3 files changed, 8 insertions, 2 deletions
diff --git a/src/nvim/arglist.c b/src/nvim/arglist.c
index bb639edc07..361bb8db12 100644
--- a/src/nvim/arglist.c
+++ b/src/nvim/arglist.c
@@ -31,6 +31,7 @@
 #include "nvim/memline_defs.h"
 #include "nvim/memory.h"
 #include "nvim/message.h"
+#include "nvim/normal.h"
 #include "nvim/option.h"
 #include "nvim/option_vars.h"
 #include "nvim/os/input.h"
@@ -1096,6 +1097,10 @@ static void do_arg_all(int count, int forceit, int keep_tabs)
 
   tabpage_T *const new_lu_tp = curtab;
 
+  // Stop Visual mode, the cursor and "VIsual" may very well be invalid after
+  // switching to another buffer.
+  reset_VIsual_and_resel();
+
   // Try closing all windows that are not in the argument list.
   // Also close windows that are not full width;
   // When 'hidden' or "forceit" set the buffer becomes hidden.
diff --git a/src/nvim/memline.c b/src/nvim/memline.c
index ce04362a3e..fb7fdfb8b2 100644
--- a/src/nvim/memline.c
+++ b/src/nvim/memline.c
@@ -1860,7 +1860,7 @@ int gchar_pos(pos_T *pos)
   FUNC_ATTR_NONNULL_ARG(1)
 {
   // When searching columns is sometimes put at the end of a line.
-  if (pos->col == MAXCOL) {
+  if (pos->col == MAXCOL || pos->col > ml_get_len(pos->lnum)) {
     return NUL;
   }
   return utf_ptr2char(ml_get_pos(pos));
diff --git a/src/nvim/ops.c b/src/nvim/ops.c
index 476c7ee8a4..d51b4cc88b 100644
--- a/src/nvim/ops.c
+++ b/src/nvim/ops.c
@@ -4345,6 +4345,7 @@ void charwise_block_prep(pos_T start, pos_T end, struct block_def *bdp, linenr_T
   colnr_T endcol = MAXCOL;
   colnr_T cs, ce;
   char *p = ml_get(lnum);
+  int plen = ml_get_len(lnum);
 
   bdp->startspaces = 0;
   bdp->endspaces = 0;
@@ -4394,7 +4395,7 @@ void charwise_block_prep(pos_T start, pos_T end, struct block_def *bdp, linenr_T
     bdp->textlen = endcol - startcol + inclusive;
   }
   bdp->textcol = startcol;
-  bdp->textstart = p + startcol;
+  bdp->textstart = startcol <= plen ? p + startcol : p;
 }
 
 /// Handle the add/subtract operator.