Add validation to make sure source info generated from the parser is actually valid

[fruffy]

No description provided.

[ChrisDodd]

Another possible approach would be to change YYLLOC_DEFAULT to something like:

#define YYLLOC_DEFAULT(Cur, Rhs, N)                                     \
    ((Cur) = (N) ? YYRHSLOC(Rhs, 1) + YYRHSLOC(Rhs, N) : yylloc)

This would set the location to the location of the lookahead token for an epsilon reduction.

[ChrisDodd]

Perhaps better:

#define YYLLOC_DEFAULT(Cur, Rhs, N)                                             \
    ((Cur) = (N) ? YYRHSLOC(Rhs, 1) + YYRHSLOC(Rhs, N)                          \
        : yylloc ? yyloc \
                 : Util::SourceInfo(driver.sources, driver.sources.getSourcePosition()))

or

#define YYLLOC_DEFAULT(Cur, Rhs, N)                                             \
    ((Cur) = (N) ? YYRHSLOC(Rhs, 1) + YYRHSLOC(Rhs, N)                          \
        : YYRHSLOC(Rhs, 0) ?  Util::SourceInfo(driver.sources, YYRHSLOC(Rhs, 0).getEnd())  \
                 : Util::SourceInfo(driver.sources, driver.sources.getSourcePosition()))

[fruffy]

Perhaps better:

#define YYLLOC_DEFAULT(Cur, Rhs, N)                                             \
    ((Cur) = (N) ? YYRHSLOC(Rhs, 1) + YYRHSLOC(Rhs, N)                          \
        : yylloc ? yyloc \
                 : Util::SourceInfo(driver.sources, driver.sources.getSourcePosition()))

or

#define YYLLOC_DEFAULT(Cur, Rhs, N)                                             \
    ((Cur) = (N) ? YYRHSLOC(Rhs, 1) + YYRHSLOC(Rhs, N)                          \
        : YYRHSLOC(Rhs, 0) ?  Util::SourceInfo(driver.sources, YYRHSLOC(Rhs, 0).getEnd())  \
                 : Util::SourceInfo(driver.sources, driver.sources.getSourcePosition()))

It might actually be nicer to have the less complex version, I looked at the reference file failures, and they seemed to be benign. Mostly a difference of 1 character in terms of start/end.