From 0d4207f2c5b7bea9683a938bc3c40fd4452c7d8d Mon Sep 17 00:00:00 2001
From: Frances Wingerter <91758128+fw-immunant@users.noreply.github.com>
Date: Thu, 3 Jul 2025 17:07:22 +0000
Subject: [PATCH 1/3] rust: `className` -> `scope`

Co-authored-by: Josh Goebel <me@joshgoebel.com>
---
 src/languages/rust.js | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/languages/rust.js b/src/languages/rust.js
index 13e7be19f2..c0795b8736 100644
--- a/src/languages/rust.js
+++ b/src/languages/rust.js
@@ -17,7 +17,7 @@ export default function(hljs) {
   const IDENT_RE = regex.concat(RAW_IDENTIFIER, hljs.IDENT_RE);
   // ============================================
   const FUNCTION_INVOKE = {
-    className: "title.function.invoke",
+    scope: "title.function.invoke",
     relevance: 0,
     begin: regex.concat(
       /\b/,
@@ -199,7 +199,7 @@ export default function(hljs) {
         illegal: null
       }),
       {
-        className: 'symbol',
+        scope: 'symbol',
         // negative lookahead to avoid matching `'`
         begin: /'[a-zA-Z_][a-zA-Z0-9_]*(?!')/
       },
@@ -220,7 +220,7 @@ export default function(hljs) {
         ]
       },
       {
-        className: 'number',
+        scope: 'number',
         variants: [
           { begin: '\\b0b([01_]+)' + NUMBER_SUFFIX },
           { begin: '\\b0o([0-7_]+)' + NUMBER_SUFFIX },
@@ -236,18 +236,18 @@ export default function(hljs) {
           /\s+/,
           UNDERSCORE_IDENT_RE
         ],
-        className: {
+        scope: {
           1: "keyword",
           3: "title.function"
         }
       },
       {
-        className: 'meta',
+        scope: 'meta',
         begin: '#!?\\[',
         end: '\\]',
         contains: [
           {
-            className: 'string',
+            scope: 'string',
             begin: /"/,
             end: /"/,
             contains: [
@@ -263,7 +263,7 @@ export default function(hljs) {
           /(?:mut\s+)?/,
           UNDERSCORE_IDENT_RE
         ],
-        className: {
+        scope: {
           1: "keyword",
           3: "keyword",
           4: "variable"
@@ -278,7 +278,7 @@ export default function(hljs) {
           /\s+/,
           /in/
         ],
-        className: {
+        scope: {
           1: "keyword",
           3: "variable",
           5: "keyword"
@@ -290,7 +290,7 @@ export default function(hljs) {
           /\s+/,
           UNDERSCORE_IDENT_RE
         ],
-        className: {
+        scope: {
           1: "keyword",
           3: "title.class"
         }
@@ -301,7 +301,7 @@ export default function(hljs) {
           /\s+/,
           UNDERSCORE_IDENT_RE
         ],
-        className: {
+        scope: {
           1: "keyword",
           3: "title.class"
         }
@@ -315,7 +315,7 @@ export default function(hljs) {
         }
       },
       {
-        className: "punctuation",
+        scope: "punctuation",
         begin: '->'
       },
       FUNCTION_INVOKE

From 98d2a772388565b04b4396fc5220d805a652447d Mon Sep 17 00:00:00 2001
From: Frances Wingerter <91758128+fw-immunant@users.noreply.github.com>
Date: Thu, 3 Jul 2025 16:58:34 +0000
Subject: [PATCH 2/3] rust: add `safe` keyword

This is a "weak" keyword, only applicable in Rust 2024+ `unsafe extern` blocks,
immediately prior to the "extern" keyword:

https://doc.rust-lang.org/reference/keywords.html#r-lex.keywords.weak.safe
---
 src/languages/rust.js | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/languages/rust.js b/src/languages/rust.js
index c0795b8736..ca3ba627c8 100644
--- a/src/languages/rust.js
+++ b/src/languages/rust.js
@@ -230,6 +230,17 @@ export default function(hljs) {
         ],
         relevance: 0
       },
+      {
+        begin: [
+          /\bsafe/,
+          /\s+/,
+          /extern/,
+        ],
+        scope: {
+          1: "keyword",
+          3: "keyword",
+        }
+      },
       {
         begin: [
           /fn/,

From 438e403c3e65fa79c47ee451267f888c58940c0d Mon Sep 17 00:00:00 2001
From: Frances Wingerter <fw@immunant.com>
Date: Thu, 3 Jul 2025 18:50:24 +0000
Subject: [PATCH 3/3] rust: add tests for safe keyword in unsafe extern block

---
 test/markup/rust/extern.expect.txt | 4 ++++
 test/markup/rust/extern.txt        | 4 ++++
 2 files changed, 8 insertions(+)
 create mode 100644 test/markup/rust/extern.expect.txt
 create mode 100644 test/markup/rust/extern.txt

diff --git a/test/markup/rust/extern.expect.txt b/test/markup/rust/extern.expect.txt
new file mode 100644
index 0000000000..ea26fda242
--- /dev/null
+++ b/test/markup/rust/extern.expect.txt
@@ -0,0 +1,4 @@
+<span class="hljs-keyword">unsafe</span> <span class="hljs-keyword">extern</span> <span class="hljs-string">&quot;C&quot;</span> {
+<span class="hljs-keyword">unsafe</span> <span class="hljs-keyword">fn</span> <span class="hljs-title function_">foo</span>();
+safe <span class="hljs-keyword">fn</span> <span class="hljs-title function_">foo</span>();
+}
diff --git a/test/markup/rust/extern.txt b/test/markup/rust/extern.txt
new file mode 100644
index 0000000000..6ebb795631
--- /dev/null
+++ b/test/markup/rust/extern.txt
@@ -0,0 +1,4 @@
+unsafe extern "C" {
+unsafe fn foo();
+safe fn foo();
+}