diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 562c082d06143d..40bfc7a0991c38 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -4375,7 +4375,14 @@ fn (mut c Checker) mark_as_referenced(mut node ast.Expr, as_interface bool) {
 								node.obj.is_auto_heap = true
 							}
 						}
-						.sum_type, .interface_, .function {}
+						.sum_type, .interface_ {}
+						.function {
+							if type_sym.info is ast.FnType {
+								if type_sym.info.is_anon {
+									node.obj.is_auto_heap = true
+								}
+							}
+						}
 						else {
 							node.obj.is_auto_heap = true
 						}