1 files changed, 6 insertions, 0 deletions
diff --git a/components/style/gecko/selector_parser.rs b/components/style/gecko/selector_parser.rs
index 336df501325..7cfb01e2794 100644
--- a/components/style/gecko/selector_parser.rs
+++ b/components/style/gecko/selector_parser.rs
@@ -445,3 +445,9 @@ unsafe impl HasFFI for SelectorList<SelectorImpl> {
 }
 unsafe impl HasSimpleFFI for SelectorList<SelectorImpl> {}
 unsafe impl HasBoxFFI for SelectorList<SelectorImpl> {}
+
+// Selector and component sizes are important for matching performance.
+size_of_test!(selectors::parser::Selector<SelectorImpl>, 8);
+size_of_test!(selectors::parser::Component<SelectorImpl>, 24);
+size_of_test!(PseudoElement, 16);
+size_of_test!(NonTSPseudoClass, 16);