diff --git a/ports/geckolib/tests/size_of.rs b/ports/geckolib/tests/size_of.rs
index eaa95dce24f..25ac3d853a7 100644
--- a/ports/geckolib/tests/size_of.rs
+++ b/ports/geckolib/tests/size_of.rs
@@ -43,7 +43,7 @@ size_of_test!(test_size_of_rule_node, RuleNode, 80);
 
 // This is huge, but we allocate it on the stack and then never move it,
 // we only pass `&mut SourcePropertyDeclaration` references around.
-size_of_test!(test_size_of_parsed_declaration, style::properties::SourcePropertyDeclaration, 576);
+size_of_test!(test_size_of_parsed_declaration, style::properties::SourcePropertyDeclaration, 608);
 
 size_of_test!(test_size_of_computed_image, computed::image::Image, 40);
 size_of_test!(test_size_of_specified_image, specified::image::Image, 40);