diff --git a/components/style/properties/longhand/position.mako.rs b/components/style/properties/longhand/position.mako.rs
index bd82f09519c..41dc76ee3b6 100644
--- a/components/style/properties/longhand/position.mako.rs
+++ b/components/style/properties/longhand/position.mako.rs
@@ -63,6 +63,11 @@
 // Flex container properties
 ${helpers.single_keyword("flex-direction", "row row-reverse column column-reverse", experimental=True)}
 
+// Flex item properties
+${helpers.predefined_type("flex-grow", "Number", "0.0", "parse_non_negative", products="gecko")}
+
+${helpers.predefined_type("flex-shrink", "Number", "1.0", "parse_non_negative", products="gecko")}
+
 // https://drafts.csswg.org/css-flexbox/#propdef-order
 <%helpers:longhand name="order">
     use values::computed::ComputedValueAsSpecified;
diff --git a/components/style/properties/longhand/svg_inherited.mako.rs b/components/style/properties/longhand/svg_inherited.mako.rs
index 29dd27a7615..445d4948cf0 100644
--- a/components/style/properties/longhand/svg_inherited.mako.rs
+++ b/components/style/properties/longhand/svg_inherited.mako.rs
@@ -34,6 +34,9 @@ ${helpers.single_keyword("stroke-linecap", "butt round square", products="gecko"
 
 ${helpers.single_keyword("stroke-linejoin", "miter round bevel", products="gecko")}
 
+${helpers.predefined_type("stroke-miterlimit", "Number", "4.0", "parse_at_least_one",
+                          products="gecko")}
+
 ${helpers.predefined_type("stroke-opacity", "Opacity", "1.0", products="gecko")}
 
 // Section 14 - Clipping, Masking and Compositing
diff --git a/components/style/properties/longhand/xul.mako.rs b/components/style/properties/longhand/xul.mako.rs
index 84e874849eb..cb5db00717c 100644
--- a/components/style/properties/longhand/xul.mako.rs
+++ b/components/style/properties/longhand/xul.mako.rs
@@ -10,3 +10,6 @@
 
 ${helpers.single_keyword("-moz-box-align", "stretch start center baseline end", products="gecko",
                          gecko_ffi_name="mBoxAlign", gecko_constant_prefix="NS_STYLE_BOX_ALIGN")}
+
+${helpers.predefined_type("-moz-box-flex", "Number", "0.0", "parse_non_negative", products="gecko",
+                          gecko_ffi_name="mBoxFlex")}