Typescript: 유형 검사기가 for-of에서 유형을 잃습니다.

TypeScript 버전 : 2.0.8

암호

// test.ts
interface Type {
  type: number;
}

interface TypeExt extends Type {
  arr: Type[];
}

const guard = (arg: Type): arg is TypeExt => arg.type === 1;
const otherFunc = (arg1: Type, arg2: TypeExt): void => {};

export function y(arg: Type): void {
  if (guard(arg)) {
    for (const ITEM/* error is here */ of arg.arr) {
      if (otherFunc(ITEM, arg)) {
      }
    }
  }
}

cmd로 컴파일 됨 : tsc --noImplicitAny test.ts

예상되는 동작 :
오류 없음

실제 행동 :

test.ts(14,16): error TS7022: 'ITEM' implicitly has type 'any' because it does not have a type annotation and is referenced directly or indirectly in its own initializer.