Error on invalid tokens

Fixes #427. Closes #449

src/lib.rs

@@ -23770,6 +23770,18 @@ mod tests {
     )
   }
 
+  #[test]
+  fn test_invalid() {
+    error_test(
+      ".a{color: hsla(120, 62.32%;}",
+      ParserError::UnexpectedToken(Token::CloseCurlyBracket),
+    );
+    error_test(
+      ".a{--foo: url(foo\\) b\\)ar)}",
+      ParserError::UnexpectedToken(Token::BadUrl("foo\\) b\\)ar".into())),
+    );
+  }
+
   #[test]
   fn test_container_queries() {
     // with name

src/properties/custom.rs

@@ -430,6 +430,12 @@ impl<'i> TokenList<'i> {
           last_is_delim = false;
           last_is_whitespace = false;
         }
+        Ok(token) if token.is_parse_error() => {
+          return Err(ParseError {
+            kind: ParseErrorKind::Basic(BasicParseErrorKind::UnexpectedToken(token.clone())),
+            location: state.source_location(),
+          })
+        }
         Ok(token) => {
           last_is_delim = matches!(token, cssparser::Token::Delim(_) | cssparser::Token::Comma);