1 files changed, 10 insertions, 0 deletions
diff --git a/src/tag.c b/src/tag.c
index c3e23f624..d07fbbe99 100644
--- a/src/tag.c
+++ b/src/tag.c
@@ -690,6 +690,16 @@ do_tag(
 		max_num_matches = MAXCOL; // If less than max_num_matches
 					  // found: all matches found.
 
+	    // A tag function may do anything, which may cause various
+	    // information to become invalid.  At least check for the tagstack
+	    // to still be the same.
+	    if (tagstack != curwin->w_tagstack)
+	    {
+		emsg(_(e_window_unexpectedly_close_while_searching_for_tags));
+		FreeWild(new_num_matches, new_matches);
+		break;
+	    }
+
 	    // If there already were some matches for the same name, move them
 	    // to the start.  Avoids that the order changes when using
 	    // ":tnext" and jumping to another file.