allow multiline comments in functions

src/parse/mod.rs

@@ -232,7 +232,11 @@ impl<'a> Parser<'a> {
                     self.whitespace();
                     match comment.node {
                         Comment::Silent => continue,
-                        Comment::Loud(s) => stmts.push(Stmt::Comment(s)),
+                        Comment::Loud(s) => {
+                            if !self.flags.in_function() {
+                                stmts.push(Stmt::Comment(s));
+                            }
+                        }
                     }
                 }
                 '\u{0}'..='\u{8}' | '\u{b}'..='\u{1f}' => {

tests/functions.rs

@@ -318,3 +318,15 @@ error!(
     }",
     "Error: Functions can only contain variable declarations and control directives."
 );
+test!(
+    allows_multiline_comment,
+    "@function foo($a) {
+        /* foo */
+        @return $a;
+    }
+
+    a {
+        color: foo(nul);
+    }",
+    "a {\n  color: nul;\n}\n"
+);