[m-users.] Warning: this disjunct will never have any solutions.

[Sean Charles (emacstheviking)]

Is it safe to ignore this given I know why …my parsing code reaches a point where it knows a syntax error has been detected:

:- pred s_exp(anode::out, latok::in, latok::out) is nondet.
s_exp(X) -->
    (
        (   op(_P) ->
            expression_body(X),
            (   cp(_)
            ;   error_pos(P),
                {throw(syntax_error(P, expected_close_paren))}
            )
        ;
            error_pos(P),
            {throw(syntax_error(P, expected_open_paren))}
        )
    ).

I can see that throwing the exception does mean there can be no solution…I expect there is a compiler switch to silence it but I don’t like doing things like that… is there a Mercury-esque technique/approach etc that I have not yet learned about?

Thanks
Sean

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