I have a fine grammar, but I get unset value warnings in droves when I add
empty %destructor declartions (the error token is not [yet] referenced).
This applies to Bison 2.5 on Fedora 17 and also 2.4.1 on Fedora13.
%union
{
struct instruction * inst;
struct expression * exp;
struct term term;
int kwd;
}
/*
%destructor {} <inst>
%destructor {} <exp>
%destructor {} <term>
*/
%destructor {} <kwd>
The offending rule:
| PARSE parsehow parsecase parsewhat SEMICOLON
{
$$=GETINSTXP(@$, parse, $4);
}
The messages:
rexxy.y:401.19-404.19: warning: unused value: $2
rexxy.y:401.19-404.19: warning: unused value: $3
It is true that $2 and $3 are not referenced in the action. In this
particular context they are valid, but have no effect.
If I comment out the destructor, the grammar is processed without errors or
warnings.
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