fix(rust) reuse the string rules inside attributes

CHANGES.md

@@ -6,6 +6,7 @@ Core Grammars:
 - enh(dos) add `batch` as an alias, issue #4395 [Hashim Khan][]
 - fix(lisp) preserve highlighting after quoted multiplication expressions [arturict][]
 - fix(rust) recognize `\\` and `\"` char-literal escapes so highlighting doesn't leak, issue #4351 [Sarath Francis][]
+- fix(rust) reuse the string rules inside attributes so raw and byte strings are highlighted there, issue #3817 [Maksim Zhukau][]
 - fix(cmake) only highlight standalone numbers, not digits that begin an identifier (e.g. `3rdparty`), issue #4170 [MarkXian][]
 - fix(cpp) require a word boundary before numeric literals so digits inside identifiers aren't highlighted as numbers, issue #4231 [Mark Xian][]
 - fix(c) only match real `atomic_*` type names, not C11 atomic functions, issue #3837 [MarkXian][]
@@ -43,6 +44,7 @@ CONTRIBUTORS
 [Nicolas Le Cam]: https://github.com/KuSh
 [Konstantin Baltsat]: https://github.com/Baltsat
 [David Pavlovschii]: https://github.com/davidpavlovschi
+[Maksim Zhukau]: https://github.com/MaksZhukov
 [Pablo]: https://github.com/MsfPablo
 [Jayesh Bhade]: https://github.com/Jaybhade
 [Hirse]: https://github.com/Hirse

src/languages/rust.js

@@ -157,6 +157,26 @@ export default function(hljs) {
     "assert_ne!",
     "debug_assert_ne!"
   ];
+  const QUOTE_STRING = hljs.inherit(hljs.QUOTE_STRING_MODE, {
+    begin: /b?"/,
+    illegal: null
+  });
+  const RAW_STRING = {
+    scope: 'string',
+    // rustc caps raw string delimiters at 255 hashes
+    begin: /b?r(#{0,255})"(.|\n)*?"\1(?!#)/
+  };
+  const CHARACTER = {
+    scope: 'string',
+    begin: /b?'/,
+    end: /'/,
+    contains: [
+      {
+        scope: "char.escape",
+        match: /\\('|"|\\|\w|x\w{2}|u\w{4}|U\w{8})/
+      }
+    ]
+  };
   const TYPES = [
     "i8",
     "i16",
@@ -197,31 +217,14 @@ export default function(hljs) {
     contains: [
       hljs.C_LINE_COMMENT_MODE,
       hljs.COMMENT('/\\*', '\\*/', { contains: [ 'self' ] }),
-      hljs.inherit(hljs.QUOTE_STRING_MODE, {
-        begin: /b?"/,
-        illegal: null
-      }),
+      QUOTE_STRING,
       {
         scope: 'symbol',
         // negative lookahead to avoid matching `'`
         begin: /'[a-zA-Z_][a-zA-Z0-9_]*(?!')/
       },
-      {
-        scope: 'string',
-        variants: [
-          { begin: /b?r(#*)"(.|\n)*?"\1(?!#)/ },
-          {
-            begin: /b?'/,
-            end: /'/,
-            contains: [
-              {
-                scope: "char.escape",
-                match: /\\('|"|\\|\w|x\w{2}|u\w{4}|U\w{8})/
-              }
-            ]
-          }
-        ]
-      },
+      RAW_STRING,
+      CHARACTER,
       {
         scope: 'number',
         variants: [
@@ -260,14 +263,10 @@ export default function(hljs) {
         begin: '#!?\\[',
         end: '\\]',
         contains: [
-          {
-            scope: 'string',
-            begin: /"/,
-            end: /"/,
-            contains: [
-              hljs.BACKSLASH_ESCAPE
-            ]
-          }
+          // attributes hold arbitrary token trees, so any string literal
+          // that is valid elsewhere is valid here too
+          QUOTE_STRING,
+          RAW_STRING
         ]
       },
       {

test/markup/rust/strings.expect.txt

@@ -22,5 +22,11 @@
 <span class="hljs-string">br&quot; &quot;</span>;
 <span class="hljs-string">br#&quot;hello&quot;#</span>;
 <span class="hljs-string">br##&quot;foo&quot;##</span>;
+<span class="hljs-string">r################&quot;many hashes&quot;################</span>;
 
 <span class="hljs-meta">#[error(<span class="hljs-string">&quot;\&quot; appears in a string&quot;</span>)]</span>
+<span class="hljs-meta">#[doc = <span class="hljs-string">r#&quot;a &quot;quoted&quot; word&quot;#</span>]</span>
+<span class="hljs-meta">#[doc = <span class="hljs-string">b&quot;bytes&quot;</span>]</span>
+<span class="hljs-meta">#[doc = <span class="hljs-string">r##&quot;multi
+line &quot;# raw&quot;##</span>]</span>
+<span class="hljs-meta">#[foo(Bar&lt;&#x27;a&gt;)]</span>

test/markup/rust/strings.txt

@@ -22,5 +22,11 @@ r##" "###
 br" ";
 br#"hello"#;
 br##"foo"##;
+r################"many hashes"################;
 
 #[error("\" appears in a string")]
+#[doc = r#"a "quoted" word"#]
+#[doc = b"bytes"]
+#[doc = r##"multi
+line "# raw"##]
+#[foo(Bar<'a>)]