& is null inside selectors at root

src/parse/common.rs

@@ -77,7 +77,6 @@ impl ContextFlags {
         (self.0 & Self::IN_KEYFRAMES) != 0
     }
 
-    #[allow(dead_code)]
     pub fn in_at_root_rule(self) -> bool {
         (self.0 & Self::IN_AT_ROOT_RULE) != 0
     }

src/parse/value/parse.rs

@@ -778,7 +778,10 @@ impl<'a> Parser<'a> {
             }
             '&' => {
                 let span = self.toks.next().unwrap().pos();
-                if self.super_selectors.is_empty() && !self.at_root_has_selector && !self.at_root {
+                if self.super_selectors.is_empty()
+                    && !self.at_root_has_selector
+                    && !self.flags.in_at_root_rule()
+                {
                     IntermediateValue::Value(HigherIntermediateValue::Literal(Value::Null))
                         .span(span)
                 } else {

tests/if.rs

@@ -171,6 +171,15 @@ test!(
       /**/  ",
     "/**/\n/**/\n/**/\n"
 );
+test!(
+    parent_selector_is_null_at_root,
+    "@if & {
+        a {
+            color: red;
+        }
+    }",
+    ""
+);
 error!(
     nothing_after_escape,
     "@if \\", "Error: Expected expression."

tests/selectors.rs

@@ -676,6 +676,11 @@ test!(
     ":a(a , b) {\n  color: &;\n}\n",
     ":a(a , b) {\n  color: :a(a , b);\n}\n"
 );
+test!(
+    parent_selector_is_null_at_root,
+    "#{inspect(&)}  {\n  color: &;\n}\n",
+    "null {\n  color: null;\n}\n"
+);
 error!(
     a_n_plus_b_n_invalid_odd,
     ":nth-child(ofdd) {\n  color: &;\n}\n", "Error: Expected \"odd\"."