From 7355c13512374e14b93f7124f67e71d300924f4c Mon Sep 17 00:00:00 2001
From: Josh Goebel <me@joshgoebel.com>
Date: Wed, 29 Dec 2021 07:01:45 -0500
Subject: [PATCH] fix(cpp) `vector<<` false positive as template begin (#3438)

---
 CHANGES.md                      | 1 +
 src/languages/cpp.js            | 2 +-
 test/markup/cpp/bugs.expect.txt | 6 ++++++
 test/markup/cpp/bugs.txt        | 6 ++++++
 4 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100644 test/markup/cpp/bugs.expect.txt
 create mode 100644 test/markup/cpp/bugs.txt

diff --git a/CHANGES.md b/CHANGES.md
index b5c98322d9..071402f28d 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -15,6 +15,7 @@ These changes should be for the better and should not be super noticeable but if
 Grammars:
 
 - enh(php) add PHP 8.1 keywords [Wojciech Kania][]
+- fix(cpp) fix `vector<<` template false positive (#3437) [Josh Goebel][]
 - enh(php) support First-class Callable Syntax (#3427) [Wojciech Kania][]
 - enh(php) support class constructor call (#3427) [Wojciech Kania][]
 - enh(php) support function invoke (#3427) [Wojciech Kania][]
diff --git a/src/languages/cpp.js b/src/languages/cpp.js
index e2cf5a9d28..54e3bced7d 100644
--- a/src/languages/cpp.js
+++ b/src/languages/cpp.js
@@ -558,7 +558,7 @@ export default function(hljs) {
       [
         PREPROCESSOR,
         { // containers: ie, `vector <int> rooms (9);`
-          begin: '\\b(deque|list|queue|priority_queue|pair|stack|vector|map|set|bitset|multiset|multimap|unordered_map|unordered_set|unordered_multiset|unordered_multimap|array|tuple|optional|variant|function)\\s*<',
+          begin: '\\b(deque|list|queue|priority_queue|pair|stack|vector|map|set|bitset|multiset|multimap|unordered_map|unordered_set|unordered_multiset|unordered_multimap|array|tuple|optional|variant|function)\\s*<(?!<)',
           end: '>',
           keywords: CPP_KEYWORDS,
           contains: [
diff --git a/test/markup/cpp/bugs.expect.txt b/test/markup/cpp/bugs.expect.txt
new file mode 100644
index 0000000000..08e8689dfc
--- /dev/null
+++ b/test/markup/cpp/bugs.expect.txt
@@ -0,0 +1,6 @@
+<span class="hljs-comment">//4. 对角矩阵</span>
+<span class="hljs-comment">//4.1 构造对角矩阵</span>
+<span class="hljs-function">Eigen::VectorXd <span class="hljs-title">vector</span><span class="hljs-params">(<span class="hljs-number">5</span>)</span></span>;                <span class="hljs-comment">//构建5维向量</span>
+vector&lt;&lt;<span class="hljs-number">1</span>,<span class="hljs-number">2</span>,<span class="hljs-number">3</span>,<span class="hljs-number">4</span>,<span class="hljs-number">5</span>;                        <span class="hljs-comment">//向量赋值</span>
+<span class="hljs-function">Eigen::MatrixXd  <span class="hljs-title">C</span><span class="hljs-params">(vector.asDiagonal())</span></span>;  <span class="hljs-comment">//使用向量生成对角阵</span>
+std::cout &lt;&lt; <span class="hljs-string">&quot;\nC= \n&quot;</span> &lt;&lt; C &lt;&lt; std::endl;
diff --git a/test/markup/cpp/bugs.txt b/test/markup/cpp/bugs.txt
new file mode 100644
index 0000000000..00c4281821
--- /dev/null
+++ b/test/markup/cpp/bugs.txt
@@ -0,0 +1,6 @@
+//4. 对角矩阵
+//4.1 构造对角矩阵
+Eigen::VectorXd vector(5);                //构建5维向量
+vector<<1,2,3,4,5;                        //向量赋值
+Eigen::MatrixXd  C(vector.asDiagonal());  //使用向量生成对角阵
+std::cout << "\nC= \n" << C << std::endl;