cli/wallet: do not panic if receiver is missing, fix #2210

Signed-off-by: Evgeniy Stratonikov <evgeniy@nspcc.ru>

cli/nep17_test.go

@@ -116,6 +116,14 @@ func TestNEP17Transfer(t *testing.T) {
 		"--from", validatorAddr,
 	}
 
+	t.Run("missing receiver", func(t *testing.T) {
+		as := append([]string{}, args[:8]...)
+		as = append(as, args[10:]...)
+		e.In.WriteString("one\r")
+		e.RunWithError(t, as...)
+		e.In.Reset()
+	})
+
 	t.Run("InvalidPassword", func(t *testing.T) {
 		e.In.WriteString("onetwothree\r")
 		e.RunWithError(t, args...)

cli/wallet/nep17.go

@@ -514,6 +514,9 @@ func transferNEP(ctx *cli.Context, standard string) error {
 	}
 
 	toFlag := ctx.Generic("to").(*flags.Address)
+	if !toFlag.IsSet {
+		return cli.NewExitError(errors.New("missing receiver address (--to)"), 1)
+	}
 	to := toFlag.Uint160()
 	token, err := getMatchingToken(ctx, wall, ctx.String("token"), standard)
 	if err != nil {