Fix incorrect error missing for missing required args.

context.go

@@ -518,11 +518,17 @@ func checkMissingFlags(flags []*Flag) error {
 
 func checkMissingChildren(node *Node) error {
 	missing := []string{}
+
+	missingArgs := []string{}
 	for _, arg := range node.Positional {
 		if arg.Required && !arg.Set {
-			missing = append(missing, strconv.Quote(arg.Summary()))
+			missingArgs = append(missingArgs, arg.Summary())
 		}
 	}
+	if len(missingArgs) > 0 {
+		missing = append(missing, strconv.Quote(strings.Join(missingArgs, " ")))
+	}
+
 	for _, child := range node.Children {
 		if child.Hidden {
 			continue

help.go

@@ -71,7 +71,8 @@ func printCommand(w *helpWriter, app *Application, cmd *Command) {
 	}
 	printNodeDetail(w, cmd)
 	if w.Summary && app.HelpFlag != nil {
-		w.Printf(`Run "%s %s --help" for more information.`, app.Name, cmd.FullPath())
+		w.Print("")
+		w.Printf(`Run "%s --help" for more information.`, cmd.FullPath())
 	}
 }
 

kong_test.go

@@ -554,3 +554,15 @@ func TestInterpolationIntoModel(t *testing.T) {
 	require.Equal(t, map[string]bool{"a": true, "b": true, "c": true, "d": true}, flag.EnumMap())
 	require.Equal(t, "One of a,b", flag2.Help)
 }
+
+func TestErrorMissingArgs(t *testing.T) {
+	var cli struct {
+		One string `arg:""`
+		Two string `arg:""`
+	}
+
+	p := mustNew(t, &cli)
+	_, err := p.Parse(nil)
+	require.Error(t, err)
+	require.Equal(t, "expected \"<one> <two>\"", err.Error())
+}