diff --git a/src/components/main/layout/block.rs b/src/components/main/layout/block.rs
index 0ba75a4a53b..a4757042e49 100644
--- a/src/components/main/layout/block.rs
+++ b/src/components/main/layout/block.rs
@@ -766,7 +766,8 @@ impl BlockFlow {
     /// If this is the root flow, shifts all kids down and adjusts our size to account for
     /// collapsed margins.
     ///
-    /// TODO(pcwalton): This is somewhat inefficient (traverses kids twice); can we do better?
+    /// TODO(#2017, pcwalton): This is somewhat inefficient (traverses kids twice); can we do
+    /// better?
     fn adjust_boxes_for_collapsed_margins_if_root(&mut self) {
         if !self.is_root() {
             return
@@ -1519,7 +1520,7 @@ impl BlockFlow {
 
             // Per CSS 2.1 § 16.3.1, text decoration propagates to all children in flow.
             //
-            // TODO(pcwalton): When we have out-of-flow children, don't unconditionally propagate.
+            // TODO(#2018, pcwalton): Do this in the cascade instead.
             let child_base = flow::mut_base(kid);
             child_base.flags_info.propagate_text_decoration_from_parent(&flags_info);
             child_base.flags_info.propagate_text_alignment_from_parent(&flags_info)
diff --git a/src/components/style/properties.rs.mako b/src/components/style/properties.rs.mako
index 030f02cb908..18c8d49a38e 100644
--- a/src/components/style/properties.rs.mako
+++ b/src/components/style/properties.rs.mako
@@ -97,29 +97,29 @@ pub mod longhands {
             % endif
             pub use self::computed_value::*;
             ${caller.body()}
-            pub fn parse_declared(input: &[ComponentValue], base_url: &Url)
-                               -> Option<DeclaredValue<SpecifiedValue>> {
-                match CSSWideKeyword::parse(input) {
-                    Some(Some(keyword)) => Some(CSSWideKeyword(keyword)),
-                    Some(None) => Some(CSSWideKeyword(${
-                        "Inherit" if THIS_STYLE_STRUCT.inherited else "Initial"})),
-                    None => parse_specified(input, base_url),
+            % if derived_from is None:
+                pub fn parse_declared(input: &[ComponentValue], base_url: &Url)
+                                   -> Option<DeclaredValue<SpecifiedValue>> {
+                    match CSSWideKeyword::parse(input) {
+                        Some(Some(keyword)) => Some(CSSWideKeyword(keyword)),
+                        Some(None) => Some(CSSWideKeyword(${
+                            "Inherit" if THIS_STYLE_STRUCT.inherited else "Initial"})),
+                        None => parse_specified(input, base_url),
+                    }
                 }
-            }
+            % endif
         }
     </%def>
 
     <%def name="longhand(name, no_super=False, derived_from=None)">
         <%self:raw_longhand name="${name}" derived_from="${derived_from}">
             ${caller.body()}
-            pub fn parse_specified(_input: &[ComponentValue], _base_url: &Url)
-                               -> Option<DeclaredValue<SpecifiedValue>> {
-                % if derived_from is None:
+            % if derived_from is None:
+                pub fn parse_specified(_input: &[ComponentValue], _base_url: &Url)
+                                   -> Option<DeclaredValue<SpecifiedValue>> {
                     parse(_input, _base_url).map(super::SpecifiedValue)
-                % else:
-                    None
-                % endif
-            }
+                }
+            % endif
         </%self:raw_longhand>
     </%def>
 
@@ -1328,12 +1328,16 @@ impl PropertyDeclaration {
         let name_lower = tmp_for_lifetime.as_str_ascii();
         match name_lower.as_slice() {
             % for property in LONGHANDS:
-                "${property.name}" => result_list.push(${property.ident}_declaration(
-                    match longhands::${property.ident}::parse_declared(value, base_url) {
-                        Some(value) => value,
-                        None => return InvalidValue,
-                    }
-                )),
+                % if property.derived_from is None:
+                    "${property.name}" => result_list.push(${property.ident}_declaration(
+                        match longhands::${property.ident}::parse_declared(value, base_url) {
+                            Some(value) => value,
+                            None => return InvalidValue,
+                        }
+                    )),
+                % else:
+                    "${property.name}" => {}
+                % endif
             % endfor
             % for shorthand in SHORTHANDS:
                 "${shorthand.name}" => match CSSWideKeyword::parse(value) {