diff --git a/components/selectors/Cargo.toml b/components/selectors/Cargo.toml
index b2437831b81..bb8e5d7f81b 100644
--- a/components/selectors/Cargo.toml
+++ b/components/selectors/Cargo.toml
@@ -23,6 +23,7 @@ bench = []
 bitflags = "1.0"
 matches = "0.1"
 cssparser = "0.25"
+derive_more = "0.13"
 log = "0.4"
 fxhash = "0.2"
 phf = "0.7.18"
diff --git a/components/style/Cargo.toml b/components/style/Cargo.toml
index 11aa564bf05..86aaa8079a4 100644
--- a/components/style/Cargo.toml
+++ b/components/style/Cargo.toml
@@ -31,6 +31,7 @@ bitflags = "1.0"
 byteorder = "1.0"
 cssparser = "0.25"
 crossbeam-channel = { version = "0.3", optional = true }
+derive_more = "0.13"
 new_debug_unreachable = "1.0"
 encoding_rs = {version = "0.8", optional = true}
 euclid = "0.19"