From aa9a943ddf3ae260782e73c26bcc9db60e5894b6 Mon Sep 17 00:00:00 2001
From: Ivan Nerazumov <64264529+cseltol@users.noreply.github.com>
Date: Sat, 13 Mar 2021 18:45:52 +0700
Subject: [PATCH 001/115] fix(installation): first PowerShell command

ExecutionPolicy to RemoteSigned command was fixed because the old command was getting denied access to change the Execution Policy property
---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index b958fae..3b7ff16 100644
--- a/README.md
+++ b/README.md
@@ -36,7 +36,7 @@ This will install Rustlings and give you access to the `rustlings` command. Run
 In PowerShell, set `ExecutionPolicy` to `RemoteSigned`:
 
 ```ps
-Set-ExecutionPolicy RemoteSigned
+Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser
 ```
 
 Then, you can run:

From 4a384cae4ac735e243bbc58184b1f409e914ddc5 Mon Sep 17 00:00:00 2001
From: Zerotask <Zerotask@users.noreply.github.com>
Date: Sat, 24 Apr 2021 12:12:49 +0200
Subject: [PATCH 002/115] docs(option): improve further information

---
 exercises/option/README.md  | 2 ++
 exercises/option/option1.rs | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/exercises/option/README.md b/exercises/option/README.md
index a304bb4..89c0028 100644
--- a/exercises/option/README.md
+++ b/exercises/option/README.md
@@ -16,3 +16,5 @@ Option types are very common in Rust code, as they have a number of uses:
 - [Option Enum Format](https://doc.rust-lang.org/stable/book/ch10-01-syntax.html#in-enum-definitions)
 - [Option Module Documentation](https://doc.rust-lang.org/std/option/)
 - [Option Enum Documentation](https://doc.rust-lang.org/std/option/enum.Option.html)
+- [if let](https://doc.rust-lang.org/rust-by-example/flow_control/if_let.html)
+- [while let](https://doc.rust-lang.org/rust-by-example/flow_control/while_let.html)
diff --git a/exercises/option/option1.rs b/exercises/option/option1.rs
index 602ff1a..17cf4f6 100644
--- a/exercises/option/option1.rs
+++ b/exercises/option/option1.rs
@@ -3,7 +3,7 @@
 
 // I AM NOT DONE
 
-// you can modify anything EXCEPT for this function's sig
+// you can modify anything EXCEPT for this function's signature
 fn print_number(maybe_number: Option<u16>) {
     println!("printing: {}", maybe_number.unwrap());
 }

From 7f0d2c2bf011838d77fc05f111aacf2b0a663f5c Mon Sep 17 00:00:00 2001
From: apogeeoak <59737221+apogeeoak@users.noreply.github.com>
Date: Sat, 24 Apr 2021 12:42:06 -0400
Subject: [PATCH 003/115] chore(iterators5): Minor formatting improvements.

---
 exercises/standard_library_types/iterators5.rs | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/exercises/standard_library_types/iterators5.rs b/exercises/standard_library_types/iterators5.rs
index 2d97bd4..6e246b4 100644
--- a/exercises/standard_library_types/iterators5.rs
+++ b/exercises/standard_library_types/iterators5.rs
@@ -1,5 +1,4 @@
 // iterators5.rs
-
 // Let's define a simple model to track Rustlings exercise progress. Progress
 // will be modelled using a hash map. The name of the exercise is the key and
 // the progress is the value. Two counting functions were created to count the
@@ -7,8 +6,7 @@
 // imperative style for loops. Recreate this counting functionality using
 // iterators. Only the two iterator methods (count_iterator and
 // count_collection_iterator) need to be modified.
-// Execute `rustlings hint
-// iterators5` for hints.
+// Execute `rustlings hint iterators5` for hints.
 //
 // Make the code compile and the tests pass.
 

From 21c9f44168394e08338fd470b5f49b1fd235986f Mon Sep 17 00:00:00 2001
From: apogeeoak <59737221+apogeeoak@users.noreply.github.com>
Date: Sat, 24 Apr 2021 13:15:34 -0400
Subject: [PATCH 004/115] feat(intro): Add intro section.

---
 exercises/intro/README.md         |  8 ++++++++
 exercises/intro/intro1.rs         | 19 +++++++++++++++++++
 exercises/intro/intro2.rs         |  9 +++++++++
 exercises/variables/variables1.rs |  8 ++------
 info.toml                         | 16 ++++++++++++++++
 5 files changed, 54 insertions(+), 6 deletions(-)
 create mode 100644 exercises/intro/README.md
 create mode 100644 exercises/intro/intro1.rs
 create mode 100644 exercises/intro/intro2.rs

diff --git a/exercises/intro/README.md b/exercises/intro/README.md
new file mode 100644
index 0000000..d32e4a8
--- /dev/null
+++ b/exercises/intro/README.md
@@ -0,0 +1,8 @@
+# Intro
+
+Rust uses the `print!` and `println!` macros to print text to the console.
+
+## Further information
+
+- [Hello World](https://doc.rust-lang.org/rust-by-example/hello.html)
+- [Formatted print](https://doc.rust-lang.org/rust-by-example/hello/print.html)
diff --git a/exercises/intro/intro1.rs b/exercises/intro/intro1.rs
new file mode 100644
index 0000000..83a78e6
--- /dev/null
+++ b/exercises/intro/intro1.rs
@@ -0,0 +1,19 @@
+// intro1.rs
+// About this `I AM NOT DONE` thing:
+// We sometimes encourage you to keep trying things on a given exercise, even
+// after you already figured it out. If you got everything working and feel
+// ready for the next exercise, remove the `I AM NOT DONE` comment below.
+// Execute the command `rustlings hint intro1` for a hint.
+
+// I AM NOT DONE
+
+fn main() {
+    println!("Hello and");
+    println!(r#"       welcome to...                      "#);
+    println!(r#"                 _   _ _                  "#);
+    println!(r#"  _ __ _   _ ___| |_| (_)_ __   __ _ ___  "#);
+    println!(r#" | '__| | | / __| __| | | '_ \ / _` / __| "#);
+    println!(r#" | |  | |_| \__ \ |_| | | | | | (_| \__ \ "#);
+    println!(r#" |_|   \__,_|___/\__|_|_|_| |_|\__, |___/ "#);
+    println!(r#"                               |___/      "#);
+}
diff --git a/exercises/intro/intro2.rs b/exercises/intro/intro2.rs
new file mode 100644
index 0000000..97a073f
--- /dev/null
+++ b/exercises/intro/intro2.rs
@@ -0,0 +1,9 @@
+// intro2.rs
+// Make the code print a greeting to the world.
+// Execute `rustlings hint intro2` for a hint.
+
+// I AM NOT DONE
+
+fn main() {
+    println!("Hello {}!");
+}
diff --git a/exercises/variables/variables1.rs b/exercises/variables/variables1.rs
index 4a3af73..d1af831 100644
--- a/exercises/variables/variables1.rs
+++ b/exercises/variables/variables1.rs
@@ -1,10 +1,6 @@
 // variables1.rs
-// Make me compile! Execute the command `rustlings hint variables1` if you want a hint :)
-
-// About this `I AM NOT DONE` thing:
-// We sometimes encourage you to keep trying things on a given exercise,
-// even after you already figured it out. If you got everything working and
-// feel ready for the next exercise, remove the `I AM NOT DONE` comment below.
+// Make me compile!
+// Execute the command `rustlings hint variables1` if you want a hint :)
 
 // I AM NOT DONE
 
diff --git a/info.toml b/info.toml
index 82e1195..c56b19f 100644
--- a/info.toml
+++ b/info.toml
@@ -1,3 +1,19 @@
+# INTRO
+
+[[exercises]]
+name = "intro1"
+path = "exercises/intro/intro1.rs"
+mode = "compile"
+hint = """
+Remove the I AM NOT DONE comment to move on to the next exercise."""
+
+[[exercises]]
+name = "intro2"
+path = "exercises/intro/intro2.rs"
+mode = "compile"
+hint = """
+Add an argument after the format string."""
+
 # VARIABLES
 
 [[exercises]]

From 9b8de65525a5576b78cf0c8e4098cdd34296338f Mon Sep 17 00:00:00 2001
From: apogeeoak <59737221+apogeeoak@users.noreply.github.com>
Date: Mon, 26 Apr 2021 20:28:17 -0400
Subject: [PATCH 005/115] fix(intro1): Add compiler error explanation.

---
 exercises/intro/intro1.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/exercises/intro/intro1.rs b/exercises/intro/intro1.rs
index 83a78e6..1c4582d 100644
--- a/exercises/intro/intro1.rs
+++ b/exercises/intro/intro1.rs
@@ -16,4 +16,8 @@ fn main() {
     println!(r#" | |  | |_| \__ \ |_| | | | | | (_| \__ \ "#);
     println!(r#" |_|   \__,_|___/\__|_|_|_| |_|\__, |___/ "#);
     println!(r#"                               |___/      "#);
+    println!();
+    println!("This exercise compiles successfully. The remaining exercises contain a compiler");
+    println!("or logic error. The central concept behind Rustlings is to fix these errors and");
+    println!("solve the exercises. Good luck!");
 }

From 166a53946cf79d01f0ae670d7778f9f7221b7cba Mon Sep 17 00:00:00 2001
From: Martin HART <82845873+martinhartxyz@users.noreply.github.com>
Date: Tue, 27 Apr 2021 20:22:13 +0200
Subject: [PATCH 006/115] Correct small typo in
 exercises/conversions/from_str.rs

---
 exercises/conversions/from_str.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/conversions/from_str.rs b/exercises/conversions/from_str.rs
index 4beebac..93a5299 100644
--- a/exercises/conversions/from_str.rs
+++ b/exercises/conversions/from_str.rs
@@ -20,7 +20,7 @@ struct Person {
 // 4. Extract the first element from the split operation and use it as the name
 // 5. Extract the other element from the split operation and parse it into a `usize` as the age
 //    with something like `"4".parse::<usize>()`
-// 5. If while extracting the name and the age something goes wrong, an error should be returned
+// 6. If while extracting the name and the age something goes wrong, an error should be returned
 // If everything goes well, then return a Result of a Person object
 
 impl FromStr for Person {

From 86cc85295ae36948963ae52882e285d7e3e29323 Mon Sep 17 00:00:00 2001
From: Martin HART <82845873+martinhartxyz@users.noreply.github.com>
Date: Tue, 27 Apr 2021 20:22:13 +0200
Subject: [PATCH 007/115] fix: Correct small typo in
 exercises/conversions/from_str.rs

---
 exercises/conversions/from_str.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/conversions/from_str.rs b/exercises/conversions/from_str.rs
index 4beebac..93a5299 100644
--- a/exercises/conversions/from_str.rs
+++ b/exercises/conversions/from_str.rs
@@ -20,7 +20,7 @@ struct Person {
 // 4. Extract the first element from the split operation and use it as the name
 // 5. Extract the other element from the split operation and parse it into a `usize` as the age
 //    with something like `"4".parse::<usize>()`
-// 5. If while extracting the name and the age something goes wrong, an error should be returned
+// 6. If while extracting the name and the age something goes wrong, an error should be returned
 // If everything goes well, then return a Result of a Person object
 
 impl FromStr for Person {

From 9569c9a9e72fb0ff792437207a579930cea8f9fb Mon Sep 17 00:00:00 2001
From: Pi Delport <pjdelport@gmail.com>
Date: Thu, 29 Apr 2021 23:31:26 +0200
Subject: [PATCH 008/115] style(standard_library_types): stray line break

---
 exercises/standard_library_types/iterators5.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/exercises/standard_library_types/iterators5.rs b/exercises/standard_library_types/iterators5.rs
index 2d97bd4..d8d4453 100644
--- a/exercises/standard_library_types/iterators5.rs
+++ b/exercises/standard_library_types/iterators5.rs
@@ -7,8 +7,7 @@
 // imperative style for loops. Recreate this counting functionality using
 // iterators. Only the two iterator methods (count_iterator and
 // count_collection_iterator) need to be modified.
-// Execute `rustlings hint
-// iterators5` for hints.
+// Execute `rustlings hint iterators5` for hints.
 //
 // Make the code compile and the tests pass.
 

From 404f3ef465f15916f3f9348190459b64d513b056 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Sat, 1 May 2021 10:12:42 +0000
Subject: [PATCH 009/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 8ca25ba..fede672 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-91-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-92-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -279,6 +279,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://github.com/hongshaoyang"><img src="https://avatars.githubusercontent.com/u/19281800?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Shao Yang Hong</b></sub></a><br /><a href="#content-hongshaoyang" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/bmacer"><img src="https://avatars.githubusercontent.com/u/13931806?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Brandon Macer</b></sub></a><br /><a href="#content-bmacer" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/stoiandan"><img src="https://avatars.githubusercontent.com/u/10388612?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Stoian Dan</b></sub></a><br /><a href="#content-stoiandan" title="Content">🖋</a></td>
+    <td align="center"><a href="https://about.me/pjdelport"><img src="https://avatars.githubusercontent.com/u/630271?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Pi Delport</b></sub></a><br /><a href="#content-PiDelport" title="Content">🖋</a></td>
   </tr>
 </table>
 

From ce40e201f0b454822074399800886068317027aa Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Sat, 1 May 2021 10:12:43 +0000
Subject: [PATCH 010/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 2f20971..4627e29 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -847,6 +847,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "PiDelport",
+      "name": "Pi Delport",
+      "avatar_url": "https://avatars.githubusercontent.com/u/630271?v=4",
+      "profile": "https://about.me/pjdelport",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From d9b69bd1a0a7a99f2c0d80933ad2eea44c8c71b2 Mon Sep 17 00:00:00 2001
From: Juan Pablo Ramirez <juan.ramirez.q@gmail.com>
Date: Sun, 9 May 2021 17:58:54 -0500
Subject: [PATCH 011/115] fix: remove trailing whitespace

---
 exercises/structs/structs3.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/structs/structs3.rs b/exercises/structs/structs3.rs
index 8d8b471..a80d062 100644
--- a/exercises/structs/structs3.rs
+++ b/exercises/structs/structs3.rs
@@ -31,7 +31,7 @@ impl Package {
     }
 
     fn get_fees(&self, cents_per_gram: i32) -> ??? {
-        // Something goes here... 
+        // Something goes here...
     }
 }
 

From 31457940846b3844d78d4a4d2b074bc8d6aaf1eb Mon Sep 17 00:00:00 2001
From: Juan Pablo Ramirez <juan.ramirez.q@gmail.com>
Date: Tue, 11 May 2021 14:50:05 -0500
Subject: [PATCH 012/115] fix: add hints to generics1 and generics2 exercises

---
 exercises/generics/generics1.rs | 2 ++
 exercises/generics/generics2.rs | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/exercises/generics/generics1.rs b/exercises/generics/generics1.rs
index 967287e..f93e64a 100644
--- a/exercises/generics/generics1.rs
+++ b/exercises/generics/generics1.rs
@@ -1,6 +1,8 @@
 // This shopping list program isn't compiling!
 // Use your knowledge of generics to fix it.
 
+// Execute `rustlings hint generics1` for hints!
+
 // I AM NOT DONE
 
 fn main() {
diff --git a/exercises/generics/generics2.rs b/exercises/generics/generics2.rs
index 0cb59ad..1501529 100644
--- a/exercises/generics/generics2.rs
+++ b/exercises/generics/generics2.rs
@@ -1,6 +1,8 @@
 // This powerful wrapper provides the ability to store a positive integer value.
 // Rewrite it using generics so that it supports wrapping ANY type.
 
+// Execute `rustlings hint generics2` for hints!
+
 // I AM NOT DONE
 
 struct Wrapper {

From 4d4fa77459392acd3581c6068aa8be9a02de12fc Mon Sep 17 00:00:00 2001
From: Juan Pablo Ramirez <juan.ramirez.q@gmail.com>
Date: Wed, 12 May 2021 10:20:07 -0500
Subject: [PATCH 013/115] fix: remove trailing whitespaces from iterators1

---
 exercises/standard_library_types/iterators1.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/exercises/standard_library_types/iterators1.rs b/exercises/standard_library_types/iterators1.rs
index 3fd519d..4606ad3 100644
--- a/exercises/standard_library_types/iterators1.rs
+++ b/exercises/standard_library_types/iterators1.rs
@@ -1,11 +1,11 @@
 // iterators1.rs
-// 
+//
 //  Make me compile by filling in the `???`s
 //
 // When performing operations on elements within a collection, iterators are essential.
-// This module helps you get familiar with the structure of using an iterator and 
+// This module helps you get familiar with the structure of using an iterator and
 // how to go through elements within an iterable collection.
-// 
+//
 // Execute `rustlings hint iterators1` for hints :D
 
 // I AM NOT DONE

From 11d2cf0d604dee3f5023c17802d69438e69fa50e Mon Sep 17 00:00:00 2001
From: Taylor Yu <tlyu@mit.edu>
Date: Sat, 15 May 2021 14:01:17 -0500
Subject: [PATCH 014/115] fix(try_from_into, from_str): hints for dyn Error

Add hints about how to return the correct type for functions that
return `Result<_, Box<dyn Error>`. Some feedback from Discord suggests
that people run into trouble with that.
---
 info.toml | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/info.toml b/info.toml
index 82e1195..0535a77 100644
--- a/info.toml
+++ b/info.toml
@@ -893,7 +893,19 @@ path = "exercises/conversions/try_from_into.rs"
 mode = "test"
 hint = """
 Follow the steps provided right before the `TryFrom` implementation.
-You can also use the example at https://doc.rust-lang.org/std/convert/trait.TryFrom.html"""
+You can also use the example at https://doc.rust-lang.org/std/convert/trait.TryFrom.html
+
+You might want to look back at the exercise errorsn (or its hints) to remind
+yourself about how `Box<dyn Error>` works.
+
+If you're trying to return a string as an error, note that neither `str`
+nor `String` implements `error::Error`. However, there is an implementation
+of `From<&str>` for `Box<dyn Error>`. This means you can use `.into()` or
+the `?` operator to convert your string into the correct error type.
+
+If you're having trouble with using the `?` operator to convert an error string,
+recall that `?` works to convert `Err(something)` into the appropriate error
+type for returning from the function."""
 
 [[exercises]]
 name = "as_ref_mut"
@@ -909,4 +921,7 @@ mode = "test"
 hint = """
 The implementation of FromStr should return an Ok with a Person object,
 or an Err with an error if the string is not valid.
-This is almost like the `try_from_into` exercise."""
+This is almost like the `try_from_into` exercise.
+
+If you're having trouble with returning the correct error type, see the
+hints for try_from_into."""

From 399ab328d8d407265c09563aa4ef4534b2503ff2 Mon Sep 17 00:00:00 2001
From: Sateesh <sateeshkumarb@yahoo.com>
Date: Mon, 17 May 2021 17:40:40 +0530
Subject: [PATCH 015/115] feat: Add move_semantics5 exercise. (#746)

* feat: Add move_semantics5 exercise.

* feat: Add option3 exercise

* Address review comments. Fix typos, sentence formatting.

* Remove unwanted newline.

* Address review comments: make comment inline, fix format in print.
---
 exercises/move_semantics/move_semantics5.rs | 14 ++++++++++++++
 exercises/option/option3.rs                 | 19 +++++++++++++++++++
 info.toml                                   | 21 +++++++++++++++++++++
 3 files changed, 54 insertions(+)
 create mode 100644 exercises/move_semantics/move_semantics5.rs
 create mode 100644 exercises/option/option3.rs

diff --git a/exercises/move_semantics/move_semantics5.rs b/exercises/move_semantics/move_semantics5.rs
new file mode 100644
index 0000000..4f8128c
--- /dev/null
+++ b/exercises/move_semantics/move_semantics5.rs
@@ -0,0 +1,14 @@
+// move_semantics5.rs
+// Make me compile without adding any newlines or removing any of the lines.
+// Execute `rustlings hint move_semantics5` for hints :)
+
+// I AM NOT DONE
+
+fn main() {
+    let mut x = 100;
+    let y = &mut x;
+    let z = &mut *y;
+    *y += 100;
+    *z += 1000;
+    assert_eq!(x, 1200);
+}
diff --git a/exercises/option/option3.rs b/exercises/option/option3.rs
new file mode 100644
index 0000000..045d2ac
--- /dev/null
+++ b/exercises/option/option3.rs
@@ -0,0 +1,19 @@
+// option3.rs
+// Make me compile! Execute `rustlings hint option3` for hints
+
+// I AM NOT DONE
+
+struct Point {
+    x: i32,
+    y: i32,
+}
+
+fn main() {
+    let y: Option<Point> = Some(Point { x: 100, y: 200 });
+
+    match y {
+        Some(p) => println!("Co-ordinates are {},{} ", p.x, p.y),
+        _ => println!("no match"),
+    }
+    y; // Fix without deleting this line.
+}
diff --git a/info.toml b/info.toml
index 0535a77..0e9f428 100644
--- a/info.toml
+++ b/info.toml
@@ -210,6 +210,17 @@ So the end goal is to:
    - since we're not creating a new vec in `main` anymore, we need to create
      a new vec in `fill_vec`, similarly to the way we did in `main`"""
 
+[[exercises]]
+name = "move_semantics5"
+path = "exercises/move_semantics/move_semantics5.rs"
+mode = "compile"
+hint = """
+Carefully reason about the range in which each mutable reference is in
+vogue. Does updating the value of referrent (x) immediately after the
+mutable reference is taken helps? Read more about 'Mutable Referenes'
+in the book's section References and Borrowing':
+https://doc.rust-lang.org/book/ch04-02-references-and-borrowing.html#mutable-references."""
+
 # PRIMITIVE TYPES
 
 [[exercises]]
@@ -578,6 +589,16 @@ For example: Some(Some(variable)) = variable2
 Also see Option::flatten
 """
 
+[[exercises]]
+name = "option3"
+path = "exercises/option/option3.rs"
+mode = "compile"
+hint = """
+The compiler says a partial move happened in the `match`
+statement. How can this be avoided? The compiler shows the correction
+needed. After making the correction as suggested by the compiler, do
+read: https://doc.rust-lang.org/std/keyword.ref.html"""
+
 [[exercises]]
 name = "result1"
 path = "exercises/error_handling/result1.rs"

From cd02abc48138f9415d1d81da86524508d501a09f Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Mon, 17 May 2021 12:11:04 +0000
Subject: [PATCH 016/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index fede672..503cf2c 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-92-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-93-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -280,6 +280,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://github.com/bmacer"><img src="https://avatars.githubusercontent.com/u/13931806?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Brandon Macer</b></sub></a><br /><a href="#content-bmacer" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/stoiandan"><img src="https://avatars.githubusercontent.com/u/10388612?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Stoian Dan</b></sub></a><br /><a href="#content-stoiandan" title="Content">🖋</a></td>
     <td align="center"><a href="https://about.me/pjdelport"><img src="https://avatars.githubusercontent.com/u/630271?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Pi Delport</b></sub></a><br /><a href="#content-PiDelport" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/sateeshkumarb"><img src="https://avatars.githubusercontent.com/u/429263?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Sateesh </b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sateeshkumarb" title="Code">💻</a> <a href="#content-sateeshkumarb" title="Content">🖋</a></td>
   </tr>
 </table>
 

From 72e615aa7ae36c0e0a7c82b3e22a33a04f579e3c Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Mon, 17 May 2021 12:11:05 +0000
Subject: [PATCH 017/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 4627e29..867f1d5 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -856,6 +856,16 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "sateeshkumarb",
+      "name": "Sateesh ",
+      "avatar_url": "https://avatars.githubusercontent.com/u/429263?v=4",
+      "profile": "https://github.com/sateeshkumarb",
+      "contributions": [
+        "code",
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 4c46e5e1a33478d6cdb5f2a08b62f5ee79e35dd9 Mon Sep 17 00:00:00 2001
From: Taylor Yu <tlyu@mit.edu>
Date: Sat, 22 May 2021 21:56:14 -0500
Subject: [PATCH 018/115] chore: minor typos in move_semantics5 hints

---
 info.toml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/info.toml b/info.toml
index 0e9f428..d8e7dd5 100644
--- a/info.toml
+++ b/info.toml
@@ -216,8 +216,8 @@ path = "exercises/move_semantics/move_semantics5.rs"
 mode = "compile"
 hint = """
 Carefully reason about the range in which each mutable reference is in
-vogue. Does updating the value of referrent (x) immediately after the
-mutable reference is taken helps? Read more about 'Mutable Referenes'
+vogue. Does updating the value of referent (x) immediately after the
+mutable reference is taken helps? Read more about 'Mutable References'
 in the book's section References and Borrowing':
 https://doc.rust-lang.org/book/ch04-02-references-and-borrowing.html#mutable-references."""
 

From 1b85828548f46f58b622b5e0c00f8c989f928807 Mon Sep 17 00:00:00 2001
From: Taylor Yu <tlyu@mit.edu>
Date: Sat, 22 May 2021 22:09:58 -0500
Subject: [PATCH 019/115] fix: move_semantics5 hints

Improve the hints for move_semantics5, as well as the explanatory
comments in the code.

Previously, it was not clear what possible changes were allowed.
It seems that reordering the statements might be the intended solution.
The previous comment about not "adding newlines" doesn't make sense,
so treating it as "adding new lines" makes it more clear.
---
 exercises/move_semantics/move_semantics5.rs |  3 ++-
 info.toml                                   | 10 +++++++---
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/exercises/move_semantics/move_semantics5.rs b/exercises/move_semantics/move_semantics5.rs
index 4f8128c..2fb7b8e 100644
--- a/exercises/move_semantics/move_semantics5.rs
+++ b/exercises/move_semantics/move_semantics5.rs
@@ -1,5 +1,6 @@
 // move_semantics5.rs
-// Make me compile without adding any newlines or removing any of the lines.
+// Make me compile without adding, removing, or changing any of the
+// lines in `main()`.
 // Execute `rustlings hint move_semantics5` for hints :)
 
 // I AM NOT DONE
diff --git a/info.toml b/info.toml
index d8e7dd5..8c8f7c1 100644
--- a/info.toml
+++ b/info.toml
@@ -216,10 +216,14 @@ path = "exercises/move_semantics/move_semantics5.rs"
 mode = "compile"
 hint = """
 Carefully reason about the range in which each mutable reference is in
-vogue. Does updating the value of referent (x) immediately after the
-mutable reference is taken helps? Read more about 'Mutable References'
+vogue. Does it help to update the value of referent (x) immediately after
+the mutable reference is taken? Read more about 'Mutable References'
 in the book's section References and Borrowing':
-https://doc.rust-lang.org/book/ch04-02-references-and-borrowing.html#mutable-references."""
+https://doc.rust-lang.org/book/ch04-02-references-and-borrowing.html#mutable-references.
+
+Additional hint:
+If you can't add, change, or remove any statements in `main()`, can you
+reorder them in a way that lets the program compile?"""
 
 # PRIMITIVE TYPES
 

From 91fc9e3118f4af603c9911698cc2a234725cb032 Mon Sep 17 00:00:00 2001
From: Taylor Yu <tlyu@mit.edu>
Date: Sun, 6 Jun 2021 17:36:44 -0500
Subject: [PATCH 020/115] fix(iterators5): derive Clone, Copy

To allow more flexibility in solutions, derive `Clone` and `Copy`
for `Progress`.
---
 exercises/standard_library_types/iterators5.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/standard_library_types/iterators5.rs b/exercises/standard_library_types/iterators5.rs
index d8d4453..765028a 100644
--- a/exercises/standard_library_types/iterators5.rs
+++ b/exercises/standard_library_types/iterators5.rs
@@ -15,7 +15,7 @@
 
 use std::collections::HashMap;
 
-#[derive(PartialEq, Eq)]
+#[derive(Clone, Copy, PartialEq, Eq)]
 enum Progress {
     None,
     Some,

From 4e079fdd0829ab271508c773aa814b21d6cff32b Mon Sep 17 00:00:00 2001
From: Taylor Yu <tlyu@mit.edu>
Date: Sun, 6 Jun 2021 17:39:13 -0500
Subject: [PATCH 021/115] chore(iterators5): conciseness hint

---
 info.toml | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/info.toml b/info.toml
index 8c8f7c1..562fe42 100644
--- a/info.toml
+++ b/info.toml
@@ -788,7 +788,10 @@ test count_iterator.
 The collection variable in count_collection_iterator is a slice of HashMaps. It
 needs to be converted into an iterator in order to use the iterator methods.
 
-The fold method can be useful in the count_collection_iterator function."""
+The fold method can be useful in the count_collection_iterator function.
+
+For a further challenge, consult the documentation for Iterator to find
+a different method that could make your code more compact than using fold."""
 
 # THREADS
 

From 50ab289da6b9eb19a7486c341b00048c516b88c0 Mon Sep 17 00:00:00 2001
From: Taylor Yu <tlyu@mit.edu>
Date: Sun, 6 Jun 2021 20:14:29 -0500
Subject: [PATCH 022/115] fix: rename result1 to errors4

Also put it in the ERROR HANDLING section where it probably belongs.
---
 .../error_handling/{result1.rs => errors4.rs} |  4 ++--
 info.toml                                     | 20 +++++++++----------
 2 files changed, 12 insertions(+), 12 deletions(-)
 rename exercises/error_handling/{result1.rs => errors4.rs} (88%)

diff --git a/exercises/error_handling/result1.rs b/exercises/error_handling/errors4.rs
similarity index 88%
rename from exercises/error_handling/result1.rs
rename to exercises/error_handling/errors4.rs
index b978001..0685c37 100644
--- a/exercises/error_handling/result1.rs
+++ b/exercises/error_handling/errors4.rs
@@ -1,5 +1,5 @@
-// result1.rs
-// Make this test pass! Execute `rustlings hint result1` for hints :)
+// errors4.rs
+// Make this test pass! Execute `rustlings hint errors4` for hints :)
 
 // I AM NOT DONE
 
diff --git a/info.toml b/info.toml
index 8c8f7c1..55875d7 100644
--- a/info.toml
+++ b/info.toml
@@ -489,6 +489,15 @@ mode = "compile"
 hint = """
 If other functions can return a `Result`, why shouldn't `main`?"""
 
+[[exercises]]
+name = "errors4"
+path = "exercises/error_handling/errors4.rs"
+mode = "test"
+hint = """
+`PositiveNonzeroInteger::new` is always creating a new instance and returning an `Ok` result.
+It should be doing some checking, returning an `Err` result if those checks fail, and only
+returning an `Ok` result if those checks determine that everything is... okay :)"""
+
 [[exercises]]
 name = "errorsn"
 path = "exercises/error_handling/errorsn.rs"
@@ -561,7 +570,7 @@ ReportCard struct generic, but also the correct property - you will need to chan
 of the struct slightly too...you can do it!
 """
 
-# OPTIONS / RESULTS
+# OPTIONS
 
 [[exercises]]
 name = "option1"
@@ -603,15 +612,6 @@ statement. How can this be avoided? The compiler shows the correction
 needed. After making the correction as suggested by the compiler, do
 read: https://doc.rust-lang.org/std/keyword.ref.html"""
 
-[[exercises]]
-name = "result1"
-path = "exercises/error_handling/result1.rs"
-mode = "test"
-hint = """
-`PositiveNonzeroInteger::new` is always creating a new instance and returning an `Ok` result.
-It should be doing some checking, returning an `Err` result if those checks fail, and only
-returning an `Ok` result if those checks determine that everything is... okay :)"""
-
 # TRAITS
 
 [[exercises]]

From 68d3ac567cd5c23f5593c2f4df51612bca3d09a9 Mon Sep 17 00:00:00 2001
From: Taylor Yu <tlyu@mit.edu>
Date: Sun, 6 Jun 2021 23:05:01 -0500
Subject: [PATCH 023/115] feature: improve error_handling exercises

Add new exercises errors5 and errors6, to introduce boxed errors and
custom error enums more gently. Delete errorsn, because it tried to do
too much too soon.
---
 exercises/error_handling/errors5.rs |  53 +++++++++++++
 exercises/error_handling/errors6.rs |  86 ++++++++++++++++++++
 exercises/error_handling/errorsn.rs | 117 ----------------------------
 info.toml                           |  61 ++++++++-------
 4 files changed, 173 insertions(+), 144 deletions(-)
 create mode 100644 exercises/error_handling/errors5.rs
 create mode 100644 exercises/error_handling/errors6.rs
 delete mode 100644 exercises/error_handling/errorsn.rs

diff --git a/exercises/error_handling/errors5.rs b/exercises/error_handling/errors5.rs
new file mode 100644
index 0000000..1b11800
--- /dev/null
+++ b/exercises/error_handling/errors5.rs
@@ -0,0 +1,53 @@
+// 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!
+
+// I AM NOT DONE
+
+use std::error;
+use std::fmt;
+use std::num::ParseIntError;
+
+// TODO: update the return type of `main()` to make this compile.
+fn main() -> Result<(), ParseIntError> {
+    let pretend_user_input = "42";
+    let x: i64 = pretend_user_input.parse()?;
+    println!("output={:?}", PositiveNonzeroInteger::new(x)?);
+    Ok(())
+}
+
+// Don't change anything below this line.
+
+#[derive(PartialEq, Debug)]
+struct PositiveNonzeroInteger(u64);
+
+#[derive(PartialEq, Debug)]
+enum CreationError {
+    Negative,
+    Zero,
+}
+
+impl PositiveNonzeroInteger {
+    fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
+        match value {
+            x if x < 0 => Err(CreationError::Negative),
+            x if x == 0 => Err(CreationError::Zero),
+            x => Ok(PositiveNonzeroInteger(x as u64))
+        }
+    }
+}
+
+// This is required so that `CreationError` can implement `error::Error`.
+impl fmt::Display for CreationError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let description = match *self {
+            CreationError::Negative => "Number is negative",
+            CreationError::Zero => "Number is zero",
+        };
+        f.write_str(description)
+    }
+}
+
+impl error::Error for CreationError {}
diff --git a/exercises/error_handling/errors6.rs b/exercises/error_handling/errors6.rs
new file mode 100644
index 0000000..cee7250
--- /dev/null
+++ b/exercises/error_handling/errors6.rs
@@ -0,0 +1,86 @@
+// errors6.rs
+
+// Using catch-all error types like `Box<dyn error::Error>` isn't recommended
+// for library code, where callers might want to make decisions based on the
+// error content, instead of printing it out or propagating it further. Here,
+// 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 :)
+
+// I AM NOT DONE
+
+// This is a custom error type that we will be using in `parse_pos_nonzero()`.
+#[derive(PartialEq, Debug)]
+enum ParsePosNonzeroError {
+    CreationError,
+    ParseIntError
+}
+
+fn parse_pos_nonzero(s: &str)
+    -> Result<PositiveNonzeroInteger, ParsePosNonzeroError>
+{
+    // TODO: change this to return an appropriate error instead of panicking
+    // when `parse()` returns an error.
+    let x: i64 = s.parse().unwrap();
+    PositiveNonzeroInteger::new(x)
+        .or(Err(ParsePosNonzeroError::CreationError))
+}
+
+// Don't change anything below this line.
+
+#[derive(PartialEq, Debug)]
+struct PositiveNonzeroInteger(u64);
+
+#[derive(PartialEq, Debug)]
+enum CreationError {
+    Negative,
+    Zero,
+}
+
+impl PositiveNonzeroInteger {
+    fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
+        match value {
+            x if x < 0 => Err(CreationError::Negative),
+            x if x == 0 => Err(CreationError::Zero),
+            x => Ok(PositiveNonzeroInteger(x as u64))
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_parse_error() {
+        assert_eq!(
+            parse_pos_nonzero("not a number"),
+            Err(ParsePosNonzeroError::ParseIntError)
+        );
+    }
+
+    #[test]
+    fn test_negative() {
+        assert_eq!(
+            parse_pos_nonzero("-555"),
+            Err(ParsePosNonzeroError::CreationError)
+        );
+    }
+
+    #[test]
+    fn test_zero() {
+        assert_eq!(
+            parse_pos_nonzero("0"),
+            Err(ParsePosNonzeroError::CreationError)
+        );
+    }
+
+    #[test]
+    fn test_positive() {
+        assert_eq!(
+            parse_pos_nonzero("42"),
+            Ok(PositiveNonzeroInteger(42))
+        );
+    }
+}
diff --git a/exercises/error_handling/errorsn.rs b/exercises/error_handling/errorsn.rs
deleted file mode 100644
index 5fe212b..0000000
--- a/exercises/error_handling/errorsn.rs
+++ /dev/null
@@ -1,117 +0,0 @@
-// errorsn.rs
-// This is a bigger error exercise than the previous ones!
-// You can do it! :)
-//
-// Edit the `read_and_validate` function ONLY. Don't create any Errors
-// that do not already exist.
-//
-// So many things could go wrong!
-//
-// - Reading from stdin could produce an io::Error
-// - Parsing the input could produce a num::ParseIntError
-// - Validating the input could produce a CreationError (defined below)
-//
-// How can we lump these errors into one general error? That is, what
-// type goes where the question marks are, and how do we return
-// that type from the body of read_and_validate?
-//
-// Execute `rustlings hint errorsn` for hints :)
-
-// I AM NOT DONE
-
-use std::error;
-use std::fmt;
-use std::io;
-
-// PositiveNonzeroInteger is a struct defined below the tests.
-fn read_and_validate(b: &mut dyn io::BufRead) -> Result<PositiveNonzeroInteger, ???> {
-    let mut line = String::new();
-    b.read_line(&mut line);
-    let num: i64 = line.trim().parse();
-    let answer = PositiveNonzeroInteger::new(num);
-    answer
-}
-
-//
-// Nothing below this needs to be modified
-//
-
-// This is a test helper function that turns a &str into a BufReader.
-fn test_with_str(s: &str) -> Result<PositiveNonzeroInteger, Box<dyn error::Error>> {
-    let mut b = io::BufReader::new(s.as_bytes());
-    read_and_validate(&mut b)
-}
-
-#[test]
-fn test_success() {
-    let x = test_with_str("42\n");
-    assert_eq!(PositiveNonzeroInteger(42), x.unwrap());
-}
-
-#[test]
-fn test_not_num() {
-    let x = test_with_str("eleven billion\n");
-    assert!(x.is_err());
-}
-
-#[test]
-fn test_non_positive() {
-    let x = test_with_str("-40\n");
-    assert!(x.is_err());
-}
-
-#[test]
-fn test_ioerror() {
-    struct Broken;
-    impl io::Read for Broken {
-        fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> {
-            Err(io::Error::new(io::ErrorKind::BrokenPipe, "uh-oh!"))
-        }
-    }
-    let mut b = io::BufReader::new(Broken);
-    assert!(read_and_validate(&mut b).is_err());
-    assert_eq!("uh-oh!", read_and_validate(&mut b).unwrap_err().to_string());
-}
-
-#[derive(PartialEq, Debug)]
-struct PositiveNonzeroInteger(u64);
-
-impl PositiveNonzeroInteger {
-    fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
-        if value == 0 {
-            Err(CreationError::Zero)
-        } else if value < 0 {
-            Err(CreationError::Negative)
-        } else {
-            Ok(PositiveNonzeroInteger(value as u64))
-        }
-    }
-}
-
-#[test]
-fn test_positive_nonzero_integer_creation() {
-    assert!(PositiveNonzeroInteger::new(10).is_ok());
-    assert_eq!(
-        Err(CreationError::Negative),
-        PositiveNonzeroInteger::new(-10)
-    );
-    assert_eq!(Err(CreationError::Zero), PositiveNonzeroInteger::new(0));
-}
-
-#[derive(PartialEq, Debug)]
-enum CreationError {
-    Negative,
-    Zero,
-}
-
-impl fmt::Display for CreationError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let description = match *self {
-            CreationError::Negative => "Number is negative",
-            CreationError::Zero => "Number is zero",
-        };
-        f.write_str(description)
-    }
-}
-
-impl error::Error for CreationError {}
diff --git a/info.toml b/info.toml
index 55875d7..63eb78b 100644
--- a/info.toml
+++ b/info.toml
@@ -499,42 +499,49 @@ It should be doing some checking, returning an `Err` result if those checks fail
 returning an `Ok` result if those checks determine that everything is... okay :)"""
 
 [[exercises]]
-name = "errorsn"
-path = "exercises/error_handling/errorsn.rs"
-mode = "test"
+name = "errors5"
+path = "exercises/error_handling/errors5.rs"
+mode = "compile"
 hint = """
-First hint: To figure out what type should go where the ??? is, take a look
-at the test helper function `test_with_str`, since it returns whatever
-`read_and_validate` returns and `test_with_str` has its signature fully
-specified.
-
-
-Next hint: There are three places in `read_and_validate` that we call a
-function that returns a `Result` (that is, the functions might fail).
-Apply the `?` operator on those calls so that we return immediately from
-`read_and_validate` if those function calls fail.
-
+Hint: There are two different possible `Result` types produced within
+`main()`, which are propagated using `?` operators. How do we declare a
+return type from `main()` that allows both?
 
 Another hint: under the hood, the `?` operator calls `From::from`
-on the error value to convert it to a boxed trait object, a Box<dyn error::Error>,
-which is polymorphic-- that means that lots of different kinds of errors
-can be returned from the same function because all errors act the same
-since they all implement the `error::Error` trait.
+on the error value to convert it to a boxed trait object, a
+`Box<dyn error::Error>`, which is polymorphic-- that means that lots of
+different kinds of errors can be returned from the same function because
+all errors act the same since they all implement the `error::Error` trait.
 Check out this section of the book:
 https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html#a-shortcut-for-propagating-errors-the--operator
 
+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.
 
-Another another hint: Note that because the `?` operator returns
-the *unwrapped* value in the `Ok` case, if we want to return a `Result` from
-`read_and_validate` for *its* success case, we'll have to rewrap a value
-that we got from the return value of a `?`ed call in an `Ok`-- this will
-look like `Ok(something)`.
+Read more about boxing errors:
+https://doc.rust-lang.org/stable/rust-by-example/error/multiple_error_types/boxing_errors.html
 
+Read more about using the `?` operator with boxed errors:
+https://doc.rust-lang.org/stable/rust-by-example/error/multiple_error_types/reenter_question_mark.html
+"""
 
-Another another another hint: `Result`s must be "used", that is, you'll
-get a warning if you don't handle a `Result` that you get in your
-function. Read more about that in the `std::result` module docs:
-https://doc.rust-lang.org/std/result/#results-must-be-used"""
+[[exercises]]
+name = "errors6"
+path = "exercises/error_handling/errors6.rs"
+mode = "test"
+hint = """
+This exercise uses a completed version of `PositiveNonzeroInteger` from
+the errors4.
+
+Below the TODO line, there is an example of using the `.or()` method
+on a `Result` to transform one type of error into another. Try using
+something similar on the `Result` from `parse()`. You might use the `?`
+operator to return early from the function, or you might use a `match`
+expression, or maybe there's another way!
+
+Read more about `.or()` in the `std::result` documentation:
+https://doc.rust-lang.org/std/result/enum.Result.html#method.or"""
 
 # Generics
 

From 48ffcbd2c4cc4d936c2c7480019190f179813cc5 Mon Sep 17 00:00:00 2001
From: ZC <zhicong.tay@gmail.com>
Date: Mon, 7 Jun 2021 18:22:55 +0800
Subject: [PATCH 024/115] fix(variables5): confine the answer further

let mut number = 3; can lead to a correct answer, so the comment helps to direct the users to the intended answer.
---
 exercises/variables/variables5.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/variables/variables5.rs b/exercises/variables/variables5.rs
index da37ae9..175eebb 100644
--- a/exercises/variables/variables5.rs
+++ b/exercises/variables/variables5.rs
@@ -4,7 +4,7 @@
 // I AM NOT DONE
 
 fn main() {
-    let number = "T-H-R-E-E";
+    let number = "T-H-R-E-E"; // don't change this line
     println!("Spell a Number : {}", number);
     number = 3;
     println!("Number plus two is : {}", number + 2);

From b7ddd09fab97fc96f032bc8c0b9e1a64e5ffbcdd Mon Sep 17 00:00:00 2001
From: Taylor Yu <tlyu@mit.edu>
Date: Wed, 9 Jun 2021 18:13:57 -0500
Subject: [PATCH 025/115] address review feedback

Adjust error text and naming to conform with best practices.
Use `map_err()` instead of `or()`. Wrap lower-level errors instead of
ignoring their details.

Also, don't "cheat" by bypassing the `new()` function in tests.

Fix a dangling reference in the try_from_into hints.
---
 exercises/error_handling/errors5.rs |  4 ++--
 exercises/error_handling/errors6.rs | 33 ++++++++++++++++++-----------
 info.toml                           | 21 ++++++++++--------
 3 files changed, 35 insertions(+), 23 deletions(-)

diff --git a/exercises/error_handling/errors5.rs b/exercises/error_handling/errors5.rs
index 1b11800..365a869 100644
--- a/exercises/error_handling/errors5.rs
+++ b/exercises/error_handling/errors5.rs
@@ -43,8 +43,8 @@ impl PositiveNonzeroInteger {
 impl fmt::Display for CreationError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let description = match *self {
-            CreationError::Negative => "Number is negative",
-            CreationError::Zero => "Number is zero",
+            CreationError::Negative => "number is negative",
+            CreationError::Zero => "number is zero",
         };
         f.write_str(description)
     }
diff --git a/exercises/error_handling/errors6.rs b/exercises/error_handling/errors6.rs
index cee7250..0f6b27a 100644
--- a/exercises/error_handling/errors6.rs
+++ b/exercises/error_handling/errors6.rs
@@ -10,11 +10,20 @@
 
 // I AM NOT DONE
 
+use std::num::ParseIntError;
+
 // This is a custom error type that we will be using in `parse_pos_nonzero()`.
 #[derive(PartialEq, Debug)]
 enum ParsePosNonzeroError {
-    CreationError,
-    ParseIntError
+    Creation(CreationError),
+    ParseInt(ParseIntError)
+}
+
+impl ParsePosNonzeroError {
+    fn from_creation(err: CreationError) -> ParsePosNonzeroError {
+        ParsePosNonzeroError::Creation(err)
+    }
+    // TODO: add another error conversion function here.
 }
 
 fn parse_pos_nonzero(s: &str)
@@ -24,7 +33,7 @@ fn parse_pos_nonzero(s: &str)
     // when `parse()` returns an error.
     let x: i64 = s.parse().unwrap();
     PositiveNonzeroInteger::new(x)
-        .or(Err(ParsePosNonzeroError::CreationError))
+        .map_err(ParsePosNonzeroError::from_creation)
 }
 
 // Don't change anything below this line.
@@ -54,17 +63,18 @@ mod test {
 
     #[test]
     fn test_parse_error() {
-        assert_eq!(
+        // We can't construct a ParseIntError, so we have to pattern match.
+        assert!(matches!(
             parse_pos_nonzero("not a number"),
-            Err(ParsePosNonzeroError::ParseIntError)
-        );
+            Err(ParsePosNonzeroError::ParseInt(_))
+        ));
     }
 
     #[test]
     fn test_negative() {
         assert_eq!(
             parse_pos_nonzero("-555"),
-            Err(ParsePosNonzeroError::CreationError)
+            Err(ParsePosNonzeroError::Creation(CreationError::Negative))
         );
     }
 
@@ -72,15 +82,14 @@ mod test {
     fn test_zero() {
         assert_eq!(
             parse_pos_nonzero("0"),
-            Err(ParsePosNonzeroError::CreationError)
+            Err(ParsePosNonzeroError::Creation(CreationError::Zero))
         );
     }
 
     #[test]
     fn test_positive() {
-        assert_eq!(
-            parse_pos_nonzero("42"),
-            Ok(PositiveNonzeroInteger(42))
-        );
+        let x = PositiveNonzeroInteger::new(42);
+        assert!(x.is_ok());
+        assert_eq!(parse_pos_nonzero("42"), Ok(x.unwrap()));
     }
 }
diff --git a/info.toml b/info.toml
index 63eb78b..7695037 100644
--- a/info.toml
+++ b/info.toml
@@ -532,16 +532,19 @@ path = "exercises/error_handling/errors6.rs"
 mode = "test"
 hint = """
 This exercise uses a completed version of `PositiveNonzeroInteger` from
-the errors4.
+errors4.
 
-Below the TODO line, there is an example of using the `.or()` method
-on a `Result` to transform one type of error into another. Try using
-something similar on the `Result` from `parse()`. You might use the `?`
-operator to return early from the function, or you might use a `match`
-expression, or maybe there's another way!
+Below the line that TODO asks you to change, there is an example of using
+the `map_err()` method on a `Result` to transform one type of error into
+another. Try using something similar on the `Result` from `parse()`. You
+might use the `?` operator to return early from the function, or you might
+use a `match` expression, or maybe there's another way!
 
-Read more about `.or()` in the `std::result` documentation:
-https://doc.rust-lang.org/std/result/enum.Result.html#method.or"""
+You can create another function inside `impl ParsePosNonzeroError` to use
+with `map_err()`.
+
+Read more about `map_err()` in the `std::result` documentation:
+https://doc.rust-lang.org/std/result/enum.Result.html#method.map_err"""
 
 # Generics
 
@@ -927,7 +930,7 @@ hint = """
 Follow the steps provided right before the `TryFrom` implementation.
 You can also use the example at https://doc.rust-lang.org/std/convert/trait.TryFrom.html
 
-You might want to look back at the exercise errorsn (or its hints) to remind
+You might want to look back at the exercise errors5 (or its hints) to remind
 yourself about how `Box<dyn Error>` works.
 
 If you're trying to return a string as an error, note that neither `str`

From 75788b1148d054e24b019c6efa47662eaf88ce74 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Thu, 24 Jun 2021 12:10:23 +0000
Subject: [PATCH 026/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 503cf2c..07e7c70 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-93-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-94-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -281,6 +281,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://github.com/stoiandan"><img src="https://avatars.githubusercontent.com/u/10388612?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Stoian Dan</b></sub></a><br /><a href="#content-stoiandan" title="Content">🖋</a></td>
     <td align="center"><a href="https://about.me/pjdelport"><img src="https://avatars.githubusercontent.com/u/630271?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Pi Delport</b></sub></a><br /><a href="#content-PiDelport" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/sateeshkumarb"><img src="https://avatars.githubusercontent.com/u/429263?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Sateesh </b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sateeshkumarb" title="Code">💻</a> <a href="#content-sateeshkumarb" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/kayuapi"><img src="https://avatars.githubusercontent.com/u/10304328?v=4?s=100" width="100px;" alt=""/><br /><sub><b>ZC</b></sub></a><br /><a href="#content-kayuapi" title="Content">🖋</a></td>
   </tr>
 </table>
 

From 73777980f1108f9362ddcf8211f0a8e9918cf996 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Thu, 24 Jun 2021 12:10:24 +0000
Subject: [PATCH 027/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 867f1d5..4e2f1ef 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -866,6 +866,15 @@
         "code",
         "content"
       ]
+    },
+    {
+      "login": "kayuapi",
+      "name": "ZC",
+      "avatar_url": "https://avatars.githubusercontent.com/u/10304328?v=4",
+      "profile": "https://github.com/kayuapi",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From d91044f3a24f65e27321d544a9ff7895919fa63e Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Thu, 24 Jun 2021 12:17:31 +0000
Subject: [PATCH 028/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 07e7c70..2f21b99 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-94-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-95-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -282,6 +282,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://about.me/pjdelport"><img src="https://avatars.githubusercontent.com/u/630271?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Pi Delport</b></sub></a><br /><a href="#content-PiDelport" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/sateeshkumarb"><img src="https://avatars.githubusercontent.com/u/429263?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Sateesh </b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sateeshkumarb" title="Code">💻</a> <a href="#content-sateeshkumarb" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/kayuapi"><img src="https://avatars.githubusercontent.com/u/10304328?v=4?s=100" width="100px;" alt=""/><br /><sub><b>ZC</b></sub></a><br /><a href="#content-kayuapi" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/hyperparabolic"><img src="https://avatars.githubusercontent.com/u/12348474?v=4?s=100" width="100px;" alt=""/><br /><sub><b>hyperparabolic</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=hyperparabolic" title="Code">💻</a></td>
   </tr>
 </table>
 

From fadade85920268fa37092ba42adb0855d82478cf Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Thu, 24 Jun 2021 12:17:32 +0000
Subject: [PATCH 029/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 4e2f1ef..e3ddb19 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -875,6 +875,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "hyperparabolic",
+      "name": "hyperparabolic",
+      "avatar_url": "https://avatars.githubusercontent.com/u/12348474?v=4",
+      "profile": "https://github.com/hyperparabolic",
+      "contributions": [
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 2dc93caddad43821743e4903d89b355df58d7a49 Mon Sep 17 00:00:00 2001
From: Taylor Yu <tlyu@mit.edu>
Date: Thu, 24 Jun 2021 21:33:41 -0500
Subject: [PATCH 030/115] fix(from_str, try_from_into): custom error types

Remove the use of trait objects as errors from `from_str` and
`try_from_into`; they seem to have caused a lot of confusion in
practice. (Also, it's considered best practice to use custom error
types instead of boxed errors in library code.) Instead, use custom
error enums, and update hints accordingly. Hints also provide
some guidance about converting errors, which could be covered
more completely in a future advanced errors section.

Also move from_str to directly after the similar exercise `from_into`,
for the sake of familiarity when solving.
---
 exercises/conversions/from_str.rs      | 56 ++++++++++++++-----
 exercises/conversions/try_from_into.rs | 74 ++++++++++++++++++--------
 info.toml                              | 53 ++++++++++--------
 3 files changed, 127 insertions(+), 56 deletions(-)

diff --git a/exercises/conversions/from_str.rs b/exercises/conversions/from_str.rs
index 4beebac..6e9e699 100644
--- a/exercises/conversions/from_str.rs
+++ b/exercises/conversions/from_str.rs
@@ -1,16 +1,31 @@
-// This does practically the same thing that TryFrom<&str> does.
+// from_str.rs
+// This is similar to from_into.rs, but this time we'll implement `FromStr`
+// and return errors instead of falling back to a default value.
 // Additionally, upon implementing FromStr, you can use the `parse` method
 // on strings to generate an object of the implementor type.
 // You can read more about it at https://doc.rust-lang.org/std/str/trait.FromStr.html
-use std::error;
+use std::num::ParseIntError;
 use std::str::FromStr;
 
-#[derive(Debug)]
+#[derive(Debug, PartialEq)]
 struct Person {
     name: String,
     age: usize,
 }
 
+// We will use this error type for the `FromStr` implementation.
+#[derive(Debug, PartialEq)]
+enum ParsePersonError {
+    // Empty input string
+    Empty,
+    // Incorrect number of fields
+    BadLen,
+    // Empty name field
+    NoName,
+    // Wrapped error from parse::<usize>()
+    ParseInt(ParseIntError),
+}
+
 // I AM NOT DONE
 
 // Steps:
@@ -24,7 +39,7 @@ struct Person {
 // If everything goes well, then return a Result of a Person object
 
 impl FromStr for Person {
-    type Err = Box<dyn error::Error>;
+    type Err = ParsePersonError;
     fn from_str(s: &str) -> Result<Person, Self::Err> {
     }
 }
@@ -40,7 +55,7 @@ mod tests {
 
     #[test]
     fn empty_input() {
-        assert!("".parse::<Person>().is_err());
+        assert_eq!("".parse::<Person>(), Err(ParsePersonError::Empty));
     }
     #[test]
     fn good_input() {
@@ -52,41 +67,56 @@ mod tests {
     }
     #[test]
     fn missing_age() {
-        assert!("John,".parse::<Person>().is_err());
+        assert!(matches!(
+            "John,".parse::<Person>(),
+            Err(ParsePersonError::ParseInt(_))
+        ));
     }
 
     #[test]
     fn invalid_age() {
-        assert!("John,twenty".parse::<Person>().is_err());
+        assert!(matches!(
+            "John,twenty".parse::<Person>(),
+            Err(ParsePersonError::ParseInt(_))
+        ));
     }
 
     #[test]
     fn missing_comma_and_age() {
-        assert!("John".parse::<Person>().is_err());
+        assert_eq!("John".parse::<Person>(), Err(ParsePersonError::BadLen));
     }
 
     #[test]
     fn missing_name() {
-        assert!(",1".parse::<Person>().is_err());
+        assert_eq!(",1".parse::<Person>(), Err(ParsePersonError::NoName));
     }
 
     #[test]
     fn missing_name_and_age() {
-        assert!(",".parse::<Person>().is_err());
+        assert!(matches!(
+            ",".parse::<Person>(),
+            Err(ParsePersonError::NoName | ParsePersonError::ParseInt(_))
+        ));
     }
 
     #[test]
     fn missing_name_and_invalid_age() {
-        assert!(",one".parse::<Person>().is_err());
+        assert!(matches!(
+            ",one".parse::<Person>(),
+            Err(ParsePersonError::NoName | ParsePersonError::ParseInt(_))
+        ));
     }
 
     #[test]
     fn trailing_comma() {
-        assert!("John,32,".parse::<Person>().is_err());
+        assert_eq!("John,32,".parse::<Person>(), Err(ParsePersonError::BadLen));
     }
 
     #[test]
     fn trailing_comma_and_some_string() {
-        assert!("John,32,man".parse::<Person>().is_err());
+        assert_eq!(
+            "John,32,man".parse::<Person>(),
+            Err(ParsePersonError::BadLen)
+        );
     }
 }
diff --git a/exercises/conversions/try_from_into.rs b/exercises/conversions/try_from_into.rs
index c0b5d98..b8ec445 100644
--- a/exercises/conversions/try_from_into.rs
+++ b/exercises/conversions/try_from_into.rs
@@ -1,9 +1,9 @@
+// try_from_into.rs
 // TryFrom is a simple and safe type conversion that may fail in a controlled way under some circumstances.
 // Basically, this is the same as From. The main difference is that this should return a Result type
 // instead of the target type itself.
 // You can read more about it at https://doc.rust-lang.org/std/convert/trait.TryFrom.html
 use std::convert::{TryFrom, TryInto};
-use std::error;
 
 #[derive(Debug, PartialEq)]
 struct Color {
@@ -12,12 +12,21 @@ struct Color {
     blue: u8,
 }
 
+// We will use this error type for these `TryFrom` conversions.
+#[derive(Debug, PartialEq)]
+enum IntoColorError {
+    // Incorrect length of slice
+    BadLen,
+    // Integer conversion error
+    IntConversion,
+}
+
 // I AM NOT DONE
 
 // Your task is to complete this implementation
 // and return an Ok result of inner type Color.
 // You need to create an implementation for a tuple of three integers,
-// an array of three integers and a slice of integers.
+// an array of three integers, and a slice of integers.
 //
 // Note that the implementation for tuple and array will be checked at compile time,
 // but the slice implementation needs to check the slice length!
@@ -25,20 +34,23 @@ struct Color {
 
 // Tuple implementation
 impl TryFrom<(i16, i16, i16)> for Color {
-    type Error = Box<dyn error::Error>;
-    fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {}
+    type Error = IntoColorError;
+    fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {
+    }
 }
 
 // Array implementation
 impl TryFrom<[i16; 3]> for Color {
-    type Error = Box<dyn error::Error>;
-    fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {}
+    type Error = IntoColorError;
+    fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {
+    }
 }
 
 // Slice implementation
 impl TryFrom<&[i16]> for Color {
-    type Error = Box<dyn error::Error>;
-    fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {}
+    type Error = IntoColorError;
+    fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {
+    }
 }
 
 fn main() {
@@ -46,15 +58,15 @@ fn main() {
     let c1 = Color::try_from((183, 65, 14));
     println!("{:?}", c1);
 
-    // Since From is implemented for Color, we should be able to use Into
+    // Since TryFrom is implemented for Color, we should be able to use TryInto
     let c2: Result<Color, _> = [183, 65, 14].try_into();
     println!("{:?}", c2);
 
     let v = vec![183, 65, 14];
-    // With slice we should use `from` function
+    // With slice we should use `try_from` function
     let c3 = Color::try_from(&v[..]);
     println!("{:?}", c3);
-    // or take slice within round brackets and use Into
+    // or take slice within round brackets and use TryInto
     let c4: Result<Color, _> = (&v[..]).try_into();
     println!("{:?}", c4);
 }
@@ -65,15 +77,24 @@ mod tests {
 
     #[test]
     fn test_tuple_out_of_range_positive() {
-        assert!(Color::try_from((256, 1000, 10000)).is_err());
+        assert_eq!(
+            Color::try_from((256, 1000, 10000)),
+            Err(IntoColorError::IntConversion)
+        );
     }
     #[test]
     fn test_tuple_out_of_range_negative() {
-        assert!(Color::try_from((-1, -10, -256)).is_err());
+        assert_eq!(
+            Color::try_from((-1, -10, -256)),
+            Err(IntoColorError::IntConversion)
+        );
     }
     #[test]
     fn test_tuple_sum() {
-        assert!(Color::try_from((-1, 255, 255)).is_err());
+        assert_eq!(
+            Color::try_from((-1, 255, 255)),
+            Err(IntoColorError::IntConversion)
+        );
     }
     #[test]
     fn test_tuple_correct() {
@@ -91,17 +112,17 @@ mod tests {
     #[test]
     fn test_array_out_of_range_positive() {
         let c: Result<Color, _> = [1000, 10000, 256].try_into();
-        assert!(c.is_err());
+        assert_eq!(c, Err(IntoColorError::IntConversion));
     }
     #[test]
     fn test_array_out_of_range_negative() {
         let c: Result<Color, _> = [-10, -256, -1].try_into();
-        assert!(c.is_err());
+        assert_eq!(c, Err(IntoColorError::IntConversion));
     }
     #[test]
     fn test_array_sum() {
         let c: Result<Color, _> = [-1, 255, 255].try_into();
-        assert!(c.is_err());
+        assert_eq!(c, Err(IntoColorError::IntConversion));
     }
     #[test]
     fn test_array_correct() {
@@ -119,17 +140,26 @@ mod tests {
     #[test]
     fn test_slice_out_of_range_positive() {
         let arr = [10000, 256, 1000];
-        assert!(Color::try_from(&arr[..]).is_err());
+        assert_eq!(
+            Color::try_from(&arr[..]),
+            Err(IntoColorError::IntConversion)
+        );
     }
     #[test]
     fn test_slice_out_of_range_negative() {
         let arr = [-256, -1, -10];
-        assert!(Color::try_from(&arr[..]).is_err());
+        assert_eq!(
+            Color::try_from(&arr[..]),
+            Err(IntoColorError::IntConversion)
+        );
     }
     #[test]
     fn test_slice_sum() {
         let arr = [-1, 255, 255];
-        assert!(Color::try_from(&arr[..]).is_err());
+        assert_eq!(
+            Color::try_from(&arr[..]),
+            Err(IntoColorError::IntConversion)
+        );
     }
     #[test]
     fn test_slice_correct() {
@@ -148,11 +178,11 @@ mod tests {
     #[test]
     fn test_slice_excess_length() {
         let v = vec![0, 0, 0, 0];
-        assert!(Color::try_from(&v[..]).is_err());
+        assert_eq!(Color::try_from(&v[..]), Err(IntoColorError::BadLen));
     }
     #[test]
     fn test_slice_insufficient_length() {
         let v = vec![0, 0];
-        assert!(Color::try_from(&v[..]).is_err());
+        assert_eq!(Color::try_from(&v[..]), Err(IntoColorError::BadLen));
     }
 }
diff --git a/info.toml b/info.toml
index ab4dc93..f5af884 100644
--- a/info.toml
+++ b/info.toml
@@ -925,6 +925,27 @@ mode = "test"
 hint = """
 Follow the steps provided right before the `From` implementation"""
 
+[[exercises]]
+name = "from_str"
+path = "exercises/conversions/from_str.rs"
+mode = "test"
+hint = """
+The implementation of FromStr should return an Ok with a Person object,
+or an Err with an error if the string is not valid.
+
+This is almost like the `from_into` exercise, but returning errors instead
+of falling back to a default value.
+
+Hint: Look at the test cases to see which error variants to return.
+
+Another hint: You can use the `map_err` method of `Result` with a function
+or a closure to wrap the error from `parse::<usize>`.
+
+Yet another hint: If you would like to propagate errors by using the `?`
+operator in your solution, you might want to look at
+https://doc.rust-lang.org/stable/rust-by-example/error/multiple_error_types/reenter_question_mark.html
+"""
+
 [[exercises]]
 name = "try_from_into"
 path = "exercises/conversions/try_from_into.rs"
@@ -933,17 +954,19 @@ hint = """
 Follow the steps provided right before the `TryFrom` implementation.
 You can also use the example at https://doc.rust-lang.org/std/convert/trait.TryFrom.html
 
-You might want to look back at the exercise errors5 (or its hints) to remind
-yourself about how `Box<dyn Error>` works.
+Hint: Is there an implementation of `TryFrom` in the standard library that
+can both do the required integer conversion and check the range of the input?
 
-If you're trying to return a string as an error, note that neither `str`
-nor `String` implements `error::Error`. However, there is an implementation
-of `From<&str>` for `Box<dyn Error>`. This means you can use `.into()` or
-the `?` operator to convert your string into the correct error type.
+Another hint: Look at the test cases to see which error variants to return.
 
-If you're having trouble with using the `?` operator to convert an error string,
-recall that `?` works to convert `Err(something)` into the appropriate error
-type for returning from the function."""
+Yet another hint: You can use the `map_err` or `or` methods of `Result` to
+convert errors.
+
+Yet another hint: If you would like to propagate errors by using the `?`
+operator in your solution, you might want to look at
+https://doc.rust-lang.org/stable/rust-by-example/error/multiple_error_types/reenter_question_mark.html
+
+Challenge: Can you make the `TryFrom` implementations generic over many integer types?"""
 
 [[exercises]]
 name = "as_ref_mut"
@@ -951,15 +974,3 @@ path = "exercises/conversions/as_ref_mut.rs"
 mode = "test"
 hint = """
 Add AsRef<str> as a trait bound to the functions."""
-
-[[exercises]]
-name = "from_str"
-path = "exercises/conversions/from_str.rs"
-mode = "test"
-hint = """
-The implementation of FromStr should return an Ok with a Person object,
-or an Err with an error if the string is not valid.
-This is almost like the `try_from_into` exercise.
-
-If you're having trouble with returning the correct error type, see the
-hints for try_from_into."""

From 3a4433d5a2961e3f3e613bd67459579fbc6277fa Mon Sep 17 00:00:00 2001
From: arlecchino <kolbma@users.noreply.github.com>
Date: Mon, 28 Jun 2021 17:08:53 +0200
Subject: [PATCH 031/115] docs: Faster git clone command

Clone only release tag without history
---
 README.md | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 2f21b99..2aa54e0 100644
--- a/README.md
+++ b/README.md
@@ -57,12 +57,12 @@ When you get a permission denied message then you have to exclude the directory
 
 ## Manually
 
-Basically: Clone the repository, checkout to the latest tag, run `cargo install`.
+Basically: Clone the repository at the latest tag, run `cargo install`.
 
 ```bash
-git clone https://github.com/rust-lang/rustlings
+# find out the latest version at https://github.com/rust-lang/rustlings/releases/latest (on edit 4.4.0)
+git clone -b 4.4.0 --depth 1 https://github.com/rust-lang/rustlings
 cd rustlings
-git checkout tags/4.4.0 # or whatever the latest version is (find out at https://github.com/rust-lang/rustlings/releases/latest)
 cargo install --force --path .
 ```
 

From 34ea029df8cb0af90524b9158990a56d6beb3d10 Mon Sep 17 00:00:00 2001
From: arlecchino <kolbma@users.noreply.github.com>
Date: Tue, 29 Jun 2021 12:03:18 +0200
Subject: [PATCH 032/115] chore: Update hint of iterators3

`collect()` needs some hint for standard_library_types/iterators3 exercise with doc link for understanding different return types via `FromIterator`.
---
 info.toml | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/info.toml b/info.toml
index ab4dc93..dedc65d 100644
--- a/info.toml
+++ b/info.toml
@@ -772,7 +772,10 @@ The division_results variable needs to be collected into a collection type.
 The result_with_list function needs to return a single Result where the success
 case is a vector of integers and the failure case is a DivisionError.
 
-The list_of_results function needs to return a vector of results."""
+The list_of_results function needs to return a vector of results.
+
+See https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.collect how 
+the `FromIterator` trait is used in `collect()`."""
 
 [[exercises]]
 name = "iterators4"

From 2e05606edca43baeeed88c693b9041442362c148 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Tue, 29 Jun 2021 10:46:40 +0000
Subject: [PATCH 033/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 2aa54e0..ecb8bde 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-95-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-96-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -283,6 +283,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://github.com/sateeshkumarb"><img src="https://avatars.githubusercontent.com/u/429263?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Sateesh </b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sateeshkumarb" title="Code">💻</a> <a href="#content-sateeshkumarb" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/kayuapi"><img src="https://avatars.githubusercontent.com/u/10304328?v=4?s=100" width="100px;" alt=""/><br /><sub><b>ZC</b></sub></a><br /><a href="#content-kayuapi" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/hyperparabolic"><img src="https://avatars.githubusercontent.com/u/12348474?v=4?s=100" width="100px;" alt=""/><br /><sub><b>hyperparabolic</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=hyperparabolic" title="Code">💻</a></td>
+    <td align="center"><a href="https://www.net4visions.at"><img src="https://avatars.githubusercontent.com/u/5228369?v=4?s=100" width="100px;" alt=""/><br /><sub><b>arlecchino</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=kolbma" title="Documentation">📖</a></td>
   </tr>
 </table>
 

From 3b4514b686b15949112a50f6ec49c79e08dcae38 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Tue, 29 Jun 2021 10:46:41 +0000
Subject: [PATCH 034/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index e3ddb19..285584b 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -884,6 +884,15 @@
       "contributions": [
         "code"
       ]
+    },
+    {
+      "login": "kolbma",
+      "name": "arlecchino",
+      "avatar_url": "https://avatars.githubusercontent.com/u/5228369?v=4",
+      "profile": "https://www.net4visions.at",
+      "contributions": [
+        "doc"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From a4a10987667ed5094763101fb885c9efc0e53bc3 Mon Sep 17 00:00:00 2001
From: arlecchino <kolbma@users.noreply.github.com>
Date: Tue, 29 Jun 2021 13:41:16 +0200
Subject: [PATCH 035/115] Update info.toml

Co-authored-by: marisa <mokou@fastmail.com>
---
 info.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/info.toml b/info.toml
index dedc65d..e91909a 100644
--- a/info.toml
+++ b/info.toml
@@ -774,7 +774,7 @@ case is a vector of integers and the failure case is a DivisionError.
 
 The list_of_results function needs to return a vector of results.
 
-See https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.collect how 
+See https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.collect for how 
 the `FromIterator` trait is used in `collect()`."""
 
 [[exercises]]

From 9bf4c5e8df576e36a1a2e9d022dae6b7d5e5f4f8 Mon Sep 17 00:00:00 2001
From: arlecchino <kolbma@users.noreply.github.com>
Date: Tue, 29 Jun 2021 20:47:32 +0200
Subject: [PATCH 036/115] chore: clippy1 hint enhancement

Added some explanation and links about floating point representation and to use the clippy suggestion. (fixes #390)
---
 info.toml | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/info.toml b/info.toml
index e91909a..afc7fdf 100644
--- a/info.toml
+++ b/info.toml
@@ -902,7 +902,15 @@ name = "clippy1"
 path = "exercises/clippy/clippy1.rs"
 mode = "clippy"
 hint = """
-Floating point calculations are usually imprecise, so asking if two values are exactly equal is asking for trouble"""
+Not every floating point value can be represented exactly in binary values in
+memory. Take a look at the description of 
+https://doc.rust-lang.org/stable/std/primitive.f32.html
+When using the binary compare operators with floating points you won't compare
+the floating point values but the binary representation in memory. This is 
+usually not what you would like to do. 
+See the suggestions of the clippy warning in compile output and use the
+machine epsilon value...
+https://doc.rust-lang.org/stable/std/primitive.f32.html#associatedconstant.EPSILON"""
 
 [[exercises]]
 name = "clippy2"

From d20e413a68772cd493561f2651cf244e822b7ca5 Mon Sep 17 00:00:00 2001
From: Richthofen <jazzplato@gmail.com>
Date: Wed, 30 Jun 2021 03:05:49 -0700
Subject: [PATCH 037/115] feat(cli): Add "next" to run the next unsolved
 exercise. (#785)

* Add "run next" to run the next unsolved exercise.

* Fix a grammar error in the message.

* Update README.md with the suggested change

Co-authored-by: marisa <mokou@fastmail.com>

* Update the README.md for "rustlings hint next".

Co-authored-by: marisa <mokou@fastmail.com>
---
 README.md   | 12 ++++++++++++
 src/main.rs | 25 ++++++++++++++++++-------
 2 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index ecb8bde..bbaea0c 100644
--- a/README.md
+++ b/README.md
@@ -97,6 +97,12 @@ In case you want to go by your own order, or want to only verify a single exerci
 rustlings run myExercise1
 ```
 
+Or simply use the following command to run the next unsolved exercise in the course:
+
+```bash
+rustlings run next
+```
+
 In case you get stuck, you can run the following command to get a hint for your
 exercise:
 
@@ -104,6 +110,12 @@ exercise:
 rustlings hint myExercise1
 ```
 
+You can also get the hint for the next unsolved exercise with the following command:
+
+``` bash
+rustlings hint next
+```
+
 To check your progress, you can run the following command:
 ```bash
 rustlings list
diff --git a/src/main.rs b/src/main.rs
index a80ce88..985fe34 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -286,13 +286,24 @@ fn spawn_watch_shell(failed_exercise_hint: &Arc<Mutex<Option<String>>>) {
 }
 
 fn find_exercise<'a>(name: &str, exercises: &'a [Exercise]) -> &'a Exercise {
-    exercises
-        .iter()
-        .find(|e| e.name == name)
-        .unwrap_or_else(|| {
-            println!("No exercise found for '{}'!", name);
-            std::process::exit(1)
-        })
+    if name.eq("next") {
+        exercises
+            .iter()
+            .find(|e| !e.looks_done())
+            .unwrap_or_else(|| {
+                println!("🎉 Congratulations! You have done all the exercises!");
+                println!("🔚 There are no more exercises to do next!");
+                std::process::exit(1)
+            })
+    } else {
+        exercises
+            .iter()
+            .find(|e| e.name == name)
+            .unwrap_or_else(|| {
+                println!("No exercise found for '{}'!", name);
+                std::process::exit(1)
+            })
+    }
 }
 
 fn watch(exercises: &[Exercise], verbose: bool) -> notify::Result<()> {

From 1043a06124a0125a1d205180ec1c8e8e0166cf3c Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Wed, 30 Jun 2021 10:06:06 +0000
Subject: [PATCH 038/115] docs: update README.md [skip ci]

---
 README.md | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index bbaea0c..db25468 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-96-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-97-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -297,6 +297,9 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://github.com/hyperparabolic"><img src="https://avatars.githubusercontent.com/u/12348474?v=4?s=100" width="100px;" alt=""/><br /><sub><b>hyperparabolic</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=hyperparabolic" title="Code">💻</a></td>
     <td align="center"><a href="https://www.net4visions.at"><img src="https://avatars.githubusercontent.com/u/5228369?v=4?s=100" width="100px;" alt=""/><br /><sub><b>arlecchino</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=kolbma" title="Documentation">📖</a></td>
   </tr>
+  <tr>
+    <td align="center"><a href="https://richthofen.io/"><img src="https://avatars.githubusercontent.com/u/7576730?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Richthofen</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=jazzplato" title="Code">💻</a></td>
+  </tr>
 </table>
 
 <!-- markdownlint-restore -->

From 03dcb582e6c816cf6cb13e55a1d91485e5dfacc3 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Wed, 30 Jun 2021 10:06:07 +0000
Subject: [PATCH 039/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 285584b..c449587 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -893,6 +893,15 @@
       "contributions": [
         "doc"
       ]
+    },
+    {
+      "login": "jazzplato",
+      "name": "Richthofen",
+      "avatar_url": "https://avatars.githubusercontent.com/u/7576730?v=4",
+      "profile": "https://richthofen.io/",
+      "contributions": [
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 6a10f900b4b4f599a13892ea03603bbeac059e3b Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Mon, 5 Jul 2021 16:56:56 +0000
Subject: [PATCH 040/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index d70cd55..9f8f90f 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-97-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-98-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -299,6 +299,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
   </tr>
   <tr>
     <td align="center"><a href="https://richthofen.io/"><img src="https://avatars.githubusercontent.com/u/7576730?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Richthofen</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=jazzplato" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/cseltol"><img src="https://avatars.githubusercontent.com/u/64264529?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ivan Nerazumov</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=cseltol" title="Documentation">📖</a></td>
   </tr>
 </table>
 

From 91d86a1de960c7efabff21e192f415592e517540 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Mon, 5 Jul 2021 16:56:57 +0000
Subject: [PATCH 041/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index c449587..a441a6a 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -902,6 +902,15 @@
       "contributions": [
         "code"
       ]
+    },
+    {
+      "login": "cseltol",
+      "name": "Ivan Nerazumov",
+      "avatar_url": "https://avatars.githubusercontent.com/u/64264529?v=4",
+      "profile": "https://github.com/cseltol",
+      "contributions": [
+        "doc"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From e422ab150738f578c4dc2560687a1e7214924d31 Mon Sep 17 00:00:00 2001
From: Laura Lindzey <lindzey@uw.edu>
Date: Mon, 5 Jul 2021 23:07:34 -0700
Subject: [PATCH 042/115] docs: Update exercise to chapter mapping for HashMap

---
 exercises/README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/README.md b/exercises/README.md
index 0c71524..eebbd0b 100644
--- a/exercises/README.md
+++ b/exercises/README.md
@@ -10,7 +10,7 @@
 | structs                | §5.1          |
 | enums                  | §6            |
 | modules                | §7.2          |
-| collections            | §8.1          |
+| collections            | §8.1, §8.3    |
 | strings                | §8.2          |
 | error_handling         | §9            |
 | generics               | §10           |

From 8774e47dc34c8a7929a8b7d7504999028935ff6e Mon Sep 17 00:00:00 2001
From: lauralindzey <65185744+lauralindzey@users.noreply.github.com>
Date: Tue, 6 Jul 2021 01:31:27 -0700
Subject: [PATCH 043/115] docs: Update collections README with HashMap link

---
 exercises/collections/README.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/exercises/collections/README.md b/exercises/collections/README.md
index 0291bc8..b6d62ac 100644
--- a/exercises/collections/README.md
+++ b/exercises/collections/README.md
@@ -20,3 +20,4 @@ structures that are used very often in Rust programs:
 ## Further information
 
 - [Storing Lists of Values with Vectors](https://doc.rust-lang.org/stable/book/ch08-01-vectors.html)
+- [Storing Keys with Associated Values in Hash Maps](https://doc.rust-lang.org/book/ch08-03-hash-maps.html)

From b017579577dccce491a5f6fefd4515ac8f7d43bd Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Wed, 7 Jul 2021 20:17:03 +0000
Subject: [PATCH 044/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 9f8f90f..d7eef8d 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-98-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-99-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -300,6 +300,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
   <tr>
     <td align="center"><a href="https://richthofen.io/"><img src="https://avatars.githubusercontent.com/u/7576730?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Richthofen</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=jazzplato" title="Code">💻</a></td>
     <td align="center"><a href="https://github.com/cseltol"><img src="https://avatars.githubusercontent.com/u/64264529?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ivan Nerazumov</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=cseltol" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/lauralindzey"><img src="https://avatars.githubusercontent.com/u/65185744?v=4?s=100" width="100px;" alt=""/><br /><sub><b>lauralindzey</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=lauralindzey" title="Documentation">📖</a></td>
   </tr>
 </table>
 

From b438049c393d78fa65ea53468dc8f6093610ca8f Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Wed, 7 Jul 2021 20:17:04 +0000
Subject: [PATCH 045/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index a441a6a..fca0d0d 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -911,6 +911,15 @@
       "contributions": [
         "doc"
       ]
+    },
+    {
+      "login": "lauralindzey",
+      "name": "lauralindzey",
+      "avatar_url": "https://avatars.githubusercontent.com/u/65185744?v=4",
+      "profile": "https://github.com/lauralindzey",
+      "contributions": [
+        "doc"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From d876649616cc8a8dd5f539f8bc1a5434b960b1e9 Mon Sep 17 00:00:00 2001
From: Rakshit Sinha <sinharaksh1t@ufl.edu>
Date: Wed, 7 Jul 2021 13:18:33 -0700
Subject: [PATCH 046/115] fix(quiz1): Updated question description (#794)

Co-authored-by: Rakshit Sinha <rakshit.sinha@oracle.com>
---
 exercises/quiz1.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/quiz1.rs b/exercises/quiz1.rs
index 2bb2c24..3af1293 100644
--- a/exercises/quiz1.rs
+++ b/exercises/quiz1.rs
@@ -5,7 +5,7 @@
 
 // Mary is buying apples. One apple usually costs 2 Rustbucks, but if you buy
 // more than 40 at once, each apple only costs 1! Write a function that calculates
-// the price of an order of apples given the order amount. No hints this time!
+// the price of an order of apples given the quantity bought. No hints this time!
 
 // I AM NOT DONE
 

From 23f700dc2375787fe8c79f4e191fb9e6aa3b2ef2 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Wed, 7 Jul 2021 20:19:47 +0000
Subject: [PATCH 047/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index d7eef8d..5497944 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-99-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-100-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -301,6 +301,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://richthofen.io/"><img src="https://avatars.githubusercontent.com/u/7576730?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Richthofen</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=jazzplato" title="Code">💻</a></td>
     <td align="center"><a href="https://github.com/cseltol"><img src="https://avatars.githubusercontent.com/u/64264529?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ivan Nerazumov</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=cseltol" title="Documentation">📖</a></td>
     <td align="center"><a href="https://github.com/lauralindzey"><img src="https://avatars.githubusercontent.com/u/65185744?v=4?s=100" width="100px;" alt=""/><br /><sub><b>lauralindzey</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=lauralindzey" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/sinharaksh1t"><img src="https://avatars.githubusercontent.com/u/28585848?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rakshit Sinha</b></sub></a><br /><a href="#content-sinharaksh1t" title="Content">🖋</a></td>
   </tr>
 </table>
 

From 33fa274bbfa85d817a39562b0461f8d42f1418c1 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Wed, 7 Jul 2021 20:19:48 +0000
Subject: [PATCH 048/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index fca0d0d..85c6670 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -920,6 +920,15 @@
       "contributions": [
         "doc"
       ]
+    },
+    {
+      "login": "sinharaksh1t",
+      "name": "Rakshit Sinha",
+      "avatar_url": "https://avatars.githubusercontent.com/u/28585848?v=4",
+      "profile": "https://github.com/sinharaksh1t",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From ba087ce64a35c93e40689d258f6dfde538b9ca22 Mon Sep 17 00:00:00 2001
From: ana <ana@ana.st>
Date: Wed, 7 Jul 2021 22:23:52 +0200
Subject: [PATCH 049/115] release: 4.5.0

Signed-off-by: ana <ana@ana.st>
---
 CHANGELOG.md | 24 ++++++++++++++++++++++++
 Cargo.lock   |  2 +-
 Cargo.toml   |  4 ++--
 README.md    |  4 ++--
 src/main.rs  |  2 +-
 5 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1686bdd..67b8cdc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,27 @@
+<a name="4.5.0"></a>
+## 4.5.0 (2021-07-07)
+
+
+#### Features
+
+*   Add move_semantics5 exercise. (#746) ([399ab328](https://github.com/rust-lang/rustlings/commit/399ab328d8d407265c09563aa4ef4534b2503ff2))
+* **cli:**  Add "next" to run the next unsolved exercise. (#785) ([d20e413a](https://github.com/rust-lang/rustlings/commit/d20e413a68772cd493561f2651cf244e822b7ca5))
+
+#### Bug Fixes
+
+*   rename result1 to errors4 ([50ab289d](https://github.com/rust-lang/rustlings/commit/50ab289da6b9eb19a7486c341b00048c516b88c0))
+*   move_semantics5 hints ([1b858285](https://github.com/rust-lang/rustlings/commit/1b85828548f46f58b622b5e0c00f8c989f928807))
+*   remove trailing whitespaces from iterators1 ([4d4fa774](https://github.com/rust-lang/rustlings/commit/4d4fa77459392acd3581c6068aa8be9a02de12fc))
+*   add hints to generics1 and generics2 exercises ([31457940](https://github.com/rust-lang/rustlings/commit/31457940846b3844d78d4a4d2b074bc8d6aaf1eb))
+*   remove trailing whitespace ([d9b69bd1](https://github.com/rust-lang/rustlings/commit/d9b69bd1a0a7a99f2c0d80933ad2eea44c8c71b2))
+* **installation:**  first PowerShell command ([aa9a943d](https://github.com/rust-lang/rustlings/commit/aa9a943ddf3ae260782e73c26bcc9db60e5894b6))
+* **iterators5:**  derive Clone, Copy ([91fc9e31](https://github.com/rust-lang/rustlings/commit/91fc9e3118f4af603c9911698cc2a234725cb032))
+* **quiz1:**  Updated question description (#794) ([d8766496](https://github.com/rust-lang/rustlings/commit/d876649616cc8a8dd5f539f8bc1a5434b960b1e9))
+* **try_from_into, from_str:**  hints for dyn Error ([11d2cf0d](https://github.com/rust-lang/rustlings/commit/11d2cf0d604dee3f5023c17802d69438e69fa50e))
+* **variables5:**  confine the answer further ([48ffcbd2](https://github.com/rust-lang/rustlings/commit/48ffcbd2c4cc4d936c2c7480019190f179813cc5))
+
+
+
 <a name="4.4.0"></a>
 ## 4.4.0 (2021-04-24)
 
diff --git a/Cargo.lock b/Cargo.lock
index cc8ff94..d291c16 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -539,7 +539,7 @@ checksum = "24d5f089152e60f62d28b835fbff2cd2e8dc0baf1ac13343bef92ab7eed84548"
 
 [[package]]
 name = "rustlings"
-version = "4.4.0"
+version = "4.5.0"
 dependencies = [
  "argh",
  "assert_cmd",
diff --git a/Cargo.toml b/Cargo.toml
index 0a75704..615a09c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "rustlings"
-version = "4.4.0"
-authors = ["Marisa <mokou@posteo.de>", "Carol (Nichols || Goulding) <carol.nichols@gmail.com>"]
+version = "4.5.0"
+authors = ["anastasie <ana@ana.st>", "Carol (Nichols || Goulding) <carol.nichols@gmail.com>"]
 edition = "2018"
 
 [dependencies]
diff --git a/README.md b/README.md
index 5497944..7313c8e 100644
--- a/README.md
+++ b/README.md
@@ -60,8 +60,8 @@ When you get a permission denied message then you have to exclude the directory
 Basically: Clone the repository at the latest tag, run `cargo install`.
 
 ```bash
-# find out the latest version at https://github.com/rust-lang/rustlings/releases/latest (on edit 4.4.0)
-git clone -b 4.4.0 --depth 1 https://github.com/rust-lang/rustlings
+# find out the latest version at https://github.com/rust-lang/rustlings/releases/latest (on edit 4.5.0)
+git clone -b 4.5.0 --depth 1 https://github.com/rust-lang/rustlings
 cd rustlings
 cargo install --force --path .
 ```
diff --git a/src/main.rs b/src/main.rs
index 985fe34..c8ebc68 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -23,7 +23,7 @@ mod run;
 mod verify;
 
 // In sync with crate version
-const VERSION: &str = "4.4.0";
+const VERSION: &str = "4.5.0";
 
 #[derive(FromArgs, PartialEq, Debug)]
 /// Rustlings is a collection of small exercises to get you used to writing and reading Rust code

From df25684cb79f8413915e00b5efef29369849cef1 Mon Sep 17 00:00:00 2001
From: ana <ana@ana.st>
Date: Thu, 29 Jul 2021 12:37:15 +0200
Subject: [PATCH 050/115] fix(move_semantics5): Clarify instructions

---
 exercises/move_semantics/move_semantics5.rs | 4 ++--
 info.toml                                   | 5 +----
 2 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/exercises/move_semantics/move_semantics5.rs b/exercises/move_semantics/move_semantics5.rs
index 2fb7b8e..5449e95 100644
--- a/exercises/move_semantics/move_semantics5.rs
+++ b/exercises/move_semantics/move_semantics5.rs
@@ -1,6 +1,6 @@
 // move_semantics5.rs
-// Make me compile without adding, removing, or changing any of the
-// lines in `main()`.
+// Make me compile only be reordering the lines in `main()`, but without
+// adding, changing or removing any of them.
 // Execute `rustlings hint move_semantics5` for hints :)
 
 // I AM NOT DONE
diff --git a/info.toml b/info.toml
index afc7fdf..d5008ed 100644
--- a/info.toml
+++ b/info.toml
@@ -220,10 +220,7 @@ vogue. Does it help to update the value of referent (x) immediately after
 the mutable reference is taken? Read more about 'Mutable References'
 in the book's section References and Borrowing':
 https://doc.rust-lang.org/book/ch04-02-references-and-borrowing.html#mutable-references.
-
-Additional hint:
-If you can't add, change, or remove any statements in `main()`, can you
-reorder them in a way that lets the program compile?"""
+"""
 
 # PRIMITIVE TYPES
 

From 03131a3d35d9842598150f9da817f7cc26e2669a Mon Sep 17 00:00:00 2001
From: Damian <54457902+dbednar230@users.noreply.github.com>
Date: Tue, 24 Aug 2021 03:48:51 -0500
Subject: [PATCH 051/115] fix(quiz1): Fix inconsistent wording (#826)

The second test expects the function to return 80 when there is an order of 40 apples, but the current wording implies returning 40 will pass as well
---
 exercises/quiz1.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/quiz1.rs b/exercises/quiz1.rs
index 3af1293..985cd97 100644
--- a/exercises/quiz1.rs
+++ b/exercises/quiz1.rs
@@ -4,7 +4,7 @@
 // - Functions
 
 // Mary is buying apples. One apple usually costs 2 Rustbucks, but if you buy
-// more than 40 at once, each apple only costs 1! Write a function that calculates
+// 40 or more at once, each apple only costs 1! Write a function that calculates
 // the price of an order of apples given the quantity bought. No hints this time!
 
 // I AM NOT DONE

From ba8f97f4188e516102852cf2b595774b3b0fb0bc Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Tue, 24 Aug 2021 08:49:23 +0000
Subject: [PATCH 052/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 7313c8e..6ae6979 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-100-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-101-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -302,6 +302,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://github.com/cseltol"><img src="https://avatars.githubusercontent.com/u/64264529?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ivan Nerazumov</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=cseltol" title="Documentation">📖</a></td>
     <td align="center"><a href="https://github.com/lauralindzey"><img src="https://avatars.githubusercontent.com/u/65185744?v=4?s=100" width="100px;" alt=""/><br /><sub><b>lauralindzey</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=lauralindzey" title="Documentation">📖</a></td>
     <td align="center"><a href="https://github.com/sinharaksh1t"><img src="https://avatars.githubusercontent.com/u/28585848?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rakshit Sinha</b></sub></a><br /><a href="#content-sinharaksh1t" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/dbednar230"><img src="https://avatars.githubusercontent.com/u/54457902?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Damian</b></sub></a><br /><a href="#content-dbednar230" title="Content">🖋</a></td>
   </tr>
 </table>
 

From 380587f12024a4d62c254d6e1cb08e1ec488caea Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Tue, 24 Aug 2021 08:49:24 +0000
Subject: [PATCH 053/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 85c6670..22df6a5 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -929,6 +929,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "dbednar230",
+      "name": "Damian",
+      "avatar_url": "https://avatars.githubusercontent.com/u/54457902?v=4",
+      "profile": "https://github.com/dbednar230",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 1cd9328a5872f1d6a95b02824e1af33a423c047a Mon Sep 17 00:00:00 2001
From: Ben Armstead <benarmstead@protonmail.com>
Date: Tue, 24 Aug 2021 12:06:30 +0000
Subject: [PATCH 054/115]  fix(cli): remove unnecessary borrows (#829)

* Update dependencies

* Format better and remove unnecessary borrows
---
 Cargo.lock      | 114 ++++++++++++++++++++++++------------------------
 src/exercise.rs |   2 +-
 src/main.rs     |   2 +-
 src/verify.rs   |  16 +++----
 4 files changed, 68 insertions(+), 66 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index d291c16..57b211b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,19 +1,21 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+version = 3
+
 [[package]]
 name = "aho-corasick"
-version = "0.7.15"
+version = "0.7.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7404febffaa47dac81aa44dba71523c9d069b1bdc50a77db41195149e17f68e5"
+checksum = "1e37cfd5e7657ada45f742d6e99ca5788580b5c529dc78faf11ece6dc702656f"
 dependencies = [
  "memchr",
 ]
 
 [[package]]
 name = "argh"
-version = "0.1.4"
+version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "91792f088f87cdc7a2cfb1d617fa5ea18d7f1dc22ef0e1b5f82f3157cdc522be"
+checksum = "2e7317a549bc17c5278d9e72bb6e62c6aa801ac2567048e39ebc1c194249323e"
 dependencies = [
  "argh_derive",
  "argh_shared",
@@ -21,9 +23,9 @@ dependencies = [
 
 [[package]]
 name = "argh_derive"
-version = "0.1.4"
+version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c4eb0c0c120ad477412dc95a4ce31e38f2113e46bd13511253f79196ca68b067"
+checksum = "60949c42375351e9442e354434b0cba2ac402c1237edf673cac3a4bf983b8d3c"
 dependencies = [
  "argh_shared",
  "heck",
@@ -34,9 +36,9 @@ dependencies = [
 
 [[package]]
 name = "argh_shared"
-version = "0.1.4"
+version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "781f336cc9826dbaddb9754cb5db61e64cab4f69668bd19dcc4a0394a86f4cb1"
+checksum = "8a61eb019cb8f415d162cb9f12130ee6bbe9168b7d953c17f4ad049e4051ca00"
 
 [[package]]
 name = "assert_cmd"
@@ -69,9 +71,9 @@ checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
 
 [[package]]
 name = "bitflags"
-version = "1.2.1"
+version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
 [[package]]
 name = "cfg-if"
@@ -156,9 +158,9 @@ dependencies = [
 
 [[package]]
 name = "filetime"
-version = "0.2.14"
+version = "0.2.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1d34cfa13a63ae058bfa601fe9e313bbdb3746427c1459185464ce0fcf62e1e8"
+checksum = "975ccf83d8d9d0d84682850a38c8169027be83368805971cc4f238c2b245bc98"
 dependencies = [
  "cfg-if 1.0.0",
  "libc",
@@ -218,18 +220,18 @@ checksum = "9b919933a397b79c37e33b77bb2aa3dc8eb6e165ad809e58ff75bc7db2e34574"
 
 [[package]]
 name = "heck"
-version = "0.3.2"
+version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "87cbf45460356b7deeb5e3415b5563308c0a9b057c85e12b06ad551f98d0a6ac"
+checksum = "6d621efb26863f0e9924c6ac577e8275e5e6b77455db64ffa6c65c904e9e132c"
 dependencies = [
  "unicode-segmentation",
 ]
 
 [[package]]
 name = "hermit-abi"
-version = "0.1.18"
+version = "0.1.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "322f4de77956e22ed0e5032c359a0f1273f1f7f0d79bfa3b8ffbc730d7fbcc5c"
+checksum = "62b467343b94ba476dcb2500d242dadbb39557df889310ac77c5d99100aaac33"
 dependencies = [
  "libc",
 ]
@@ -269,9 +271,9 @@ dependencies = [
 
 [[package]]
 name = "instant"
-version = "0.1.9"
+version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "61124eeebbd69b8190558df225adf7e4caafce0d743919e5d6b19652314ec5ec"
+checksum = "bee0328b1209d157ef001c94dd85b4f8f64139adb0eac2659f4b08382b2f474d"
 dependencies = [
  "cfg-if 1.0.0",
 ]
@@ -287,9 +289,9 @@ dependencies = [
 
 [[package]]
 name = "itoa"
-version = "0.4.7"
+version = "0.4.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dd25036021b0de88a0aff6b850051563c6516d0bf53f8638938edbb9de732736"
+checksum = "b71991ff56294aa922b450139ee08b3bfc70982c6b2c7562771375cf73542dd4"
 
 [[package]]
 name = "kernel32-sys"
@@ -315,15 +317,15 @@ checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"
 
 [[package]]
 name = "libc"
-version = "0.2.93"
+version = "0.2.100"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9385f66bf6105b241aa65a61cb923ef20efc665cb9f9bb50ac2f0c4b7f378d41"
+checksum = "a1fa8cddc8fbbee11227ef194b5317ed014b8acbf15139bd716a18ad3fe99ec5"
 
 [[package]]
 name = "lock_api"
-version = "0.4.3"
+version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5a3c91c24eae6777794bb1997ad98bbb87daf92890acab859f7eaa4320333176"
+checksum = "0382880606dff6d15c9476c416d18690b72742aa7b605bb6dd6ec9030fbf07eb"
 dependencies = [
  "scopeguard",
 ]
@@ -339,9 +341,9 @@ dependencies = [
 
 [[package]]
 name = "memchr"
-version = "2.3.4"
+version = "2.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ee1c47aaa256ecabcaea351eae4a9b01ef39ed810004e298d2511ed284b1525"
+checksum = "308cc39be01b73d0d18f82a0e7b2a3df85245f84af96fdddc5d202d27e47b86a"
 
 [[package]]
 name = "mio"
@@ -405,9 +407,9 @@ checksum = "61807f77802ff30975e01f4f071c8ba10c022052f98b3294119f3e615d13e5be"
 
 [[package]]
 name = "notify"
-version = "4.0.16"
+version = "4.0.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2599080e87c9bd051ddb11b10074f4da7b1223298df65d4c2ec5bcf309af1533"
+checksum = "ae03c8c853dba7bfd23e571ff0cff7bc9dceb40a4cd684cd1681824183f45257"
 dependencies = [
  "bitflags",
  "filetime",
@@ -466,9 +468,9 @@ dependencies = [
 
 [[package]]
 name = "predicates"
-version = "1.0.7"
+version = "1.0.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "eeb433456c1a57cc93554dea3ce40b4c19c4057e41c55d4a0f3d84ea71c325aa"
+checksum = "f49cfaf7fdaa3bfacc6fa3e7054e65148878354a5cfddcf661df4c851f8021df"
 dependencies = [
  "difference",
  "float-cmp",
@@ -485,9 +487,9 @@ checksum = "57e35a3326b75e49aa85f5dc6ec15b41108cf5aee58eabb1f274dd18b73c2451"
 
 [[package]]
 name = "predicates-tree"
-version = "1.0.2"
+version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "15f553275e5721409451eb85e15fd9a860a6e5ab4496eb215987502b5f5391f2"
+checksum = "d7dd0fd014130206c9352efbdc92be592751b2b9274dff685348341082c6ea3d"
 dependencies = [
  "predicates-core",
  "treeline",
@@ -495,9 +497,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.26"
+version = "1.0.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a152013215dca273577e18d2bf00fa862b89b24169fb78c4c95aeb07992c9cec"
+checksum = "5c7ed8b8c7b886ea3ed7dde405212185f423ab44682667c8c6dd14aa1d9f6612"
 dependencies = [
  "unicode-xid",
 ]
@@ -513,18 +515,18 @@ dependencies = [
 
 [[package]]
 name = "redox_syscall"
-version = "0.2.6"
+version = "0.2.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8270314b5ccceb518e7e578952f0b72b88222d02e8f77f5ecf7abbb673539041"
+checksum = "8383f39639269cde97d255a32bdb68c047337295414940c68bdd30c2e13203ff"
 dependencies = [
  "bitflags",
 ]
 
 [[package]]
 name = "regex"
-version = "1.4.6"
+version = "1.5.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2a26af418b574bd56588335b3a3659a65725d4e636eb1016c2f9e3b38c7cc759"
+checksum = "d07a8629359eb56f1e2fb1652bb04212c072a87ba68546a04065d525673ac461"
 dependencies = [
  "aho-corasick",
  "memchr",
@@ -533,9 +535,9 @@ dependencies = [
 
 [[package]]
 name = "regex-syntax"
-version = "0.6.23"
+version = "0.6.25"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "24d5f089152e60f62d28b835fbff2cd2e8dc0baf1ac13343bef92ab7eed84548"
+checksum = "f497285884f3fcff424ffc933e56d7cbca511def0c9831a7f9b5f6153e3cc89b"
 
 [[package]]
 name = "rustlings"
@@ -576,18 +578,18 @@ checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
 
 [[package]]
 name = "serde"
-version = "1.0.125"
+version = "1.0.129"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "558dc50e1a5a5fa7112ca2ce4effcb321b0300c0d4ccf0776a9f60cd89031171"
+checksum = "d1f72836d2aa753853178eda473a3b9d8e4eefdaf20523b919677e6de489f8f1"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.125"
+version = "1.0.129"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b093b7a2bb58203b5da3056c05b4ec1fed827dcfdb37347a8841695263b3d06d"
+checksum = "e57ae87ad533d9a56427558b516d0adac283614e347abf85b0dc0cbbf0a249f3"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -596,9 +598,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.64"
+version = "1.0.66"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "799e97dc9fdae36a5c8b8f2cae9ce2ee9fdce2058c57a93e6099d919fd982f79"
+checksum = "336b10da19a12ad094b59d870ebde26a45402e5b470add4b5fd03c5048a32127"
 dependencies = [
  "itoa",
  "ryu",
@@ -607,9 +609,9 @@ dependencies = [
 
 [[package]]
 name = "slab"
-version = "0.4.3"
+version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f173ac3d1a7e3b28003f40de0b5ce7fe2710f9b9dc3fc38664cebee46b3b6527"
+checksum = "c307a32c1c5c437f38c7fd45d753050587732ba8628319fbdf12a7e289ccc590"
 
 [[package]]
 name = "smallvec"
@@ -619,9 +621,9 @@ checksum = "fe0f37c9e8f3c5a4a66ad655a93c74daac4ad00c441533bf5c6e7990bb42604e"
 
 [[package]]
 name = "syn"
-version = "1.0.70"
+version = "1.0.75"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b9505f307c872bab8eb46f77ae357c8eba1fdacead58ee5a850116b1d7f82883"
+checksum = "b7f58f7e8eaa0009c5fec437aabf511bd9933e4b2d7407bd05273c01a8906ea7"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -630,9 +632,9 @@ dependencies = [
 
 [[package]]
 name = "terminal_size"
-version = "0.1.16"
+version = "0.1.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "86ca8ced750734db02076f44132d802af0b33b09942331f4459dde8636fd2406"
+checksum = "633c1a546cee861a1a6d0dc69ebeca693bf4296661ba7852b9d21d159e0506df"
 dependencies = [
  "libc",
  "winapi 0.3.9",
@@ -664,9 +666,9 @@ checksum = "a7f741b240f1a48843f9b8e0444fb55fb2a4ff67293b50a9179dfd5ea67f8d41"
 
 [[package]]
 name = "unicode-segmentation"
-version = "1.7.1"
+version = "1.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bb0d2e7be6ae3a5fa87eed5fb451aff96f2573d2694942e40543ae0bbe19c796"
+checksum = "8895849a949e7845e06bd6dc1aa51731a103c42707010a5b591c0038fb73385b"
 
 [[package]]
 name = "unicode-width"
@@ -676,9 +678,9 @@ checksum = "9337591893a19b88d8d87f2cec1e73fad5cdfd10e5a6f349f498ad6ea2ffb1e3"
 
 [[package]]
 name = "unicode-xid"
-version = "0.2.1"
+version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f7fe0bb3479651439c9112f72b6c505038574c9fbb575ed1bf3b797fa39dd564"
+checksum = "8ccb82d61f80a663efe1f787a51b16b5a51e3314d6ac365b08639f52387b33f3"
 
 [[package]]
 name = "walkdir"
diff --git a/src/exercise.rs b/src/exercise.rs
index d934cfd..53457ac 100644
--- a/src/exercise.rs
+++ b/src/exercise.rs
@@ -162,7 +162,7 @@ path = "{}.rs""#,
 
         if cmd.status.success() {
             Ok(CompiledExercise {
-                exercise: &self,
+                exercise: self,
                 _handle: FileHandle,
             })
         } else {
diff --git a/src/main.rs b/src/main.rs
index c8ebc68..1e34347 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -203,7 +203,7 @@ fn main() {
         Subcommands::Run(subargs) => {
             let exercise = find_exercise(&subargs.name, &exercises);
 
-            run(&exercise, verbose).unwrap_or_else(|_| std::process::exit(1));
+            run(exercise, verbose).unwrap_or_else(|_| std::process::exit(1));
         }
 
         Subcommands::Hint(subargs) => {
diff --git a/src/verify.rs b/src/verify.rs
index b98598a..fd59fa5 100644
--- a/src/verify.rs
+++ b/src/verify.rs
@@ -14,9 +14,9 @@ pub fn verify<'a>(
 ) -> Result<(), &'a Exercise> {
     for exercise in start_at {
         let compile_result = match exercise.mode {
-            Mode::Test => compile_and_test(&exercise, RunMode::Interactive, verbose),
-            Mode::Compile => compile_and_run_interactively(&exercise),
-            Mode::Clippy => compile_only(&exercise),
+            Mode::Test => compile_and_test(exercise, RunMode::Interactive, verbose),
+            Mode::Compile => compile_and_run_interactively(exercise),
+            Mode::Clippy => compile_only(exercise),
         };
         if !compile_result.unwrap_or(false) {
             return Err(exercise);
@@ -42,11 +42,11 @@ fn compile_only(exercise: &Exercise) -> Result<bool, ()> {
     progress_bar.set_message(format!("Compiling {}...", exercise).as_str());
     progress_bar.enable_steady_tick(100);
 
-    let _ = compile(&exercise, &progress_bar)?;
+    let _ = compile(exercise, &progress_bar)?;
     progress_bar.finish_and_clear();
 
     success!("Successfully compiled {}!", exercise);
-    Ok(prompt_for_completion(&exercise, None))
+    Ok(prompt_for_completion(exercise, None))
 }
 
 // Compile the given Exercise and run the resulting binary in an interactive mode
@@ -55,7 +55,7 @@ fn compile_and_run_interactively(exercise: &Exercise) -> Result<bool, ()> {
     progress_bar.set_message(format!("Compiling {}...", exercise).as_str());
     progress_bar.enable_steady_tick(100);
 
-    let compilation = compile(&exercise, &progress_bar)?;
+    let compilation = compile(exercise, &progress_bar)?;
 
     progress_bar.set_message(format!("Running {}...", exercise).as_str());
     let result = compilation.run();
@@ -73,7 +73,7 @@ fn compile_and_run_interactively(exercise: &Exercise) -> Result<bool, ()> {
 
     success!("Successfully ran {}!", exercise);
 
-    Ok(prompt_for_completion(&exercise, Some(output.stdout)))
+    Ok(prompt_for_completion(exercise, Some(output.stdout)))
 }
 
 // Compile the given Exercise as a test harness and display
@@ -94,7 +94,7 @@ fn compile_and_test(exercise: &Exercise, run_mode: RunMode, verbose: bool) -> Re
             }
             success!("Successfully tested {}", &exercise);
             if let RunMode::Interactive = run_mode {
-                Ok(prompt_for_completion(&exercise, None))
+                Ok(prompt_for_completion(exercise, None))
             } else {
                 Ok(true)
             }

From 2f0ff258b1c3780971d9b7896d8ede7848fefcdb Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Tue, 24 Aug 2021 12:06:44 +0000
Subject: [PATCH 055/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 6ae6979..c867258 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-101-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-102-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -303,6 +303,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://github.com/lauralindzey"><img src="https://avatars.githubusercontent.com/u/65185744?v=4?s=100" width="100px;" alt=""/><br /><sub><b>lauralindzey</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=lauralindzey" title="Documentation">📖</a></td>
     <td align="center"><a href="https://github.com/sinharaksh1t"><img src="https://avatars.githubusercontent.com/u/28585848?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rakshit Sinha</b></sub></a><br /><a href="#content-sinharaksh1t" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/dbednar230"><img src="https://avatars.githubusercontent.com/u/54457902?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Damian</b></sub></a><br /><a href="#content-dbednar230" title="Content">🖋</a></td>
+    <td align="center"><a href="https://benarmstead.co.uk"><img src="https://avatars.githubusercontent.com/u/70973680?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ben Armstead</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=benarmstead" title="Code">💻</a></td>
   </tr>
 </table>
 

From a64dbdcc043ae907c003ff940b43f0315283899d Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Tue, 24 Aug 2021 12:06:45 +0000
Subject: [PATCH 056/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 22df6a5..7816a0b 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -938,6 +938,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "benarmstead",
+      "name": "Ben Armstead",
+      "avatar_url": "https://avatars.githubusercontent.com/u/70973680?v=4",
+      "profile": "https://benarmstead.co.uk",
+      "contributions": [
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 96fc3017642b1b4b224390320111c6e305c736a3 Mon Sep 17 00:00:00 2001
From: diannasoriel <mokou@fastmail.com>
Date: Thu, 26 Aug 2021 10:30:18 +0200
Subject: [PATCH 057/115] chore(quiz1): revert wording

---
 exercises/quiz1.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/quiz1.rs b/exercises/quiz1.rs
index 985cd97..3af1293 100644
--- a/exercises/quiz1.rs
+++ b/exercises/quiz1.rs
@@ -4,7 +4,7 @@
 // - Functions
 
 // Mary is buying apples. One apple usually costs 2 Rustbucks, but if you buy
-// 40 or more at once, each apple only costs 1! Write a function that calculates
+// more than 40 at once, each apple only costs 1! Write a function that calculates
 // the price of an order of apples given the quantity bought. No hints this time!
 
 // I AM NOT DONE

From dfd2fab4f33d1bf59e2e5ee03123c0c9a67a9481 Mon Sep 17 00:00:00 2001
From: anuk909 <34924662+anuk909@users.noreply.github.com>
Date: Fri, 3 Sep 2021 11:41:12 +0300
Subject: [PATCH 058/115] feat(modules): update exercises, add modules3 (#822)

Co-authored-by: diannasoriel <mokou@fastmail.com>
---
 exercises/README.md           |  2 +-
 exercises/modules/README.md   |  2 +-
 exercises/modules/modules1.rs |  6 ++++++
 exercises/modules/modules2.rs |  8 ++++++--
 exercises/modules/modules3.rs | 18 ++++++++++++++++++
 info.toml                     | 18 +++++++++++++-----
 6 files changed, 45 insertions(+), 9 deletions(-)
 create mode 100644 exercises/modules/modules3.rs

diff --git a/exercises/README.md b/exercises/README.md
index eebbd0b..73754db 100644
--- a/exercises/README.md
+++ b/exercises/README.md
@@ -9,7 +9,7 @@
 | primitive_types        | §4.3          |
 | structs                | §5.1          |
 | enums                  | §6            |
-| modules                | §7.2          |
+| modules                | §7            |
 | collections            | §8.1, §8.3    |
 | strings                | §8.2          |
 | error_handling         | §9            |
diff --git a/exercises/modules/README.md b/exercises/modules/README.md
index 6582b00..3dc8a48 100644
--- a/exercises/modules/README.md
+++ b/exercises/modules/README.md
@@ -4,4 +4,4 @@ In this section we'll give you an introduction to Rust's module system.
 
 ## Further information
 
-- [The Module System](https://doc.rust-lang.org/book/ch07-02-defining-modules-to-control-scope-and-privacy.html)
+- [The Module System](https://doc.rust-lang.org/book/ch07-00-managing-growing-projects-with-packages-crates-and-modules.html)
diff --git a/exercises/modules/modules1.rs b/exercises/modules/modules1.rs
index 812dfee..1a2bd0d 100644
--- a/exercises/modules/modules1.rs
+++ b/exercises/modules/modules1.rs
@@ -4,7 +4,13 @@
 // I AM NOT DONE
 
 mod sausage_factory {
+    // Don't let anybody outside of this module see this!
+    fn get_secret_recipe() -> String {
+        String::from("Ginger")
+    }
+
     fn make_sausage() {
+        get_secret_recipe();
         println!("sausage!");
     }
 }
diff --git a/exercises/modules/modules2.rs b/exercises/modules/modules2.rs
index fde439d..687bb78 100644
--- a/exercises/modules/modules2.rs
+++ b/exercises/modules/modules2.rs
@@ -1,11 +1,15 @@
 // modules2.rs
+// You can bring module paths into scopes and provide new names for them with the
+// 'use' and 'as' keywords. Fix these 'use' statments to make the code compile.
 // Make me compile! Execute `rustlings hint modules2` for hints :)
 
 // I AM NOT DONE
 
 mod delicious_snacks {
-    use self::fruits::PEAR as fruit;
-    use self::veggies::CUCUMBER as veggie;
+
+    // TODO: Fix these use statments
+    use self::fruits::PEAR as ???
+    use self::veggies::CUCUMBER as ???
 
     mod fruits {
         pub const PEAR: &'static str = "Pear";
diff --git a/exercises/modules/modules3.rs b/exercises/modules/modules3.rs
new file mode 100644
index 0000000..8eed77d
--- /dev/null
+++ b/exercises/modules/modules3.rs
@@ -0,0 +1,18 @@
+// modules3.rs
+// You can use the 'use' keyword to bring module paths from modules from anywhere
+// and especially from the Rust standard library into your scope.
+// Bring SystemTime and UNIX_EPOCH
+// from the std::time module. Bonus style points if you can do it with one line!
+// Make me compile! Execute `rustlings hint modules3` for hints :)
+
+// I AM NOT DONE
+
+// TODO: Complete this use statement
+use ???
+
+fn main() {
+    match SystemTime::now().duration_since(UNIX_EPOCH) {
+        Ok(n) => println!("1970-01-01 00:00:00 UTC was {} seconds ago!", n.as_secs()),
+        Err(_) => panic!("SystemTime before UNIX EPOCH!"),
+    }
+}
diff --git a/info.toml b/info.toml
index d5008ed..0f68d05 100644
--- a/info.toml
+++ b/info.toml
@@ -362,11 +362,19 @@ name = "modules2"
 path = "exercises/modules/modules2.rs"
 mode = "compile"
 hint = """
-The delicious_snacks module is trying to present an external
-interface (the `fruit` and `veggie` constants) that is different than
-its internal structure (the `fruits` and `veggies` modules and
-associated constants). It's almost there except for one keyword missing for
-each constant."""
+The delicious_snacks module is trying to present an external interface that is 
+different than its internal structure (the `fruits` and `veggies` modules and
+associated constants). Complete the `use` statemants to fit the uses in main and
+find the one keyword missing for both constants."""
+
+[[exercises]]
+name = "modules3"
+path = "exercises/modules/modules3.rs"
+mode = "compile"
+hint = """
+UNIX_EPOCH and SystemTime are declared in the std::time module. Add a use statement
+for these two to bring them into scope. You can use nested paths or the glob
+operator to bring these two in using only one line."""
 
 # COLLECTIONS
 

From 5423f1be29abc97a5659cac05a819a36d62182f5 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Fri, 3 Sep 2021 08:41:42 +0000
Subject: [PATCH 059/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index c867258..608bba9 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-102-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-103-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -304,6 +304,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://github.com/sinharaksh1t"><img src="https://avatars.githubusercontent.com/u/28585848?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rakshit Sinha</b></sub></a><br /><a href="#content-sinharaksh1t" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/dbednar230"><img src="https://avatars.githubusercontent.com/u/54457902?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Damian</b></sub></a><br /><a href="#content-dbednar230" title="Content">🖋</a></td>
     <td align="center"><a href="https://benarmstead.co.uk"><img src="https://avatars.githubusercontent.com/u/70973680?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ben Armstead</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=benarmstead" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/anuk909"><img src="https://avatars.githubusercontent.com/u/34924662?v=4?s=100" width="100px;" alt=""/><br /><sub><b>anuk909</b></sub></a><br /><a href="#content-anuk909" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/commits?author=anuk909" title="Code">💻</a></td>
   </tr>
 </table>
 

From 44d8047249bc4c32ccc1cbc5de848caea0df8c2f Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Fri, 3 Sep 2021 08:41:43 +0000
Subject: [PATCH 060/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 7816a0b..03e8dd1 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -947,6 +947,16 @@
       "contributions": [
         "code"
       ]
+    },
+    {
+      "login": "anuk909",
+      "name": "anuk909",
+      "avatar_url": "https://avatars.githubusercontent.com/u/34924662?v=4",
+      "profile": "https://github.com/anuk909",
+      "contributions": [
+        "content",
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 1c3beb0a59178c950dc05fe8ee2346b017429ae0 Mon Sep 17 00:00:00 2001
From: granddaifuku <49578068+granddaifuku@users.noreply.github.com>
Date: Mon, 6 Sep 2021 23:32:39 +0900
Subject: [PATCH 061/115] fix(modules2): fix typo (#835)

---
 exercises/modules/modules2.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/exercises/modules/modules2.rs b/exercises/modules/modules2.rs
index 687bb78..87f0c45 100644
--- a/exercises/modules/modules2.rs
+++ b/exercises/modules/modules2.rs
@@ -1,13 +1,13 @@
 // modules2.rs
 // You can bring module paths into scopes and provide new names for them with the
-// 'use' and 'as' keywords. Fix these 'use' statments to make the code compile.
+// 'use' and 'as' keywords. Fix these 'use' statements to make the code compile.
 // Make me compile! Execute `rustlings hint modules2` for hints :)
 
 // I AM NOT DONE
 
 mod delicious_snacks {
 
-    // TODO: Fix these use statments
+    // TODO: Fix these use statements
     use self::fruits::PEAR as ???
     use self::veggies::CUCUMBER as ???
 

From 6c41adef63d777a90bf2a80f0abb5efeb872f52b Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Mon, 6 Sep 2021 14:33:03 +0000
Subject: [PATCH 062/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 608bba9..e28a481 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-103-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-104-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -305,6 +305,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://github.com/dbednar230"><img src="https://avatars.githubusercontent.com/u/54457902?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Damian</b></sub></a><br /><a href="#content-dbednar230" title="Content">🖋</a></td>
     <td align="center"><a href="https://benarmstead.co.uk"><img src="https://avatars.githubusercontent.com/u/70973680?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ben Armstead</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=benarmstead" title="Code">💻</a></td>
     <td align="center"><a href="https://github.com/anuk909"><img src="https://avatars.githubusercontent.com/u/34924662?v=4?s=100" width="100px;" alt=""/><br /><sub><b>anuk909</b></sub></a><br /><a href="#content-anuk909" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/commits?author=anuk909" title="Code">💻</a></td>
+    <td align="center"><a href="https://granddaifuku.com/"><img src="https://avatars.githubusercontent.com/u/49578068?v=4?s=100" width="100px;" alt=""/><br /><sub><b>granddaifuku</b></sub></a><br /><a href="#content-granddaifuku" title="Content">🖋</a></td>
   </tr>
 </table>
 

From de22b132731bd6f9bae6d0a90707d29e9d3bc389 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Mon, 6 Sep 2021 14:33:05 +0000
Subject: [PATCH 063/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 03e8dd1..5a932d9 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -957,6 +957,15 @@
         "content",
         "code"
       ]
+    },
+    {
+      "login": "granddaifuku",
+      "name": "granddaifuku",
+      "avatar_url": "https://avatars.githubusercontent.com/u/49578068?v=4",
+      "profile": "https://granddaifuku.com/",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 6efa7d5d1554f8973346e9e15dbd5268306a2458 Mon Sep 17 00:00:00 2001
From: "joakim.kartveit" <joakim.kartveit@edigard.no>
Date: Thu, 9 Sep 2021 15:53:05 +0200
Subject: [PATCH 064/115] Added ignore for .iml files

---
 .gitignore | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.gitignore b/.gitignore
index 06de871..253f8f3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,4 @@ exercises/clippy/Cargo.toml
 exercises/clippy/Cargo.lock
 .idea
 .vscode
+*.iml

From a7dc080b95e49146fbaafe6922a6de2f8cb1582a Mon Sep 17 00:00:00 2001
From: ana <ana@ana.st>
Date: Tue, 21 Sep 2021 10:36:11 +0200
Subject: [PATCH 065/115] feat: add more watch commands

Includes:
- quit, to quit the shell instead of having to press Cmd/Ctrl-C or Cmd/Ctrl-D
- help, to display an overview of all the commands available in watch mode.

Closes #842.
---
 src/main.rs | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/main.rs b/src/main.rs
index 1e34347..06b4177 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -264,7 +264,7 @@ fn main() {
 
 fn spawn_watch_shell(failed_exercise_hint: &Arc<Mutex<Option<String>>>) {
     let failed_exercise_hint = Arc::clone(failed_exercise_hint);
-    println!("Type 'hint' or open the corresponding README.md file to get help or type 'clear' to clear the screen.");
+    println!("Welcome to watch mode! You can type 'help' to get an overview of the commands you can use here.");
     thread::spawn(move || loop {
         let mut input = String::new();
         match io::stdin().read_line(&mut input) {
@@ -276,6 +276,18 @@ fn spawn_watch_shell(failed_exercise_hint: &Arc<Mutex<Option<String>>>) {
                     }
                 } else if input.eq("clear") {
                     println!("\x1B[2J\x1B[1;1H");
+                } else if input.eq("quit") {
+                    println!("Bye!");
+                    std::process::exit(0);
+                } else if input.eq("help") {
+                    println!("Commands available to you in watch mode:");
+                    println!("  hint  - prints the current exercise's hint");
+                    println!("  clear - clears the screen");
+                    println!("  quit  - quits watch mode");
+                    println!("  help  - displays this help message");
+                    println!("");
+                    println!("Watch mode automatically re-evaluates the current exercise");
+                    println!("when you edit a file's contents.")
                 } else {
                     println!("unknown command: {}", input);
                 }

From 0a11bad71402b5403143d642f439f57931278c07 Mon Sep 17 00:00:00 2001
From: Weilet <32561597+Weilet@users.noreply.github.com>
Date: Tue, 21 Sep 2021 16:43:44 +0800
Subject: [PATCH 066/115] feat(quiz1): add default function name in comment
 (#838)

---
 exercises/quiz1.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/quiz1.rs b/exercises/quiz1.rs
index 3af1293..b13b928 100644
--- a/exercises/quiz1.rs
+++ b/exercises/quiz1.rs
@@ -10,7 +10,7 @@
 // I AM NOT DONE
 
 // Put your function here!
-// fn ..... {
+// fn calculate_apple_price {
 
 // Don't modify this function!
 #[test]

From fe726f5bcafd35c56b66c9b17a962b7a5cab5ece Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Tue, 21 Sep 2021 08:44:03 +0000
Subject: [PATCH 067/115] docs: update README.md [skip ci]

---
 README.md | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index e28a481..af0cbb8 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-104-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-105-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -307,6 +307,9 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://github.com/anuk909"><img src="https://avatars.githubusercontent.com/u/34924662?v=4?s=100" width="100px;" alt=""/><br /><sub><b>anuk909</b></sub></a><br /><a href="#content-anuk909" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/commits?author=anuk909" title="Code">💻</a></td>
     <td align="center"><a href="https://granddaifuku.com/"><img src="https://avatars.githubusercontent.com/u/49578068?v=4?s=100" width="100px;" alt=""/><br /><sub><b>granddaifuku</b></sub></a><br /><a href="#content-granddaifuku" title="Content">🖋</a></td>
   </tr>
+  <tr>
+    <td align="center"><a href="https://weilet.me"><img src="https://avatars.githubusercontent.com/u/32561597?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Weilet</b></sub></a><br /><a href="#content-Weilet" title="Content">🖋</a></td>
+  </tr>
 </table>
 
 <!-- markdownlint-restore -->

From 9ddd4ca33a4cb2a6b02b03a574682c92de5d7253 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Tue, 21 Sep 2021 08:44:04 +0000
Subject: [PATCH 068/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 5a932d9..8811aef 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -966,6 +966,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "Weilet",
+      "name": "Weilet",
+      "avatar_url": "https://avatars.githubusercontent.com/u/32561597?v=4",
+      "profile": "https://weilet.me",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 06d5c0973a3dffa3c6c6f70acb775d4c6630323c Mon Sep 17 00:00:00 2001
From: LIU JIE <isjieliu@163.com>
Date: Tue, 21 Sep 2021 17:50:15 +0800
Subject: [PATCH 069/115] fix(cli): typo in exercise.rs (#848)

---
 src/exercise.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/exercise.rs b/src/exercise.rs
index 53457ac..ec694df 100644
--- a/src/exercise.rs
+++ b/src/exercise.rs
@@ -133,7 +133,7 @@ path = "{}.rs""#,
                     "Failed to write 📎 Clippy 📎 Cargo.toml file."
                 };
                 fs::write(CLIPPY_CARGO_TOML_PATH, cargo_toml).expect(cargo_toml_error_msg);
-                // To support the ability to run the clipy exercises, build
+                // To support the ability to run the clippy exercises, build
                 // an executable, in addition to running clippy. With a
                 // compilation failure, this would silently fail. But we expect
                 // clippy to reflect the same failure while compiling later.

From 9ef63c0b9b892dd572a76db9c95947e77f82eb3c Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Tue, 21 Sep 2021 09:50:31 +0000
Subject: [PATCH 070/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index af0cbb8..94ab10f 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-105-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-106-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -309,6 +309,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
   </tr>
   <tr>
     <td align="center"><a href="https://weilet.me"><img src="https://avatars.githubusercontent.com/u/32561597?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Weilet</b></sub></a><br /><a href="#content-Weilet" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/Millione"><img src="https://avatars.githubusercontent.com/u/38575932?v=4?s=100" width="100px;" alt=""/><br /><sub><b>LIU JIE</b></sub></a><br /><a href="#content-Millione" title="Content">🖋</a></td>
   </tr>
 </table>
 

From e9c0ca6be2a73c4dc890f2ebeaaec8aeaad06650 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Tue, 21 Sep 2021 09:50:32 +0000
Subject: [PATCH 071/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 8811aef..44d2439 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -975,6 +975,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "Millione",
+      "name": "LIU JIE",
+      "avatar_url": "https://avatars.githubusercontent.com/u/38575932?v=4",
+      "profile": "https://github.com/Millione",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 3352b5a4d380df65763b4e64fc9e8938a3adfd80 Mon Sep 17 00:00:00 2001
From: ana <ana@ana.st>
Date: Fri, 24 Sep 2021 13:04:30 +0200
Subject: [PATCH 072/115] chore: improve println! usage

---
 src/main.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main.rs b/src/main.rs
index 06b4177..d01a827 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -285,7 +285,7 @@ fn spawn_watch_shell(failed_exercise_hint: &Arc<Mutex<Option<String>>>) {
                     println!("  clear - clears the screen");
                     println!("  quit  - quits watch mode");
                     println!("  help  - displays this help message");
-                    println!("");
+                    println!();
                     println!("Watch mode automatically re-evaluates the current exercise");
                     println!("when you edit a file's contents.")
                 } else {

From 1caef0b43494c8b8cdd6c9260147e70d510f1aca Mon Sep 17 00:00:00 2001
From: Antoine Busch <antoine.busch@gmail.com>
Date: Tue, 14 Sep 2021 20:34:40 +1000
Subject: [PATCH 073/115] feat: Add "quit" command to `rustlings watch`

closes: #842
---
 src/main.rs | 122 +++++++++++++++++++++++++++++++---------------------
 1 file changed, 72 insertions(+), 50 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index d01a827..30096df 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -10,7 +10,8 @@ use std::fs;
 use std::io::{self, prelude::*};
 use std::path::Path;
 use std::process::{Command, Stdio};
-use std::sync::mpsc::channel;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::mpsc::{RecvTimeoutError, channel};
 use std::sync::{Arc, Mutex};
 use std::thread;
 use std::time::Duration;
@@ -217,52 +218,60 @@ fn main() {
         }
 
         Subcommands::Watch(_subargs) => {
-            if let Err(e) = watch(&exercises, verbose) {
-                println!(
-                    "Error: Could not watch your progress. Error message was {:?}.",
-                    e
-                );
-                println!("Most likely you've run out of disk space or your 'inotify limit' has been reached.");
-                std::process::exit(1);
+            match watch(&exercises, verbose) {
+                Err(e) => {
+                    println!(
+                        "Error: Could not watch your progress. Error message was {:?}.",
+                        e
+                    );
+                    println!("Most likely you've run out of disk space or your 'inotify limit' has been reached.");
+                    std::process::exit(1);
+                }
+                Ok(WatchStatus::Finished) => {
+                    println!(
+                        "{emoji} All exercises completed! {emoji}",
+                        emoji = Emoji("🎉", "★")
+                    );
+                    println!();
+                    println!("+----------------------------------------------------+");
+                    println!("|          You made it to the Fe-nish line!          |");
+                    println!("+--------------------------  ------------------------+");
+                    println!("                          \\/                         ");
+                    println!("     ▒▒          ▒▒▒▒▒▒▒▒      ▒▒▒▒▒▒▒▒          ▒▒   ");
+                    println!("   ▒▒▒▒  ▒▒    ▒▒        ▒▒  ▒▒        ▒▒    ▒▒  ▒▒▒▒ ");
+                    println!("   ▒▒▒▒  ▒▒  ▒▒            ▒▒            ▒▒  ▒▒  ▒▒▒▒ ");
+                    println!(" ░░▒▒▒▒░░▒▒  ▒▒            ▒▒            ▒▒  ▒▒░░▒▒▒▒ ");
+                    println!("   ▓▓▓▓▓▓▓▓  ▓▓      ▓▓██  ▓▓  ▓▓██      ▓▓  ▓▓▓▓▓▓▓▓ ");
+                    println!("     ▒▒▒▒    ▒▒      ████  ▒▒  ████      ▒▒░░  ▒▒▒▒   ");
+                    println!("       ▒▒  ▒▒▒▒▒▒        ▒▒▒▒▒▒        ▒▒▒▒▒▒  ▒▒     ");
+                    println!("         ▒▒▒▒▒▒▒▒▒▒▓▓▓▓▓▓▒▒▒▒▒▒▒▒▓▓▒▒▓▓▒▒▒▒▒▒▒▒       ");
+                    println!("           ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒         ");
+                    println!("             ▒▒▒▒▒▒▒▒▒▒██▒▒▒▒▒▒██▒▒▒▒▒▒▒▒▒▒           ");
+                    println!("           ▒▒  ▒▒▒▒▒▒▒▒▒▒██████▒▒▒▒▒▒▒▒▒▒  ▒▒         ");
+                    println!("         ▒▒    ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒    ▒▒       ");
+                    println!("       ▒▒    ▒▒    ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒    ▒▒    ▒▒     ");
+                    println!("       ▒▒  ▒▒    ▒▒                  ▒▒    ▒▒  ▒▒     ");
+                    println!("           ▒▒  ▒▒                      ▒▒  ▒▒         ");
+                    println!();
+                    println!("We hope you enjoyed learning about the various aspects of Rust!");
+                    println!(
+                        "If you noticed any issues, please don't hesitate to report them to our repo."
+                    );
+                    println!("You can also contribute your own exercises to help the greater community!");
+                    println!();
+                    println!("Before reporting an issue or contributing, please read our guidelines:");
+                    println!("https://github.com/rust-lang/rustlings/blob/main/CONTRIBUTING.md");
+                }
+                Ok(WatchStatus::Unfinished) => {
+                    println!("We hope you're enjoying learning about Rust!");
+                    println!("If you want to continue working on the exercises at a later point, you can simply run `rustlings watch` again");
+                }
             }
-            println!(
-                "{emoji} All exercises completed! {emoji}",
-                emoji = Emoji("🎉", "★")
-            );
-            println!();
-            println!("+----------------------------------------------------+");
-            println!("|          You made it to the Fe-nish line!          |");
-            println!("+--------------------------  ------------------------+");
-            println!("                          \\/                         ");
-            println!("     ▒▒          ▒▒▒▒▒▒▒▒      ▒▒▒▒▒▒▒▒          ▒▒   ");
-            println!("   ▒▒▒▒  ▒▒    ▒▒        ▒▒  ▒▒        ▒▒    ▒▒  ▒▒▒▒ ");
-            println!("   ▒▒▒▒  ▒▒  ▒▒            ▒▒            ▒▒  ▒▒  ▒▒▒▒ ");
-            println!(" ░░▒▒▒▒░░▒▒  ▒▒            ▒▒            ▒▒  ▒▒░░▒▒▒▒ ");
-            println!("   ▓▓▓▓▓▓▓▓  ▓▓      ▓▓██  ▓▓  ▓▓██      ▓▓  ▓▓▓▓▓▓▓▓ ");
-            println!("     ▒▒▒▒    ▒▒      ████  ▒▒  ████      ▒▒░░  ▒▒▒▒   ");
-            println!("       ▒▒  ▒▒▒▒▒▒        ▒▒▒▒▒▒        ▒▒▒▒▒▒  ▒▒     ");
-            println!("         ▒▒▒▒▒▒▒▒▒▒▓▓▓▓▓▓▒▒▒▒▒▒▒▒▓▓▒▒▓▓▒▒▒▒▒▒▒▒       ");
-            println!("           ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒         ");
-            println!("             ▒▒▒▒▒▒▒▒▒▒██▒▒▒▒▒▒██▒▒▒▒▒▒▒▒▒▒           ");
-            println!("           ▒▒  ▒▒▒▒▒▒▒▒▒▒██████▒▒▒▒▒▒▒▒▒▒  ▒▒         ");
-            println!("         ▒▒    ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒    ▒▒       ");
-            println!("       ▒▒    ▒▒    ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒    ▒▒    ▒▒     ");
-            println!("       ▒▒  ▒▒    ▒▒                  ▒▒    ▒▒  ▒▒     ");
-            println!("           ▒▒  ▒▒                      ▒▒  ▒▒         ");
-            println!();
-            println!("We hope you enjoyed learning about the various aspects of Rust!");
-            println!(
-                "If you noticed any issues, please don't hesitate to report them to our repo."
-            );
-            println!("You can also contribute your own exercises to help the greater community!");
-            println!();
-            println!("Before reporting an issue or contributing, please read our guidelines:");
-            println!("https://github.com/rust-lang/rustlings/blob/main/CONTRIBUTING.md");
         }
     }
 }
 
-fn spawn_watch_shell(failed_exercise_hint: &Arc<Mutex<Option<String>>>) {
+fn spawn_watch_shell(failed_exercise_hint: &Arc<Mutex<Option<String>>>, should_quit: Arc<AtomicBool>) {
     let failed_exercise_hint = Arc::clone(failed_exercise_hint);
     println!("Welcome to watch mode! You can type 'help' to get an overview of the commands you can use here.");
     thread::spawn(move || loop {
@@ -270,15 +279,15 @@ fn spawn_watch_shell(failed_exercise_hint: &Arc<Mutex<Option<String>>>) {
         match io::stdin().read_line(&mut input) {
             Ok(_) => {
                 let input = input.trim();
-                if input.eq("hint") {
+                if input == "hint" {
                     if let Some(hint) = &*failed_exercise_hint.lock().unwrap() {
                         println!("{}", hint);
                     }
-                } else if input.eq("clear") {
+                } else if input == "clear" {
                     println!("\x1B[2J\x1B[1;1H");
                 } else if input.eq("quit") {
+                    should_quit.store(true, Ordering::SeqCst);
                     println!("Bye!");
-                    std::process::exit(0);
                 } else if input.eq("help") {
                     println!("Commands available to you in watch mode:");
                     println!("  hint  - prints the current exercise's hint");
@@ -318,7 +327,12 @@ fn find_exercise<'a>(name: &str, exercises: &'a [Exercise]) -> &'a Exercise {
     }
 }
 
-fn watch(exercises: &[Exercise], verbose: bool) -> notify::Result<()> {
+enum WatchStatus {
+    Finished,
+    Unfinished,
+}
+
+fn watch(exercises: &[Exercise], verbose: bool) -> notify::Result<WatchStatus> {
     /* Clears the terminal with an ANSI escape code.
     Works in UNIX and newer Windows terminals. */
     fn clear_screen() {
@@ -326,6 +340,7 @@ fn watch(exercises: &[Exercise], verbose: bool) -> notify::Result<()> {
     }
 
     let (tx, rx) = channel();
+    let should_quit = Arc::new(AtomicBool::new(false));
 
     let mut watcher: RecommendedWatcher = Watcher::new(tx, Duration::from_secs(2))?;
     watcher.watch(Path::new("./exercises"), RecursiveMode::Recursive)?;
@@ -334,12 +349,12 @@ fn watch(exercises: &[Exercise], verbose: bool) -> notify::Result<()> {
 
     let to_owned_hint = |t: &Exercise| t.hint.to_owned();
     let failed_exercise_hint = match verify(exercises.iter(), verbose) {
-        Ok(_) => return Ok(()),
+        Ok(_) => return Ok(WatchStatus::Finished),
         Err(exercise) => Arc::new(Mutex::new(Some(to_owned_hint(exercise)))),
     };
-    spawn_watch_shell(&failed_exercise_hint);
+    spawn_watch_shell(&failed_exercise_hint, Arc::clone(&should_quit));
     loop {
-        match rx.recv() {
+        match rx.recv_timeout(Duration::from_secs(1)) {
             Ok(event) => match event {
                 DebouncedEvent::Create(b) | DebouncedEvent::Chmod(b) | DebouncedEvent::Write(b) => {
                     if b.extension() == Some(OsStr::new("rs")) && b.exists() {
@@ -355,7 +370,7 @@ fn watch(exercises: &[Exercise], verbose: bool) -> notify::Result<()> {
                             );
                         clear_screen();
                         match verify(pending_exercises, verbose) {
-                            Ok(_) => return Ok(()),
+                            Ok(_) => return Ok(WatchStatus::Finished),
                             Err(exercise) => {
                                 let mut failed_exercise_hint = failed_exercise_hint.lock().unwrap();
                                 *failed_exercise_hint = Some(to_owned_hint(exercise));
@@ -365,8 +380,15 @@ fn watch(exercises: &[Exercise], verbose: bool) -> notify::Result<()> {
                 }
                 _ => {}
             },
+            Err(RecvTimeoutError::Timeout) => {
+                // the timeout expired, just check the `should_quit` variable below then loop again
+            }
             Err(e) => println!("watch error: {:?}", e),
         }
+        // Check if we need to exit
+        if should_quit.load(Ordering::SeqCst) {
+            return Ok(WatchStatus::Unfinished);
+        }
     }
 }
 

From c4b59aa593fc4ae952f69133068cb8f8f5ac0866 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Sat, 25 Sep 2021 08:47:55 +0000
Subject: [PATCH 074/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 94ab10f..8435a10 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-106-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-107-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -310,6 +310,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
   <tr>
     <td align="center"><a href="https://weilet.me"><img src="https://avatars.githubusercontent.com/u/32561597?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Weilet</b></sub></a><br /><a href="#content-Weilet" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/Millione"><img src="https://avatars.githubusercontent.com/u/38575932?v=4?s=100" width="100px;" alt=""/><br /><sub><b>LIU JIE</b></sub></a><br /><a href="#content-Millione" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/abusch"><img src="https://avatars.githubusercontent.com/u/506344?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Antoine Büsch</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=abusch" title="Code">💻</a></td>
   </tr>
 </table>
 

From a1b9c50f36513ce8f8ba26dfdaec2bb427fffeb6 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Sat, 25 Sep 2021 08:47:56 +0000
Subject: [PATCH 075/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 44d2439..345a7ec 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -984,6 +984,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "abusch",
+      "name": "Antoine Büsch",
+      "avatar_url": "https://avatars.githubusercontent.com/u/506344?v=4",
+      "profile": "https://github.com/abusch",
+      "contributions": [
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From d75759e829fdcd64ef071cf4b6eae2a011a7718b Mon Sep 17 00:00:00 2001
From: frogtd <31412003+frogtd@users.noreply.github.com>
Date: Sat, 25 Sep 2021 04:52:18 -0400
Subject: [PATCH 076/115] fix(move_semantics5): change &mut *y to &mut x (#814)

Instead of having to explain why
```rs
let mut x = 100;
let y = &mut x;
let mut z_owned = *y;
let z = &mut z_owned;
*y += 100;
*z += 1000;
```
and
```rs
let mut x = 100;
let y = &mut x;
let z = &mut *y;
*y += 100;
*z += 1000;
```
are different, you still get the point across about having only one mutable reference.
As it stands, this exercise does too much (dereferencing and having only one mutable reference), and by doing so confuses people.

Example of someone being confused by this:
<https://discord.com/channels/273534239310479360/273541522815713281/872689531428692040>
---
 exercises/move_semantics/move_semantics5.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/move_semantics/move_semantics5.rs b/exercises/move_semantics/move_semantics5.rs
index 5449e95..1afe16c 100644
--- a/exercises/move_semantics/move_semantics5.rs
+++ b/exercises/move_semantics/move_semantics5.rs
@@ -8,7 +8,7 @@
 fn main() {
     let mut x = 100;
     let y = &mut x;
-    let z = &mut *y;
+    let z = &mut x;
     *y += 100;
     *z += 1000;
     assert_eq!(x, 1200);

From e106d7a4f4d375fd8648cde25e4e7a1c4c6bdeac Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Sat, 25 Sep 2021 08:53:04 +0000
Subject: [PATCH 077/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 8435a10..ac1d84d 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-107-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-108-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -311,6 +311,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://weilet.me"><img src="https://avatars.githubusercontent.com/u/32561597?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Weilet</b></sub></a><br /><a href="#content-Weilet" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/Millione"><img src="https://avatars.githubusercontent.com/u/38575932?v=4?s=100" width="100px;" alt=""/><br /><sub><b>LIU JIE</b></sub></a><br /><a href="#content-Millione" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/abusch"><img src="https://avatars.githubusercontent.com/u/506344?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Antoine Büsch</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=abusch" title="Code">💻</a></td>
+    <td align="center"><a href="https://frogtd.com/"><img src="https://avatars.githubusercontent.com/u/31412003?v=4?s=100" width="100px;" alt=""/><br /><sub><b>frogtd</b></sub></a><br /><a href="#content-frogtd" title="Content">🖋</a></td>
   </tr>
 </table>
 

From ab5ecbee7a8fab44867cd18ab030dc9de7185360 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Sat, 25 Sep 2021 08:53:05 +0000
Subject: [PATCH 078/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 345a7ec..d18743c 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -993,6 +993,15 @@
       "contributions": [
         "code"
       ]
+    },
+    {
+      "login": "frogtd",
+      "name": "frogtd",
+      "avatar_url": "https://avatars.githubusercontent.com/u/31412003?v=4",
+      "profile": "https://frogtd.com/",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 882d535ba8628d5e0b37e8664b3e2f26260b2671 Mon Sep 17 00:00:00 2001
From: Taylor Yu <tlyu@mit.edu>
Date: Wed, 9 Jun 2021 23:26:10 -0500
Subject: [PATCH 079/115] feat: add advanced_errs1

New section and exercise to demonstrate the `From` trait for errors
and its usefulness with the `?` operator.
---
 exercises/advanced_errors/advanced_errs1.rs | 98 +++++++++++++++++++++
 info.toml                                   | 20 +++++
 2 files changed, 118 insertions(+)
 create mode 100644 exercises/advanced_errors/advanced_errs1.rs

diff --git a/exercises/advanced_errors/advanced_errs1.rs b/exercises/advanced_errors/advanced_errs1.rs
new file mode 100644
index 0000000..4bc7b63
--- /dev/null
+++ b/exercises/advanced_errors/advanced_errs1.rs
@@ -0,0 +1,98 @@
+// advanced_errs1.rs
+
+// Remember back in errors6, we had multiple mapping functions so that we
+// could translate lower-level errors into our custom error type using
+// `map_err()`? What if we could use the `?` operator directly instead?
+
+// Make this code compile! Execute `rustlings hint advanced_errs1` for
+// hints :)
+
+// I AM NOT DONE
+
+use std::num::ParseIntError;
+use std::str::FromStr;
+
+// This is a custom error type that we will be using in the `FromStr`
+// implementation.
+#[derive(PartialEq, Debug)]
+enum ParsePosNonzeroError {
+    Creation(CreationError),
+    ParseInt(ParseIntError),
+}
+
+impl From<CreationError> for ParsePosNonzeroError {
+    fn from(e: CreationError) -> Self {
+        // TODO: complete this implementation so that the `?` operator will
+        // work for `CreationError`
+    }
+}
+
+// TODO: implement another instance of the `From` trait here so that the
+// `?` operator will work in the other place in the `FromStr`
+// implementation below.
+
+// Don't change anything below this line.
+
+impl FromStr for PositiveNonzeroInteger {
+    type Err = ParsePosNonzeroError;
+    fn from_str(s: &str) -> Result<PositiveNonzeroInteger, Self::Err> {
+        let x: i64 = s.parse()?;
+        Ok(PositiveNonzeroInteger::new(x)?)
+    }
+}
+
+#[derive(PartialEq, Debug)]
+struct PositiveNonzeroInteger(u64);
+
+#[derive(PartialEq, Debug)]
+enum CreationError {
+    Negative,
+    Zero,
+}
+
+impl PositiveNonzeroInteger {
+    fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
+        match value {
+            x if x < 0 => Err(CreationError::Negative),
+            x if x == 0 => Err(CreationError::Zero),
+            x => Ok(PositiveNonzeroInteger(x as u64)),
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_parse_error() {
+        // We can't construct a ParseIntError, so we have to pattern match.
+        assert!(matches!(
+            PositiveNonzeroInteger::from_str("not a number"),
+            Err(ParsePosNonzeroError::ParseInt(_))
+        ));
+    }
+
+    #[test]
+    fn test_negative() {
+        assert_eq!(
+            PositiveNonzeroInteger::from_str("-555"),
+            Err(ParsePosNonzeroError::Creation(CreationError::Negative))
+        );
+    }
+
+    #[test]
+    fn test_zero() {
+        assert_eq!(
+            PositiveNonzeroInteger::from_str("0"),
+            Err(ParsePosNonzeroError::Creation(CreationError::Zero))
+        );
+    }
+
+    #[test]
+    fn test_positive() {
+        let x = PositiveNonzeroInteger::new(42);
+        assert!(x.is_ok());
+        assert_eq!(PositiveNonzeroInteger::from_str("42"), Ok(x.unwrap()));
+    }
+}
diff --git a/info.toml b/info.toml
index f5af884..8e24b7d 100644
--- a/info.toml
+++ b/info.toml
@@ -974,3 +974,23 @@ path = "exercises/conversions/as_ref_mut.rs"
 mode = "test"
 hint = """
 Add AsRef<str> as a trait bound to the functions."""
+
+# ADVANCED ERRORS
+
+[[exercises]]
+name = "advanced_errs1"
+path = "exercises/advanced_errors/advanced_errs1.rs"
+mode = "test"
+hint = """
+This exercise uses an updated version of the code in errors6. The parsing
+code is now in an implementation of the `FromStr` trait. Note that the
+parsing code uses `?` directly, without any calls to `map_err()`. There is
+one partial implementation of the `From` trait example that you should
+complete.
+
+Details: The `?` operator calls `From::from()` on the error type to convert
+it to the error type of the return type of the surrounding function.
+
+Hint: You will need to write another implementation of `From` that has a
+different input type.
+"""

From abd6b70c72dc6426752ff41f09160b839e5c449e Mon Sep 17 00:00:00 2001
From: Taylor Yu <tlyu@mit.edu>
Date: Fri, 25 Jun 2021 16:52:10 -0500
Subject: [PATCH 080/115] feat: add advanced_errs2

New exercise to demonstrate traits that make it easier for other code
to consume our custom error types.
---
 exercises/advanced_errors/advanced_errs2.rs | 203 ++++++++++++++++++++
 info.toml                                   |  32 +++
 2 files changed, 235 insertions(+)
 create mode 100644 exercises/advanced_errors/advanced_errs2.rs

diff --git a/exercises/advanced_errors/advanced_errs2.rs b/exercises/advanced_errors/advanced_errs2.rs
new file mode 100644
index 0000000..d9d44d0
--- /dev/null
+++ b/exercises/advanced_errors/advanced_errs2.rs
@@ -0,0 +1,203 @@
+// advanced_errs2.rs
+
+// This exercise demonstrates a few traits that are useful for custom error
+// types to implement, especially so that other code can consume the custom
+// error type more usefully.
+
+// Make this compile, and make the tests pass!
+// Execute `rustlings hint advanced_errs2` for hints.
+
+// Steps:
+// 1. Implement a missing trait so that `main()` will compile.
+// 2. Complete the partial implementation of `From` for
+//    `ParseClimateError`.
+// 3. Handle the missing error cases in the `FromStr` implementation for
+//    `Climate`.
+// 4. Complete the partial implementation of `Display` for
+//    `ParseClimateError`.
+
+// I AM NOT DONE
+
+use std::error::Error;
+use std::fmt::{self, Display, Formatter};
+use std::num::{ParseFloatError, ParseIntError};
+use std::str::FromStr;
+
+// This is the custom error type that we will be using for the parser for
+// `Climate`.
+#[derive(Debug, PartialEq)]
+enum ParseClimateError {
+    Empty,
+    BadLen,
+    NoCity,
+    ParseInt(ParseIntError),
+    ParseFloat(ParseFloatError),
+}
+
+// This `From` implementation allows the `?` operator to work on
+// `ParseIntError` values.
+impl From<ParseIntError> for ParseClimateError {
+    fn from(e: ParseIntError) -> Self {
+        Self::ParseInt(e)
+    }
+}
+
+// This `From` implementation allows the `?` operator to work on
+// `ParseFloatError` values.
+impl From<ParseFloatError> for ParseClimateError {
+    fn from(e: ParseFloatError) -> Self {
+        // TODO: Complete this function
+    }
+}
+
+// TODO: Implement a missing trait so that `main()` below will compile. It
+// is not necessary to implement any methods inside the missing trait.
+
+// The `Display` trait allows for other code to obtain the error formatted
+// as a user-visible string.
+impl Display for ParseClimateError {
+    // TODO: Complete this function so that it produces the correct strings
+    // for each error variant.
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        // Imports the variants to make the following code more compact.
+        use ParseClimateError::*;
+        match self {
+            NoCity => write!(f, "no city name"),
+            ParseFloat(e) => write!(f, "error parsing temperature: {}", e),
+            _ => write!(f, "unhandled error!"),
+        }
+    }
+}
+
+#[derive(Debug, PartialEq)]
+struct Climate {
+    city: String,
+    year: u32,
+    temp: f32,
+}
+
+// Parser for `Climate`.
+// 1. Split the input string into 3 fields: city, year, temp.
+// 2. Return an error if the string is empty or has the wrong number of
+//    fields.
+// 3. Return an error if the city name is empty.
+// 4. Parse the year as a `u32` and return an error if that fails.
+// 5. Parse the temp as a `f32` and return an error if that fails.
+// 6. Return an `Ok` value containing the completed `Climate` value.
+impl FromStr for Climate {
+    type Err = ParseClimateError;
+    // TODO: Complete this function by making it handle the missing error
+    // cases.
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let v: Vec<_> = s.split(',').collect();
+        let (city, year, temp) = match &v[..] {
+            [city, year, temp] => (city.to_string(), year, temp),
+            _ => return Err(ParseClimateError::BadLen),
+        };
+        let year: u32 = year.parse()?;
+        let temp: f32 = temp.parse()?;
+        Ok(Climate { city, year, temp })
+    }
+}
+
+// Don't change anything below this line (other than to enable ignored
+// tests).
+
+fn main() -> Result<(), Box<dyn Error>> {
+    println!("{:?}", "Hong Kong,1999,25.7".parse::<Climate>()?);
+    println!("{:?}", "".parse::<Climate>()?);
+    Ok(())
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    #[test]
+    fn test_empty() {
+        let res = "".parse::<Climate>();
+        assert_eq!(res, Err(ParseClimateError::Empty));
+        assert_eq!(res.unwrap_err().to_string(), "empty input");
+    }
+    #[test]
+    fn test_short() {
+        let res = "Boston,1991".parse::<Climate>();
+        assert_eq!(res, Err(ParseClimateError::BadLen));
+        assert_eq!(res.unwrap_err().to_string(), "incorrect number of fields");
+    }
+    #[test]
+    fn test_long() {
+        let res = "Paris,1920,17.2,extra".parse::<Climate>();
+        assert_eq!(res, Err(ParseClimateError::BadLen));
+        assert_eq!(res.unwrap_err().to_string(), "incorrect number of fields");
+    }
+    #[test]
+    fn test_no_city() {
+        let res = ",1997,20.5".parse::<Climate>();
+        assert_eq!(res, Err(ParseClimateError::NoCity));
+        assert_eq!(res.unwrap_err().to_string(), "no city name");
+    }
+    #[test]
+    fn test_parse_int_neg() {
+        let res = "Barcelona,-25,22.3".parse::<Climate>();
+        assert!(matches!(res, Err(ParseClimateError::ParseInt(_))));
+        let err = res.unwrap_err();
+        if let ParseClimateError::ParseInt(ref inner) = err {
+            assert_eq!(
+                err.to_string(),
+                format!("error parsing year: {}", inner.to_string())
+            );
+        } else {
+            unreachable!();
+        };
+    }
+    #[test]
+    fn test_parse_int_bad() {
+        let res = "Beijing,foo,15.0".parse::<Climate>();
+        assert!(matches!(res, Err(ParseClimateError::ParseInt(_))));
+        let err = res.unwrap_err();
+        if let ParseClimateError::ParseInt(ref inner) = err {
+            assert_eq!(
+                err.to_string(),
+                format!("error parsing year: {}", inner.to_string())
+            );
+        } else {
+            unreachable!();
+        };
+    }
+    #[test]
+    fn test_parse_float() {
+        let res = "Manila,2001,bar".parse::<Climate>();
+        assert!(matches!(res, Err(ParseClimateError::ParseFloat(_))));
+        let err = res.unwrap_err();
+        if let ParseClimateError::ParseFloat(ref inner) = err {
+            assert_eq!(
+                err.to_string(),
+                format!("error parsing temperature: {}", inner.to_string())
+            );
+        } else {
+            unreachable!();
+        };
+    }
+    #[test]
+    fn test_parse_good() {
+        let res = "Munich,2015,23.1".parse::<Climate>();
+        assert_eq!(
+            res,
+            Ok(Climate {
+                city: "Munich".to_string(),
+                year: 2015,
+                temp: 23.1,
+            })
+        );
+    }
+    #[test]
+    #[ignore]
+    fn test_downcast() {
+        let res = "São Paulo,-21,28.5".parse::<Climate>();
+        assert!(matches!(res, Err(ParseClimateError::ParseInt(_))));
+        let err = res.unwrap_err();
+        let inner: Option<&(dyn Error + 'static)> = err.source();
+        assert!(inner.is_some());
+        assert!(inner.unwrap().is::<ParseIntError>());
+    }
+}
diff --git a/info.toml b/info.toml
index 8e24b7d..1b8c65d 100644
--- a/info.toml
+++ b/info.toml
@@ -994,3 +994,35 @@ it to the error type of the return type of the surrounding function.
 Hint: You will need to write another implementation of `From` that has a
 different input type.
 """
+
+[[exercises]]
+name = "advanced_errs2"
+path = "exercises/advanced_errors/advanced_errs2.rs"
+mode = "test"
+hint = """
+This exercise demonstrates a few traits that are useful for custom error
+types to implement. These traits make it easier for other code to consume
+the custom error type.
+
+Follow the steps in the comment near the top of the file. You will have to
+supply a missing trait implementation, and complete a few incomplete ones.
+
+You may find these pages to be helpful references:
+https://doc.rust-lang.org/stable/rust-by-example/error/multiple_error_types/define_error_type.html
+https://doc.rust-lang.org/stable/rust-by-example/error/multiple_error_types/boxing_errors.html
+https://doc.rust-lang.org/stable/rust-by-example/error/multiple_error_types/wrap_error.html
+
+Hint: What trait must our error type have for `main()` to return the return
+type that it returns?
+
+Another hint: It's not necessary to implement any methods inside the missing
+trait. (Some methods have default implementations that are supplied by the
+trait.)
+
+Another hint: Consult the tests to determine which error variants (and which
+error message text) to produce for certain error conditions.
+
+Challenge: There is one test that is marked `#[ignore]`. Can you supply the
+missing code that will make it pass? You may want to consult the standard
+library documentation for a certain trait for more hints.
+"""

From d57c1830280b2dbc1b9fe2ac3f48b51add591412 Mon Sep 17 00:00:00 2001
From: ana <ana@ana.st>
Date: Sat, 25 Sep 2021 11:23:05 +0200
Subject: [PATCH 081/115] release: 4.6.0

---
 CHANGELOG.md |  26 ++++++++++++
 Cargo.lock   |   2 +-
 Cargo.toml   |   2 +-
 README.md    |   4 +-
 src/main.rs  | 109 ++++++++++++++++++++++++++-------------------------
 5 files changed, 86 insertions(+), 57 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 67b8cdc..fcc39e4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,29 @@
+<a name="4.6.0"></a>
+## 4.6.0 (2021-09-25)
+
+
+#### Features
+
+*   add advanced_errs2 ([abd6b70c](https://github.com/rust-lang/rustlings/commit/abd6b70c72dc6426752ff41f09160b839e5c449e))
+*   add advanced_errs1 ([882d535b](https://github.com/rust-lang/rustlings/commit/882d535ba8628d5e0b37e8664b3e2f26260b2671))
+*   Add a farewell message when quitting `watch` ([1caef0b4](https://github.com/rust-lang/rustlings/commit/1caef0b43494c8b8cdd6c9260147e70d510f1aca))
+*   add more watch commands ([a7dc080b](https://github.com/rust-lang/rustlings/commit/a7dc080b95e49146fbaafe6922a6de2f8cb1582a), closes [#842](https://github.com/rust-lang/rustlings/issues/842))
+* **modules:**  update exercises, add modules3 (#822) ([dfd2fab4](https://github.com/rust-lang/rustlings/commit/dfd2fab4f33d1bf59e2e5ee03123c0c9a67a9481))
+* **quiz1:**  add default function name in comment (#838) ([0a11bad7](https://github.com/rust-lang/rustlings/commit/0a11bad71402b5403143d642f439f57931278c07))
+
+#### Bug Fixes
+
+*   Correct small typo in exercises/conversions/from_str.rs ([86cc8529](https://github.com/rust-lang/rustlings/commit/86cc85295ae36948963ae52882e285d7e3e29323))
+* **cli:**  typo in exercise.rs (#848) ([06d5c097](https://github.com/rust-lang/rustlings/commit/06d5c0973a3dffa3c6c6f70acb775d4c6630323c))
+* **from_str, try_from_into:**  custom error types ([2dc93cad](https://github.com/rust-lang/rustlings/commit/2dc93caddad43821743e4903d89b355df58d7a49))
+* **modules2:**  fix typo (#835) ([1c3beb0a](https://github.com/rust-lang/rustlings/commit/1c3beb0a59178c950dc05fe8ee2346b017429ae0))
+* **move_semantics5:**
+  *  change &mut *y to &mut x (#814) ([d75759e8](https://github.com/rust-lang/rustlings/commit/d75759e829fdcd64ef071cf4b6eae2a011a7718b))
+  *  Clarify instructions ([df25684c](https://github.com/rust-lang/rustlings/commit/df25684cb79f8413915e00b5efef29369849cef1))
+* **quiz1:**  Fix inconsistent wording (#826) ([03131a3d](https://github.com/rust-lang/rustlings/commit/03131a3d35d9842598150f9da817f7cc26e2669a))
+
+
+
 <a name="4.5.0"></a>
 ## 4.5.0 (2021-07-07)
 
diff --git a/Cargo.lock b/Cargo.lock
index 57b211b..e536d1b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -541,7 +541,7 @@ checksum = "f497285884f3fcff424ffc933e56d7cbca511def0c9831a7f9b5f6153e3cc89b"
 
 [[package]]
 name = "rustlings"
-version = "4.5.0"
+version = "4.6.0"
 dependencies = [
  "argh",
  "assert_cmd",
diff --git a/Cargo.toml b/Cargo.toml
index 615a09c..3b2a85a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "rustlings"
-version = "4.5.0"
+version = "4.6.0"
 authors = ["anastasie <ana@ana.st>", "Carol (Nichols || Goulding) <carol.nichols@gmail.com>"]
 edition = "2018"
 
diff --git a/README.md b/README.md
index ac1d84d..18e0b73 100644
--- a/README.md
+++ b/README.md
@@ -60,8 +60,8 @@ When you get a permission denied message then you have to exclude the directory
 Basically: Clone the repository at the latest tag, run `cargo install`.
 
 ```bash
-# find out the latest version at https://github.com/rust-lang/rustlings/releases/latest (on edit 4.5.0)
-git clone -b 4.5.0 --depth 1 https://github.com/rust-lang/rustlings
+# find out the latest version at https://github.com/rust-lang/rustlings/releases/latest (on edit 4.6.0)
+git clone -b 4.6.0 --depth 1 https://github.com/rust-lang/rustlings
 cd rustlings
 cargo install --force --path .
 ```
diff --git a/src/main.rs b/src/main.rs
index 30096df..32e7bba 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -11,7 +11,7 @@ use std::io::{self, prelude::*};
 use std::path::Path;
 use std::process::{Command, Stdio};
 use std::sync::atomic::{AtomicBool, Ordering};
-use std::sync::mpsc::{RecvTimeoutError, channel};
+use std::sync::mpsc::{channel, RecvTimeoutError};
 use std::sync::{Arc, Mutex};
 use std::thread;
 use std::time::Duration;
@@ -24,7 +24,7 @@ mod run;
 mod verify;
 
 // In sync with crate version
-const VERSION: &str = "4.5.0";
+const VERSION: &str = "4.6.0";
 
 #[derive(FromArgs, PartialEq, Debug)]
 /// Rustlings is a collection of small exercises to get you used to writing and reading Rust code
@@ -217,61 +217,64 @@ fn main() {
             verify(&exercises, verbose).unwrap_or_else(|_| std::process::exit(1));
         }
 
-        Subcommands::Watch(_subargs) => {
-            match watch(&exercises, verbose) {
-                Err(e) => {
-                    println!(
-                        "Error: Could not watch your progress. Error message was {:?}.",
-                        e
-                    );
-                    println!("Most likely you've run out of disk space or your 'inotify limit' has been reached.");
-                    std::process::exit(1);
-                }
-                Ok(WatchStatus::Finished) => {
-                    println!(
-                        "{emoji} All exercises completed! {emoji}",
-                        emoji = Emoji("🎉", "★")
-                    );
-                    println!();
-                    println!("+----------------------------------------------------+");
-                    println!("|          You made it to the Fe-nish line!          |");
-                    println!("+--------------------------  ------------------------+");
-                    println!("                          \\/                         ");
-                    println!("     ▒▒          ▒▒▒▒▒▒▒▒      ▒▒▒▒▒▒▒▒          ▒▒   ");
-                    println!("   ▒▒▒▒  ▒▒    ▒▒        ▒▒  ▒▒        ▒▒    ▒▒  ▒▒▒▒ ");
-                    println!("   ▒▒▒▒  ▒▒  ▒▒            ▒▒            ▒▒  ▒▒  ▒▒▒▒ ");
-                    println!(" ░░▒▒▒▒░░▒▒  ▒▒            ▒▒            ▒▒  ▒▒░░▒▒▒▒ ");
-                    println!("   ▓▓▓▓▓▓▓▓  ▓▓      ▓▓██  ▓▓  ▓▓██      ▓▓  ▓▓▓▓▓▓▓▓ ");
-                    println!("     ▒▒▒▒    ▒▒      ████  ▒▒  ████      ▒▒░░  ▒▒▒▒   ");
-                    println!("       ▒▒  ▒▒▒▒▒▒        ▒▒▒▒▒▒        ▒▒▒▒▒▒  ▒▒     ");
-                    println!("         ▒▒▒▒▒▒▒▒▒▒▓▓▓▓▓▓▒▒▒▒▒▒▒▒▓▓▒▒▓▓▒▒▒▒▒▒▒▒       ");
-                    println!("           ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒         ");
-                    println!("             ▒▒▒▒▒▒▒▒▒▒██▒▒▒▒▒▒██▒▒▒▒▒▒▒▒▒▒           ");
-                    println!("           ▒▒  ▒▒▒▒▒▒▒▒▒▒██████▒▒▒▒▒▒▒▒▒▒  ▒▒         ");
-                    println!("         ▒▒    ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒    ▒▒       ");
-                    println!("       ▒▒    ▒▒    ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒    ▒▒    ▒▒     ");
-                    println!("       ▒▒  ▒▒    ▒▒                  ▒▒    ▒▒  ▒▒     ");
-                    println!("           ▒▒  ▒▒                      ▒▒  ▒▒         ");
-                    println!();
-                    println!("We hope you enjoyed learning about the various aspects of Rust!");
-                    println!(
-                        "If you noticed any issues, please don't hesitate to report them to our repo."
-                    );
-                    println!("You can also contribute your own exercises to help the greater community!");
-                    println!();
-                    println!("Before reporting an issue or contributing, please read our guidelines:");
-                    println!("https://github.com/rust-lang/rustlings/blob/main/CONTRIBUTING.md");
-                }
-                Ok(WatchStatus::Unfinished) => {
-                    println!("We hope you're enjoying learning about Rust!");
-                    println!("If you want to continue working on the exercises at a later point, you can simply run `rustlings watch` again");
-                }
+        Subcommands::Watch(_subargs) => match watch(&exercises, verbose) {
+            Err(e) => {
+                println!(
+                    "Error: Could not watch your progress. Error message was {:?}.",
+                    e
+                );
+                println!("Most likely you've run out of disk space or your 'inotify limit' has been reached.");
+                std::process::exit(1);
             }
-        }
+            Ok(WatchStatus::Finished) => {
+                println!(
+                    "{emoji} All exercises completed! {emoji}",
+                    emoji = Emoji("🎉", "★")
+                );
+                println!();
+                println!("+----------------------------------------------------+");
+                println!("|          You made it to the Fe-nish line!          |");
+                println!("+--------------------------  ------------------------+");
+                println!("                          \\/                         ");
+                println!("     ▒▒          ▒▒▒▒▒▒▒▒      ▒▒▒▒▒▒▒▒          ▒▒   ");
+                println!("   ▒▒▒▒  ▒▒    ▒▒        ▒▒  ▒▒        ▒▒    ▒▒  ▒▒▒▒ ");
+                println!("   ▒▒▒▒  ▒▒  ▒▒            ▒▒            ▒▒  ▒▒  ▒▒▒▒ ");
+                println!(" ░░▒▒▒▒░░▒▒  ▒▒            ▒▒            ▒▒  ▒▒░░▒▒▒▒ ");
+                println!("   ▓▓▓▓▓▓▓▓  ▓▓      ▓▓██  ▓▓  ▓▓██      ▓▓  ▓▓▓▓▓▓▓▓ ");
+                println!("     ▒▒▒▒    ▒▒      ████  ▒▒  ████      ▒▒░░  ▒▒▒▒   ");
+                println!("       ▒▒  ▒▒▒▒▒▒        ▒▒▒▒▒▒        ▒▒▒▒▒▒  ▒▒     ");
+                println!("         ▒▒▒▒▒▒▒▒▒▒▓▓▓▓▓▓▒▒▒▒▒▒▒▒▓▓▒▒▓▓▒▒▒▒▒▒▒▒       ");
+                println!("           ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒         ");
+                println!("             ▒▒▒▒▒▒▒▒▒▒██▒▒▒▒▒▒██▒▒▒▒▒▒▒▒▒▒           ");
+                println!("           ▒▒  ▒▒▒▒▒▒▒▒▒▒██████▒▒▒▒▒▒▒▒▒▒  ▒▒         ");
+                println!("         ▒▒    ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒    ▒▒       ");
+                println!("       ▒▒    ▒▒    ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒    ▒▒    ▒▒     ");
+                println!("       ▒▒  ▒▒    ▒▒                  ▒▒    ▒▒  ▒▒     ");
+                println!("           ▒▒  ▒▒                      ▒▒  ▒▒         ");
+                println!();
+                println!("We hope you enjoyed learning about the various aspects of Rust!");
+                println!(
+                    "If you noticed any issues, please don't hesitate to report them to our repo."
+                );
+                println!(
+                    "You can also contribute your own exercises to help the greater community!"
+                );
+                println!();
+                println!("Before reporting an issue or contributing, please read our guidelines:");
+                println!("https://github.com/rust-lang/rustlings/blob/main/CONTRIBUTING.md");
+            }
+            Ok(WatchStatus::Unfinished) => {
+                println!("We hope you're enjoying learning about Rust!");
+                println!("If you want to continue working on the exercises at a later point, you can simply run `rustlings watch` again");
+            }
+        },
     }
 }
 
-fn spawn_watch_shell(failed_exercise_hint: &Arc<Mutex<Option<String>>>, should_quit: Arc<AtomicBool>) {
+fn spawn_watch_shell(
+    failed_exercise_hint: &Arc<Mutex<Option<String>>>,
+    should_quit: Arc<AtomicBool>,
+) {
     let failed_exercise_hint = Arc::clone(failed_exercise_hint);
     println!("Welcome to watch mode! You can type 'help' to get an overview of the commands you can use here.");
     thread::spawn(move || loop {

From bf33829da240375d086f96267fc2e02fa6b07001 Mon Sep 17 00:00:00 2001
From: Zhenghao Lu <54395432+EmisonLu@users.noreply.github.com>
Date: Mon, 27 Sep 2021 16:03:28 +0800
Subject: [PATCH 082/115] fix(structs3): remove redundant 'return' (#852)

---
 exercises/structs/structs3.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/exercises/structs/structs3.rs b/exercises/structs/structs3.rs
index a80d062..b3aa282 100644
--- a/exercises/structs/structs3.rs
+++ b/exercises/structs/structs3.rs
@@ -18,11 +18,11 @@ impl Package {
         if weight_in_grams <= 0 {
             // Something goes here...
         } else {
-            return Package {
+            Package {
                 sender_country,
                 recipient_country,
                 weight_in_grams,
-            };
+            }
         }
     }
 

From fed4fe78bbc0f4a9dbace1a556811a9f506237b6 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Mon, 27 Sep 2021 08:03:46 +0000
Subject: [PATCH 083/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 18e0b73..1c3709c 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-108-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-109-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -312,6 +312,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://github.com/Millione"><img src="https://avatars.githubusercontent.com/u/38575932?v=4?s=100" width="100px;" alt=""/><br /><sub><b>LIU JIE</b></sub></a><br /><a href="#content-Millione" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/abusch"><img src="https://avatars.githubusercontent.com/u/506344?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Antoine Büsch</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=abusch" title="Code">💻</a></td>
     <td align="center"><a href="https://frogtd.com/"><img src="https://avatars.githubusercontent.com/u/31412003?v=4?s=100" width="100px;" alt=""/><br /><sub><b>frogtd</b></sub></a><br /><a href="#content-frogtd" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/EmisonLu"><img src="https://avatars.githubusercontent.com/u/54395432?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Zhenghao Lu</b></sub></a><br /><a href="#content-EmisonLu" title="Content">🖋</a></td>
   </tr>
 </table>
 

From e3cfaa246dbef9ebea5ca020bdbaf018194b4974 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Mon, 27 Sep 2021 08:03:47 +0000
Subject: [PATCH 084/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index d18743c..21089c5 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -1002,6 +1002,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "EmisonLu",
+      "name": "Zhenghao Lu",
+      "avatar_url": "https://avatars.githubusercontent.com/u/54395432?v=4",
+      "profile": "https://github.com/EmisonLu",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 46c28d5cef3d8446b5a356b19d8dbc725f91a3a0 Mon Sep 17 00:00:00 2001
From: Fredrik Enestad <fredrik@enestad.com>
Date: Thu, 30 Sep 2021 10:18:36 +0200
Subject: [PATCH 085/115] fix(move_semantics5): correct typo (#857)

---
 exercises/move_semantics/move_semantics5.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/move_semantics/move_semantics5.rs b/exercises/move_semantics/move_semantics5.rs
index 1afe16c..c4704f9 100644
--- a/exercises/move_semantics/move_semantics5.rs
+++ b/exercises/move_semantics/move_semantics5.rs
@@ -1,5 +1,5 @@
 // move_semantics5.rs
-// Make me compile only be reordering the lines in `main()`, but without
+// Make me compile only by reordering the lines in `main()`, but without
 // adding, changing or removing any of them.
 // Execute `rustlings hint move_semantics5` for hints :)
 

From 574bbffe0b11b5426970e4710a2275776690e85e Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Thu, 30 Sep 2021 08:18:52 +0000
Subject: [PATCH 086/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 1c3709c..6e5ce3f 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-109-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-110-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -313,6 +313,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://github.com/abusch"><img src="https://avatars.githubusercontent.com/u/506344?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Antoine Büsch</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=abusch" title="Code">💻</a></td>
     <td align="center"><a href="https://frogtd.com/"><img src="https://avatars.githubusercontent.com/u/31412003?v=4?s=100" width="100px;" alt=""/><br /><sub><b>frogtd</b></sub></a><br /><a href="#content-frogtd" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/EmisonLu"><img src="https://avatars.githubusercontent.com/u/54395432?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Zhenghao Lu</b></sub></a><br /><a href="#content-EmisonLu" title="Content">🖋</a></td>
+    <td align="center"><a href="https://soundtrackyourbrand.com"><img src="https://avatars.githubusercontent.com/u/762956?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Fredrik Enestad</b></sub></a><br /><a href="#content-fredr" title="Content">🖋</a></td>
   </tr>
 </table>
 

From ae54c17b6a5ca63705192011d11d371bb51eee97 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Thu, 30 Sep 2021 08:18:53 +0000
Subject: [PATCH 087/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 21089c5..fe18385 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -1011,6 +1011,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "fredr",
+      "name": "Fredrik Enestad",
+      "avatar_url": "https://avatars.githubusercontent.com/u/762956?v=4",
+      "profile": "https://soundtrackyourbrand.com",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 1c0fe3cbcca85f90b3985985b8e265ee872a2ab2 Mon Sep 17 00:00:00 2001
From: rlch <rjmbowie@gmail.com>
Date: Sat, 2 Oct 2021 23:59:23 +1000
Subject: [PATCH 088/115] fix: few spelling mistakes

---
 info.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/info.toml b/info.toml
index 2140663..5eece6d 100644
--- a/info.toml
+++ b/info.toml
@@ -364,7 +364,7 @@ mode = "compile"
 hint = """
 The delicious_snacks module is trying to present an external interface that is 
 different than its internal structure (the `fruits` and `veggies` modules and
-associated constants). Complete the `use` statemants to fit the uses in main and
+associated constants). Complete the `use` statements to fit the uses in main and
 find the one keyword missing for both constants."""
 
 [[exercises]]

From 1663a16eade6ca646b6ed061735f7982434d530d Mon Sep 17 00:00:00 2001
From: xuesong <ylj7117789@163.com>
Date: Mon, 18 Oct 2021 19:57:12 +0800
Subject: [PATCH 089/115] fix(traits1): rename test functions to snake case
 (#854)

Co-authored-by: zhangshaozhi <zhangshaozhi@ZhangshaozhideMacBook-Pro.local>
---
 exercises/advanced_errors/advanced_errs2.rs | 1 -
 exercises/traits/traits1.rs                 | 4 ++--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/exercises/advanced_errors/advanced_errs2.rs b/exercises/advanced_errors/advanced_errs2.rs
index d9d44d0..54e669f 100644
--- a/exercises/advanced_errors/advanced_errs2.rs
+++ b/exercises/advanced_errors/advanced_errs2.rs
@@ -64,7 +64,6 @@ impl Display for ParseClimateError {
         match self {
             NoCity => write!(f, "no city name"),
             ParseFloat(e) => write!(f, "error parsing temperature: {}", e),
-            _ => write!(f, "unhandled error!"),
         }
     }
 }
diff --git a/exercises/traits/traits1.rs b/exercises/traits/traits1.rs
index 2ef9e11..15e08f2 100644
--- a/exercises/traits/traits1.rs
+++ b/exercises/traits/traits1.rs
@@ -29,12 +29,12 @@ mod tests {
     use super::*;
 
     #[test]
-    fn is_FooBar() {
+    fn is_foo_bar() {
         assert_eq!(String::from("Foo").append_bar(), String::from("FooBar"));
     }
 
     #[test]
-    fn is_BarBar() {
+    fn is_bar_bar() {
         assert_eq!(
             String::from("").append_bar().append_bar(),
             String::from("BarBar")

From b24b295d88d0f5598c5b0fe0ff926d29ab3c5828 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Mon, 18 Oct 2021 11:57:33 +0000
Subject: [PATCH 090/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 6e5ce3f..a3ef758 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-110-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-111-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -314,6 +314,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://frogtd.com/"><img src="https://avatars.githubusercontent.com/u/31412003?v=4?s=100" width="100px;" alt=""/><br /><sub><b>frogtd</b></sub></a><br /><a href="#content-frogtd" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/EmisonLu"><img src="https://avatars.githubusercontent.com/u/54395432?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Zhenghao Lu</b></sub></a><br /><a href="#content-EmisonLu" title="Content">🖋</a></td>
     <td align="center"><a href="https://soundtrackyourbrand.com"><img src="https://avatars.githubusercontent.com/u/762956?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Fredrik Enestad</b></sub></a><br /><a href="#content-fredr" title="Content">🖋</a></td>
+    <td align="center"><a href="http://xuesong.pydevops.com"><img src="https://avatars.githubusercontent.com/u/18476085?v=4?s=100" width="100px;" alt=""/><br /><sub><b>xuesong</b></sub></a><br /><a href="#content-xuesongbj" title="Content">🖋</a></td>
   </tr>
 </table>
 

From 71da9068e71ee395a30083dfc516e7dc110a2a8f Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Mon, 18 Oct 2021 11:57:34 +0000
Subject: [PATCH 091/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index fe18385..d7c7d46 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -1020,6 +1020,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "xuesongbj",
+      "name": "xuesong",
+      "avatar_url": "https://avatars.githubusercontent.com/u/18476085?v=4",
+      "profile": "http://xuesong.pydevops.com",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 359f81dd0bf5cc82016c56d374b38bf4de8f5893 Mon Sep 17 00:00:00 2001
From: ana <ana@ana.st>
Date: Fri, 29 Oct 2021 14:27:36 +0200
Subject: [PATCH 092/115] chore: upgrade edition to 2021

---
 Cargo.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Cargo.toml b/Cargo.toml
index 3b2a85a..3003269 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,7 +2,7 @@
 name = "rustlings"
 version = "4.6.0"
 authors = ["anastasie <ana@ana.st>", "Carol (Nichols || Goulding) <carol.nichols@gmail.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 argh = "0.1.4"

From d1ee2daf14f19105e6db3f9c610f44293d688532 Mon Sep 17 00:00:00 2001
From: Michael Walsh <48160144+MpdWalsh@users.noreply.github.com>
Date: Sat, 30 Oct 2021 16:55:58 -0600
Subject: [PATCH 093/115] fix(structs3.rs): assigned value to cents_per_gram in
 test

Intended to simplify the lesson by removing the need to figure out what the value is meant to be based on the tests.

Previous commits (https://github.com/rust-lang/rustlings/commit/9ca08b8f2b09366e97896a4a8cf9ff3bb4d54380 and https://github.com/rust-lang/rustlings/commit/114b54cbdb977234b39e5f180d937c14c78bb8b2#diff-ce1c232ff0ddaff909351bb84cb5bff423b5b9e04f21fd4db7ffe443e598e174) removed the mathematical complexity, and I feel this addition is a needed change to further streamline the exercise.
---
 exercises/structs/structs3.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/structs/structs3.rs b/exercises/structs/structs3.rs
index b3aa282..1a81531 100644
--- a/exercises/structs/structs3.rs
+++ b/exercises/structs/structs3.rs
@@ -73,7 +73,7 @@ mod tests {
         let sender_country = String::from("Spain");
         let recipient_country = String::from("Spain");
 
-        let cents_per_gram = ???;
+        let cents_per_gram = 3;
 
         let package = Package::new(sender_country, recipient_country, 1500);
 

From e08b6cf3ef157dd7dc65b920b36723a4c480179c Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Sun, 31 Oct 2021 16:25:35 +0000
Subject: [PATCH 094/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index a3ef758..c0ba6ce 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-111-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-112-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -315,6 +315,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://github.com/EmisonLu"><img src="https://avatars.githubusercontent.com/u/54395432?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Zhenghao Lu</b></sub></a><br /><a href="#content-EmisonLu" title="Content">🖋</a></td>
     <td align="center"><a href="https://soundtrackyourbrand.com"><img src="https://avatars.githubusercontent.com/u/762956?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Fredrik Enestad</b></sub></a><br /><a href="#content-fredr" title="Content">🖋</a></td>
     <td align="center"><a href="http://xuesong.pydevops.com"><img src="https://avatars.githubusercontent.com/u/18476085?v=4?s=100" width="100px;" alt=""/><br /><sub><b>xuesong</b></sub></a><br /><a href="#content-xuesongbj" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/MpdWalsh"><img src="https://avatars.githubusercontent.com/u/48160144?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Michael Walsh</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=MpdWalsh" title="Code">💻</a></td>
   </tr>
 </table>
 

From cb661896a21aa00d46b894cdc4a7632f7569479c Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Sun, 31 Oct 2021 16:25:36 +0000
Subject: [PATCH 095/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index d7c7d46..cda0377 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -1029,6 +1029,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "MpdWalsh",
+      "name": "Michael Walsh",
+      "avatar_url": "https://avatars.githubusercontent.com/u/48160144?v=4",
+      "profile": "https://github.com/MpdWalsh",
+      "contributions": [
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 8ef4869b264094e5a9b50452b4534823a9df19c3 Mon Sep 17 00:00:00 2001
From: alirezaghey <alireza.q1357@gmail.com>
Date: Wed, 15 Dec 2021 10:44:21 +0100
Subject: [PATCH 096/115] fix(functions5): Remove wrong new line and small
 English improvements (#885)

---
 info.toml | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/info.toml b/info.toml
index 5eece6d..95850c6 100644
--- a/info.toml
+++ b/info.toml
@@ -114,8 +114,7 @@ path = "exercises/functions/functions5.rs"
 mode = "compile"
 hint = """
 This is a really common error that can be fixed by removing one character.
-It happens because Rust distinguishes between expressions and statements: expressions return
-a value based on its operand, and statements simply return a () type which behaves just like `void` in C/C++ language.
+It happens because Rust distinguishes between expressions and statements: expressions return a value based on their operand(s), and statements simply return a () type which behaves just like `void` in C/C++ language.
 We want to return a value of `i32` type from the `square` function, but it is returning a `()` type...
 They are not the same. There are two solutions:
 1. Add a `return` ahead of `num * num;`

From 72b2c9f54f5f4d246616af767a1a842223702a13 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Wed, 15 Dec 2021 09:44:38 +0000
Subject: [PATCH 097/115] docs: update README.md [skip ci]

---
 README.md | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index c0ba6ce..7595a9e 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-112-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-113-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -317,6 +317,9 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="http://xuesong.pydevops.com"><img src="https://avatars.githubusercontent.com/u/18476085?v=4?s=100" width="100px;" alt=""/><br /><sub><b>xuesong</b></sub></a><br /><a href="#content-xuesongbj" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/MpdWalsh"><img src="https://avatars.githubusercontent.com/u/48160144?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Michael Walsh</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=MpdWalsh" title="Code">💻</a></td>
   </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/alirezaghey"><img src="https://avatars.githubusercontent.com/u/26653424?v=4?s=100" width="100px;" alt=""/><br /><sub><b>alirezaghey</b></sub></a><br /><a href="#content-alirezaghey" title="Content">🖋</a></td>
+  </tr>
 </table>
 
 <!-- markdownlint-restore -->

From 527a5b1182483aa467556c1a36d9322440befa43 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Wed, 15 Dec 2021 09:44:39 +0000
Subject: [PATCH 098/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index cda0377..6bf3853 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -1038,6 +1038,15 @@
       "contributions": [
         "code"
       ]
+    },
+    {
+      "login": "alirezaghey",
+      "name": "alirezaghey",
+      "avatar_url": "https://avatars.githubusercontent.com/u/26653424?v=4",
+      "profile": "https://github.com/alirezaghey",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From f2650de369810867d2763e935ac0963c32ec420e Mon Sep 17 00:00:00 2001
From: Franklin van Nes <franklin.vannes@gmail.com>
Date: Wed, 15 Dec 2021 11:46:27 -0500
Subject: [PATCH 099/115] fix(clippy1): Updated code to test correctness clippy
 lint with approx_constant lint rule

closes #888
---
 exercises/clippy/clippy1.rs | 16 +++++++++++-----
 info.toml                   | 16 ++++++++--------
 2 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/exercises/clippy/clippy1.rs b/exercises/clippy/clippy1.rs
index bdb5dd2..c5f84a9 100644
--- a/exercises/clippy/clippy1.rs
+++ b/exercises/clippy/clippy1.rs
@@ -8,10 +8,16 @@
 
 // I AM NOT DONE
 
+use std::f32;
+
 fn main() {
-    let x = 1.2331f64;
-    let y = 1.2332f64;
-    if y != x {
-        println!("Success!");
-    }
+    let pi = 3.14f32;
+    let radius = 5.00f32;
+
+    let area = pi * f32::powi(radius, 2);
+
+    println!(
+        "The area of a circle with radius {:.2} is {:.5}!",
+        radius, area
+    )
 }
diff --git a/info.toml b/info.toml
index 95850c6..0c03def 100644
--- a/info.toml
+++ b/info.toml
@@ -906,15 +906,15 @@ name = "clippy1"
 path = "exercises/clippy/clippy1.rs"
 mode = "clippy"
 hint = """
-Not every floating point value can be represented exactly in binary values in
-memory. Take a look at the description of 
-https://doc.rust-lang.org/stable/std/primitive.f32.html
-When using the binary compare operators with floating points you won't compare
-the floating point values but the binary representation in memory. This is 
-usually not what you would like to do. 
+Rust stores the highest precision version of any long or inifinite precision
+mathematical constants in the rust standard library.
+https://doc.rust-lang.org/stable/std/f32/consts/index.html
+
+We may be tempted to use our own approximations for certain mathematical constants,
+but clippy recognizes those imprecise mathematical constants as a source of 
+potential error.
 See the suggestions of the clippy warning in compile output and use the
-machine epsilon value...
-https://doc.rust-lang.org/stable/std/primitive.f32.html#associatedconstant.EPSILON"""
+appropriate replacement constant from std::f32::consts..."""
 
 [[exercises]]
 name = "clippy2"

From 8d675198d81eedb02ef3124321670000f0f6fd6c Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Thu, 16 Dec 2021 13:11:14 +0000
Subject: [PATCH 100/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 7595a9e..469e1ef 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-113-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-114-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -319,6 +319,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
   </tr>
   <tr>
     <td align="center"><a href="https://github.com/alirezaghey"><img src="https://avatars.githubusercontent.com/u/26653424?v=4?s=100" width="100px;" alt=""/><br /><sub><b>alirezaghey</b></sub></a><br /><a href="#content-alirezaghey" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/frvannes16"><img src="https://avatars.githubusercontent.com/u/3188475?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Franklin van Nes</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=frvannes16" title="Code">💻</a></td>
   </tr>
 </table>
 

From 81fb3967805a939f1149f0451afd94d566ab4d2a Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Thu, 16 Dec 2021 13:11:15 +0000
Subject: [PATCH 101/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 6bf3853..f04a0ce 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -1047,6 +1047,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "frvannes16",
+      "name": "Franklin van Nes",
+      "avatar_url": "https://avatars.githubusercontent.com/u/3188475?v=4",
+      "profile": "https://github.com/frvannes16",
+      "contributions": [
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 9b27e8d993ca20232fe38a412750c3f845a83b65 Mon Sep 17 00:00:00 2001
From: Galih wisnuaji <code.yuune@gmail.com>
Date: Fri, 24 Dec 2021 13:48:43 +0700
Subject: [PATCH 102/115] chore : replace filter_map() with find_map()

---
 src/exercise.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/exercise.rs b/src/exercise.rs
index ec694df..e4a4145 100644
--- a/src/exercise.rs
+++ b/src/exercise.rs
@@ -217,8 +217,7 @@ path = "{}.rs""#,
         let matched_line_index = source
             .lines()
             .enumerate()
-            .filter_map(|(i, line)| if re.is_match(line) { Some(i) } else { None })
-            .next()
+            .find_map(|(i, line)| if re.is_match(line) { Some(i) } else { None })
             .expect("This should not happen at all");
 
         let min_line = ((matched_line_index as i32) - (CONTEXT as i32)).max(0) as usize;

From f61f9f379638c0142f759ece850c768807a8abfd Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Fri, 24 Dec 2021 12:28:07 +0000
Subject: [PATCH 103/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 469e1ef..1a878ef 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-114-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-115-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -320,6 +320,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
   <tr>
     <td align="center"><a href="https://github.com/alirezaghey"><img src="https://avatars.githubusercontent.com/u/26653424?v=4?s=100" width="100px;" alt=""/><br /><sub><b>alirezaghey</b></sub></a><br /><a href="#content-alirezaghey" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/frvannes16"><img src="https://avatars.githubusercontent.com/u/3188475?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Franklin van Nes</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=frvannes16" title="Code">💻</a></td>
+    <td align="center"><a href="https://nekonako.github.io"><img src="https://avatars.githubusercontent.com/u/46141275?v=4?s=100" width="100px;" alt=""/><br /><sub><b>nekonako</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nekonako" title="Code">💻</a></td>
   </tr>
 </table>
 

From 7dce8c8b612a68ccfc1165358e075c4837b0bf92 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Fri, 24 Dec 2021 12:28:08 +0000
Subject: [PATCH 104/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index f04a0ce..6c3319c 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -1056,6 +1056,15 @@
       "contributions": [
         "code"
       ]
+    },
+    {
+      "login": "nekonako",
+      "name": "nekonako",
+      "avatar_url": "https://avatars.githubusercontent.com/u/46141275?v=4",
+      "profile": "https://nekonako.github.io",
+      "contributions": [
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 1622e8c198d89739765c915203efff0091bdeb78 Mon Sep 17 00:00:00 2001
From: ZX <67887489+tan-zx@users.noreply.github.com>
Date: Wed, 29 Dec 2021 14:55:37 +0800
Subject: [PATCH 105/115] fix(quiz1): update to say quiz covers "If"

---
 exercises/quiz1.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/exercises/quiz1.rs b/exercises/quiz1.rs
index b13b928..7bd3f58 100644
--- a/exercises/quiz1.rs
+++ b/exercises/quiz1.rs
@@ -2,6 +2,7 @@
 // This is a quiz for the following sections:
 // - Variables
 // - Functions
+// - If
 
 // Mary is buying apples. One apple usually costs 2 Rustbucks, but if you buy
 // more than 40 at once, each apple only costs 1! Write a function that calculates

From af84359bdb49282dbd26a72cb67d25a3823290db Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Thu, 30 Dec 2021 11:59:05 +0000
Subject: [PATCH 106/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 1a878ef..6fe96b5 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-115-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-116-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -321,6 +321,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://github.com/alirezaghey"><img src="https://avatars.githubusercontent.com/u/26653424?v=4?s=100" width="100px;" alt=""/><br /><sub><b>alirezaghey</b></sub></a><br /><a href="#content-alirezaghey" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/frvannes16"><img src="https://avatars.githubusercontent.com/u/3188475?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Franklin van Nes</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=frvannes16" title="Code">💻</a></td>
     <td align="center"><a href="https://nekonako.github.io"><img src="https://avatars.githubusercontent.com/u/46141275?v=4?s=100" width="100px;" alt=""/><br /><sub><b>nekonako</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nekonako" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/tan-zx"><img src="https://avatars.githubusercontent.com/u/67887489?v=4?s=100" width="100px;" alt=""/><br /><sub><b>ZX</b></sub></a><br /><a href="#content-tan-zx" title="Content">🖋</a></td>
   </tr>
 </table>
 

From 17e3e75331ea508efddd9a7d507bf76a16fd9a24 Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Thu, 30 Dec 2021 11:59:06 +0000
Subject: [PATCH 107/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 6c3319c..91b2a48 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -1065,6 +1065,15 @@
       "contributions": [
         "code"
       ]
+    },
+    {
+      "login": "tan-zx",
+      "name": "ZX",
+      "avatar_url": "https://avatars.githubusercontent.com/u/67887489?v=4",
+      "profile": "https://github.com/tan-zx",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From 71a06044e6a96ff756dc31d7b0ed665ae4badb57 Mon Sep 17 00:00:00 2001
From: radicale <radicale@users.noreply.github.com>
Date: Fri, 4 Feb 2022 14:39:09 +0100
Subject: [PATCH 108/115] fix(clippy1): Set clippy::float_cmp lint to deny
 (#907)

---
 src/exercise.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/exercise.rs b/src/exercise.rs
index e4a4145..6e49a9a 100644
--- a/src/exercise.rs
+++ b/src/exercise.rs
@@ -154,7 +154,7 @@ path = "{}.rs""#,
                 Command::new("cargo")
                     .args(&["clippy", "--manifest-path", CLIPPY_CARGO_TOML_PATH])
                     .args(RUSTC_COLOR_ARGS)
-                    .args(&["--", "-D", "warnings"])
+                    .args(&["--", "-D", "warnings","-D","clippy::float_cmp"])
                     .output()
             }
         }

From cbcde345409c3e550112e449242848eaa3391bb6 Mon Sep 17 00:00:00 2001
From: zydxhs <johnsmithcry@gmail.com>
Date: Fri, 4 Feb 2022 22:00:24 +0800
Subject: [PATCH 109/115] fix(errors1): Add a comment to make the purpose more
 clear (#486)

Signed-off-by: zydxhs <johnsmithcry@163.com>
---
 exercises/error_handling/errors1.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/exercises/error_handling/errors1.rs b/exercises/error_handling/errors1.rs
index 9c24d85..5844a49 100644
--- a/exercises/error_handling/errors1.rs
+++ b/exercises/error_handling/errors1.rs
@@ -36,6 +36,7 @@ mod tests {
     fn explains_why_generating_nametag_text_fails() {
         assert_eq!(
             generate_nametag_text("".into()),
+            // Don't change this line
             Err("`name` was empty; it must be nonempty.".into())
         );
     }

From 4f7ff5d9c7b2d8b045194c1a9469d37e30257c4a Mon Sep 17 00:00:00 2001
From: Yang Wen <kevin.wenyang@gmail.com>
Date: Fri, 4 Feb 2022 22:12:02 +0800
Subject: [PATCH 110/115] fix(structs3): Add a hint for panic (#608)

as a totally newbie to Rust, I don't know panic statement from https://doc.rust-lang.org/book/ and rustlings in the beginning. After a hard searching of [should_panic], then I figure out panic statement.

So it's helpful to tell the learner that write a panic statement here.
---
 exercises/structs/structs3.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/structs/structs3.rs b/exercises/structs/structs3.rs
index 1a81531..e84f2eb 100644
--- a/exercises/structs/structs3.rs
+++ b/exercises/structs/structs3.rs
@@ -16,7 +16,7 @@ struct Package {
 impl Package {
     fn new(sender_country: String, recipient_country: String, weight_in_grams: i32) -> Package {
         if weight_in_grams <= 0 {
-            // Something goes here...
+            // panic statement goes here...
         } else {
             Package {
                 sender_country,

From 52c7f8a85901b6714c732d2107823750de0d452f Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Fri, 4 Feb 2022 14:13:31 +0000
Subject: [PATCH 111/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 6fe96b5..b4f6a7e 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-116-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-117-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -322,6 +322,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://github.com/frvannes16"><img src="https://avatars.githubusercontent.com/u/3188475?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Franklin van Nes</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=frvannes16" title="Code">💻</a></td>
     <td align="center"><a href="https://nekonako.github.io"><img src="https://avatars.githubusercontent.com/u/46141275?v=4?s=100" width="100px;" alt=""/><br /><sub><b>nekonako</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nekonako" title="Code">💻</a></td>
     <td align="center"><a href="https://github.com/tan-zx"><img src="https://avatars.githubusercontent.com/u/67887489?v=4?s=100" width="100px;" alt=""/><br /><sub><b>ZX</b></sub></a><br /><a href="#content-tan-zx" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/sundevilyang"><img src="https://avatars.githubusercontent.com/u/1499214?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Yang Wen</b></sub></a><br /><a href="#content-sundevilyang" title="Content">🖋</a></td>
   </tr>
 </table>
 

From a2e74a2a4bebdd48e9c4336c08c02222e36e2e6d Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Fri, 4 Feb 2022 14:13:32 +0000
Subject: [PATCH 112/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 91b2a48..3f24644 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -1074,6 +1074,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "sundevilyang",
+      "name": "Yang Wen",
+      "avatar_url": "https://avatars.githubusercontent.com/u/1499214?v=4",
+      "profile": "https://github.com/sundevilyang",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

From bc5686174463ad6f4f6b824b0e9b97c3039d4886 Mon Sep 17 00:00:00 2001
From: Brandon High <highb@users.noreply.github.com>
Date: Fri, 4 Feb 2022 06:38:55 -0800
Subject: [PATCH 113/115] doc: Add hints on how to get gcc installed (#741)

---
 README.md  |  1 +
 install.sh | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/README.md b/README.md
index b4f6a7e..835200e 100644
--- a/README.md
+++ b/README.md
@@ -16,6 +16,7 @@ Alternatively, for a first-time Rust learner, there are several other resources:
 ## Getting Started
 
 _Note: If you're on MacOS, make sure you've installed Xcode and its developer tools by typing `xcode-select --install`._
+_Note: If you're on Linux, make sure you've installed gcc. Deb: `sudo apt install gcc`. Yum: `sudo yum -y install gcc`._
 
 You will need to have Rust installed. You can get it by visiting https://rustup.rs. This'll also install Cargo, Rust's package/project manager.
 
diff --git a/install.sh b/install.sh
index e986e74..68b8da3 100755
--- a/install.sh
+++ b/install.sh
@@ -12,6 +12,18 @@ else
     exit 1
 fi
 
+if [ -x "$(command -v cc)" ]
+then
+    echo "SUCCESS: cc is installed"
+else
+    echo "ERROR: cc does not seem to be installed."
+    echo "Please download (g)cc using your package manager."
+    echo "OSX: xcode-select --install"
+    echo "Deb: sudo apt install gcc"
+    echo "Yum: sudo yum -y install gcc"
+    exit 1
+fi
+
 if [ -x "$(command -v rustc)" ]
 then
     echo "SUCCESS: Rust is installed"

From e96112ab998f6b121b2ea7ddf27d9e99e37dba0f Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Fri, 4 Feb 2022 14:39:42 +0000
Subject: [PATCH 114/115] docs: update README.md [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 835200e..c9bb8b8 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-117-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-118-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # rustlings 🦀❤️
@@ -324,6 +324,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
     <td align="center"><a href="https://nekonako.github.io"><img src="https://avatars.githubusercontent.com/u/46141275?v=4?s=100" width="100px;" alt=""/><br /><sub><b>nekonako</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nekonako" title="Code">💻</a></td>
     <td align="center"><a href="https://github.com/tan-zx"><img src="https://avatars.githubusercontent.com/u/67887489?v=4?s=100" width="100px;" alt=""/><br /><sub><b>ZX</b></sub></a><br /><a href="#content-tan-zx" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/sundevilyang"><img src="https://avatars.githubusercontent.com/u/1499214?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Yang Wen</b></sub></a><br /><a href="#content-sundevilyang" title="Content">🖋</a></td>
+    <td align="center"><a href="https://brandon-high.com"><img src="https://avatars.githubusercontent.com/u/759848?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Brandon High</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=highb" title="Documentation">📖</a></td>
   </tr>
 </table>
 

From dc36ca6d84e66e1304f662770d560b3fcde7c35d Mon Sep 17 00:00:00 2001
From: "allcontributors[bot]"
 <46447321+allcontributors[bot]@users.noreply.github.com>
Date: Fri, 4 Feb 2022 14:39:43 +0000
Subject: [PATCH 115/115] docs: update .all-contributorsrc [skip ci]

---
 .all-contributorsrc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.all-contributorsrc b/.all-contributorsrc
index 3f24644..8207a03 100644
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -1083,6 +1083,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "highb",
+      "name": "Brandon High",
+      "avatar_url": "https://avatars.githubusercontent.com/u/759848?v=4",
+      "profile": "https://brandon-high.com",
+      "contributions": [
+        "doc"
+      ]
     }
   ],
   "contributorsPerLine": 8,