Auto merge of #20192 - servo:derive-all-the-things, r=emilio

Derive ToCss for DeclaredValue

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components/style/properties/properties.mako.rs

@@ -1308,7 +1308,7 @@ impl ShorthandId {
 
 /// Servo's representation of a declared value for a given `T`, which is the
 /// declared value for that property.
-#[derive(Clone, Debug, Eq, PartialEq)]
+#[derive(Clone, Debug, Eq, PartialEq, ToCss)]
 pub enum DeclaredValue<'a, T: 'a> {
     /// A known specified value from the stylesheet.
     Value(&'a T),
@@ -1360,6 +1360,19 @@ pub struct UnparsedValue {
     from_shorthand: Option<ShorthandId>,
 }
 
+impl ToCss for UnparsedValue {
+    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
+    where
+        W: Write,
+    {
+        // https://drafts.csswg.org/css-variables/#variables-in-shorthands
+        if self.from_shorthand.is_none() {
+            dest.write_str(&*self.css)?;
+        }
+        Ok(())
+    }
+}
+
 impl UnparsedValue {
     fn substitute_variables(
         &self,
@@ -1425,25 +1438,6 @@ impl UnparsedValue {
     }
 }
 
-impl<'a, T: ToCss> ToCss for DeclaredValue<'a, T> {
-    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
-    where
-        W: Write,
-    {
-        match *self {
-            DeclaredValue::Value(ref inner) => inner.to_css(dest),
-            DeclaredValue::WithVariables(ref with_variables) => {
-                // https://drafts.csswg.org/css-variables/#variables-in-shorthands
-                if with_variables.from_shorthand.is_none() {
-                    dest.write_str(&*with_variables.css)?
-                }
-                Ok(())
-            },
-            DeclaredValue::CSSWideKeyword(ref keyword) => keyword.to_css(dest),
-        }
-    }
-}
-
 /// An identifier for a given property declaration, which can be either a
 /// longhand or a custom property.
 #[derive(Clone, Copy, PartialEq)]
@@ -1742,14 +1736,7 @@ impl ToCss for VariableDeclaration {
     where
         W: fmt::Write,
     {
-        // https://drafts.csswg.org/css-variables/#variables-in-shorthands
+        self.value.to_css(dest)
-        match self.value.from_shorthand {
-            None => {
-                dest.write_str(&*self.value.css)?
-            }
-            Some(..) => {},
-        }
-        Ok(())
     }
 }