diff --git a/components/style/properties/longhand/table.mako.rs b/components/style/properties/longhand/table.mako.rs
index 67c4e25accb3..6758033dc92f 100644
--- a/components/style/properties/longhand/table.mako.rs
+++ b/components/style/properties/longhand/table.mako.rs
@@ -10,35 +10,10 @@ ${helpers.single_keyword("table-layout", "auto fixed",
                          gecko_ffi_name="mLayoutStrategy", animation_value_type="discrete",
                          spec="https://drafts.csswg.org/css-tables/#propdef-table-layout")}
 
-<%helpers:longhand name="-x-span" products="gecko"
-                   spec="Internal-only (for `<col span>` pres attr)"
-                   animation_value_type="none"
-                   internal="True">
-    pub type SpecifiedValue = computed_value::T;
-    pub mod computed_value {
-        use std::fmt;
-        use style_traits::ToCss;
-
-        #[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
-        pub struct T(pub i32);
-
-        impl ToCss for T {
-            fn to_css<W>(&self, _: &mut W) -> fmt::Result where W: fmt::Write {
-                Ok(())
-            }
-        }
-    }
-
-    #[inline]
-    pub fn get_initial_value() -> computed_value::T {
-        computed_value::T(1)
-    }
-
-    // never parse it, only set via presentation attribute
-    fn parse<'i, 't>(
-        _: &ParserContext,
-        input: &mut Parser<'i, 't>,
-    ) -> Result<SpecifiedValue, ParseError<'i>> {
-        Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError))
-    }
-</%helpers:longhand>
+${helpers.predefined_type("-x-span",
+                          "XSpan",
+                          "computed::XSpan(1)",
+                          products="gecko",
+                          spec="Internal-only (for `<col span>` pres attr)",
+                          animation_value_type="none",
+                          internal=True)}
diff --git a/components/style/values/computed/mod.rs b/components/style/values/computed/mod.rs
index e99bab154c4d..4a74cabf72c0 100644
--- a/components/style/values/computed/mod.rs
+++ b/components/style/values/computed/mod.rs
@@ -53,6 +53,7 @@ pub use self::length::{CSSPixelLength, NonNegativeLength, NonNegativeLengthOrPer
 pub use self::percentage::Percentage;
 pub use self::position::Position;
 pub use self::svg::{SVGLength, SVGOpacity, SVGPaint, SVGPaintKind, SVGStrokeDashArray, SVGWidth};
+pub use self::table::XSpan;
 pub use self::text::{InitialLetter, LetterSpacing, LineHeight, WordSpacing};
 pub use self::time::Time;
 pub use self::transform::{TimingFunction, TransformOrigin};
@@ -77,6 +78,7 @@ pub mod percentage;
 pub mod position;
 pub mod rect;
 pub mod svg;
+pub mod table;
 pub mod text;
 pub mod time;
 pub mod transform;
diff --git a/components/style/values/computed/table.rs b/components/style/values/computed/table.rs
new file mode 100644
index 000000000000..da44de8aae5c
--- /dev/null
+++ b/components/style/values/computed/table.rs
@@ -0,0 +1,7 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! Computed types for table properties.
+
+pub use values::specified::table::XSpan;
diff --git a/components/style/values/specified/mod.rs b/components/style/values/specified/mod.rs
index fef43cbf747d..2f01f66029e4 100644
--- a/components/style/values/specified/mod.rs
+++ b/components/style/values/specified/mod.rs
@@ -49,6 +49,7 @@ pub use self::rect::LengthOrNumberRect;
 pub use self::percentage::Percentage;
 pub use self::position::{Position, PositionComponent};
 pub use self::svg::{SVGLength, SVGOpacity, SVGPaint, SVGPaintKind, SVGStrokeDashArray, SVGWidth};
+pub use self::table::XSpan;
 pub use self::text::{InitialLetter, LetterSpacing, LineHeight, WordSpacing};
 pub use self::time::Time;
 pub use self::transform::{TimingFunction, TransformOrigin};
@@ -76,6 +77,7 @@ pub mod percentage;
 pub mod position;
 pub mod rect;
 pub mod svg;
+pub mod table;
 pub mod text;
 pub mod time;
 pub mod transform;
diff --git a/components/style/values/specified/table.rs b/components/style/values/specified/table.rs
new file mode 100644
index 000000000000..a86fe0167fd5
--- /dev/null
+++ b/components/style/values/specified/table.rs
@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! Specified types for table properties.
+
+use cssparser::Parser;
+use parser::{Parse, ParserContext};
+use std::fmt;
+use style_traits::{ToCss, StyleParseErrorKind, ParseError};
+
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
+/// span. for `<col span>` pres attr
+pub struct XSpan(pub i32);
+
+impl Parse for XSpan {
+    // never parse it, only set via presentation attribute
+    fn parse<'i, 't>(_: &ParserContext, input: &mut Parser<'i, 't>) -> Result<XSpan, ParseError<'i>> {
+        Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError))
+    }
+}
+
+impl ToCss for XSpan {
+    fn to_css<W>(&self, _: &mut W) -> fmt::Result where W: fmt::Write {
+        Ok(())
+    }
+}