(Finsert_file_contents): Declare buffer as unsigned

char.  When comparing with file size convert same_at_start to
distance to buffer start.  If the file matches the buffer
contents truncate the buffer to the size of the file.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/fileio.c b/src/fileio.c
index 60473ede63d..8d02ca3fdaa 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -2694,10 +2694,12 @@ and (2) it puts less data in the undo list.")
       immediate_quit = 0;
       /* If the file matches the buffer completely,
          there's no need to replace anything.  */
-      if (same_at_start == st.st_size)
+      if (same_at_start - BEGV == st.st_size)
         {
           close (fd);
           specpdl_ptr--;
+          /* Truncate the buffer to the size of the file.  */
+          del_range_1 (same_at_start, same_at_end, 0);
           goto handled;
         }
       immediate_quit = 1;