Comment 14 for bug 1294669

so it appears the ! token is the culprit at a guess:

ps = {parser_state = 524288, token_state = 0x1629768, token = 0x11f4008 "!", token_buffer_size = 1520, input_line_terminator = 0, eof_encountered = 0, prompt_string_pointer = 0x6fc920 <ps1_prompt>, current_command_line_count = 0, remember_on_history = 1, history_expansion_inhibited = 0, last_command_exit_value = 1, pipestatus = 0x11fd588, last_shell_builtin = 0x0, this_shell_builtin = 0x0, expand_aliases = 1, echo_input_at_read = 0}
#14 0x0000000000420e43 in parse_command () at .././eval.c:231