Fix #711

core/odin/parser/parser.odin

@@ -1653,7 +1653,15 @@ parse_field_list :: proc(p: ^Parser, follow: tokenizer.Token_Kind, allowed_flags
 
 			names := make([]^ast.Expr, 1);
 			names[0] = ast.new(ast.Ident, tok.pos, end_pos(tok));
-			names[0].derived.(ast.Ident).name = tok.text;
+			switch ident in &names[0].derived {
+				case ast.Ident: {
+					ident.name = tok.text;
+				}
+
+				case: {
+					unreachable();
+				}
+			}
 
 			flags := check_field_flag_prefixes(p, len(list), allowed_flags, eaf.flags);