diff --git a/components/style/properties/longhand/font.mako.rs b/components/style/properties/longhand/font.mako.rs
index ff837bbaee4d..da8aa34c8f47 100644
--- a/components/style/properties/longhand/font.mako.rs
+++ b/components/style/properties/longhand/font.mako.rs
@@ -411,12 +411,11 @@ ${helpers.single_keyword("font-variant-position",
 
         impl ToCss for FeatureTagValue {
             fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-                let s = match self.value {
-                    1 => format!("\"{}\"", self.tag),
-                    0 => format!("\"{}\" off", self.tag),
-                    x => format!("\"{}\" {}", self.tag, x)
-                };
-                dest.write_str(&s)
+                match self.value {
+                    1 => write!(dest, "\"{}\"", self.tag),
+                    0 => write!(dest, "\"{}\" off", self.tag),
+                    x => write!(dest, "\"{}\" {}", self.tag, x)
+                }
             }
         }