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
|
tests/cases/conformance/types/typeAliases/directDependenceBetweenTypeAliases.ts(4,6): error TS2456: Type alias 'T0' circularly references itself.
tests/cases/conformance/types/typeAliases/directDependenceBetweenTypeAliases.ts(5,6): error TS2456: Type alias 'T0_1' circularly references itself.
tests/cases/conformance/types/typeAliases/directDependenceBetweenTypeAliases.ts(6,6): error TS2456: Type alias 'T0_2' circularly references itself.
tests/cases/conformance/types/typeAliases/directDependenceBetweenTypeAliases.ts(7,6): error TS2456: Type alias 'T0_3' circularly references itself.
tests/cases/conformance/types/typeAliases/directDependenceBetweenTypeAliases.ts(14,6): error TS2456: Type alias 'T2' circularly references itself.
tests/cases/conformance/types/typeAliases/directDependenceBetweenTypeAliases.ts(25,5): error TS2502: 'x' is referenced directly or indirectly in its own type annotation.
tests/cases/conformance/types/typeAliases/directDependenceBetweenTypeAliases.ts(26,6): error TS2456: Type alias 'T5' circularly references itself.
==== tests/cases/conformance/types/typeAliases/directDependenceBetweenTypeAliases.ts (7 errors) ====
// It is an error for the type specified in a type alias to depend on that type alias
// A type alias directly depends on the type it aliases.
type T0 = T0
~~
!!! error TS2456: Type alias 'T0' circularly references itself.
type T0_1 = T0_2
~~~~
!!! error TS2456: Type alias 'T0_1' circularly references itself.
type T0_2 = T0_3
~~~~
!!! error TS2456: Type alias 'T0_2' circularly references itself.
type T0_3 = T0_1
~~~~
!!! error TS2456: Type alias 'T0_3' circularly references itself.
// A type reference directly depends on the referenced type and each of the type arguments, if any.
interface I<T> {}
type T1 = I<T1>
// A union type directly depends on each of the constituent types.
type T2 = T2 | string
~~
!!! error TS2456: Type alias 'T2' circularly references itself.
class C<T> {}
type T2_1 = T2_1[] | number
// An array type directly depends on its element type.
type T3 = T3[]
// A tuple type directly depends on each of its element types.
type T4 = [number, T4]
// A type query directly depends on the type of the referenced entity.
var x: T5[] = []
~
!!! error TS2502: 'x' is referenced directly or indirectly in its own type annotation.
type T5 = typeof x
~~
!!! error TS2456: Type alias 'T5' circularly references itself.
class C1<T> {}
type T6 = T7 | number
type T7 = typeof yy
var yy: [string, T8[]];
type T8 = C<T6>
// legal cases
type T9 = () => T9
type T10 = { x: T10 } | { new(v: T10): string }
type T11 = T12[]
type T12 = [T13, string]
type T13 = typeof zz
var zz: { x: T11 }
|
