小编920*_*sms的帖子

我该如何修复该错误The left-hand side of a 'for...in' statement cannot use a type annotation.？未编译的相关代码是一个简单的 for...in 循环：

const roles = ['a', 'b', 'c'] as const
type Roles = typeof roles[number] // 'a' | 'b' | 'c'

const roles = {
  'a': '...',
  'b': '...',
  'c': '...',
}

for (const role: Roles in roles) {
  const isRole = roles.includes(roles)
}

我知道不可能输入常量role，但如果我不这样做，则const isRole = roles.includes(roles)不会有效：Argument of type 'string' is not assignable to parameter of type '"a" | "b" …