In the current libstd, .try_into() and .parse() are different for how they should work.
.try_into(), as a fallible version of .into(), mostly transforms the "shape" of the value to fit another type.
.parse() can be considered the reverse of .to_string(), will read the string content to reconstruct a value in the target type.
Additionally, TryFrom must satisfy this relationship, which is not bound for FromStr:
-
T: From<S>⇒T: TryFrom<S, Error=!>
As a concrete example:
use std::convert::TryInto;
use serde_json::{Value, json};
fn main() {
let a: Value = "[1, 2, 3]".try_into().unwrap();
let b: Value = "[1, 2, 3]".parse().unwrap();
assert_eq!(dbg!(a), json!("[1, 2, 3]"));
assert_eq!(dbg!(b), json!( [1, 2, 3] ));
}