MIssing info for some chains

[nrc]

E.g., rust-lang/rls#277:

let slice = "\"1,2,3,,4\"";

let result: Vec<i32> = slice[1 .. slice.len()-1]
    .split(',')
    .filter(|e| e.len() > 0) // methods up to here have info, but not the later ones.
    .map(|x| x.parse().map_err(|_| "parse error"))
    .collect::<Result<_,_>>()
    .unwrap()

[nrc]

Fixed by rust-lang/rust#45798