How to collect an iterator into a Result?

I currently have the following function:

fn filter_files<P>(input_path: P) -> Result<Vec<DirEntry>, Box<dyn error::Error>> where P: AsRef<Path> {
    fs::read_dir(input_path)?
        .into_iter()
        .filter_map(|res| res.ok())
        .filter(|dir_entry| dir_entry.file_name().to_str().unwrap().starts_with("_x"))
        .collect()
}

Where I am attempting to filter out files that start with _x. I would like to have this function return the filtered Vec<DirEntry> directly instead of having to make a variable. My issue is that I can not get the function signature correct. I am getting an error with

error[E0277]: a value of type `Result<Vec<DirEntry>, Box<dyn std::error::Error>>` cannot be built from an iterator over elements of type `DirEntry`
    --> src/main.rs:18:10
     |
18   |         .collect()
     |          ^^^^^^^ value of type `Result<Vec<DirEntry>, Box<dyn std::error::Error>>` cannot be built from `std::iter::Iterator<Item=DirEntry>`

I am wondering what the correct signature for this function's return type should be given that the fs::read_dir(...) could return an io::Error I know that I need to be returning a Result type. Is the usage of collect() correct or is this an incorrect usage.

The error is a little misleading here, you can collect into a Result but only when the iterators items are of type Result<A, E>.

Since you know all your items exist and did not result in an error (your items are of type DirEntry not Result<DirEntry, _>) what you want to do instead is to wrap your known good result in a variant of Result such as Ok:

fn filter_files<P>(input_path: P) -> std::io::Result<Vec<DirEntry>> where P: AsRef<Path> {
    Ok(fs::read_dir(input_path)?
        .into_iter()
        .filter_map(|res| res.ok())
        .filter(|dir_entry| dir_entry.file_name().to_str().unwrap().starts_with("_x"))
        .collect())
}