diff --git a/lib/checkstl.cpp b/lib/checkstl.cpp
index 6d51bd928..ebeb7f44f 100644
--- a/lib/checkstl.cpp
+++ b/lib/checkstl.cpp
@@ -2439,7 +2439,7 @@ void CheckStl::checkMutexes()
                     continue;
                 if (isLocalMutex(var, tok->scope()))
                     localMutexError(tok);
-            } else if (Token::Match(tok, "%var% (|{ %var% )|}")) {
+            } else if (Token::Match(tok, "%var% (|{ %var% )|}|,")) {
                 if (!isLockGuard(var))
                     continue;
                 const Variable* mvar = tok->tokAt(2)->variable();
diff --git a/test/teststl.cpp b/test/teststl.cpp
index 677efae2a..240e20709 100644
--- a/test/teststl.cpp
+++ b/test/teststl.cpp
@@ -4429,6 +4429,22 @@ private:
               true);
         ASSERT_EQUALS("", errout.str());
 
+        check("void f() {\n"
+              "    static std::mutex m;\n"
+              "    static std::unique_lock<std::mutex> g(m, std::defer_lock);\n"
+              "    static std::lock(g);\n"
+              "}\n",
+              true);
+        ASSERT_EQUALS("[test.cpp:3]: (warning) Lock guard is defined globally. Lock guards are intended to be local. A global lock guard could lead to a deadlock since it won't unlock until the end of the program.\n", errout.str());
+
+        check("void f() {\n"
+              "    static std::mutex m;\n"
+              "    std::unique_lock<std::mutex> g(m, std::defer_lock);\n"
+              "    std::lock(g);\n"
+              "}\n",
+              true);
+        ASSERT_EQUALS("", errout.str());
+
         check("void f() {\n"
               "    std::mutex m;\n"
               "    std::lock_guard<std::mutex> g(m);\n"
@@ -4436,6 +4452,21 @@ private:
               true);
         ASSERT_EQUALS("[test.cpp:3]: (warning) The lock is ineffective because the mutex is locked at the same scope as the mutex itself.\n", errout.str());
 
+        check("void f() {\n"
+              "    std::mutex m;\n"
+              "    std::unique_lock<std::mutex> g(m);\n"
+              "}\n",
+              true);
+        ASSERT_EQUALS("[test.cpp:3]: (warning) The lock is ineffective because the mutex is locked at the same scope as the mutex itself.\n", errout.str());
+
+        check("void f() {\n"
+              "    std::mutex m;\n"
+              "    std::unique_lock<std::mutex> g(m, std::defer_lock);\n"
+              "    std::lock(g);\n"
+              "}\n",
+              true);
+        ASSERT_EQUALS("[test.cpp:3]: (warning) The lock is ineffective because the mutex is locked at the same scope as the mutex itself.\n", errout.str());
+
         check("void g();\n"
               "void f() {\n"
               "    static std::mutex m;\n"