diff --git a/components/style/stylesheets/rule_parser.rs b/components/style/stylesheets/rule_parser.rs
index 44943259b38..a780ebce250 100644
--- a/components/style/stylesheets/rule_parser.rs
+++ b/components/style/stylesheets/rule_parser.rs
@@ -189,6 +189,13 @@ impl<'a, 'i> AtRuleParser<'i> for TopLevelRuleParser<'a> {
                     return Err(input.new_custom_error(StyleParseErrorKind::UnexpectedImportRule))
                 }
 
+                // FIXME(emilio): We should always be able to have a loader
+                // around! See bug 1533783.
+                if self.loader.is_none() {
+                    error!("Saw @import rule, but no way to trigger the load");
+                    return Err(input.new_custom_error(StyleParseErrorKind::UnexpectedImportRule))
+                }
+
                 let url_string = input.expect_url_or_string()?.as_ref().to_owned();
                 let url = CssUrl::parse_from_string(url_string, &self.context);