1 files changed, 1 insertions, 0 deletions
diff --git a/src/annotate.cc b/src/annotate.cc
index 33c0aebb..352690c6 100644
--- a/src/annotate.cc
+++ b/src/annotate.cc
@@ -42,6 +42,7 @@ void annotation_t::parse(std::istream& in)
 {
   do {
     istream_pos_type pos = in.tellg();
+    assert(pos != -1);
 
     char buf[256];
     char c = peek_next_nonws(in);