Fix handling of extra tokens in ts_tree_cursor_current_field_id

cli/src/tests/tree_test.rs

@@ -190,7 +190,7 @@ fn test_tree_edit() {
 }
 
 #[test]
-fn test_tree_walk() {
+fn test_tree_cursor() {
     let mut parser = Parser::new();
     parser.set_language(get_language("rust")).unwrap();
 
@@ -225,6 +225,43 @@ fn test_tree_walk() {
     assert_eq!(cursor.node().is_named(), true);
 }
 
+#[test]
+fn test_tree_cursor_fields() {
+    let mut parser = Parser::new();
+    parser.set_language(get_language("javascript")).unwrap();
+
+    let tree = parser
+        .parse("function /*1*/ bar /*2*/ () {}", None)
+        .unwrap();
+
+    let mut cursor = tree.walk();
+    assert_eq!(cursor.node().kind(), "program");
+
+    cursor.goto_first_child();
+    assert_eq!(cursor.node().kind(), "function_declaration");
+    assert_eq!(cursor.field_name(), None);
+
+    cursor.goto_first_child();
+    assert_eq!(cursor.node().kind(), "function");
+    assert_eq!(cursor.field_name(), None);
+
+    cursor.goto_next_sibling();
+    assert_eq!(cursor.node().kind(), "comment");
+    assert_eq!(cursor.field_name(), None);
+
+    cursor.goto_next_sibling();
+    assert_eq!(cursor.node().kind(), "identifier");
+    assert_eq!(cursor.field_name(), Some("name"));
+
+    cursor.goto_next_sibling();
+    assert_eq!(cursor.node().kind(), "comment");
+    assert_eq!(cursor.field_name(), None);
+
+    cursor.goto_next_sibling();
+    assert_eq!(cursor.node().kind(), "formal_parameters");
+    assert_eq!(cursor.field_name(), Some("parameters"));
+}
+
 #[test]
 fn test_tree_node_equality() {
     let mut parser = Parser::new();

lib/src/tree_cursor.c

@@ -273,6 +273,7 @@ TSFieldId ts_tree_cursor_current_field_id(const TSTreeCursor *_self) {
 
     while (field_map < field_map_end) {
       if (
+        !ts_subtree_extra(*entry->subtree) &&
         !field_map->inherited &&
         field_map->child_index == entry->structural_child_index
       ) return field_map->field_id;