Updates for Rust 1.82 (#2449)

Rust 1.82 adds `&raw` expressions, and marks some attributes as unsafe.

src/android/interoperability/java/src/lib.rs

@@ -20,7 +20,8 @@ use jni::sys::jstring;
 use jni::JNIEnv;
 
 /// HelloWorld::hello method implementation.
-#[no_mangle]
+// SAFETY: There is no other global function of this name.
+#[unsafe(no_mangle)]
 pub extern "system" fn Java_HelloWorld_hello(
     mut env: JNIEnv,
     _class: JClass,

src/android/interoperability/with-c.md

@@ -6,14 +6,13 @@ Similarly, you can export Rust functions and call them from C.
 You can do it by hand if you want:
 
 ```rust
-extern "C" {
-    fn abs(x: i32) -> i32;
+unsafe extern "C" {
+    safe fn abs(x: i32) -> i32;
 }
 
 fn main() {
     let x = -42;
-    // SAFETY: `abs` doesn't have any safety requirements.
-    let abs_x = unsafe { abs(x) };
+    let abs_x = abs(x);
     println!("{x}, {abs_x}");
 }
 ```

src/android/interoperability/with-c/hand-written.md

@@ -3,14 +3,13 @@
 We can declare external functions by hand:
 
 ```rust
-extern "C" {
-    fn abs(x: i32) -> i32;
+unsafe extern "C" {
+    safe fn abs(x: i32) -> i32;
 }
 
 fn main() {
     let x = -42;
-    // SAFETY: `abs` doesn't have any safety requirements.
-    let abs_x = unsafe { abs(x) };
+    let abs_x = abs(x);
     println!("{x}, {abs_x}");
 }
 ```

src/android/interoperability/with-c/rust.md

@@ -42,8 +42,8 @@ Build, push, and run the binary on your device:
 
 <details>
 
-`#[no_mangle]` disables Rust's usual name mangling, so the exported symbol will
-just be the name of the function. You can also use
-`#[export_name = "some_name"]` to specify whatever name you want.
+`#[unsafe(no_mangle)]` disables Rust's usual name mangling, so the exported
+symbol will just be the name of the function. You can also use
+`#[unsafe(export_name = "some_name")]` to specify whatever name you want.
 
 </details>

src/android/interoperability/with-c/rust/libanalyze/analyze.rs

@@ -19,7 +19,8 @@
 use std::os::raw::c_int;
 
 /// Analyze the numbers.
-#[no_mangle]
+// SAFETY: There is no other global function of this name.
+#[unsafe(no_mangle)]
 pub extern "C" fn analyze_numbers(x: c_int, y: c_int) {
     if x < y {
         println!("x ({x}) is smallest!");