Understanding Rust Error E0268

Rust Error E0268: Misuse of loop keywords

Rust Error E0268 occurs when a loop keyword, such as `break` or `continue`, is used outside of a loop. These keywords are required to be within a loop like `for`, `while`, or a `loop` block for the code to be considered valid.

Erroneous code example:

#![allow(unused)]
fn main() {
  fn some_func() {
    break; // error: `break` outside of a loop
  }
}

The error in this code snippet is caused by the usage of `break` outside of a loop. To fix this error, make sure the `break` or `continue` keywords are used only inside a loop structure.

Correct code example:

#![allow(unused)]
fn main() {
  fn some_func() {
   for _ in 0..10 {
        break; // ok!
    }
  }
}

In this corrected example, the `break` keyword is used within a `for` loop, making it a valid use.

Common causes of Rust Error E0268

1. Missed loop structure: You might have forgotten to include a loop surrounding the `break` or `continue` keyword.

2. Incorrect loop keyword placement: You might have accidentally placed the `break` or `continue` keyword outside the loop braces.

3. Mismatched or missing braces: Check your code to ensure all braces are correctly placed and paired.

By ensuring that loop keywords are used within the intended loop structures, Rust Error E0268 can be easily avoided and fixed.

Further reading

To delve deeper into Rust control flow structures and loop constructs, visit the official Rust documentation on [Control Flow](https://doc.rust-lang.org/book/ch03-05-control-flow.html).

Recommended Reading

• Rust Control Flow