Merge branch 'main' of https://github.com/rust-lang/rustlings into upstream-changes

2026-01-09 12:19:18 +00:00 · 2021-09-17 12:17:03 -06:00 · 2021-09-17 12:17:03 -06:00 · 59a7f0c23c
commit 59a7f0c23c
parent 81ead79f01 74af578beb
26 changed files with 605 additions and 139 deletions
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@ -847,6 +847,125 @@
      "contributions": [
        "content"
      ]
+    },
+    {
+      "login": "PiDelport",
+      "name": "Pi Delport",
+      "avatar_url": "https://avatars.githubusercontent.com/u/630271?v=4",
+      "profile": "https://about.me/pjdelport",
+      "contributions": [
+        "content"
+      ]
+    },
+    {
+      "login": "sateeshkumarb",
+      "name": "Sateesh ",
+      "avatar_url": "https://avatars.githubusercontent.com/u/429263?v=4",
+      "profile": "https://github.com/sateeshkumarb",
+      "contributions": [
+        "code",
+        "content"
+      ]
+    },
+    {
+      "login": "kayuapi",
+      "name": "ZC",
+      "avatar_url": "https://avatars.githubusercontent.com/u/10304328?v=4",
+      "profile": "https://github.com/kayuapi",
+      "contributions": [
+        "content"
+      ]
+    },
+    {
+      "login": "hyperparabolic",
+      "name": "hyperparabolic",
+      "avatar_url": "https://avatars.githubusercontent.com/u/12348474?v=4",
+      "profile": "https://github.com/hyperparabolic",
+      "contributions": [
+        "code"
+      ]
+    },
+    {
+      "login": "kolbma",
+      "name": "arlecchino",
+      "avatar_url": "https://avatars.githubusercontent.com/u/5228369?v=4",
+      "profile": "https://www.net4visions.at",
+      "contributions": [
+        "doc"
+      ]
+    },
+    {
+      "login": "jazzplato",
+      "name": "Richthofen",
+      "avatar_url": "https://avatars.githubusercontent.com/u/7576730?v=4",
+      "profile": "https://richthofen.io/",
+      "contributions": [
+        "code"
+      ]
+    },
+    {
+      "login": "cseltol",
+      "name": "Ivan Nerazumov",
+      "avatar_url": "https://avatars.githubusercontent.com/u/64264529?v=4",
+      "profile": "https://github.com/cseltol",
+      "contributions": [
+        "doc"
+      ]
+    },
+    {
+      "login": "lauralindzey",
+      "name": "lauralindzey",
+      "avatar_url": "https://avatars.githubusercontent.com/u/65185744?v=4",
+      "profile": "https://github.com/lauralindzey",
+      "contributions": [
+        "doc"
+      ]
+    },
+    {
+      "login": "sinharaksh1t",
+      "name": "Rakshit Sinha",
+      "avatar_url": "https://avatars.githubusercontent.com/u/28585848?v=4",
+      "profile": "https://github.com/sinharaksh1t",
+      "contributions": [
+        "content"
+      ]
+    },
+    {
+      "login": "dbednar230",
+      "name": "Damian",
+      "avatar_url": "https://avatars.githubusercontent.com/u/54457902?v=4",
+      "profile": "https://github.com/dbednar230",
+      "contributions": [
+        "content"
+      ]
+    },
+    {
+      "login": "benarmstead",
+      "name": "Ben Armstead",
+      "avatar_url": "https://avatars.githubusercontent.com/u/70973680?v=4",
+      "profile": "https://benarmstead.co.uk",
+      "contributions": [
+        "code"
+      ]
+    },
+    {
+      "login": "anuk909",
+      "name": "anuk909",
+      "avatar_url": "https://avatars.githubusercontent.com/u/34924662?v=4",
+      "profile": "https://github.com/anuk909",
+      "contributions": [
+        "content",
+        "code"
+      ]
+    },
+    {
+      "login": "granddaifuku",
+      "name": "granddaifuku",
+      "avatar_url": "https://avatars.githubusercontent.com/u/49578068?v=4",
+      "profile": "https://granddaifuku.com/",
+      "contributions": [
+        "content"
+      ]
    }
  ],
  "contributorsPerLine": 8,
--- a/.gitignore
+++ b/.gitignore
@ -7,3 +7,4 @@ exercises/clippy/Cargo.toml
 exercises/clippy/Cargo.lock
 .idea
 .vscode
+*.iml
--- 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)

--- 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",
@ -533,13 +535,13 @@ 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"
-version = "4.4.0"
+version = "4.5.0"
 dependencies = [
 "argh",
 "assert_cmd",
@ -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"
--- 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]
--- 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-104-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->

 # rustlings 🦀❤️
@ -36,7 +36,7 @@ This will install Rustlings and give you access to the `rustlings` command. Run
 In PowerShell (Run as Administrator), set `ExecutionPolicy` to `RemoteSigned`:

 ```ps
-Set-ExecutionPolicy RemoteSigned
+Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser
 ```

 Then, you can run:
@ -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 4.5.0)
+git clone -b 4.5.0 --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 .
 ```

@ -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
@ -279,6 +291,21 @@ 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>
+    <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>
+  <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>
+    <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>
+    <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>

--- a/exercises/README.md
+++ b/exercises/README.md
@ -9,8 +9,8 @@
 | primitive_types        | §4.3          |
 | structs                | §5.1          |
 | enums                  | §6            |
-| modules                | §7.2          |
-| collections            | §8.1          |
+| modules                | §7            |
+| collections            | §8.1, §8.3    |
 | strings                | §8.2          |
 | error_handling         | §9            |
 | generics               | §10           |
--- 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)
--- a/exercises/conversions/from_str.rs
+++ b/exercises/conversions/from_str.rs
@ -28,7 +28,7 @@ impl error::Error for NameAndAgeNeeded {}
 // 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 {
--- a/exercises/error_handling/errors4.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 :)

 fn main() {}

--- a/exercises/error_handling/errors5.rs
+++ 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 {}
--- a/exercises/error_handling/errors6.rs
+++ b/exercises/error_handling/errors6.rs
@ -0,0 +1,95 @@
+// 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
+
+use std::num::ParseIntError;
+
+// This is a custom error type that we will be using in `parse_pos_nonzero()`.
+#[derive(PartialEq, Debug)]
+enum ParsePosNonzeroError {
+    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)
+    -> 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)
+        .map_err(ParsePosNonzeroError::from_creation)
+}
+
+// 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() {
+        // We can't construct a ParseIntError, so we have to pattern match.
+        assert!(matches!(
+            parse_pos_nonzero("not a number"),
+            Err(ParsePosNonzeroError::ParseInt(_))
+        ));
+    }
+
+    #[test]
+    fn test_negative() {
+        assert_eq!(
+            parse_pos_nonzero("-555"),
+            Err(ParsePosNonzeroError::Creation(CreationError::Negative))
+        );
+    }
+
+    #[test]
+    fn test_zero() {
+        assert_eq!(
+            parse_pos_nonzero("0"),
+            Err(ParsePosNonzeroError::Creation(CreationError::Zero))
+        );
+    }
+
+    #[test]
+    fn test_positive() {
+        let x = PositiveNonzeroInteger::new(42);
+        assert!(x.is_ok());
+        assert_eq!(parse_pos_nonzero("42"), Ok(x.unwrap()));
+    }
+}
--- a/exercises/generics/generics1.rs
+++ b/exercises/generics/generics1.rs
@ -1,6 +1,10 @@
 // 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() {
    let mut shopping_list: Vec<&str> = Vec::new();
    shopping_list.push("milk");
--- 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)
--- a/exercises/modules/modules1.rs
+++ b/exercises/modules/modules1.rs
@ -3,7 +3,13 @@


 mod sausage_factory {
-    pub fn make_sausage() {
+    // 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!");
    }
 }
--- a/exercises/modules/modules2.rs
+++ b/exercises/modules/modules2.rs
@ -1,4 +1,6 @@
 // modules2.rs
+// You can bring module paths into scopes and provide new names for them with the
+// 'use' and 'as' keywords. Fix these 'use' statements to make the code compile.
 // Make me compile! Execute `rustlings hint modules2` for hints :)


--- a/exercises/modules/modules3.rs
+++ 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!"),
+    }
+}
--- a/exercises/move_semantics/move_semantics5.rs
+++ b/exercises/move_semantics/move_semantics5.rs
@ -0,0 +1,15 @@
+// move_semantics5.rs
+// 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
+
+fn main() {
+    let mut x = 100;
+    let y = &mut x;
+    let z = &mut *y;
+    *y += 100;
+    *z += 1000;
+    assert_eq!(x, 1200);
+}
--- a/exercises/option/option3.rs
+++ 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.
+}
--- 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!


 // Put your function here!
@ -22,8 +22,10 @@ fn calculate_apple_price(num: i32) -> i32 {
 #[test]
 fn verify_test() {
    let price1 = calculate_apple_price(35);
-    let price2 = calculate_apple_price(65);
+    let price2 = calculate_apple_price(40);
+    let price3 = calculate_apple_price(65);

    assert_eq!(70, price1);
-    assert_eq!(65, price2);
+    assert_eq!(80, price2);
+    assert_eq!(65, price3);
 }
--- 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.

@ -16,7 +14,7 @@ fn main() {}

 use std::collections::HashMap;

-#[derive(PartialEq, Eq)]
+#[derive(Clone, Copy, PartialEq, Eq)]
 enum Progress {
    None,
    Some,
--- a/exercises/variables/variables5.rs
+++ b/exercises/variables/variables5.rs
@ -3,7 +3,7 @@


 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);
    let number = 3;
    println!("Number plus two is : {}", number + 2);
--- a/info.toml
+++ b/info.toml
@ -210,6 +210,18 @@ 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 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.
+"""
+
 # PRIMITIVE TYPES

 [[exercises]]
@ -350,11 +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

@ -475,42 +495,61 @@ hint = """
 If other functions can return a `Result`, why shouldn't `main`?"""

 [[exercises]]
-name = "errorsn"
-path = "exercises/error_handling/errorsn.rs"
+name = "errors4"
+path = "exercises/error_handling/errors4.rs"
 mode = "test"
 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.
+`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 = "errors5"
+path = "exercises/error_handling/errors5.rs"
+mode = "compile"
+hint = """
+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
+errors4.
+
+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!
+
+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

@ -546,7 +585,7 @@ 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"
@ -579,13 +618,14 @@ Also see Option::flatten
 """

 [[exercises]]
-name = "result1"
-path = "exercises/error_handling/result1.rs"
-mode = "test"
+name = "option3"
+path = "exercises/option/option3.rs"
+mode = "compile"
 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 :)"""
+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"""

 # TRAITS

@ -737,7 +777,10 @@ 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 for how 
+the `FromIterator` trait is used in `collect()`."""

 [[exercises]]
 name = "iterators4"
@ -763,7 +806,10 @@ 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

@ -861,7 +907,15 @@ 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"
@ -893,7 +947,19 @@ 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 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`
+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 +975,7 @@ 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."""
--- 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 {
--- 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
@ -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) => {
@ -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<()> {
--- 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)
            }