diff --git a/sphinx/domains/cpp.py b/sphinx/domains/cpp.py
index 9248a35e0..23df1f7dd 100644
--- a/sphinx/domains/cpp.py
+++ b/sphinx/domains/cpp.py
@@ -530,7 +530,7 @@ _id_operator_v2 = {
     '()': 'cl',
     '[]': 'ix',
     '.*': 'ds',  # this one is not overloadable, but we need it for expressions
-    '?': 'cn',
+    '?': 'qu',
 }
 _id_operator_unary_v2 = {
     '++': 'pp_',
diff --git a/tests/test_domain_cpp.py b/tests/test_domain_cpp.py
index 230c97ccd..dc7ffe658 100644
--- a/tests/test_domain_cpp.py
+++ b/tests/test_domain_cpp.py
@@ -326,8 +326,8 @@ def test_domain_cpp_ast_expressions():
     exprCheck('5 .* 42', 'dsL5EL42E')
     exprCheck('5 ->* 42', 'pmL5EL42E')
     # conditional
-    exprCheck('5 ? 7 : 3', 'cnL5EL7EL3E')
-    exprCheck('5 = 6 ? 7 = 8 : 3', 'aSL5EcnL6EaSL7EL8EL3E')
+    exprCheck('5 ? 7 : 3', 'quL5EL7EL3E')
+    exprCheck('5 = 6 ? 7 = 8 : 3', 'aSL5EquL6EaSL7EL8EL3E')
     # assignment
     exprCheck('a = 5', 'aS1aL5E')
     exprCheck('a *= 5', 'mL1aL5E')