7 files changed, 28 insertions, 18 deletions
diff --git a/exercises/error_handling/errors1.rs b/exercises/error_handling/errors1.rs
index c417fb2..bcee972 100644
--- a/exercises/error_handling/errors1.rs
+++ b/exercises/error_handling/errors1.rs
@@ -3,16 +3,16 @@
 // you pass it an empty string. It'd be nicer if it explained what the problem
 // was, instead of just sometimes returning `None`. Thankfully, Rust has a similar
 // construct to `Option` that can be used to express error conditions. Let's use it!
-// Execute `rustlings hint errors1` for hints!
+// Execute `rustlings hint errors1` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
 pub fn generate_nametag_text(name: String) -> Option<String> {
-    if name.len() > 0 {
-        Some(format!("Hi! My name is {}", name))
-    } else {
+    if name.is_empty() {
         // Empty names aren't allowed.
         None
+    } else {
+        Some(format!("Hi! My name is {}", name))
     }
 }
 
diff --git a/exercises/error_handling/errors2.rs b/exercises/error_handling/errors2.rs
index aad3a93..1cd8fc6 100644
--- a/exercises/error_handling/errors2.rs
+++ b/exercises/error_handling/errors2.rs
@@ -14,7 +14,8 @@
 // and add.
 
 // There are at least two ways to implement this that are both correct-- but
-// one is a lot shorter! Execute `rustlings hint errors2` for hints to both ways.
+// one is a lot shorter!
+// Execute `rustlings hint errors2` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
diff --git a/exercises/error_handling/errors3.rs b/exercises/error_handling/errors3.rs
index 460ac5c..a2d2d19 100644
--- a/exercises/error_handling/errors3.rs
+++ b/exercises/error_handling/errors3.rs
@@ -2,7 +2,7 @@
 // This is a program that is trying to use a completed version of the
 // `total_cost` function from the previous exercise. It's not working though!
 // Why not? What should we do to fix it?
-// Execute `rustlings hint errors3` for hints!
+// Execute `rustlings hint errors3` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
diff --git a/exercises/error_handling/errors4.rs b/exercises/error_handling/errors4.rs
index 0685c37..0efe8cc 100644
--- a/exercises/error_handling/errors4.rs
+++ b/exercises/error_handling/errors4.rs
@@ -1,5 +1,5 @@
 // errors4.rs
-// Make this test pass! Execute `rustlings hint errors4` for hints :)
+// Execute `rustlings hint errors4` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
@@ -14,6 +14,7 @@ enum CreationError {
 
 impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
+        // Hmm...? Why is this only returning an Ok value?
         Ok(PositiveNonzeroInteger(value as u64))
     }
 }
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)?);
diff --git a/exercises/error_handling/errors6.rs b/exercises/error_handling/errors6.rs
index 847a049..1306fb0 100644
--- a/exercises/error_handling/errors6.rs
+++ b/exercises/error_handling/errors6.rs
@@ -6,7 +6,7 @@
 // we define a custom error type to make it possible for callers to decide
 // what to do next when our function returns an error.
 
-// Make these tests pass! Execute `rustlings hint errors6` for hints :)
+// Execute `rustlings hint errors6` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
@@ -20,7 +20,11 @@ enum ParsePosNonzeroError {
 }
 
 impl ParsePosNonzeroError {
+    fn from_creation(err: CreationError) -> ParsePosNonzeroError {
+        ParsePosNonzeroError::Creation(err)
+    }
     // TODO: add another error conversion function here.
+    // fn from_parseint...
 }
 
 fn parse_pos_nonzero(s: &str)
diff --git a/exercises/error_handling/mod.rs b/exercises/error_handling/mod.rs
deleted file mode 100644
index 539fa23..0000000
--- a/exercises/error_handling/mod.rs
+++ /dev/null
@@ -1,6 +0,0 @@
-mod errors1;
-mod errors2;
-mod errors3;
-mod errors4;
-mod errors5;
-mod errors6;