erec: fix error markup for errors starting at column 0

For errors starting at column 0, we must not subtract 1 to avoid underflow.

Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/src/erec.c b/src/erec.c
index 7451d94c..a157d2fa 100644
--- a/src/erec.c
+++ b/src/erec.c
@@ -138,7 +138,8 @@ void erec_print(FILE *f, const struct error_record *erec)
 		end = 0;
 		for (l = erec->num_locations - 1; l >= 0; l--) {
 			loc = &erec->locations[l];
-			for (i = loc->first_column - 1; i < loc->last_column; i++)
+			for (i = loc->first_column ? loc->first_column - 1 : 0;
+			     i < loc->last_column; i++)
 				buf[i] = l ? '~' : '^';
 			end = max(end, loc->last_column);
 		}