diff --git a/pymbolic/mapper/optimize.py b/pymbolic/mapper/optimize.py
index 5be7d68..c6c2a1f 100644
--- a/pymbolic/mapper/optimize.py
+++ b/pymbolic/mapper/optimize.py
@@ -48,16 +48,25 @@
 AstDefNodeT = TypeVar("AstDefNodeT", ast.FunctionDef, ast.ClassDef)
 
 
+_NOT_SEEN = object()
+
+
 def _get_def_from_ast_container(
             container: Iterable[ast.AST],
             name: str,
             node_type: type[AstDefNodeT]
         ) -> AstDefNodeT:
+    # Return the last definition in the container, not the first.
+    # This is relevant, e.g., in the case of @overload of methods.
+    result = _NOT_SEEN
     for entry in container:
         if isinstance(entry, node_type) and entry.name == name:
-            return entry
+            result = entry
+
+    if result is _NOT_SEEN:
+        raise ValueError(f"symbol '{name}' not found")
 
-    raise ValueError(f"symbol '{name}' not found")
+    return result
 
 
 @lru_cache