to_line blowing up

[Mike Stump]

Ok, so call me confused, how can:

void
fe_file_change (const struct line_map *new_map)
{
   unsigned int to_line = SOURCE_LINE (new_map, new_map->to_line);

possibly be right?  to_line is a normal line number, and 
new_map->to_line is a normal line number?  Therefore, what can 
SOURCE_LINE do to this, but confuse the line number?

Related to this, should from_line ever be > to_line in the map?

If one compiles:

	int i;

as a C++ file, and watches what the above code does, one should be able 
to see it go bad.

:-(