support special fns to single channel rgb/rgba/hsl/hsla

src/builtin/functions/color/hsl.rs

@@ -6,7 +6,7 @@ use num_traits::One;
 use crate::{
     args::CallArgs,
     color::Color,
-    common::QuoteKind,
+    common::{Brackets, ListSeparator, QuoteKind},
     error::SassResult,
     parse::Parser,
     unit::Unit,
@@ -35,6 +35,24 @@ fn inner_hsl(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
                 .into());
         }
 
+        if channels.iter().any(Value::is_special_function) {
+            let channel_sep = if channels.len() < 3 {
+                ListSeparator::Space
+            } else {
+                ListSeparator::Comma
+            };
+
+            return Ok(Value::String(
+                format!(
+                    "{}({})",
+                    name,
+                    Value::List(channels, channel_sep, Brackets::None)
+                        .to_css_string(args.span(), false)?
+                ),
+                QuoteKind::None,
+            ));
+        }
+
         let lightness = match channels.pop() {
             Some(Value::Dimension(Some(n), ..)) => n / Number::from(100),
             Some(Value::Dimension(None, ..)) => todo!(),

src/builtin/functions/color/rgb.rs

@@ -5,7 +5,7 @@ use num_traits::One;
 use crate::{
     args::CallArgs,
     color::Color,
-    common::QuoteKind,
+    common::{Brackets, ListSeparator, QuoteKind},
     error::SassResult,
     parse::Parser,
     unit::Unit,
@@ -37,6 +37,24 @@ fn inner_rgb(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
                 .into());
         }
 
+        if channels.iter().any(Value::is_special_function) {
+            let channel_sep = if channels.len() < 3 {
+                ListSeparator::Space
+            } else {
+                ListSeparator::Comma
+            };
+
+            return Ok(Value::String(
+                format!(
+                    "{}({})",
+                    name,
+                    Value::List(channels, channel_sep, Brackets::None)
+                        .to_css_string(args.span(), false)?
+                ),
+                QuoteKind::None,
+            ));
+        }
+
         let blue = match channels.pop() {
             Some(Value::Dimension(Some(n), Unit::None, _)) => n,
             Some(Value::Dimension(Some(n), Unit::Percent, _)) => {

tests/media.rs

@@ -233,7 +233,7 @@ test!(
     "@media (max-width: 0px) {\n  a {\n    color: red;\n  }\n}\n\na {\n  color: red;\n}\n"
 );
 test!(
-  #[ignore = "we move to top of media"]
+    #[ignore = "we move to top of media"]
     plain_import_inside_media_is_not_moved_to_top,
     r#"@media foo {
       a {