mappedTypeWithAsClauseAndLateBoundProperty.ts(3,1): error TS2741: Property 'length' is missing in type '{ [x: number]: number; toString: () => string; toLocaleString: { (): string; (locales: string | string[], options?: (NumberFormatOptions & DateTimeFormatOptions) | undefined): string; }; pop: () => number | undefined; push: (...items: number[]) => number; concat: { (...items: ConcatArray<number>[]): number[]; (...items: (number | ConcatArray<number>)[]): number[]; }; join: (separator?: string | undefined) => string; reverse: () => number[]; shift: () => number | undefined; slice: (start?: number | undefined, end?: number | undefined) => number[]; sort: (compareFn?: ((a: number, b: number) => number) | undefined) => number[]; splice: { (start: number, deleteCount?: number | undefined): number[]; (start: number, deleteCount: number, ...items: number[]): number[]; }; unshift: (...items: number[]) => number; indexOf: (searchElement: number, fromIndex?: number | undefined) => number; lastIndexOf: (searchElement: number, fromIndex?: number | undefined) => number; every: { <S extends number>(predicate: (value: number, index: number, array: number[]) => value is S, thisArg?: any): this is S[]; (predicate: (value: number, index: number, array: number[]) => unknown, thisArg?: any): boolean; }; some: (predicate: (value: number, index: number, array: number[]) => unknown, thisArg?: any) => boolean; forEach: (callbackfn: (value: number, index: number, array: number[]) => void, thisArg?: any) => void; map: <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]; filter: { <S extends number>(predicate: (value: number, index: number, array: number[]) => value is S, thisArg?: any): S[]; (predicate: (value: number, index: number, array: number[]) => unknown, thisArg?: any): number[]; }; reduce: { (callbackfn: (previousValue: number, currentValue: number, currentIndex: number, array: number[]) => number): number; (callbackfn: (previousValue: number, currentValue: number, currentIndex: number, array: number[]) => number, initialValue: number): number; <U>(callbackfn: (previousValue: U, currentValue: number, currentIndex: number, array: number[]) => U, initialValue: U): U; }; reduceRight: { (callbackfn: (previousValue: number, currentValue: number, currentIndex: number, array: number[]) => number): number; (callbackfn: (previousValue: number, currentValue: number, currentIndex: number, array: number[]) => number, initialValue: number): number; <U>(callbackfn: (previousValue: U, currentValue: number, currentIndex: number, array: number[]) => U, initialValue: U): U; }; find: { <S extends number>(predicate: (value: number, index: number, obj: number[]) => value is S, thisArg?: any): S | undefined; (predicate: (value: number, index: number, obj: number[]) => unknown, thisArg?: any): number | undefined; }; findIndex: (predicate: (value: number, index: number, obj: number[]) => unknown, thisArg?: any) => number; fill: (value: number, start?: number | undefined, end?: number | undefined) => number[]; copyWithin: (target: number, start: number, end?: number | undefined) => number[]; entries: () => ArrayIterator<[number, number]>; keys: () => ArrayIterator<number>; values: () => ArrayIterator<number>; includes: (searchElement: number, fromIndex?: number | undefined) => boolean; flatMap: <U, This = undefined>(callback: (this: This, value: number, index: number, array: number[]) => U | readonly U[], thisArg?: This | undefined) => U[]; flat: <A, D extends number = 1>(this: A, depth?: D | undefined) => FlatArray<A, D>[]; [Symbol.iterator]: () => ArrayIterator<number>; readonly [Symbol.unscopables]: { [x: number]: boolean | undefined; length?: boolean | undefined; toString?: boolean | undefined; toLocaleString?: boolean | undefined; pop?: boolean | undefined; push?: boolean | undefined; concat?: boolean | undefined; join?: boolean | undefined; reverse?: boolean | undefined; shift?: boolean | undefined; slice?: boolean | undefined; sort?: boolean | undefined; splice?: boolean | undefined; unshift?: boolean | undefined; indexOf?: boolean | undefined; lastIndexOf?: boolean | undefined; every?: boolean | undefined; some?: boolean | undefined; forEach?: boolean | undefined; map?: boolean | undefined; filter?: boolean | undefined; reduce?: boolean | undefined; reduceRight?: boolean | undefined; find?: boolean | undefined; findIndex?: boolean | undefined; fill?: boolean | undefined; copyWithin?: boolean | undefined; entries?: boolean | undefined; keys?: boolean | undefined; values?: boolean | undefined; includes?: boolean | undefined; flatMap?: boolean | undefined; flat?: boolean | undefined; [Symbol.iterator]?: boolean | undefined; readonly [Symbol.unscopables]?: boolean | undefined; }; }' but required in type 'number[]'.


==== mappedTypeWithAsClauseAndLateBoundProperty.ts (1 errors) ====
    declare let tgt2: number[];
    declare let src2: { [K in keyof number[] as Exclude<K, "length">]: (number[])[K] };
    tgt2 = src2; // Should error
    ~~~~
!!! error TS2741: Property 'length' is missing in type '{ [x: number]: number; toString: () => string; toLocaleString: { (): string; (locales: string | string[], options?: (NumberFormatOptions & DateTimeFormatOptions) | undefined): string; }; pop: () => number | undefined; push: (...items: number[]) => number; concat: { (...items: ConcatArray<number>[]): number[]; (...items: (number | ConcatArray<number>)[]): number[]; }; join: (separator?: string | undefined) => string; reverse: () => number[]; shift: () => number | undefined; slice: (start?: number | undefined, end?: number | undefined) => number[]; sort: (compareFn?: ((a: number, b: number) => number) | undefined) => number[]; splice: { (start: number, deleteCount?: number | undefined): number[]; (start: number, deleteCount: number, ...items: number[]): number[]; }; unshift: (...items: number[]) => number; indexOf: (searchElement: number, fromIndex?: number | undefined) => number; lastIndexOf: (searchElement: number, fromIndex?: number | undefined) => number; every: { <S extends number>(predicate: (value: number, index: number, array: number[]) => value is S, thisArg?: any): this is S[]; (predicate: (value: number, index: number, array: number[]) => unknown, thisArg?: any): boolean; }; some: (predicate: (value: number, index: number, array: number[]) => unknown, thisArg?: any) => boolean; forEach: (callbackfn: (value: number, index: number, array: number[]) => void, thisArg?: any) => void; map: <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]; filter: { <S extends number>(predicate: (value: number, index: number, array: number[]) => value is S, thisArg?: any): S[]; (predicate: (value: number, index: number, array: number[]) => unknown, thisArg?: any): number[]; }; reduce: { (callbackfn: (previousValue: number, currentValue: number, currentIndex: number, array: number[]) => number): number; (callbackfn: (previousValue: number, currentValue: number, currentIndex: number, array: number[]) => number, initialValue: number): number; <U>(callbackfn: (previousValue: U, currentValue: number, currentIndex: number, array: number[]) => U, initialValue: U): U; }; reduceRight: { (callbackfn: (previousValue: number, currentValue: number, currentIndex: number, array: number[]) => number): number; (callbackfn: (previousValue: number, currentValue: number, currentIndex: number, array: number[]) => number, initialValue: number): number; <U>(callbackfn: (previousValue: U, currentValue: number, currentIndex: number, array: number[]) => U, initialValue: U): U; }; find: { <S extends number>(predicate: (value: number, index: number, obj: number[]) => value is S, thisArg?: any): S | undefined; (predicate: (value: number, index: number, obj: number[]) => unknown, thisArg?: any): number | undefined; }; findIndex: (predicate: (value: number, index: number, obj: number[]) => unknown, thisArg?: any) => number; fill: (value: number, start?: number | undefined, end?: number | undefined) => number[]; copyWithin: (target: number, start: number, end?: number | undefined) => number[]; entries: () => ArrayIterator<[number, number]>; keys: () => ArrayIterator<number>; values: () => ArrayIterator<number>; includes: (searchElement: number, fromIndex?: number | undefined) => boolean; flatMap: <U, This = undefined>(callback: (this: This, value: number, index: number, array: number[]) => U | readonly U[], thisArg?: This | undefined) => U[]; flat: <A, D extends number = 1>(this: A, depth?: D | undefined) => FlatArray<A, D>[]; [Symbol.iterator]: () => ArrayIterator<number>; readonly [Symbol.unscopables]: { [x: number]: boolean | undefined; length?: boolean | undefined; toString?: boolean | undefined; toLocaleString?: boolean | undefined; pop?: boolean | undefined; push?: boolean | undefined; concat?: boolean | undefined; join?: boolean | undefined; reverse?: boolean | undefined; shift?: boolean | undefined; slice?: boolean | undefined; sort?: boolean | undefined; splice?: boolean | undefined; unshift?: boolean | undefined; indexOf?: boolean | undefined; lastIndexOf?: boolean | undefined; every?: boolean | undefined; some?: boolean | undefined; forEach?: boolean | undefined; map?: boolean | undefined; filter?: boolean | undefined; reduce?: boolean | undefined; reduceRight?: boolean | undefined; find?: boolean | undefined; findIndex?: boolean | undefined; fill?: boolean | undefined; copyWithin?: boolean | undefined; entries?: boolean | undefined; keys?: boolean | undefined; values?: boolean | undefined; includes?: boolean | undefined; flatMap?: boolean | undefined; flat?: boolean | undefined; [Symbol.iterator]?: boolean | undefined; readonly [Symbol.unscopables]?: boolean | undefined; }; }' but required in type 'number[]'.
!!! related TS2728 lib.es5.d.ts:--:--: 'length' is declared here.
    