I believe its last usage was in the following code:

    if (prop == NULL)
            prop = stack->sym->prop;

This code was previously used to print the file name and line number of
associated symbols in sym_check_print_recursive(), which was removed by
commit 9d0d2660 ("kconfig: recursive checks drop file/lineno").
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>