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tests/cases/compiler/deepComparisons.ts(2,9): error TS2322: Type 'T' is not assignable to type 'Extract<T, string>'.
tests/cases/compiler/deepComparisons.ts(3,9): error TS2322: Type 'T[K1]' is not assignable to type 'Extract<T[K1], string>'.
Type 'T[keyof T]' is not assignable to type 'Extract<T[K1], string>'.
Type 'T[string] | T[number] | T[symbol]' is not assignable to type 'Extract<T[K1], string>'.
Type 'T[string]' is not assignable to type 'Extract<T[K1], string>'.
tests/cases/compiler/deepComparisons.ts(4,9): error TS2322: Type 'T[K1][K2]' is not assignable to type 'Extract<T[K1][K2], string>'.
Type 'T[K1][keyof T[K1]]' is not assignable to type 'Extract<T[K1][K2], string>'.
Type 'T[K1][string] | T[K1][number] | T[K1][symbol]' is not assignable to type 'Extract<T[K1][K2], string>'.
Type 'T[K1][string]' is not assignable to type 'Extract<T[K1][K2], string>'.
Type 'T[keyof T][string]' is not assignable to type 'Extract<T[K1][K2], string>'.
Type 'T[string][string] | T[number][string] | T[symbol][string]' is not assignable to type 'Extract<T[K1][K2], string>'.
Type 'T[string][string]' is not assignable to type 'Extract<T[K1][K2], string>'.
==== tests/cases/compiler/deepComparisons.ts (3 errors) ====
function f1<T, K1 extends keyof T, K2 extends keyof T[K1]>() {
let v1: Extract<T, string> = 0 as any as T; // Error
~~
!!! error TS2322: Type 'T' is not assignable to type 'Extract<T, string>'.
let v2: Extract<T[K1], string> = 0 as any as T[K1]; // Error
~~
!!! error TS2322: Type 'T[K1]' is not assignable to type 'Extract<T[K1], string>'.
!!! error TS2322: Type 'T[keyof T]' is not assignable to type 'Extract<T[K1], string>'.
!!! error TS2322: Type 'T[string] | T[number] | T[symbol]' is not assignable to type 'Extract<T[K1], string>'.
!!! error TS2322: Type 'T[string]' is not assignable to type 'Extract<T[K1], string>'.
let v3: Extract<T[K1][K2], string> = 0 as any as T[K1][K2]; // No error
~~
!!! error TS2322: Type 'T[K1][K2]' is not assignable to type 'Extract<T[K1][K2], string>'.
!!! error TS2322: Type 'T[K1][keyof T[K1]]' is not assignable to type 'Extract<T[K1][K2], string>'.
!!! error TS2322: Type 'T[K1][string] | T[K1][number] | T[K1][symbol]' is not assignable to type 'Extract<T[K1][K2], string>'.
!!! error TS2322: Type 'T[K1][string]' is not assignable to type 'Extract<T[K1][K2], string>'.
!!! error TS2322: Type 'T[keyof T][string]' is not assignable to type 'Extract<T[K1][K2], string>'.
!!! error TS2322: Type 'T[string][string] | T[number][string] | T[symbol][string]' is not assignable to type 'Extract<T[K1][K2], string>'.
!!! error TS2322: Type 'T[string][string]' is not assignable to type 'Extract<T[K1][K2], string>'.
}
type Foo<T> = { x: Foo<T> };
type Bar<T> = { x: Bar<T[]> };
function f2<U>() {
let x: Foo<U> = 0 as any as Bar<U>; // Error, excessive stack depth
}
type Foo1<T> = { x: Foo2<T> };
type Foo2<T> = { x: Foo1<T> };
function f3<U>() {
let x: Foo1<U> = 0 as any as Bar<U>; // No error!
}
// Repro from #46500
type F<T> = {} & (
T extends [any, ...any[]]
? { [K in keyof T]?: F<T[K]> }
: T extends any[]
? F<T[number]>[]
: T extends { [K: string]: any }
? { [K in keyof T]?: F<T[K]> }
: { x: string }
);
declare function f<T = any>(): F<T>;
function g() {
return f() as F<any>;
}
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