Mismatched types in if let statement: found Option expected Result
rust
Solution
You linked to the documentation of `next`, but you're not using `next` (not directly anyway), you're using a for loop. In a for loop the type of the iteration variable (i.e. the type of `line` in your code) is the `Item` type of the iterator, which in your case is `Result<String>`.
The type of `next` is `Option<Item>` because you might call `next` on an iterator that already reached the end. The body of a for loop won't ever execute after the end of the iteration, so there's no point in the iteration variable being an option.
Problem
I am trying to parse a file that has a pipe delimiter between each value and each line is a new record. I am iterating over each line like this: ``` use std::fs::File; use std::io::BufReader; use std::io::prelude::*; fn main() { let source_file = File::open("input.txt").unwrap(); let reader = BufReader::new(source_file); for line in reader.lines() { if let Some(channel_line) = line { println!("yay"); } } } ``` Playground However, I get an error: ``` error[E0308]: mismatched types --> src/main.rs:9:20 | 9 | if let Some(channel_line) = line { | ^^^^^^^^^^^^^^^^^^ expected enum `std::result::Result`, found enum `std::option::Option` | = note: expected type `std::result::Result<std::string::String, std::io::Error>` = note: found type `std::option::Option<_>` ``` This error is confusing to me as the found type is what I expected namely `Option<Result<String, Error>>` as indicated by the docs so it would make sense to unwrap the `Option` before the result assuming I am not missing something.