autoland: changeset 531883:67dcbffe8b5b4873ed8719089c6dddc5e2c9060d

author	Emilio Cobos Álvarez <emilio@crisal.io>
	Thu, 21 May 2020 12:10:34 +0000
changeset 531883	67dcbffe8b5b4873ed8719089c6dddc5e2c9060d
parent 531882	f60ba533e3943462c9d75e4475a0b1ee6317682f
child 531884	c161d7a53845bad9e2bebc9f76af9e6633507efb
push id	116937
push user	ealvarez@mozilla.com
push date	Mon, 25 May 2020 10:22:46 +0000
treeherder	autoland@9d8f9a2cd37f [default view] [failures only]
perfherder	[talos] [build metrics] [platform microbench] (compared to previous push)
reviewers	jwatt
bugs	1639756
milestone	78.0a1
first release with	nightly linux32 df5bfb667b9d / 78.0a1 / 20200525214409 / files nightly linux64 df5bfb667b9d / 78.0a1 / 20200525214409 / files nightly mac df5bfb667b9d / 78.0a1 / 20200525214409 / files nightly win32 df5bfb667b9d / 78.0a1 / 20200525214409 / files nightly win64 df5bfb667b9d / 78.0a1 / 20200525214409 / files
last release without	nightly linux32 9155018d4978 / 78.0a1 / 20200525093440 / files nightly linux64 9155018d4978 / 78.0a1 / 20200525093440 / files nightly mac 9155018d4978 / 78.0a1 / 20200525093440 / files nightly win32 9155018d4978 / 78.0a1 / 20200525093440 / files nightly win64 9155018d4978 / 78.0a1 / 20200525093440 / files

--- a/servo/components/style/gecko/selector_parser.rs
+++ b/servo/components/style/gecko/selector_parser.rs
@@ -349,17 +349,17 @@ impl<'a, 'i> ::selectors::Parser<'i> for
 
     #[inline]
     fn parse_host(&self) -> bool {
         true
     }
 
     #[inline]
     fn parse_is_and_where(&self) -> bool {
-        static_prefs::pref!("layout.css.is-where-selectors.enabled")
+        self.in_user_agent_stylesheet() || static_prefs::pref!("layout.css.is-where-selectors.enabled")
     }
 
     #[inline]
     fn parse_part(&self) -> bool {
         self.chrome_rules_enabled() || static_prefs::pref!("layout.css.shadow-parts.enabled")
     }
 
     fn parse_non_ts_pseudo_class(