diff --git a/src/errors.h b/src/errors.h
index 969301f..5ba6d52 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -301,3 +301,5 @@
 	INIT(=N_("E1136: <Cmd> mapping must end with <CR> before second <Cmd>"));
 EXTERN char e_cmd_maping_must_not_include_str_key[]
 	INIT(= N_("E1137: <Cmd> mapping must not include %s key"));
+EXTERN char e_using_bool_as_number[]
+	INIT(= N_("E1138: Using a Bool as a Number"));
diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
index 63bfdd8..b7897fe 100644
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -1292,6 +1292,13 @@
   call CheckDefFailure(["var x = 'a' .. 0z32"], 'E1105:', 1)
   call CheckDefFailure(["var x = 'a' .. function('len')"], 'E1105:', 1)
   call CheckDefFailure(["var x = 'a' .. function('len', ['a'])"], 'E1105:', 1)
+
+  call CheckScriptFailure(['vim9script', 'var x = 1 + v:none'], 'E611:', 2)
+  call CheckScriptFailure(['vim9script', 'var x = 1 + v:null'], 'E611:', 2)
+  call CheckScriptFailure(['vim9script', 'var x = 1 + v:true'], 'E1138:', 2)
+  call CheckScriptFailure(['vim9script', 'var x = 1 + v:false'], 'E1138:', 2)
+  call CheckScriptFailure(['vim9script', 'var x = 1 + true'], 'E1138:', 2)
+  call CheckScriptFailure(['vim9script', 'var x = 1 + false'], 'E1138:', 2)
 endfunc
 
 func Test_expr5_fails_channel()
diff --git a/src/typval.c b/src/typval.c
index 7c55d3a..0e2513a 100644
--- a/src/typval.c
+++ b/src/typval.c
@@ -213,7 +213,10 @@
 	case VAR_SPECIAL:
 	    if (!want_bool && in_vim9script())
 	    {
-		emsg(_("E611: Using a Special as a Number"));
+		if (varp->v_type == VAR_BOOL)
+		    emsg(_(e_using_bool_as_number));
+		else
+		    emsg(_("E611: Using a Special as a Number"));
 		break;
 	    }
 	    return varp->vval.v_number == VVAL_TRUE ? 1 : 0;
diff --git a/src/version.c b/src/version.c
index 80d2af9..0f0ccda 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2012,
+/**/
     2011,
 /**/
     2010,