Merge branch '5.0-dev'

1 files changed, 14 insertions, 4 deletions

diff --git a/exercises/error_handling/errors5.rs b/exercises/error_handling/errors5.rs
index 365a869..67411c5 100644
--- a/exercises/error_handling/errors5.rs
+++ b/exercises/error_handling/errors5.rs
@@ -1,8 +1,18 @@
 // errors5.rs
 
-// This program uses a completed version of the code from errors4.
-// It won't compile right now! Why?
-// Execute `rustlings hint errors5` for hints!
+// This program uses an altered version of the code from errors4.
+
+// This exercise uses some concepts that we won't get to until later in the course, like `Box` and the
+// `From` trait. It's not important to understand them in detail right now, but you can read ahead if you like.
+
+// In short, this particular use case for boxes is for when you want to own a value and you care only that it is a 
+// type which implements a particular trait. To do so, The Box is declared as of type Box<dyn Trait> where Trait is the trait
+// the compiler looks for on any value used in that context. For this exercise, that context is the potential errors
+// which can be returned in a Result.
+
+// What can we use to describe both errors? In other words, is there a trait which both errors implement?
+
+// Execute `rustlings hint errors5` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
@@ -11,7 +21,7 @@ use std::fmt;
 use std::num::ParseIntError;
 
 // TODO: update the return type of `main()` to make this compile.
-fn main() -> Result<(), ParseIntError> {
+fn main() -> Result<(), Box<dyn ???>> {
     let pretend_user_input = "42";
     let x: i64 = pretend_user_input.parse()?;
     println!("output={:?}", PositiveNonzeroInteger::new(x)?);