diff --git a/sphinx/writers/latex.py b/sphinx/writers/latex.py
index 845c0d8e608..00e8db942a2 100644
--- a/sphinx/writers/latex.py
+++ b/sphinx/writers/latex.py
@@ -892,6 +892,7 @@ def visit_desc_parameterlist(self, node: Element) -> None:
 
     def depart_desc_parameterlist(self, node: Element) -> None:
         # close parameterlist, open return annotation
+        assert not self.orphan_tp_list
         self.body.append('}' + CR + '{')
 
     def visit_desc_type_parameter_list(self, node: Element) -> None: