Patterns used to bind names must be irrefutable. That is, they must guarantee that a name will be extracted in all cases. Instead of pattern matching the loop variable, consider using a match
or if let
inside the loop body. For instance:
let xs : Vec<Option<i32>> = vec![Some(1), None]; // This fails because `None` is not covered. for Some(x) in xs { // ... }
Match inside the loop instead:
let xs : Vec<Option<i32>> = vec![Some(1), None]; for item in xs { match item { Some(x) => {}, None => {}, } }
Or use if let
:
let xs : Vec<Option<i32>> = vec![Some(1), None]; for item in xs { if let Some(x) = item { // ... } }