fix: Correctly enclose negated downleveled interval media queries in parens (Alternative A)

src/media_query.rs

@@ -449,10 +449,19 @@ impl<'i> ToCss for MediaCondition<'i> {
   {
     match *self {
       MediaCondition::Feature(ref f) => f.to_css(dest),
-      MediaCondition::Not(ref c) => {
-        dest.write_str("not ")?;
-        c.to_css(dest)
-      }
+      MediaCondition::Not(ref c) => match **c {
+        MediaCondition::Feature(ref f) => {
+          dest.write_str("not ")?;
+          dest.in_negated_media_feature = true;
+          f.to_css(dest)?;
+          dest.in_negated_media_feature = false;
+          Ok(())
+        }
+        _ => {
+          dest.write_str("not ")?;
+          c.to_css(dest)
+        }
+      },
       MediaCondition::InParens(ref c) => {
         dest.write_char('(')?;
         c.to_css(dest)?;
@@ -672,9 +681,16 @@ impl<'i> ToCss for MediaFeature<'i> {
       } => {
         if let Some(targets) = dest.targets {
           if !Feature::MediaIntervalSyntax.is_compatible(targets) {
+            if dest.in_negated_media_feature {
+              dest.write_char('(')?;
+            }
             write_min_max(&start_operator.opposite(), name, start, dest)?;
             dest.write_str(" and (")?;
-            return write_min_max(end_operator, name, end, dest);
+            write_min_max(end_operator, name, end, dest)?;
+            if dest.in_negated_media_feature {
+              dest.write_char(')')?;
+            }
+            return Ok(());
           }
         }
 
@@ -991,7 +1007,7 @@ fn process_condition<'i>(
 #[cfg(test)]
 mod tests {
   use super::*;
-  use crate::stylesheet::PrinterOptions;
+  use crate::{stylesheet::PrinterOptions, targets::Browsers};
 
   fn parse(s: &str) -> MediaQuery {
     let mut input = ParserInput::new(&s);
@@ -1038,4 +1054,20 @@ mod tests {
     assert_eq!(and("only screen", "all"), "only screen");
     assert_eq!(and("print", "print"), "print");
   }
+
+  #[test]
+  fn test_negated_interval_parens() {
+    let media_query = parse("screen and not (200px <= width < 500px)");
+    let printer_options = PrinterOptions {
+      targets: Some(Browsers {
+        firefox: Some(62 << 16),
+        ..Browsers::default()
+      }),
+      ..PrinterOptions::default()
+    };
+    assert_eq!(
+      media_query.to_css_string(printer_options).unwrap(),
+      "screen and not ((min-width: 200px) and (max-width: 499.999px))"
+    );
+  }
 }

src/printer.rs

@@ -72,6 +72,7 @@ pub struct Printer<'a, 'b, 'c, W> {
   /// the vendor prefix of whatever is being printed.
   pub(crate) vendor_prefix: VendorPrefix,
   pub(crate) in_calc: bool,
+  pub(crate) in_negated_media_feature: bool,
   pub(crate) css_module: Option<CssModule<'a, 'b, 'c>>,
   pub(crate) dependencies: Option<Vec<Dependency>>,
   pub(crate) remove_imports: bool,
@@ -98,6 +99,7 @@ impl<'a, 'b, 'c, W: std::fmt::Write + Sized> Printer<'a, 'b, 'c, W> {
       targets: options.targets,
       vendor_prefix: VendorPrefix::empty(),
       in_calc: false,
+      in_negated_media_feature: false,
       css_module: None,
       dependencies: if options.analyze_dependencies.is_some() {
         Some(Vec::new())