2<T>'.
!!! error TS2420: Types of property 'foo' are incompatible.
!!! error TS2420: Type '<Tstring>(x: Tstring) => number' is not assignable to type '(x: T) => T'.
!!! error TS2420: Type 'number' is not assignable to type 'T'.
foo<Tstring>(x: Tstring): number {
return null;
}
}
|
