Understanding Rust Error E0762: Unterminated Character Literal

Rust Error E0762 Overview

Rust error E0762 occurs when a character literal is not correctly terminated with a single quote. In this case, the Rust compiler is unable to determine the boundary of the character literal, causing a syntax error.

Erroneous Code Example

#![allow(unused)]
fn main() {
static C: char = '●; // error!
}

In the code example above, the character literal '● is missing the closing single quote, causing error E0762.

Fixing Rust Error E0762

To fix this error, simply add the missing single quote at the end of the character literal:

#![allow(unused)]
fn main() {
static C: char = '●'; // ok!
}

Now, the character literal is correctly defined and the error is resolved.

Common Mistakes and Scenarios

1. Unintentionally leaving out the closing single quote:

let letter: char = 'a;
let emoji: char = '😀;

To fix this, include the closing single quote for each character literal:

let letter: char = 'a';
let emoji: char = '😀';

2. Using double quotes instead of single quotes:

let letter: char = "a";

Replace double quotes with single quotes to define a character literal:

let letter: char = 'a';

3. Incorrectly defining a multi-byte character:

let unicode_char: char = '世; // incorrect

Again, remember to add the closing single quote:

let unicode_char: char = '世'; // correct