TCC v32: Parsing IF %@exec[command | command] == 0 ...?

v:\> if %@exec[echo foo | findstr foo] == 0 echo yes
foo
yes

v:\> if %@exec[echo foo | findstr foo] == 0 echo yes
FINDSTR: Cannot open ==
FINDSTR: Cannot open 0
FINDSTR: Cannot open echo
FINDSTR: Cannot open yes
TCC: Syntax error "@exec[echo"
Usage : IF [/I] [NOT] condition [.AND. | .OR. | .XOR. [NOT] condition ...] command