diff --git a/components/style/properties/data.py b/components/style/properties/data.py
index a54bd6c25ae..7b5a791de90 100644
--- a/components/style/properties/data.py
+++ b/components/style/properties/data.py
@@ -47,7 +47,7 @@ class Keyword(object):
 class Longhand(object):
     def __init__(self, style_struct, name, derived_from=None, keyword=None,
                  custom_cascade=False, experimental=False, internal=False,
-                 gecko_ffi_name=None):
+                 need_clone=False, gecko_ffi_name=None):
         self.name = name
         self.keyword = keyword
         self.ident = to_rust_ident(name)
@@ -56,6 +56,7 @@ class Longhand(object):
         self.experimental = ("layout.%s.enabled" % name) if experimental else None
         self.custom_cascade = custom_cascade
         self.internal = internal
+        self.need_clone = need_clone
         self.gecko_ffi_name = gecko_ffi_name or "m" + self.camel_case
         self.derived_from = (derived_from or "").split()
 
diff --git a/components/style/properties/longhand/box.mako.rs b/components/style/properties/longhand/box.mako.rs
index 9b89fa282b8..039c1fdbb9c 100644
--- a/components/style/properties/longhand/box.mako.rs
+++ b/components/style/properties/longhand/box.mako.rs
@@ -9,15 +9,13 @@
 <% data.new_style_struct("Box",
                          inherited=False,
                          gecko_ffi_name="nsStyleDisplay",
-                         additional_methods=[Method("clone_display", "longhands::display::computed_value::T"),
-                                             Method("clone_position", "longhands::position::computed_value::T"),
-                                             Method("is_floated", "bool"),
+                         additional_methods=[Method("is_floated", "bool"),
                                              Method("overflow_x_is_visible", "bool"),
                                              Method("overflow_y_is_visible", "bool"),
                                              Method("transition_count", "usize")]) %>
 
 // TODO(SimonSapin): don't parse `inline-table`, since we don't support it
-<%helpers:longhand name="display" custom_cascade="${product == 'servo'}">
+<%helpers:longhand name="display" need_clone="True" custom_cascade="${product == 'servo'}">
     <%
         values = """inline block inline-block
             table inline-table table-row-group table-header-group table-footer-group
@@ -89,7 +87,7 @@
 
 </%helpers:longhand>
 
-${helpers.single_keyword("position", "static absolute relative fixed", extra_gecko_values="sticky")}
+${helpers.single_keyword("position", "static absolute relative fixed", need_clone=True, extra_gecko_values="sticky")}
 
 <%helpers:single_keyword_computed name="float" values="none left right" gecko_ffi_name="mFloats">
     impl ToComputedValue for SpecifiedValue {
diff --git a/components/style/properties/properties.mako.rs b/components/style/properties/properties.mako.rs
index 0868b23f91c..afe5cb01487 100644
--- a/components/style/properties/properties.mako.rs
+++ b/components/style/properties/properties.mako.rs
@@ -54,15 +54,9 @@ pub mod longhands {
     <%include file="/longhand/padding.mako.rs" />
     <%include file="/longhand/position.mako.rs" />
 
-    <% data.new_style_struct("InheritedBox", inherited=True, gecko_ffi_name="nsStyleVisibility",
-                       additional_methods=[Method("clone_direction",
-                                                  "longhands::direction::computed_value::T"),
-                                           Method("clone_writing_mode",
-                                                  "longhands::writing_mode::computed_value::T"),
-                                           Method("clone_text_orientation",
-                                                  "longhands::text_orientation::computed_value::T")]) %>
+    <% data.new_style_struct("InheritedBox", inherited=True, gecko_ffi_name="nsStyleVisibility") %>
 
-    ${helpers.single_keyword("direction", "ltr rtl")}
+    ${helpers.single_keyword("direction", "ltr rtl", need_clone=True)}
 
     // CSS 2.1, Section 10 - Visual formatting model details
 
@@ -92,10 +86,7 @@ pub mod longhands {
                       "computed::LengthOrPercentageOrNone::None",
                       "parse_non_negative")}
 
-    <% data.new_style_struct("InheritedText", inherited=True, gecko_ffi_name="nsStyleText",
-                       additional_methods=([Method("clone__servo_text_decorations_in_effect",
-                                                  "longhands::_servo_text_decorations_in_effect::computed_value::T")]
-                                           if product == "servo" else [])) %>
+    <% data.new_style_struct("InheritedText", inherited=True, gecko_ffi_name="nsStyleText") %>
 
     <%helpers:longhand name="line-height">
         use cssparser::ToCss;
@@ -1076,11 +1067,9 @@ pub mod longhands {
         }
     </%helpers:longhand>
 
-    <% data.new_style_struct("Color", inherited=True, gecko_ffi_name="nsStyleColor",
-                       additional_methods=[Method("clone_color",
-                                                  "longhands::color::computed_value::T")]) %>
+    <% data.new_style_struct("Color", inherited=True, gecko_ffi_name="nsStyleColor") %>
 
-    <%helpers:raw_longhand name="color">
+    <%helpers:raw_longhand name="color" need_clone="True">
         use cssparser::Color as CSSParserColor;
         use cssparser::RGBA;
         use values::specified::{CSSColor, CSSRGBA};
@@ -1119,12 +1108,7 @@ pub mod longhands {
     // CSS 2.1, Section 15 - Fonts
 
     <% data.new_style_struct("Font", inherited=True, gecko_ffi_name="nsStyleFont",
-                       additional_methods=[Method("clone_font_size",
-                                                  "longhands::font_size::computed_value::T"),
-                                           Method("clone_font_weight",
-                                                  "longhands::font_weight::computed_value::T"),
-                                           Method("compute_font_hash", is_mut=True)]) %>
-
+                       additional_methods=[Method("compute_font_hash", is_mut=True)]) %>
     <%helpers:longhand name="font-family">
         use self::computed_value::FontFamily;
         use values::computed::ComputedValueAsSpecified;
@@ -1238,7 +1222,7 @@ pub mod longhands {
     ${helpers.single_keyword("font-style", "normal italic oblique")}
     ${helpers.single_keyword("font-variant", "normal small-caps")}
 
-    <%helpers:longhand name="font-weight">
+    <%helpers:longhand name="font-weight" need_clone="True">
         use cssparser::ToCss;
         use std::fmt;
 
@@ -1356,7 +1340,7 @@ pub mod longhands {
         }
     </%helpers:longhand>
 
-    <%helpers:longhand name="font-size">
+    <%helpers:longhand name="font-size" need_clone="True">
         use app_units::Au;
         use cssparser::ToCss;
         use std::fmt;
@@ -1724,7 +1708,7 @@ pub mod longhands {
     <% data.switch_to_style_struct("InheritedText") %>
 
     <%helpers:longhand name="-servo-text-decorations-in-effect"
-                    derived_from="display text-decoration" products="servo">
+                    derived_from="display text-decoration" need_clone="True" products="servo">
         use cssparser::{RGBA, ToCss};
         use std::fmt;
 
@@ -1970,11 +1954,13 @@ pub mod longhands {
     // http://dev.w3.org/csswg/css-writing-modes/
     <% data.switch_to_style_struct("InheritedBox") %>
 
-    ${helpers.single_keyword("writing-mode", "horizontal-tb vertical-rl vertical-lr", experimental=True)}
+    ${helpers.single_keyword("writing-mode", "horizontal-tb vertical-rl vertical-lr",
+                             experimental=True, need_clone=True)}
 
     // FIXME(SimonSapin): Add 'mixed' and 'upright' (needs vertical text support)
     // FIXME(SimonSapin): initial (first) value should be 'mixed', when that's implemented
-    ${helpers.single_keyword("text-orientation", "sideways sideways-left sideways-right", experimental=True)}
+    ${helpers.single_keyword("text-orientation", "sideways sideways-left sideways-right",
+                             experimental=True, need_clone=True)}
 
     // CSS Color Module Level 4
     // https://drafts.csswg.org/css-color/
@@ -5678,6 +5664,10 @@ pub mod style_struct_traits {
                 fn set_${longhand.ident}(&mut self, v: longhands::${longhand.ident}::computed_value::T);
                 #[allow(non_snake_case)]
                 fn copy_${longhand.ident}_from(&mut self, other: &Self);
+                % if longhand.need_clone:
+                    #[allow(non_snake_case)]
+                    fn clone_${longhand.ident}(&self) -> longhands::${longhand.ident}::computed_value::T;
+                % endif
             % endfor
             % for additional in style_struct.additional_methods:
                 #[allow(non_snake_case)]
diff --git a/ports/geckolib/properties.mako.rs b/ports/geckolib/properties.mako.rs
index 422b7116b29..edf67a70851 100644
--- a/ports/geckolib/properties.mako.rs
+++ b/ports/geckolib/properties.mako.rs
@@ -220,6 +220,21 @@ impl ${style_struct.trait_name} for ${style_struct.gecko_struct_name} {
     fn copy_${longhand.ident}_from(&mut self, other: &Self) {
         self.gecko.${longhand.gecko_ffi_name} = other.gecko.${longhand.gecko_ffi_name};
     }
+
+    %if longhand.need_clone:
+    fn clone_${longhand.ident}(&self) -> longhands::${longhand.ident}::computed_value::T {
+        use gecko_style_structs as gss;
+        use style::properties::longhands::${longhand.ident}::computed_value::T as Keyword;
+        // FIXME(bholley): Align binary representations and ditch |match| for cast + static_asserts
+        match self.gecko.${longhand.gecko_ffi_name} as u32 {
+            % for value in longhand.keyword.values_for('gecko'):
+            gss::${longhand.keyword.gecko_constant(value)} => Keyword::${to_rust_ident(value)},
+            % endfor
+            x => panic!("Found unexpected value in style struct for ${longhand.name} property: {}", x),
+        }
+    }
+
+    % endif
     % endfor
 
     /*
@@ -232,6 +247,11 @@ impl ${style_struct.trait_name} for ${style_struct.gecko_struct_name} {
     fn copy_${longhand.ident}_from(&mut self, _: &Self) {
         unimplemented!()
     }
+    % if longhand.need_clone:
+    fn clone_${longhand.ident}(&self) -> longhands::${longhand.ident}::computed_value::T {
+        unimplemented!()
+    }
+    % endif
     % endfor
     <% additionals = [x for x in style_struct.additional_methods
                       if not (skip_additionals and x.name in skip_additionals)] %>