E4110

E4110#

The loop is not expected to yield a value, please remove the argument of the break or add an else branch.

This error occurs when using a break statement with an argument in a loop that is not expected to yield a value. This applies to:

  • while loops

  • for loops with update expressions

  • for .. in .. iteration loops

These loop constructs do not have a mechanism to return a value from the loop body. If you need to break with a value, you must either:

  1. Remove the argument from the break statement if you don’t need to return a value, or

  2. Add an else branch to handle the case when the loop completes normally and provide a return value

错误示例#

pub fn f(x: Int) -> Unit {
  for i in 0..=x {
    break i
//  ^^^^^^^^ Error: The for loop is not expected to yield a value, please
//                  remove the argument of the `break` or add an `else` branch.
  }
}

建议#

To fix this error, you can:

  • Remove the argument from the break statement. For example,

pub fn f(x: Int) -> Unit {
  for i in 0..=x {
    break
  }
}

  • Add an else branch to handle the case when the loop completes normally and provide a return value. For example,

pub fn f(x: Int) -> Int {
  for i in 0..=x {
    break i
  } else {
    42
  }
}
目录