Update to 1.42

rust-lang · steveklabnik · Dec 9, 2020 · Nov 30, 2020 · Dec 2, 2020 · Dec 2, 2020
commit 6e988056292ce5af6910412b8d220d314e836e6e
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
@@ -12,8 +12,8 @@ jobs:
     - name: Install Rust
       run: |
         rustup set profile minimal
-        rustup toolchain install 1.41.0 -c rust-docs
-        rustup default 1.41.0
+        rustup toolchain install 1.42 -c rust-docs
+        rustup default 1.42
     - name: Install mdbook
       run: |
         mkdir bin

diff --git a/listings/ch03-common-programming-concepts/no-listing-19-statements-vs-expressions/output.txt b/listings/ch03-common-programming-concepts/no-listing-19-statements-vs-expressions/output.txt
@@ -1,9 +1,32 @@
 $ cargo run
    Compiling functions v0.1.0 (file:///projects/functions)
+error[E0658]: `let` expressions in this position are experimental
+ --> src/main.rs:2:14
+  |
+2 |     let x = (let y = 6);
+  |              ^^^^^^^^^
+  |
+  = note: for more information, see https://github.com/rust-lang/rust/issues/53667
+
 error: expected expression, found statement (`let`)
  --> src/main.rs:2:14
   |
 2 |     let x = (let y = 6);
-  |              ^^^
+  |              ^^^^^^^^^
+  |
+  = note: variable declaration using `let` is a statement
+
+warning: unnecessary parentheses around assigned value
+ --> src/main.rs:2:13
+  |
+2 |     let x = (let y = 6);
+  |             ^^^^^^^^^^^ help: remove these parentheses
   |
-  = note: variable declaration using `let` is a statement
+  = note: `#[warn(unused_parens)]` on by default
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0658`.
+error: could not compile `functions`.
+
+To learn more, run the command again with --verbose.
diff --git a/...ings/ch03-common-programming-concepts/no-listing-31-arms-must-return-same-type/output.txt b/...ings/ch03-common-programming-concepts/no-listing-31-arms-must-return-same-type/output.txt
@@ -1,6 +1,6 @@
 $ cargo run
    Compiling branches v0.1.0 (file:///projects/branches)
-error[E0308]: if and else have incompatible types
+error[E0308]: `if` and `else` have incompatible types
  --> src/main.rs:4:44
   |
 4 |     let number = if condition { 5 } else { "six" };

diff --git a/...ch05-using-structs-to-structure-related-data/no-listing-02-reference-in-struct/output.txt b/...ch05-using-structs-to-structure-related-data/no-listing-02-reference-in-struct/output.txt
@@ -4,13 +4,26 @@ error[E0106]: missing lifetime specifier
  --> src/main.rs:2:15
   |
 2 |     username: &str,
-  |               ^ expected lifetime parameter
+  |               ^ expected named lifetime parameter
+  |
+help: consider introducing a named lifetime parameter
+  |
+1 | struct User<'lifetime> {
+2 |     username: &'lifetime str,
+  |
 
 error[E0106]: missing lifetime specifier
  --> src/main.rs:3:12
   |
 3 |     email: &str,
-  |            ^ expected lifetime parameter
+  |            ^ expected named lifetime parameter
+  |
+help: consider introducing a named lifetime parameter
+  |
+1 | struct User<'lifetime> {
+2 |     username: &str,
+3 |     email: &'lifetime str,
+  |
 
 error: aborting due to 2 previous errors
 

diff --git a/listings/ch07-managing-growing-projects/listing-07-03/output.txt b/listings/ch07-managing-growing-projects/listing-07-03/output.txt
@@ -4,13 +4,25 @@ error[E0603]: module `hosting` is private
  --> src/lib.rs:9:28
   |
 9 |     crate::front_of_house::hosting::add_to_waitlist();
-  |                            ^^^^^^^
+  |                            ^^^^^^^ this module is private
+  |
+note: the module `hosting` is defined here
+ --> src/lib.rs:2:5
+  |
+2 |     mod hosting {
+  |     ^^^^^^^^^^^
 
 error[E0603]: module `hosting` is private
   --> src/lib.rs:12:21
    |
 12 |     front_of_house::hosting::add_to_waitlist();
-   |                     ^^^^^^^
+   |                     ^^^^^^^ this module is private
+   |
+note: the module `hosting` is defined here
+  --> src/lib.rs:2:5
+   |
+2  |     mod hosting {
+   |     ^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 

diff --git a/listings/ch07-managing-growing-projects/listing-07-05/output.txt b/listings/ch07-managing-growing-projects/listing-07-05/output.txt
@@ -4,13 +4,25 @@ error[E0603]: function `add_to_waitlist` is private
  --> src/lib.rs:9:37
   |
 9 |     crate::front_of_house::hosting::add_to_waitlist();
-  |                                     ^^^^^^^^^^^^^^^
+  |                                     ^^^^^^^^^^^^^^^ this function is private
+  |
+note: the function `add_to_waitlist` is defined here
+ --> src/lib.rs:3:9
+  |
+3 |         fn add_to_waitlist() {}
+  |         ^^^^^^^^^^^^^^^^^^^^
 
 error[E0603]: function `add_to_waitlist` is private
   --> src/lib.rs:12:30
    |
 12 |     front_of_house::hosting::add_to_waitlist();
-   |                              ^^^^^^^^^^^^^^^
+   |                              ^^^^^^^^^^^^^^^ this function is private
+   |
+note: the function `add_to_waitlist` is defined here
+  --> src/lib.rs:3:9
+   |
+3  |         fn add_to_waitlist() {}
+   |         ^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 

diff --git a/listings/ch08-common-collections/output-only-01-not-char-boundary/output.txt b/listings/ch08-common-collections/output-only-01-not-char-boundary/output.txt
@@ -2,5 +2,5 @@ $ cargo run
    Compiling collections v0.1.0 (file:///projects/collections)
     Finished dev [unoptimized + debuginfo] target(s) in 0.43s
      Running `target/debug/collections`
-thread 'main' panicked at 'byte index 1 is not a char boundary; it is inside 'З' (bytes 0..2) of `Здравствуйте`', src/libcore/str/mod.rs:2069:5
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+thread 'main' panicked at 'byte index 1 is not a char boundary; it is inside 'З' (bytes 0..2) of `Здравствуйте`', src/libcore/str/mod.rs:2154:5
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/listings/ch09-error-handling/listing-09-01/output.txt b/listings/ch09-error-handling/listing-09-01/output.txt
@@ -2,5 +2,5 @@ $ cargo run
    Compiling panic v0.1.0 (file:///projects/panic)
     Finished dev [unoptimized + debuginfo] target(s) in 0.27s
      Running `target/debug/panic`
-thread 'main' panicked at 'index out of bounds: the len is 3 but the index is 99', /rustc/5e1a799842ba6ed4a57e91f7ab9435947482f7d8/src/libcore/slice/mod.rs:2806:10
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+thread 'main' panicked at 'index out of bounds: the len is 3 but the index is 99', /rustc/b8cedc00407a4c56a3bda1ed605c6fc166655447/src/libcore/slice/mod.rs:2791:10
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/listings/ch09-error-handling/listing-09-04/output.txt b/listings/ch09-error-handling/listing-09-04/output.txt
@@ -3,4 +3,4 @@ $ cargo run
     Finished dev [unoptimized + debuginfo] target(s) in 0.73s
      Running `target/debug/error-handling`
 thread 'main' panicked at 'Problem opening the file: Os { code: 2, kind: NotFound, message: "No such file or directory" }', src/main.rs:8:23
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/listings/ch09-error-handling/no-listing-01-panic/output.txt b/listings/ch09-error-handling/no-listing-01-panic/output.txt
@@ -3,4 +3,4 @@ $ cargo run
     Finished dev [unoptimized + debuginfo] target(s) in 0.25s
      Running `target/debug/panic`
 thread 'main' panicked at 'crash and burn', src/main.rs:2:5
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/listings/ch10-generic-types-traits-and-lifetimes/listing-10-05/output.txt b/listings/ch10-generic-types-traits-and-lifetimes/listing-10-05/output.txt
@@ -1,14 +1,14 @@
 $ cargo run
    Compiling chapter10 v0.1.0 (file:///projects/chapter10)
-error[E0369]: binary operation `>` cannot be applied to type `T`
+error[E0369]: binary operation `>` cannot be applied to type `&T`
  --> src/main.rs:5:17
   |
 5 |         if item > largest {
-  |            ---- ^ ------- T
+  |            ---- ^ ------- &T
   |            |
-  |            T
+  |            &T
   |
-  = note: `T` might need a bound for `std::cmp::PartialOrd`
+  = note: an implementation of `std::cmp::PartialOrd` might be missing for `&T`
 
 error: aborting due to previous error
 

diff --git a/listings/ch10-generic-types-traits-and-lifetimes/listing-10-21/output.txt b/listings/ch10-generic-types-traits-and-lifetimes/listing-10-21/output.txt
@@ -4,9 +4,13 @@ error[E0106]: missing lifetime specifier
  --> src/main.rs:9:33
   |
 9 | fn longest(x: &str, y: &str) -> &str {
-  |                                 ^ expected lifetime parameter
+  |                                 ^ expected named lifetime parameter
   |
   = help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from `x` or `y`
+help: consider introducing a named lifetime parameter
+  |
+9 | fn longest<'lifetime>(x: &str, y: &str) -> &'lifetime str {
+  |           ^^^^^^^^^^^                      ^^^^^^^^^^
 
 error: aborting due to previous error
 

diff --git a/listings/ch11-writing-automated-tests/listing-11-03/output.txt b/listings/ch11-writing-automated-tests/listing-11-03/output.txt
@@ -11,7 +11,7 @@ failures:
 
 ---- tests::another stdout ----
 thread 'main' panicked at 'Make this test fail', src/lib.rs:10:9
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 
 
 failures:

diff --git a/listings/ch11-writing-automated-tests/listing-11-10/output.txt b/listings/ch11-writing-automated-tests/listing-11-10/output.txt
@@ -13,8 +13,8 @@ failures:
 I got the value 8
 thread 'main' panicked at 'assertion failed: `(left == right)`
   left: `5`,
- right: `10`', src/lib.rs:19:9
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+ right: `10`', src/lib.rs:20:9
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 
 
 failures:

diff --git a/listings/ch11-writing-automated-tests/no-listing-03-introducing-a-bug/output.txt b/listings/ch11-writing-automated-tests/no-listing-03-introducing-a-bug/output.txt
@@ -11,7 +11,7 @@ failures:
 
 ---- tests::larger_can_hold_smaller stdout ----
 thread 'main' panicked at 'assertion failed: larger.can_hold(&smaller)', src/lib.rs:28:9
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 
 
 failures:

diff --git a/listings/ch11-writing-automated-tests/no-listing-04-bug-in-add-two/output.txt b/listings/ch11-writing-automated-tests/no-listing-04-bug-in-add-two/output.txt
@@ -12,7 +12,7 @@ failures:
 thread 'main' panicked at 'assertion failed: `(left == right)`
   left: `4`,
  right: `5`', src/lib.rs:11:9
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 
 
 failures:

diff --git a/listings/ch11-writing-automated-tests/no-listing-06-greeter-with-bug/output.txt b/listings/ch11-writing-automated-tests/no-listing-06-greeter-with-bug/output.txt
@@ -10,7 +10,7 @@ failures:
 
 ---- tests::greeting_contains_name stdout ----
 thread 'main' panicked at 'assertion failed: result.contains("Carol")', src/lib.rs:12:9
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 
 
 failures:

diff --git a/listings/ch11-writing-automated-tests/no-listing-07-custom-failure-message/output.txt b/listings/ch11-writing-automated-tests/no-listing-07-custom-failure-message/output.txt
@@ -10,7 +10,7 @@ failures:
 
 ---- tests::greeting_contains_name stdout ----
 thread 'main' panicked at 'Greeting did not contain name, value was `Hello!`', src/lib.rs:12:9
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 
 
 failures:

diff --git a/listings/ch11-writing-automated-tests/no-listing-09-guess-with-panic-msg-bug/output.txt b/listings/ch11-writing-automated-tests/no-listing-09-guess-with-panic-msg-bug/output.txt
@@ -10,7 +10,7 @@ failures:
 
 ---- tests::greater_than_100 stdout ----
 thread 'main' panicked at 'Guess value must be greater than or equal to 1, got 200.', src/lib.rs:13:13
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: panic did not contain expected string
       panic message: `"Guess value must be greater than or equal to 1, got 200."`,
  expected substring: `"Guess value must be less than or equal to 100"`

diff --git a/listings/ch11-writing-automated-tests/output-only-01-show-output/output.txt b/listings/ch11-writing-automated-tests/output-only-01-show-output/output.txt
@@ -23,7 +23,7 @@ I got the value 8
 thread 'main' panicked at 'assertion failed: `(left == right)`
   left: `5`,
  right: `10`', src/lib.rs:19:9
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 
 
 failures:

diff --git a/listings/ch12-an-io-project/listing-12-07/output.txt b/listings/ch12-an-io-project/listing-12-07/output.txt
@@ -3,4 +3,4 @@ $ cargo run
     Finished dev [unoptimized + debuginfo] target(s) in 0.0s
      Running `target/debug/minigrep`
 thread 'main' panicked at 'index out of bounds: the len is 1 but the index is 1', src/main.rs:27:21
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/listings/ch12-an-io-project/listing-12-08/output.txt b/listings/ch12-an-io-project/listing-12-08/output.txt
@@ -3,4 +3,4 @@ $ cargo run
     Finished dev [unoptimized + debuginfo] target(s) in 0.0s
      Running `target/debug/minigrep`
 thread 'main' panicked at 'not enough arguments', src/main.rs:26:13
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/listings/ch12-an-io-project/listing-12-16/output.txt b/listings/ch12-an-io-project/listing-12-16/output.txt
@@ -12,7 +12,7 @@ failures:
 thread 'main' panicked at 'assertion failed: `(left == right)`
   left: `["safe, fast, productive."]`,
  right: `[]`', src/lib.rs:44:9
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 
 
 failures:

diff --git a/listings/ch12-an-io-project/output-only-02-missing-lifetimes/output.txt b/listings/ch12-an-io-project/output-only-02-missing-lifetimes/output.txt
@@ -4,9 +4,13 @@ error[E0106]: missing lifetime specifier
   --> src/lib.rs:28:51
    |
 28 | pub fn search(query: &str, contents: &str) -> Vec<&str> {
-   |                                                   ^ expected lifetime parameter
+   |                                                   ^ expected named lifetime parameter
    |
    = help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from `query` or `contents`
+help: consider introducing a named lifetime parameter
+   |
+28 | pub fn search<'lifetime>(query: &str, contents: &str) -> Vec<&'lifetime str> {
+   |              ^^^^^^^^^^^                                     ^^^^^^^^^^
 
 error: aborting due to previous error
 

diff --git a/listings/ch13-functional-features/no-listing-01-failing-cacher-test/output.txt b/listings/ch13-functional-features/no-listing-01-failing-cacher-test/output.txt
@@ -12,7 +12,7 @@ failures:
 thread 'main' panicked at 'assertion failed: `(left == right)`
   left: `1`,
  right: `2`', src/lib.rs:43:9
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 
 
 failures:

diff --git a/listings/ch14-more-about-cargo/output-only-01-adder-crate/add/Cargo.lock b/listings/ch14-more-about-cargo/output-only-01-adder-crate/add/Cargo.lock
diff --git a/listings/ch15-smart-pointers/listing-15-23/output.txt b/listings/ch15-smart-pointers/listing-15-23/output.txt
@@ -9,8 +9,8 @@ test tests::it_sends_an_over_75_percent_warning_message ... FAILED
 failures:
 
 ---- tests::it_sends_an_over_75_percent_warning_message stdout ----
-thread 'main' panicked at 'already borrowed: BorrowMutError', src/libcore/result.rs:1188:5
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+thread 'main' panicked at 'already borrowed: BorrowMutError', /rustc/b8cedc00407a4c56a3bda1ed605c6fc166655447/src/libcore/cell.rs:878:9
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 
 
 failures:

diff --git a/listings/ch16-fearless-concurrency/listing-16-14/output.txt b/listings/ch16-fearless-concurrency/listing-16-14/output.txt
@@ -3,8 +3,15 @@ $ cargo run
 error[E0277]: `std::rc::Rc<std::sync::Mutex<i32>>` cannot be sent between threads safely
    --> src/main.rs:11:22
     |
-11  |         let handle = thread::spawn(move || {
-    |                      ^^^^^^^^^^^^^ `std::rc::Rc<std::sync::Mutex<i32>>` cannot be sent between threads safely
+11  |           let handle = thread::spawn(move || {
+    |  ______________________^^^^^^^^^^^^^_-
+    | |                      |
+    | |                      `std::rc::Rc<std::sync::Mutex<i32>>` cannot be sent between threads safely
+12  | |             let mut num = counter.lock().unwrap();
+13  | |
+14  | |             *num += 1;
+15  | |         });
+    | |_________- within this `[closure@src/main.rs:11:36: 15:10 counter:std::rc::Rc<std::sync::Mutex<i32>>]`
     |
     = help: within `[closure@src/main.rs:11:36: 15:10 counter:std::rc::Rc<std::sync::Mutex<i32>>]`, the trait `std::marker::Send` is not implemented for `std::rc::Rc<std::sync::Mutex<i32>>`
     = note: required because it appears within the type `[closure@src/main.rs:11:36: 15:10 counter:std::rc::Rc<std::sync::Mutex<i32>>]`

diff --git a/listings/ch19-advanced-features/no-listing-18-returns-closure/output.txt b/listings/ch19-advanced-features/no-listing-18-returns-closure/output.txt
@@ -10,21 +10,9 @@ error[E0277]: the size for values of type `(dyn std::ops::Fn(i32) -> i32 + 'stat
   = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
   = note: the return type of a function must have a statically known size
 
-error[E0308]: mismatched types
- --> src/lib.rs:2:5
-  |
-1 | fn returns_closure() -> dyn Fn(i32) -> i32 {
-  |                         ------------------ expected `(dyn std::ops::Fn(i32) -> i32 + 'static)` because of return type
-2 |     |x| x + 1
-  |     ^^^^^^^^^ expected trait `std::ops::Fn`, found closure
-  |
-  = note: expected trait object `(dyn std::ops::Fn(i32) -> i32 + 'static)`
-                  found closure `[closure@src/lib.rs:2:5: 2:14]`
-
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 
-Some errors have detailed explanations: E0277, E0308.
-For more information about an error, try `rustc --explain E0277`.
+For more information about this error, try `rustc --explain E0277`.
 error: could not compile `functions-example`.
 
 To learn more, run the command again with --verbose.
diff --git a/listings/ch20-web-server/no-listing-01-define-threadpool-struct/output.txt b/listings/ch20-web-server/no-listing-01-define-threadpool-struct/output.txt
@@ -1,6 +1,6 @@
 $ cargo check
     Checking hello v0.1.0 (file:///projects/hello)
-error[E0599]: no function or associated item named `new` found for type `hello::ThreadPool` in the current scope
+error[E0599]: no function or associated item named `new` found for struct `hello::ThreadPool` in the current scope
   --> src/bin/main.rs:11:28
    |
 11 |     let pool = ThreadPool::new(4);

diff --git a/listings/ch20-web-server/no-listing-02-impl-threadpool-new/output.txt b/listings/ch20-web-server/no-listing-02-impl-threadpool-new/output.txt
@@ -1,6 +1,6 @@
 $ cargo check
     Checking hello v0.1.0 (file:///projects/hello)
-error[E0599]: no method named `execute` found for type `hello::ThreadPool` in the current scope
+error[E0599]: no method named `execute` found for struct `hello::ThreadPool` in the current scope
   --> src/bin/main.rs:16:14
    |
 16 |         pool.execute(|| {