Merge pull request #2246 from multiversx/multi-transfer-marker-constraints

MultiTransfer marker - constrained argument

Author: andrei-marinica

framework/base/src/types/interaction/tx_payment/tx_payment_multi_transfer_marker.rs

@@ -1,14 +1,17 @@
 use crate::{
     contract_base::{SendRawWrapper, TransferExecuteFailed},
-    types::{BigUint, ManagedAddress, MultiTransfer, PaymentVec, TxFrom, TxToSpecified},
+    types::{
+        BigUint, ManagedAddress, MultiTransfer, MultiTransferMarkerArg, PaymentVec, TxFrom,
+        TxToSpecified,
+    },
 };
 
 use super::{FullPaymentData, FunctionCall, TxEnv, TxPayment};
 
 impl<Env, P> TxPayment<Env> for MultiTransfer<P>
 where
     Env: TxEnv,
-    P: AsRef<PaymentVec<Env::Api>>,
+    P: MultiTransferMarkerArg + AsRef<PaymentVec<Env::Api>>,
 {
     fn is_no_payment(&self, _env: &Env) -> bool {
         let pv = self.0.as_ref();

framework/base/src/types/managed/wrapped/token.rs

@@ -20,7 +20,7 @@ pub use esdt_token_data::EsdtTokenData;
 pub use esdt_token_identifier::{EsdtTokenIdentifier, TokenIdentifier};
 pub use esdt_token_payment::{EsdtTokenPayment, EsdtTokenPaymentRefs, MultiEsdtPayment};
 pub use multi_egld_or_esdt_token_payment::MultiEgldOrEsdtPayment;
-pub use multi_transfer_marker::MultiTransfer;
+pub use multi_transfer_marker::{MultiTransfer, MultiTransferMarkerArg};
 pub use payment::Payment;
 pub use payment_refs::PaymentRefs;
 pub use payment_vec::PaymentVec;

framework/base/src/types/managed/wrapped/token/multi_transfer_marker.rs

@@ -1,7 +1,26 @@
+use crate::{
+    api::ManagedTypeApi,
+    types::{ManagedRef, PaymentVec},
+};
+
 /// A wrapper that forces payments to go via MultiESDTtransfer, even if it wouldn't be necessary, such as:
 /// - Just EGLD
 /// - Single fungible ESDT transfers,
 /// - Single NFT transfers.
 ///
 /// This contrasts with unwrapped PaymentVec, tries to use the simplest possible transfer type.
-pub struct MultiTransfer<P>(pub P);
+pub struct MultiTransfer<P>(pub P)
+where
+    P: MultiTransferMarkerArg;
+
+/// Marks an allowed generic argument for MultiTransfer.
+#[diagnostic::on_unimplemented(
+    message = "Type `{Self}` cannot be used in `MultiTransfer`",
+    label = "unsupported MultiTransfer argument",
+    note = "only `PaymentVec` and its references can be used as `MultiTransfer` arguments for now, please do signal the team if any other type is desired"
+)]
+pub trait MultiTransferMarkerArg {}
+
+impl<M: ManagedTypeApi> MultiTransferMarkerArg for PaymentVec<M> {}
+impl<M: ManagedTypeApi> MultiTransferMarkerArg for &PaymentVec<M> {}
+impl<M: ManagedTypeApi> MultiTransferMarkerArg for ManagedRef<'_, M, PaymentVec<M>> {}