From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 17 Apr 2024 14:02:58 +0200
Subject: Adding upstream version 1.64.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 .../listing-04-01/Cargo.lock                       |  4 +++
 .../listing-04-01/Cargo.toml                       |  6 ++++
 .../listing-04-01/rustfmt-ignore                   |  3 ++
 .../listing-04-01/src/main.rs                      |  9 ++++++
 .../listing-04-02/Cargo.lock                       |  6 ++++
 .../listing-04-02/Cargo.toml                       |  6 ++++
 .../listing-04-02/src/main.rs                      |  6 ++++
 .../listing-04-03/Cargo.lock                       |  4 +++
 .../listing-04-03/Cargo.toml                       |  6 ++++
 .../listing-04-03/rustfmt-ignore                   |  3 ++
 .../listing-04-03/src/main.rs                      | 23 ++++++++++++++
 .../listing-04-04/Cargo.lock                       |  4 +++
 .../listing-04-04/Cargo.toml                       |  6 ++++
 .../listing-04-04/rustfmt-ignore                   |  3 ++
 .../listing-04-04/src/main.rs                      | 29 +++++++++++++++++
 .../listing-04-05/Cargo.lock                       |  6 ++++
 .../listing-04-05/Cargo.toml                       |  6 ++++
 .../listing-04-05/src/main.rs                      | 13 ++++++++
 .../listing-04-06/Cargo.lock                       |  6 ++++
 .../listing-04-06/Cargo.toml                       |  6 ++++
 .../listing-04-06/output.txt                       | 12 ++++++++
 .../listing-04-06/src/main.rs                      |  9 ++++++
 .../listing-04-07/Cargo.lock                       |  6 ++++
 .../listing-04-07/Cargo.toml                       |  6 ++++
 .../listing-04-07/src/main.rs                      | 21 +++++++++++++
 .../listing-04-08/Cargo.lock                       |  6 ++++
 .../listing-04-08/Cargo.toml                       |  6 ++++
 .../listing-04-08/src/main.rs                      | 24 +++++++++++++++
 .../listing-04-09/Cargo.lock                       |  6 ++++
 .../listing-04-09/Cargo.toml                       |  6 ++++
 .../listing-04-09/src/main.rs                      | 36 ++++++++++++++++++++++
 .../no-listing-01-can-mutate-string/Cargo.lock     |  6 ++++
 .../no-listing-01-can-mutate-string/Cargo.toml     |  6 ++++
 .../no-listing-01-can-mutate-string/src/main.rs    |  9 ++++++
 .../no-listing-02-string-scope/Cargo.lock          |  4 +++
 .../no-listing-02-string-scope/Cargo.toml          |  6 ++++
 .../no-listing-02-string-scope/rustfmt-ignore      |  3 ++
 .../no-listing-02-string-scope/src/main.rs         | 10 ++++++
 .../no-listing-03-string-move/Cargo.lock           |  6 ++++
 .../no-listing-03-string-move/Cargo.toml           |  6 ++++
 .../no-listing-03-string-move/src/main.rs          |  6 ++++
 .../no-listing-04-cant-use-after-move/Cargo.lock   |  6 ++++
 .../no-listing-04-cant-use-after-move/Cargo.toml   |  6 ++++
 .../no-listing-04-cant-use-after-move/output.txt   | 17 ++++++++++
 .../no-listing-04-cant-use-after-move/src/main.rs  |  8 +++++
 .../no-listing-05-clone/Cargo.lock                 |  6 ++++
 .../no-listing-05-clone/Cargo.toml                 |  6 ++++
 .../no-listing-05-clone/src/main.rs                |  8 +++++
 .../no-listing-06-copy/Cargo.lock                  |  6 ++++
 .../no-listing-06-copy/Cargo.toml                  |  6 ++++
 .../no-listing-06-copy/src/main.rs                 |  8 +++++
 .../no-listing-07-reference/Cargo.lock             |  6 ++++
 .../no-listing-07-reference/Cargo.toml             |  6 ++++
 .../no-listing-07-reference/src/main.rs            | 15 +++++++++
 .../Cargo.lock                                     |  4 +++
 .../Cargo.toml                                     |  6 ++++
 .../rustfmt-ignore                                 |  3 ++
 .../src/main.rs                                    | 14 +++++++++
 .../no-listing-09-fixes-listing-04-06/Cargo.lock   |  6 ++++
 .../no-listing-09-fixes-listing-04-06/Cargo.toml   |  6 ++++
 .../no-listing-09-fixes-listing-04-06/src/main.rs  |  9 ++++++
 .../Cargo.lock                                     |  6 ++++
 .../Cargo.toml                                     |  6 ++++
 .../output.txt                                     | 15 +++++++++
 .../src/main.rs                                    | 10 ++++++
 .../Cargo.lock                                     |  6 ++++
 .../Cargo.toml                                     |  6 ++++
 .../src/main.rs                                    | 11 +++++++
 .../Cargo.lock                                     |  6 ++++
 .../Cargo.toml                                     |  6 ++++
 .../output.txt                                     | 16 ++++++++++
 .../src/main.rs                                    | 11 +++++++
 .../no-listing-13-reference-scope-ends/Cargo.lock  |  6 ++++
 .../no-listing-13-reference-scope-ends/Cargo.toml  |  6 ++++
 .../no-listing-13-reference-scope-ends/src/main.rs | 13 ++++++++
 .../no-listing-14-dangling-reference/Cargo.lock    |  6 ++++
 .../no-listing-14-dangling-reference/Cargo.toml    |  6 ++++
 .../no-listing-14-dangling-reference/output.txt    | 16 ++++++++++
 .../no-listing-14-dangling-reference/src/main.rs   |  9 ++++++
 .../Cargo.lock                                     |  4 +++
 .../Cargo.toml                                     |  6 ++++
 .../rustfmt-ignore                                 |  3 ++
 .../src/main.rs                                    | 13 ++++++++
 .../no-listing-16-no-dangle/Cargo.lock             |  6 ++++
 .../no-listing-16-no-dangle/Cargo.toml             |  6 ++++
 .../no-listing-16-no-dangle/src/main.rs            | 11 +++++++
 .../no-listing-17-slice/Cargo.lock                 |  6 ++++
 .../no-listing-17-slice/Cargo.toml                 |  6 ++++
 .../no-listing-17-slice/src/main.rs                |  8 +++++
 .../no-listing-18-first-word-slice/Cargo.lock      |  6 ++++
 .../no-listing-18-first-word-slice/Cargo.toml      |  6 ++++
 .../no-listing-18-first-word-slice/src/main.rs     | 15 +++++++++
 .../no-listing-19-slice-error/Cargo.lock           |  6 ++++
 .../no-listing-19-slice-error/Cargo.toml           |  6 ++++
 .../no-listing-19-slice-error/output.txt           | 16 ++++++++++
 .../no-listing-19-slice-error/src/main.rs          | 23 ++++++++++++++
 96 files changed, 815 insertions(+)
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-01/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-01/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-01/rustfmt-ignore
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-01/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-02/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-02/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-02/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-03/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-03/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-03/rustfmt-ignore
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-03/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-04/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-04/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-04/rustfmt-ignore
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-04/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-05/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-05/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-05/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-06/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-06/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-06/output.txt
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-06/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-07/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-07/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-07/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-08/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-08/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-08/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-09/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-09/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/listing-04-09/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-01-can-mutate-string/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-01-can-mutate-string/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-01-can-mutate-string/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-02-string-scope/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-02-string-scope/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-02-string-scope/rustfmt-ignore
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-02-string-scope/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-03-string-move/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-03-string-move/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-03-string-move/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/output.txt
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-05-clone/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-05-clone/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-05-clone/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-06-copy/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-06-copy/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-06-copy/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-07-reference/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-07-reference/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-07-reference/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/rustfmt-ignore
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-09-fixes-listing-04-06/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-09-fixes-listing-04-06/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-09-fixes-listing-04-06/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-10-multiple-mut-not-allowed/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-10-multiple-mut-not-allowed/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-10-multiple-mut-not-allowed/output.txt
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-10-multiple-mut-not-allowed/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-11-muts-in-separate-scopes/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-11-muts-in-separate-scopes/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-11-muts-in-separate-scopes/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-12-immutable-and-mutable-not-allowed/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-12-immutable-and-mutable-not-allowed/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-12-immutable-and-mutable-not-allowed/output.txt
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-12-immutable-and-mutable-not-allowed/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-13-reference-scope-ends/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-13-reference-scope-ends/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-13-reference-scope-ends/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-14-dangling-reference/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-14-dangling-reference/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-14-dangling-reference/output.txt
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-14-dangling-reference/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-15-dangling-reference-annotated/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-15-dangling-reference-annotated/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-15-dangling-reference-annotated/rustfmt-ignore
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-15-dangling-reference-annotated/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-16-no-dangle/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-16-no-dangle/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-16-no-dangle/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-17-slice/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-17-slice/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-17-slice/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-18-first-word-slice/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-18-first-word-slice/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-18-first-word-slice/src/main.rs
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-19-slice-error/Cargo.lock
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-19-slice-error/Cargo.toml
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-19-slice-error/output.txt
 create mode 100644 src/doc/book/listings/ch04-understanding-ownership/no-listing-19-slice-error/src/main.rs

(limited to 'src/doc/book/listings/ch04-understanding-ownership')

diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-01/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/listing-04-01/Cargo.lock
new file mode 100644
index 000000000..9e4e62ddf
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-01/Cargo.lock
@@ -0,0 +1,4 @@
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-01/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/listing-04-01/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-01/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-01/rustfmt-ignore b/src/doc/book/listings/ch04-understanding-ownership/listing-04-01/rustfmt-ignore
new file mode 100644
index 000000000..9a53c718a
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-01/rustfmt-ignore
@@ -0,0 +1,3 @@
+We have some weird comments pointing out borrowing scopes that we don't want to change;
+unfortunately I haven't found a way to skip them with rustfmt that works so for now we're going to
+manually skip those listings. See: https://github.com/rust-lang/rustfmt/issues/4028
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-01/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/listing-04-01/src/main.rs
new file mode 100644
index 000000000..148ad84c9
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-01/src/main.rs
@@ -0,0 +1,9 @@
+fn main() {
+    // ANCHOR: here
+    {                      // s is not valid here, it’s not yet declared
+        let s = "hello";   // s is valid from this point forward
+
+        // do stuff with s
+    }                      // this scope is now over, and s is no longer valid
+    // ANCHOR_END: here
+}
\ No newline at end of file
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-02/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/listing-04-02/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-02/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-02/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/listing-04-02/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-02/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-02/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/listing-04-02/src/main.rs
new file mode 100644
index 000000000..de0f1b325
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-02/src/main.rs
@@ -0,0 +1,6 @@
+fn main() {
+    // ANCHOR: here
+    let x = 5;
+    let y = x;
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-03/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/listing-04-03/Cargo.lock
new file mode 100644
index 000000000..9e4e62ddf
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-03/Cargo.lock
@@ -0,0 +1,4 @@
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-03/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/listing-04-03/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-03/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-03/rustfmt-ignore b/src/doc/book/listings/ch04-understanding-ownership/listing-04-03/rustfmt-ignore
new file mode 100644
index 000000000..9a53c718a
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-03/rustfmt-ignore
@@ -0,0 +1,3 @@
+We have some weird comments pointing out borrowing scopes that we don't want to change;
+unfortunately I haven't found a way to skip them with rustfmt that works so for now we're going to
+manually skip those listings. See: https://github.com/rust-lang/rustfmt/issues/4028
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-03/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/listing-04-03/src/main.rs
new file mode 100644
index 000000000..b001cc5f4
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-03/src/main.rs
@@ -0,0 +1,23 @@
+fn main() {
+    let s = String::from("hello");  // s comes into scope
+
+    takes_ownership(s);             // s's value moves into the function...
+                                    // ... and so is no longer valid here
+
+    let x = 5;                      // x comes into scope
+
+    makes_copy(x);                  // x would move into the function,
+                                    // but i32 is Copy, so it's okay to still
+                                    // use x afterward
+
+} // Here, x goes out of scope, then s. But because s's value was moved, nothing
+  // special happens.
+
+fn takes_ownership(some_string: String) { // some_string comes into scope
+    println!("{}", some_string);
+} // Here, some_string goes out of scope and `drop` is called. The backing
+  // memory is freed.
+
+fn makes_copy(some_integer: i32) { // some_integer comes into scope
+    println!("{}", some_integer);
+} // Here, some_integer goes out of scope. Nothing special happens.
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-04/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/listing-04-04/Cargo.lock
new file mode 100644
index 000000000..9e4e62ddf
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-04/Cargo.lock
@@ -0,0 +1,4 @@
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-04/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/listing-04-04/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-04/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-04/rustfmt-ignore b/src/doc/book/listings/ch04-understanding-ownership/listing-04-04/rustfmt-ignore
new file mode 100644
index 000000000..9a53c718a
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-04/rustfmt-ignore
@@ -0,0 +1,3 @@
+We have some weird comments pointing out borrowing scopes that we don't want to change;
+unfortunately I haven't found a way to skip them with rustfmt that works so for now we're going to
+manually skip those listings. See: https://github.com/rust-lang/rustfmt/issues/4028
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-04/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/listing-04-04/src/main.rs
new file mode 100644
index 000000000..e206bec7a
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-04/src/main.rs
@@ -0,0 +1,29 @@
+fn main() {
+    let s1 = gives_ownership();         // gives_ownership moves its return
+                                        // value into s1
+
+    let s2 = String::from("hello");     // s2 comes into scope
+
+    let s3 = takes_and_gives_back(s2);  // s2 is moved into
+                                        // takes_and_gives_back, which also
+                                        // moves its return value into s3
+} // Here, s3 goes out of scope and is dropped. s2 was moved, so nothing
+  // happens. s1 goes out of scope and is dropped.
+
+fn gives_ownership() -> String {             // gives_ownership will move its
+                                             // return value into the function
+                                             // that calls it
+
+    let some_string = String::from("yours"); // some_string comes into scope
+
+    some_string                              // some_string is returned and
+                                             // moves out to the calling
+                                             // function
+}
+
+// This function takes a String and returns one
+fn takes_and_gives_back(a_string: String) -> String { // a_string comes into
+                                                      // scope
+
+    a_string  // a_string is returned and moves out to the calling function
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-05/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/listing-04-05/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-05/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-05/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/listing-04-05/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-05/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-05/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/listing-04-05/src/main.rs
new file mode 100644
index 000000000..22aee1419
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-05/src/main.rs
@@ -0,0 +1,13 @@
+fn main() {
+    let s1 = String::from("hello");
+
+    let (s2, len) = calculate_length(s1);
+
+    println!("The length of '{}' is {}.", s2, len);
+}
+
+fn calculate_length(s: String) -> (String, usize) {
+    let length = s.len(); // len() returns the length of a String
+
+    (s, length)
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-06/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/listing-04-06/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-06/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-06/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/listing-04-06/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-06/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-06/output.txt b/src/doc/book/listings/ch04-understanding-ownership/listing-04-06/output.txt
new file mode 100644
index 000000000..1176f4e3a
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-06/output.txt
@@ -0,0 +1,12 @@
+$ cargo run
+   Compiling ownership v0.1.0 (file:///projects/ownership)
+error[E0596]: cannot borrow `*some_string` as mutable, as it is behind a `&` reference
+ --> src/main.rs:8:5
+  |
+7 | fn change(some_string: &String) {
+  |                        ------- help: consider changing this to be a mutable reference: `&mut String`
+8 |     some_string.push_str(", world");
+  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `some_string` is a `&` reference, so the data it refers to cannot be borrowed as mutable
+
+For more information about this error, try `rustc --explain E0596`.
+error: could not compile `ownership` due to previous error
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-06/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/listing-04-06/src/main.rs
new file mode 100644
index 000000000..330ffa68a
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-06/src/main.rs
@@ -0,0 +1,9 @@
+fn main() {
+    let s = String::from("hello");
+
+    change(&s);
+}
+
+fn change(some_string: &String) {
+    some_string.push_str(", world");
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-07/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/listing-04-07/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-07/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-07/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/listing-04-07/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-07/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-07/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/listing-04-07/src/main.rs
new file mode 100644
index 000000000..3bb3c8580
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-07/src/main.rs
@@ -0,0 +1,21 @@
+// ANCHOR: here
+fn first_word(s: &String) -> usize {
+    // ANCHOR: as_bytes
+    let bytes = s.as_bytes();
+    // ANCHOR_END: as_bytes
+
+    // ANCHOR: iter
+    for (i, &item) in bytes.iter().enumerate() {
+        // ANCHOR_END: iter
+        // ANCHOR: inside_for
+        if item == b' ' {
+            return i;
+        }
+    }
+
+    s.len()
+    // ANCHOR_END: inside_for
+}
+// ANCHOR_END: here
+
+fn main() {}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-08/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/listing-04-08/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-08/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-08/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/listing-04-08/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-08/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-08/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/listing-04-08/src/main.rs
new file mode 100644
index 000000000..b6182fe2b
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-08/src/main.rs
@@ -0,0 +1,24 @@
+fn first_word(s: &String) -> usize {
+    let bytes = s.as_bytes();
+
+    for (i, &item) in bytes.iter().enumerate() {
+        if item == b' ' {
+            return i;
+        }
+    }
+
+    s.len()
+}
+
+// ANCHOR: here
+fn main() {
+    let mut s = String::from("hello world");
+
+    let word = first_word(&s); // word will get the value 5
+
+    s.clear(); // this empties the String, making it equal to ""
+
+    // word still has the value 5 here, but there's no more string that
+    // we could meaningfully use the value 5 with. word is now totally invalid!
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-09/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/listing-04-09/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-09/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-09/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/listing-04-09/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-09/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/listing-04-09/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/listing-04-09/src/main.rs
new file mode 100644
index 000000000..5a6ceaa1e
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/listing-04-09/src/main.rs
@@ -0,0 +1,36 @@
+// ANCHOR: here
+fn first_word(s: &str) -> &str {
+    // ANCHOR_END: here
+    let bytes = s.as_bytes();
+
+    for (i, &item) in bytes.iter().enumerate() {
+        if item == b' ' {
+            return &s[0..i];
+        }
+    }
+
+    &s[..]
+}
+
+// ANCHOR: usage
+fn main() {
+    let my_string = String::from("hello world");
+
+    // `first_word` works on slices of `String`s, whether partial or whole
+    let word = first_word(&my_string[0..6]);
+    let word = first_word(&my_string[..]);
+    // `first_word` also works on references to `String`s, which are equivalent
+    // to whole slices of `String`s
+    let word = first_word(&my_string);
+
+    let my_string_literal = "hello world";
+
+    // `first_word` works on slices of string literals, whether partial or whole
+    let word = first_word(&my_string_literal[0..6]);
+    let word = first_word(&my_string_literal[..]);
+
+    // Because string literals *are* string slices already,
+    // this works too, without the slice syntax!
+    let word = first_word(my_string_literal);
+}
+// ANCHOR_END: usage
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-01-can-mutate-string/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-01-can-mutate-string/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-01-can-mutate-string/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-01-can-mutate-string/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-01-can-mutate-string/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-01-can-mutate-string/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-01-can-mutate-string/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-01-can-mutate-string/src/main.rs
new file mode 100644
index 000000000..b68f0f1e7
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-01-can-mutate-string/src/main.rs
@@ -0,0 +1,9 @@
+fn main() {
+    // ANCHOR: here
+    let mut s = String::from("hello");
+
+    s.push_str(", world!"); // push_str() appends a literal to a String
+
+    println!("{}", s); // This will print `hello, world!`
+                       // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-02-string-scope/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-02-string-scope/Cargo.lock
new file mode 100644
index 000000000..9e4e62ddf
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-02-string-scope/Cargo.lock
@@ -0,0 +1,4 @@
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-02-string-scope/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-02-string-scope/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-02-string-scope/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-02-string-scope/rustfmt-ignore b/src/doc/book/listings/ch04-understanding-ownership/no-listing-02-string-scope/rustfmt-ignore
new file mode 100644
index 000000000..9a53c718a
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-02-string-scope/rustfmt-ignore
@@ -0,0 +1,3 @@
+We have some weird comments pointing out borrowing scopes that we don't want to change;
+unfortunately I haven't found a way to skip them with rustfmt that works so for now we're going to
+manually skip those listings. See: https://github.com/rust-lang/rustfmt/issues/4028
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-02-string-scope/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-02-string-scope/src/main.rs
new file mode 100644
index 000000000..7e6d46f83
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-02-string-scope/src/main.rs
@@ -0,0 +1,10 @@
+fn main() {
+    // ANCHOR: here
+    {
+        let s = String::from("hello"); // s is valid from this point forward
+
+        // do stuff with s
+    }                                  // this scope is now over, and s is no
+                                       // longer valid
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-03-string-move/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-03-string-move/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-03-string-move/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-03-string-move/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-03-string-move/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-03-string-move/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-03-string-move/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-03-string-move/src/main.rs
new file mode 100644
index 000000000..a5817e714
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-03-string-move/src/main.rs
@@ -0,0 +1,6 @@
+fn main() {
+    // ANCHOR: here
+    let s1 = String::from("hello");
+    let s2 = s1;
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/output.txt b/src/doc/book/listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/output.txt
new file mode 100644
index 000000000..6435eeb44
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/output.txt
@@ -0,0 +1,17 @@
+$ cargo run
+   Compiling ownership v0.1.0 (file:///projects/ownership)
+error[E0382]: borrow of moved value: `s1`
+ --> src/main.rs:5:28
+  |
+2 |     let s1 = String::from("hello");
+  |         -- move occurs because `s1` has type `String`, which does not implement the `Copy` trait
+3 |     let s2 = s1;
+  |              -- value moved here
+4 | 
+5 |     println!("{}, world!", s1);
+  |                            ^^ value borrowed here after move
+  |
+  = note: this error originates in the macro `$crate::format_args_nl` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+For more information about this error, try `rustc --explain E0382`.
+error: could not compile `ownership` due to previous error
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/src/main.rs
new file mode 100644
index 000000000..d0b9f1879
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/src/main.rs
@@ -0,0 +1,8 @@
+fn main() {
+    // ANCHOR: here
+    let s1 = String::from("hello");
+    let s2 = s1;
+
+    println!("{}, world!", s1);
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-05-clone/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-05-clone/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-05-clone/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-05-clone/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-05-clone/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-05-clone/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-05-clone/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-05-clone/src/main.rs
new file mode 100644
index 000000000..4e61cc1a1
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-05-clone/src/main.rs
@@ -0,0 +1,8 @@
+fn main() {
+    // ANCHOR: here
+    let s1 = String::from("hello");
+    let s2 = s1.clone();
+
+    println!("s1 = {}, s2 = {}", s1, s2);
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-06-copy/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-06-copy/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-06-copy/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-06-copy/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-06-copy/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-06-copy/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-06-copy/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-06-copy/src/main.rs
new file mode 100644
index 000000000..63a1fae24
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-06-copy/src/main.rs
@@ -0,0 +1,8 @@
+fn main() {
+    // ANCHOR: here
+    let x = 5;
+    let y = x;
+
+    println!("x = {}, y = {}", x, y);
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-07-reference/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-07-reference/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-07-reference/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-07-reference/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-07-reference/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-07-reference/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-07-reference/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-07-reference/src/main.rs
new file mode 100644
index 000000000..fd32a5fc9
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-07-reference/src/main.rs
@@ -0,0 +1,15 @@
+// ANCHOR: all
+fn main() {
+    // ANCHOR: here
+    let s1 = String::from("hello");
+
+    let len = calculate_length(&s1);
+    // ANCHOR_END: here
+
+    println!("The length of '{}' is {}.", s1, len);
+}
+
+fn calculate_length(s: &String) -> usize {
+    s.len()
+}
+// ANCHOR_END: all
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/Cargo.lock
new file mode 100644
index 000000000..9e4e62ddf
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/Cargo.lock
@@ -0,0 +1,4 @@
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/rustfmt-ignore b/src/doc/book/listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/rustfmt-ignore
new file mode 100644
index 000000000..9a53c718a
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/rustfmt-ignore
@@ -0,0 +1,3 @@
+We have some weird comments pointing out borrowing scopes that we don't want to change;
+unfortunately I haven't found a way to skip them with rustfmt that works so for now we're going to
+manually skip those listings. See: https://github.com/rust-lang/rustfmt/issues/4028
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/src/main.rs
new file mode 100644
index 000000000..6686a801c
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/src/main.rs
@@ -0,0 +1,14 @@
+fn main() {
+    let s1 = String::from("hello");
+
+    let len = calculate_length(&s1);
+
+    println!("The length of '{}' is {}.", s1, len);
+}
+
+// ANCHOR: here
+fn calculate_length(s: &String) -> usize { // s is a reference to a String
+    s.len()
+} // Here, s goes out of scope. But because it does not have ownership of what
+  // it refers to, it is not dropped.
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-09-fixes-listing-04-06/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-09-fixes-listing-04-06/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-09-fixes-listing-04-06/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-09-fixes-listing-04-06/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-09-fixes-listing-04-06/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-09-fixes-listing-04-06/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-09-fixes-listing-04-06/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-09-fixes-listing-04-06/src/main.rs
new file mode 100644
index 000000000..fdf7f0a6f
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-09-fixes-listing-04-06/src/main.rs
@@ -0,0 +1,9 @@
+fn main() {
+    let mut s = String::from("hello");
+
+    change(&mut s);
+}
+
+fn change(some_string: &mut String) {
+    some_string.push_str(", world");
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-10-multiple-mut-not-allowed/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-10-multiple-mut-not-allowed/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-10-multiple-mut-not-allowed/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-10-multiple-mut-not-allowed/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-10-multiple-mut-not-allowed/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-10-multiple-mut-not-allowed/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-10-multiple-mut-not-allowed/output.txt b/src/doc/book/listings/ch04-understanding-ownership/no-listing-10-multiple-mut-not-allowed/output.txt
new file mode 100644
index 000000000..71c29f68f
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-10-multiple-mut-not-allowed/output.txt
@@ -0,0 +1,15 @@
+$ cargo run
+   Compiling ownership v0.1.0 (file:///projects/ownership)
+error[E0499]: cannot borrow `s` as mutable more than once at a time
+ --> src/main.rs:5:14
+  |
+4 |     let r1 = &mut s;
+  |              ------ first mutable borrow occurs here
+5 |     let r2 = &mut s;
+  |              ^^^^^^ second mutable borrow occurs here
+6 | 
+7 |     println!("{}, {}", r1, r2);
+  |                        -- first borrow later used here
+
+For more information about this error, try `rustc --explain E0499`.
+error: could not compile `ownership` due to previous error
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-10-multiple-mut-not-allowed/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-10-multiple-mut-not-allowed/src/main.rs
new file mode 100644
index 000000000..ddbf8120f
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-10-multiple-mut-not-allowed/src/main.rs
@@ -0,0 +1,10 @@
+fn main() {
+    // ANCHOR: here
+    let mut s = String::from("hello");
+
+    let r1 = &mut s;
+    let r2 = &mut s;
+
+    println!("{}, {}", r1, r2);
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-11-muts-in-separate-scopes/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-11-muts-in-separate-scopes/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-11-muts-in-separate-scopes/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-11-muts-in-separate-scopes/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-11-muts-in-separate-scopes/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-11-muts-in-separate-scopes/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-11-muts-in-separate-scopes/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-11-muts-in-separate-scopes/src/main.rs
new file mode 100644
index 000000000..4b1a5a383
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-11-muts-in-separate-scopes/src/main.rs
@@ -0,0 +1,11 @@
+fn main() {
+    // ANCHOR: here
+    let mut s = String::from("hello");
+
+    {
+        let r1 = &mut s;
+    } // r1 goes out of scope here, so we can make a new reference with no problems.
+
+    let r2 = &mut s;
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-12-immutable-and-mutable-not-allowed/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-12-immutable-and-mutable-not-allowed/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-12-immutable-and-mutable-not-allowed/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-12-immutable-and-mutable-not-allowed/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-12-immutable-and-mutable-not-allowed/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-12-immutable-and-mutable-not-allowed/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-12-immutable-and-mutable-not-allowed/output.txt b/src/doc/book/listings/ch04-understanding-ownership/no-listing-12-immutable-and-mutable-not-allowed/output.txt
new file mode 100644
index 000000000..df94c30e9
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-12-immutable-and-mutable-not-allowed/output.txt
@@ -0,0 +1,16 @@
+$ cargo run
+   Compiling ownership v0.1.0 (file:///projects/ownership)
+error[E0502]: cannot borrow `s` as mutable because it is also borrowed as immutable
+ --> src/main.rs:6:14
+  |
+4 |     let r1 = &s; // no problem
+  |              -- immutable borrow occurs here
+5 |     let r2 = &s; // no problem
+6 |     let r3 = &mut s; // BIG PROBLEM
+  |              ^^^^^^ mutable borrow occurs here
+7 | 
+8 |     println!("{}, {}, and {}", r1, r2, r3);
+  |                                -- immutable borrow later used here
+
+For more information about this error, try `rustc --explain E0502`.
+error: could not compile `ownership` due to previous error
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-12-immutable-and-mutable-not-allowed/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-12-immutable-and-mutable-not-allowed/src/main.rs
new file mode 100644
index 000000000..0da04c010
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-12-immutable-and-mutable-not-allowed/src/main.rs
@@ -0,0 +1,11 @@
+fn main() {
+    // ANCHOR: here
+    let mut s = String::from("hello");
+
+    let r1 = &s; // no problem
+    let r2 = &s; // no problem
+    let r3 = &mut s; // BIG PROBLEM
+
+    println!("{}, {}, and {}", r1, r2, r3);
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-13-reference-scope-ends/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-13-reference-scope-ends/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-13-reference-scope-ends/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-13-reference-scope-ends/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-13-reference-scope-ends/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-13-reference-scope-ends/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-13-reference-scope-ends/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-13-reference-scope-ends/src/main.rs
new file mode 100644
index 000000000..861944966
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-13-reference-scope-ends/src/main.rs
@@ -0,0 +1,13 @@
+fn main() {
+    // ANCHOR: here
+    let mut s = String::from("hello");
+
+    let r1 = &s; // no problem
+    let r2 = &s; // no problem
+    println!("{} and {}", r1, r2);
+    // variables r1 and r2 will not be used after this point
+
+    let r3 = &mut s; // no problem
+    println!("{}", r3);
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-14-dangling-reference/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-14-dangling-reference/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-14-dangling-reference/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-14-dangling-reference/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-14-dangling-reference/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-14-dangling-reference/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-14-dangling-reference/output.txt b/src/doc/book/listings/ch04-understanding-ownership/no-listing-14-dangling-reference/output.txt
new file mode 100644
index 000000000..fddca683b
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-14-dangling-reference/output.txt
@@ -0,0 +1,16 @@
+$ cargo run
+   Compiling ownership v0.1.0 (file:///projects/ownership)
+error[E0106]: missing lifetime specifier
+ --> src/main.rs:5:16
+  |
+5 | fn dangle() -> &String {
+  |                ^ expected named lifetime parameter
+  |
+  = help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from
+help: consider using the `'static` lifetime
+  |
+5 | fn dangle() -> &'static String {
+  |                ~~~~~~~~
+
+For more information about this error, try `rustc --explain E0106`.
+error: could not compile `ownership` due to previous error
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-14-dangling-reference/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-14-dangling-reference/src/main.rs
new file mode 100644
index 000000000..b10269781
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-14-dangling-reference/src/main.rs
@@ -0,0 +1,9 @@
+fn main() {
+    let reference_to_nothing = dangle();
+}
+
+fn dangle() -> &String {
+    let s = String::from("hello");
+
+    &s
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-15-dangling-reference-annotated/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-15-dangling-reference-annotated/Cargo.lock
new file mode 100644
index 000000000..9e4e62ddf
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-15-dangling-reference-annotated/Cargo.lock
@@ -0,0 +1,4 @@
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-15-dangling-reference-annotated/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-15-dangling-reference-annotated/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-15-dangling-reference-annotated/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-15-dangling-reference-annotated/rustfmt-ignore b/src/doc/book/listings/ch04-understanding-ownership/no-listing-15-dangling-reference-annotated/rustfmt-ignore
new file mode 100644
index 000000000..9a53c718a
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-15-dangling-reference-annotated/rustfmt-ignore
@@ -0,0 +1,3 @@
+We have some weird comments pointing out borrowing scopes that we don't want to change;
+unfortunately I haven't found a way to skip them with rustfmt that works so for now we're going to
+manually skip those listings. See: https://github.com/rust-lang/rustfmt/issues/4028
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-15-dangling-reference-annotated/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-15-dangling-reference-annotated/src/main.rs
new file mode 100644
index 000000000..9fbb372a0
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-15-dangling-reference-annotated/src/main.rs
@@ -0,0 +1,13 @@
+fn main() {
+    let reference_to_nothing = dangle();
+}
+
+// ANCHOR: here
+fn dangle() -> &String { // dangle returns a reference to a String
+
+    let s = String::from("hello"); // s is a new String
+
+    &s // we return a reference to the String, s
+} // Here, s goes out of scope, and is dropped. Its memory goes away.
+  // Danger!
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-16-no-dangle/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-16-no-dangle/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-16-no-dangle/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-16-no-dangle/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-16-no-dangle/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-16-no-dangle/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-16-no-dangle/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-16-no-dangle/src/main.rs
new file mode 100644
index 000000000..9c20a3b2d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-16-no-dangle/src/main.rs
@@ -0,0 +1,11 @@
+fn main() {
+    let string = no_dangle();
+}
+
+// ANCHOR: here
+fn no_dangle() -> String {
+    let s = String::from("hello");
+
+    s
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-17-slice/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-17-slice/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-17-slice/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-17-slice/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-17-slice/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-17-slice/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-17-slice/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-17-slice/src/main.rs
new file mode 100644
index 000000000..44163af99
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-17-slice/src/main.rs
@@ -0,0 +1,8 @@
+fn main() {
+    // ANCHOR: here
+    let s = String::from("hello world");
+
+    let hello = &s[0..5];
+    let world = &s[6..11];
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-18-first-word-slice/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-18-first-word-slice/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-18-first-word-slice/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-18-first-word-slice/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-18-first-word-slice/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-18-first-word-slice/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-18-first-word-slice/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-18-first-word-slice/src/main.rs
new file mode 100644
index 000000000..f44a970da
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-18-first-word-slice/src/main.rs
@@ -0,0 +1,15 @@
+// ANCHOR: here
+fn first_word(s: &String) -> &str {
+    let bytes = s.as_bytes();
+
+    for (i, &item) in bytes.iter().enumerate() {
+        if item == b' ' {
+            return &s[0..i];
+        }
+    }
+
+    &s[..]
+}
+// ANCHOR_END: here
+
+fn main() {}
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-19-slice-error/Cargo.lock b/src/doc/book/listings/ch04-understanding-ownership/no-listing-19-slice-error/Cargo.lock
new file mode 100644
index 000000000..2aa4918e5
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-19-slice-error/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ownership"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-19-slice-error/Cargo.toml b/src/doc/book/listings/ch04-understanding-ownership/no-listing-19-slice-error/Cargo.toml
new file mode 100644
index 000000000..e8847526d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-19-slice-error/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ownership"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-19-slice-error/output.txt b/src/doc/book/listings/ch04-understanding-ownership/no-listing-19-slice-error/output.txt
new file mode 100644
index 000000000..62dc4ad52
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-19-slice-error/output.txt
@@ -0,0 +1,16 @@
+$ cargo run
+   Compiling ownership v0.1.0 (file:///projects/ownership)
+error[E0502]: cannot borrow `s` as mutable because it is also borrowed as immutable
+  --> src/main.rs:18:5
+   |
+16 |     let word = first_word(&s);
+   |                           -- immutable borrow occurs here
+17 | 
+18 |     s.clear(); // error!
+   |     ^^^^^^^^^ mutable borrow occurs here
+19 | 
+20 |     println!("the first word is: {}", word);
+   |                                       ---- immutable borrow later used here
+
+For more information about this error, try `rustc --explain E0502`.
+error: could not compile `ownership` due to previous error
diff --git a/src/doc/book/listings/ch04-understanding-ownership/no-listing-19-slice-error/src/main.rs b/src/doc/book/listings/ch04-understanding-ownership/no-listing-19-slice-error/src/main.rs
new file mode 100644
index 000000000..99e04018d
--- /dev/null
+++ b/src/doc/book/listings/ch04-understanding-ownership/no-listing-19-slice-error/src/main.rs
@@ -0,0 +1,23 @@
+fn first_word(s: &String) -> &str {
+    let bytes = s.as_bytes();
+
+    for (i, &item) in bytes.iter().enumerate() {
+        if item == b' ' {
+            return &s[0..i];
+        }
+    }
+
+    &s[..]
+}
+
+// ANCHOR: here
+fn main() {
+    let mut s = String::from("hello world");
+
+    let word = first_word(&s);
+
+    s.clear(); // error!
+
+    println!("the first word is: {}", word);
+}
+// ANCHOR_END: here
-- 
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