diff --git a/components/style/properties.mako.rs b/components/style/properties.mako.rs
index 2912d4ea871..760672efdbd 100644
--- a/components/style/properties.mako.rs
+++ b/components/style/properties.mako.rs
@@ -546,7 +546,25 @@ pub mod longhands {
${single_keyword("position", "static absolute relative fixed")}
- ${single_keyword("float", "none left right")}
+
+ <%self:single_keyword_computed name="float" values="none left right">
+ use values::computed::Context;
+
+ impl ToComputedValue for SpecifiedValue {
+ type ComputedValue = computed_value::T;
+
+ #[inline]
+ fn to_computed_value(&self, context: &Context) -> computed_value::T {
+ if context.positioned {
+ SpecifiedValue::none
+ } else {
+ *self
+ }
+ }
+ }
+
+
+
${single_keyword("clear", "none left right both")}
<%self:longhand name="-servo-display-for-hypothetical-box" derived_from="display">
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index c5c75cff9a5..39fc9811d6a 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -4165,6 +4165,12 @@
]
},
"testharness": {
+ "css/float_relative_to_position.html": [
+ {
+ "path": "css/float_relative_to_position.html",
+ "url": "/_mozilla/css/float_relative_to_position.html"
+ }
+ ],
"css/test_variable_legal_values.html": [
{
"path": "css/test_variable_legal_values.html",
diff --git a/tests/wpt/mozilla/tests/css/float_relative_to_position.html b/tests/wpt/mozilla/tests/css/float_relative_to_position.html
new file mode 100644
index 00000000000..bdeb133ef11
--- /dev/null
+++ b/tests/wpt/mozilla/tests/css/float_relative_to_position.html
@@ -0,0 +1,40 @@
+
+
+
+
+Tests the relationship between float and position
+
+
+
+
+
+
+
+
+
+
+