patch 9.0.0018: going over the end of the typahead

Problem:    Going over the end of the typahead.
Solution:   Put a NUL after the typeahead.

src/term.c

@@ -5393,6 +5393,7 @@ check_termcode(
 	if (*tp == ESC && !p_ek && (State & MODE_INSERT))
 	    continue;
 
+	tp[len] = NUL;
 	key_name[0] = NUL;	// no key name found yet
 	key_name[1] = NUL;	// no key name found yet
 	modifiers = 0;		// no modifiers yet

src/testdir/test_mapping.vim

@@ -1715,4 +1715,14 @@ func Test_map_after_timed_out_nop()
   call delete('Xtest_map_after_timed_out_nop')
 endfunc
 
+func Test_using_past_typeahead()
+  nnoremap :00 0
+  exe "norm :set \x80\xfb0=0\<CR>"
+  exe "sil norm :0\x0f\<C-U>\<CR>"
+
+  exe "norm :set \x80\xfb0=\<CR>"
+  nunmap :00
+endfunc
+
+
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -735,6 +735,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    18,
 /**/
     17,
 /**/