support 2 arg special rgb/rgba

README.md

@@ -90,7 +90,7 @@ These numbers come from a default run of the Sass specification as shown above.
 
 ```
 2021-07-24
-PASSING: 4018
+PASSING: 4177
-FAILING: 2238
+FAILING: 2079
 TOTAL: 6256
 ```

src/builtin/functions/color/rgb.rs

@@ -154,20 +154,23 @@ fn inner_rgb(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
 
         Ok(Value::Color(Box::new(color)))
     } else if len == 2 {
-        let color = match args.get_err(0, "color")? {
+        let color = args.get_err(0, "color")?;
+        let alpha = args.get_err(1, "alpha")?;
+
+        if color.is_special_function() || (alpha.is_special_function() && !color.is_color()) {
+            return Ok(Value::String(
+                format!(
+                    "{}({})",
+                    name,
+                    Value::List(vec![color, alpha], ListSeparator::Comma, Brackets::None)
+                        .to_css_string(args.span(), false)?
+                ),
+                QuoteKind::None,
+            ));
+        }
+
+        let color = match color {
             Value::Color(c) => c,
-            v if v.is_special_function() => {
-                let alpha = args.get_err(1, "alpha")?;
-                return Ok(Value::String(
-                    format!(
-                        "{}({}, {})",
-                        name,
-                        v.to_css_string(args.span(), parser.options.is_compressed())?,
-                        alpha.to_css_string(args.span(), parser.options.is_compressed())?
-                    ),
-                    QuoteKind::None,
-                ));
-            }
             v => {
                 return Err((
                     format!("$color: {} is not a color.", v.inspect(args.span())?),
@@ -176,7 +179,22 @@ fn inner_rgb(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
                     .into())
             }
         };
-        let alpha = match args.get_err(1, "alpha")? {
+
+        if alpha.is_special_function() {
+            return Ok(Value::String(
+                format!(
+                    "{}({}, {}, {}, {})",
+                    name,
+                    color.red().to_string(false),
+                    color.green().to_string(false),
+                    color.blue().to_string(false),
+                    alpha.to_css_string(args.span(), false)?,
+                ),
+                QuoteKind::None,
+            ));
+        }
+
+        let alpha = match alpha {
             Value::Dimension(Some(n), Unit::None, _) => n,
             Value::Dimension(Some(n), Unit::Percent, _) => n / Number::from(100),
             Value::Dimension(None, ..) => todo!(),
@@ -190,19 +208,6 @@ fn inner_rgb(name: &'static str, mut args: CallArgs, parser: &mut Parser) -> Sas
                 )
                     .into())
             }
-            v if v.is_special_function() => {
-                return Ok(Value::String(
-                    format!(
-                        "{}({}, {}, {}, {})",
-                        name,
-                        color.red().to_string(parser.options.is_compressed()),
-                        color.green().to_string(parser.options.is_compressed()),
-                        color.blue().to_string(parser.options.is_compressed()),
-                        v.to_css_string(args.span(), parser.options.is_compressed())?
-                    ),
-                    QuoteKind::None,
-                ));
-            }
             v => {
                 return Err((
                     format!("$alpha: {} is not a number.", v.inspect(args.span())?),

src/value/mod.rs

@@ -344,6 +344,10 @@ impl Value {
         }
     }
 
+    pub fn is_color(&self) -> bool {
+        matches!(self, Value::Color(..))
+    }
+
     pub fn is_special_function(&self) -> bool {
         match self {
             Value::String(s, QuoteKind::None) => is_special_function(s),

tests/color.rs

@@ -762,6 +762,16 @@ test!(
     "a {\n  color: hsla(var(--foo));\n}\n",
     "a {\n  color: hsla(var(--foo));\n}\n"
 );
+test!(
+    rgb_special_fn_2_arg_first_non_color,
+    "a {\n  color: rgb(1, var(--foo));\n}\n",
+    "a {\n  color: rgb(1, var(--foo));\n}\n"
+);
+test!(
+    rgb_special_fn_2_arg_first_is_color,
+    "a {\n  color: rgb(rgb(1%, 1, 1), var(--foo));;\n}\n",
+    "a {\n  color: rgb(3, 1, 1, var(--foo));\n}\n"
+);
 test!(
     #[ignore = "we do not check if interpolation occurred"]
     interpolated_named_color_is_not_color,