- const char *file_name; /* Interned file name, or NULL. */
- int first_line; /* 1-based line number, or 0 if none. */
- int last_line; /* 1-based exclusive last line (0=none). */
- int first_column; /* 1-based first column, or 0 if none. */
- int last_column; /* 1-based exclusive last column (0=none). */
+ /* Interned file name, or NULL. */
+ const char *file_name;
+
+ /* Nonnull if this came from a source file. */
+ struct lex_source *src;
+
+ /* The starting and ending point of the cause. One of:
+
+ - Both empty, with all their members zero.
+
+ - A range of lines, with 0 < start.line <= end.line and start.column =
+ end.column = 0.
+
+ - A range of columns spanning one or more lines. If it's on a single
+ line, then start.line = end.line and 0 < start.column <= end.column.
+ If it's across multiple lines, then 0 < start.line < end.line and the
+ column members are both positive.
+
+ Both 'start' and 'end' are inclusive, line-wise and column-wise.
+ */
+ struct msg_point start, end;