--- a/tools/clang-tidy/config.yaml
+++ b/tools/clang-tidy/config.yaml
@@ -59,16 +59,18 @@ clang_checkers:
   - name: misc-string-integer-assignment
     publish: !!bool yes
   - name: misc-suspicious-missing-comma
     publish: !!bool yes
   - name: misc-suspicious-semicolon
     publish: !!bool yes
   - name: misc-swapped-arguments
     publish: !!bool yes
+  - name: misc-unused-alias-decls
+    publish: !!bool yes
   - name: misc-unused-using-decls
     publish: !!bool yes
   - name: modernize-avoid-bind
     publish: !!bool yes
     restricted-platforms:
       - win32
       - win64
   - name: modernize-loop-convert

new file mode 100644
--- /dev/null
+++ b/tools/clang-tidy/test/misc-unused-alias-decls.cpp
@@ -0,0 +1,18 @@
+// https://clang.llvm.org/extra/clang-tidy/checks/misc-unused-alias-decls.html
+
+namespace n1 {
+    namespace n2 {
+         namespace n3 {
+             int qux = 42;
+         }
+    }
+}
+
+namespace n1_unused = ::n1;     // WARNING
+namespace n12_unused = n1::n2;  // WARNING
+namespace n123 = n1::n2::n3;    // OK
+
+int test()
+{
+  return n123::qux;
+}

new file mode 100644
--- /dev/null
+++ b/tools/clang-tidy/test/misc-unused-alias-decls.json
@@ -0,0 +1,1 @@
+"[[\"warning\", \"namespace alias decl 'n1_unused' is unused\", \"misc-unused-alias-decls\"], [\"warning\", \"namespace alias decl 'n12_unused' is unused\", \"misc-unused-alias-decls\"]]"
\ No newline at end of file