Complete day 4.2

day-4/src/main.rs

@@ -17,16 +17,14 @@ fn parse_passports(input: &str) -> Result<Vec<HashMap<&str, &str>>, &str> {
                 .trim()
                 .split(|c| c == ' ' || c == '\n')
                 .map(|field| {
-                    let split = field
+                    let split = field.find(':').ok_or("Invalid passport entry; no separator")?;
-                        .find(':')
-                        .ok_or("Invalid passport entry; no separator")?;
                     let item = field.split_at(split);
 
                     let key = item.0;
                     let value = item
                         .1
                         .strip_prefix(":")
-                        .expect("We've already checked the separator exists");
+                        .ok_or("Invalid entry; value too short")?;
 
                     Ok((key, value))
                 })