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
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
|
=== tests/cases/conformance/types/typeRelationships/typeInference/genericCallWithObjectTypeArgsAndConstraints3.ts ===
// Generic call with constraints infering type parameter from object member properties
class Base {
>Base : Base
x: string;
>x : string
}
class Derived extends Base {
>Derived : Derived
>Base : Base
y: string;
>y : string
}
class Derived2 extends Base {
>Derived2 : Derived2
>Base : Base
z: string;
>z : string
}
function f<T extends Base>(a: { x: T; y: T }) {
>f : <T extends Base>(a: { x: T; y: T; }) => T
>a : { x: T; y: T; }
>x : T
>y : T
var r: T;
>r : T
return r;
>r : T
}
var r1 = f({ x: new Derived(), y: new Derived2() }); // error because neither is supertype of the other
>r1 : any
>f({ x: new Derived(), y: new Derived2() }) : any
>f : <T extends Base>(a: { x: T; y: T; }) => T
>{ x: new Derived(), y: new Derived2() } : { x: Derived; y: Derived2; }
>x : Derived
>new Derived() : Derived
>Derived : typeof Derived
>y : Derived2
>new Derived2() : Derived2
>Derived2 : typeof Derived2
function f2<T extends Base, U extends { x: T; y: T }>(a: U) {
>f2 : <T extends Base, U extends { x: T; y: T; }>(a: U) => T
>x : T
>y : T
>a : U
var r: T;
>r : T
return r;
>r : T
}
var r2 = f2({ x: new Derived(), y: new Derived2() }); // ok
>r2 : Base
>f2({ x: new Derived(), y: new Derived2() }) : Base
>f2 : <T extends Base, U extends { x: T; y: T; }>(a: U) => T
>{ x: new Derived(), y: new Derived2() } : { x: Derived; y: Derived2; }
>x : Derived
>new Derived() : Derived
>Derived : typeof Derived
>y : Derived2
>new Derived2() : Derived2
>Derived2 : typeof Derived2
var r3 = f2({ x: new Derived(), y: new Derived2() }); // ok
>r3 : Base
>f2({ x: new Derived(), y: new Derived2() }) : Base
>f2 : <T extends Base, U extends { x: T; y: T; }>(a: U) => T
>{ x: new Derived(), y: new Derived2() } : { x: Derived; y: Derived2; }
>x : Derived
>new Derived() : Derived
>Derived : typeof Derived
>y : Derived2
>new Derived2() : Derived2
>Derived2 : typeof Derived2
function f3<T extends Base>(y: (a: T) => T, x: T) {
>f3 : <T extends Base>(y: (a: T) => T, x: T) => T
>y : (a: T) => T
>a : T
>x : T
return y(null);
>y(null) : T
>y : (a: T) => T
>null : null
}
// all ok - second argument is processed before x is fixed
var r4 = f3(x => x, new Base());
>r4 : Base
>f3(x => x, new Base()) : Base
>f3 : <T extends Base>(y: (a: T) => T, x: T) => T
>x => x : (x: Base) => Base
>x : Base
>x : Base
>new Base() : Base
>Base : typeof Base
var r5 = f3(x => x, new Derived());
>r5 : Derived
>f3(x => x, new Derived()) : Derived
>f3 : <T extends Base>(y: (a: T) => T, x: T) => T
>x => x : (x: Derived) => Derived
>x : Derived
>x : Derived
>new Derived() : Derived
>Derived : typeof Derived
var r6 = f3(x => x, null);
>r6 : any
>f3(x => x, null) : any
>f3 : <T extends Base>(y: (a: T) => T, x: T) => T
>x => x : (x: any) => any
>x : any
>x : any
>null : null
|
