Rfc 2070 panic implementation deprecated (#467)

* Make changes to code examples.

* Explain that panic_implementation has been deprecated

* Update attributes in source code.

blog/content/second-edition/posts/01-freestanding-rust-binary/index.md

@@ -134,17 +134,19 @@ This sets the panic strategy to `abort` for both the `dev` profile (used for `ca
 
 ### Panic Implementation
 
-The `panic_impl` language item defines the function that the compiler should invoke when a [panic] occurs. Instead of providing the language item directly, we can use the [`panic_implementation`] attribute to create a `panic` function:
+The `panic_impl` language item defines the function that the compiler should invoke when a [panic] occurs. Instead of providing the language item directly, we can use the [`panic_handler`] attribute to create a `panic` function. This used to take the for [`panic_implementation`], which has been deprecated and replaced by [`panic_handler`].
 
 [`panic_implementation`]: https://github.com/rust-lang/rfcs/blob/master/text/2070-panic-implementation.md#panic_implementation
 
+Note: [`panic_implementation`] has been deprecated, and we now use [`panic_handler`] instead
+
 ```rust
 // in main.rs
 
 use core::panic::PanicInfo;
 
 /// This function is called on panic.
-#[panic_implementation]
+#[panic_handler]
 #[no_mangle]
 pub fn panic(_info: &PanicInfo) -> ! {
     loop {}
@@ -157,11 +159,11 @@ The [`PanicInfo` parameter][PanicInfo] contains the file and line where the pani
 [diverging function]: https://doc.rust-lang.org/book/first-edition/functions.html#diverging-functions
 [“never” type]: https://doc.rust-lang.org/nightly/std/primitive.never.html
 
-When we try `cargo build` now, we get an error that “#[panic_implementation] is an unstable feature”.
+When we try `cargo build` now, we get an error that “#[panic_handler] is an unstable feature”.
 
 #### Enabling Unstable Features
 
-The `panic_implementation` attribute was recently added and is thus still unstable and protected by a so-called _feature gate_. A feature gate is a special attribute that you have to specify at the top of your `main.rs` in order to use the corresponding feature. By doing this you basically say: “I know that this feature is unstable and that it might stop working without any warnings. I want to use it anyway.”
+The `panic_handler` attribute was recently added and is thus still unstable and protected by a so-called _feature gate_. A feature gate is a special attribute that you have to specify at the top of your `main.rs` in order to use the corresponding feature. By doing this you basically say: “I know that this feature is unstable and that it might stop working without any warnings. I want to use it anyway.”
 
 Feature gates are not available in the stable or beta Rust compilers, only [nightly Rust] makes it possible to opt-in. This means that you have to use a nightly compiler for OS development for the near future (until all unstable features that we need are added are stabilized).
 
@@ -171,8 +173,6 @@ To manage Rust installations I highly recommend [rustup]. It allows you to insta
 
 [rustup]: https://www.rustup.rs/
 
-After installing a nightly Rust compiler, you can enable the unstable `panic_implementation` feature by inserting `#![feature(panic_implementation)]` right at the top of `main.rs`.
-
 Now we fixed both language item errors. However, if we try to compile it now, another language item is required:
 
 ```
@@ -196,14 +196,13 @@ Our freestanding executable does not have access to the Rust runtime and `crt0`,
 To tell the Rust compiler that we don't want to use the normal entry point chain, we add the `#![no_main]` attribute.
 
 ```rust
-#![feature(panic_implementation)]
 #![no_std]
 #![no_main]
 
 use core::panic::PanicInfo;
 
 /// This function is called on panic.
-#[panic_implementation]
+#[panic_handler]
 #[no_mangle]
 pub fn panic(_info: &PanicInfo) -> ! {
     loop {}
@@ -311,14 +310,13 @@ A minimal freestanding Rust binary looks like this:
 `src/main.rs`:
 
 ```rust
-#![feature(panic_implementation)] // required for defining the panic handler
 #![no_std] // don't link the Rust standard library
 #![no_main] // disable all Rust-level entry points
 
 use core::panic::PanicInfo;
 
 /// This function is called on panic.
-#[panic_implementation]
+#[panic_handler]
 #[no_mangle]
 pub fn panic(_info: &PanicInfo) -> ! {
     loop {}

blog/content/second-edition/posts/02-minimal-rust-kernel/index.md

@@ -199,14 +199,13 @@ Compiling for our new target will use Linux conventions (I'm not quite sure why,
 ```rust
 // src/main.rs
 
-#![feature(panic_implementation)] // required for defining the panic handler
 #![no_std] // don't link the Rust standard library
 #![no_main] // disable all Rust-level entry points
 
 use core::panic::PanicInfo;
 
 /// This function is called on panic.
-#[panic_implementation]
+#[panic_handler]
 #[no_mangle]
 pub fn panic(_info: &PanicInfo) -> ! {
     loop {}

blog/content/second-edition/posts/03-vga-text-buffer/index.md

@@ -627,7 +627,7 @@ Now that we have a `println` macro, we can use it in our panic function to print
 // in main.rs
 
 /// This function is called on panic.
-#[panic_implementation]
+#[panic_handler]
 #[no_mangle]
 pub fn panic(info: &PanicInfo) -> ! {
     println!("{}", info);

blog/content/second-edition/posts/04-unit-testing/index.md

@@ -37,7 +37,7 @@ error[E0152]: duplicate lang item found: `panic_impl`.
    = note: first defined in crate `std`.
 ```
 
-The problem is that unit tests are built for the host machine, with the `std` library included. This makes sense because they should be able to run as a normal application on the host operating system. Since the standard library has it's own `panic_implementation` function, we get the above error. To fix it, we use [conditional compilation] to include our implementation of the panic handler only in non-test environments:
+The problem is that unit tests are built for the host machine, with the `std` library included. This makes sense because they should be able to run as a normal application on the host operating system. Since the standard library has it's own `panic_handler` function, we get the above error. To fix it, we use [conditional compilation] to include our implementation of the panic handler only in non-test environments:
 
 [conditional compilation]: https://doc.rust-lang.org/reference/attributes.html#conditional-compilation
 
@@ -48,7 +48,7 @@ The problem is that unit tests are built for the host machine, with the `std` li
 use core::panic::PanicInfo;
 
 #[cfg(not(test))] // only compile when the test flag is not set
-#[panic_implementation]
+#[panic_handler]
 #[no_mangle]
 pub fn panic(info: &PanicInfo) -> ! {
     println!("{}", info);

blog/content/second-edition/posts/05-integration-tests/index.md

@@ -329,7 +329,6 @@ Cargo allows to add [additional executables] to a project by putting them inside
 ```rust
 // src/bin/test-something.rs
 
-#![feature(panic_implementation)]
 #![no_std]
 #![cfg_attr(not(test), no_main)]
 #![cfg_attr(test, allow(dead_code, unused_macros, unused_imports))]
@@ -344,7 +343,7 @@ pub extern "C" fn _start() -> ! {
 }
 
 #[cfg(not(test))]
-#[panic_implementation]
+#[panic_handle]
 #[no_mangle]
 pub fn panic(_info: &PanicInfo) -> ! {
     loop {}
@@ -402,7 +401,6 @@ pub unsafe fn exit_qemu() {
 ```rust
 // src/main.rs
 
-#![feature(panic_implementation)] // required for defining the panic handler
 #![no_std] // don't link the Rust standard library
 #![cfg_attr(not(test), no_main)] // disable all Rust-level entry points
 #![cfg_attr(test, allow(dead_code, unused_macros, unused_imports))]
@@ -425,7 +423,7 @@ pub extern "C" fn _start() -> ! {
 
 /// This function is called on panic.
 #[cfg(not(test))]
-#[panic_implementation]
+#[panic_handler]
 #[no_mangle]
 pub fn panic(info: &PanicInfo) -> ! {
     println!("{}", info);
@@ -464,7 +462,6 @@ We are finally able to create our first integration test executable. We start si
 ```rust
 // in src/bin/test-basic-boot.rs
 
-#![feature(panic_implementation)] // required for defining the panic handler
 #![no_std] // don't link the Rust standard library
 #![cfg_attr(not(test), no_main)] // disable all Rust-level entry points
 #![cfg_attr(test, allow(dead_code, unused_macros, unused_imports))]
@@ -490,7 +487,7 @@ pub extern "C" fn _start() -> ! {
 
 /// This function is called on panic.
 #[cfg(not(test))]
-#[panic_implementation]
+#[panic_handler]
 #[no_mangle]
 pub fn panic(info: &PanicInfo) -> ! {
     serial_println!("failed");
@@ -531,7 +528,6 @@ To test that our panic handler is really invoked on a panic, we create a `test-p
 ```rust
 // in src/bin/test-panic.rs
 
-#![feature(panic_implementation)]
 #![no_std]
 #![cfg_attr(not(test), no_main)]
 #![cfg_attr(test, allow(dead_code, unused_macros, unused_imports))]
@@ -549,7 +545,7 @@ pub extern "C" fn _start() -> ! {
 }
 
 #[cfg(not(test))]
-#[panic_implementation]
+#[panic_handler]
 #[no_mangle]
 pub fn panic(_info: &PanicInfo) -> ! {
     serial_println!("ok");

src/bin/test-basic-boot.rs

@@ -1,4 +1,3 @@
-#![feature(panic_implementation)] // required for defining the panic handler
 #![no_std] // don't link the Rust standard library
 #![cfg_attr(not(test), no_main)] // disable all Rust-level entry points
 #![cfg_attr(test, allow(dead_code, unused_macros, unused_imports))]
@@ -25,7 +24,7 @@ pub extern "C" fn _start() -> ! {
 
 /// This function is called on panic.
 #[cfg(not(test))]
-#[panic_implementation]
+#[panic_handler]
 #[no_mangle]
 pub fn panic(info: &PanicInfo) -> ! {
     serial_println!("failed");

src/bin/test-exception-breakpoint.rs

@@ -1,4 +1,3 @@
-#![feature(panic_implementation)]
 #![feature(abi_x86_interrupt)]
 #![no_std]
 #![cfg_attr(not(test), no_main)]
@@ -45,7 +44,7 @@ pub extern "C" fn _start() -> ! {
 
 /// This function is called on panic.
 #[cfg(not(test))]
-#[panic_implementation]
+#[panic_handler]
 #[no_mangle]
 pub fn panic(info: &PanicInfo) -> ! {
     serial_println!("failed");

src/bin/test-exception-double-fault-stack-overflow.rs

@@ -1,4 +1,3 @@
-#![feature(panic_implementation)]
 #![feature(abi_x86_interrupt)]
 #![no_std]
 #![cfg_attr(not(test), no_main)]
@@ -39,7 +38,7 @@ pub extern "C" fn _start() -> ! {
 
 /// This function is called on panic.
 #[cfg(not(test))]
-#[panic_implementation]
+#[panic_handler]
 #[no_mangle]
 pub fn panic(info: &PanicInfo) -> ! {
     serial_println!("failed");

src/bin/test-panic.rs

@@ -1,4 +1,3 @@
-#![feature(panic_implementation)]
 #![no_std]
 #![cfg_attr(not(test), no_main)]
 #![cfg_attr(test, allow(dead_code, unused_macros, unused_imports))]
@@ -16,7 +15,7 @@ pub extern "C" fn _start() -> ! {
 }
 
 #[cfg(not(test))]
-#[panic_implementation]
+#[panic_handler]
 #[no_mangle]
 pub fn panic(_info: &PanicInfo) -> ! {
     serial_println!("ok");

src/main.rs

@@ -1,4 +1,3 @@
-#![feature(panic_implementation)] // required for defining the panic handler
 #![feature(abi_x86_interrupt)]
 #![no_std] // don't link the Rust standard library
 #![cfg_attr(not(test), no_main)] // disable all Rust-level entry points
@@ -35,7 +34,7 @@ pub extern "C" fn _start() -> ! {
 
 /// This function is called on panic.
 #[cfg(not(test))]
-#[panic_implementation]
+#[panic_handler]
 #[no_mangle]
 pub fn panic(info: &PanicInfo) -> ! {
     println!("{}", info);