better handle silent comments in maps and fn args

src/parse/args.rs

@@ -48,6 +48,7 @@ impl<'a> Parser<'a> {
                         match &tok.kind {
                             ',' => {
                                 self.toks.next();
+                                self.whitespace_or_comment();
                                 args.push(FuncArg {
                                     name: name.node.into(),
                                     default: Some(default),

src/parse/value/parse.rs

@@ -1062,9 +1062,16 @@ impl<'a, 'b: 'a> IntermediateValueIterator<'a, 'b> {
         let paren_toks = &mut t.node.into_iter().peekmore();
 
         let mut map = SassMap::new();
-        let key = self
-            .parser
-            .parse_value_from_vec(read_until_char(paren_toks, ':')?, true)?;
+        let key_toks = read_until_char(paren_toks, ':')?;
+        if key_toks.iter().all(|t| t.is_whitespace()) {
+            return Ok(Spanned {
+                node: HigherIntermediateValue::Paren(Box::new(HigherIntermediateValue::Literal(
+                    Value::Map(map),
+                ))),
+                span: t.span,
+            });
+        }
+        let key = self.parser.parse_value_from_vec(key_toks, true)?;
 
         if paren_toks.peek().is_none() {
             return Ok(Spanned {
@@ -1096,13 +1103,14 @@ impl<'a, 'b: 'a> IntermediateValueIterator<'a, 'b> {
             let key = self
                 .parser
                 .parse_value_from_vec(read_until_char(paren_toks, ':')?, true)?;
+
             devour_whitespace(paren_toks);
             let val = self
                 .parser
                 .parse_value_from_vec(read_until_char(paren_toks, ',')?, true)?;
             span = span.merge(val.span);
             devour_whitespace(paren_toks);
-            if map.insert(key.node, val.node) {
+            if map.insert(key.node.clone(), val.node) {
                 return Err(("Duplicate key.", key.span).into());
             }
             if paren_toks.peek().is_none() {

src/utils/chars.rs

@@ -4,7 +4,7 @@ use peekmore::PeekMoreIterator;
 
 use crate::{error::SassResult, Token};
 
-use super::{read_until_closing_paren, read_until_closing_quote};
+use super::{read_until_closing_paren, read_until_closing_quote, read_until_newline};
 /// Reads until the char is found, consuming the char,
 /// or until the end of the iterator is hit
 pub(crate) fn read_until_char(
@@ -24,6 +24,13 @@ pub(crate) fn read_until_char(
                 v.extend(read_until_closing_paren(toks)?);
                 continue;
             }
+            '/' => {
+                match toks.peek() {
+                    Some(Token { kind: '/', .. }) => read_until_newline(toks),
+                    _ => v.push(tok),
+                };
+                continue;
+            }
             t if t == c => break,
             _ => {}
         }

tests/args.rs

@@ -86,3 +86,16 @@ test!(
     }",
     "a {\n  color: red;\n}\n"
 );
+test!(
+    comment_after_comma_in_func_args,
+    "@mixin a(
+      $foo,//foo
+    ) {
+        color: $foo;
+    }
+
+    a {
+        @include a(red);
+    }",
+    "a {\n  color: red;\n}\n"
+);

tests/map.rs

@@ -197,3 +197,11 @@ test!(
     "a {\n  color: (a: b)==(a: c);\n}\n",
     "a {\n  color: false;\n}\n"
 );
+test!(
+    empty_with_single_line_comments,
+    "$foo: (\n  \n  // :/a.b\n  \n  );
+    a {
+        color: inspect($foo);
+    }",
+    "a {\n  color: ();\n}\n"
+);