TypeScript 2.0.3 possible bug?

results.txt

test1.ts(8,12): error TS1005: '=' expected.
test1.ts(9,27): error TS1005: ')' expected.
test1.ts(9,39): error TS1005: ';' expected.
test1.ts(9,41): error TS1005: '=>' expected.
test1.ts(11,6): error TS1068: Unexpected token. A constructor, method, accessor, or property was expected.
test1.ts(13,1): error TS1128: Declaration or statement expected.

test1.ts

class Test1 {
  async hello() {
    return ["hello", "world"];
  }

  test() {
    // should be OK but fail with TypeScript 2.0.3
    (async () => {
      for (let i in await this.hello()) {
      }
    });
  }
}

test2.ts

class Test2 {
  async hello() {
    return ["hello", "world"];
  }

  async test() {
    for (let i in await this.hello()) {
    }
  }
}

test3.ts

class Test3 {
  async hello() {
    return ["hello", "world"];
  }

  test() {
    const fn = async () => {
      for (let i in await this.hello()) {
      }
    };
    fn();
  }
}

test4.ts

class Test4 {
  async hello() {
    return ["hello", "world"];
  }

  test() {
    (async () => {
      await this.hello();
    });
  }
}

tsconfig.json

{
    "compilerOptions": {
        "module": "commonjs",
        "target": "es6",
        "noImplicitAny": true,
        "strictNullChecks": true
    }
}