accounts/abi: fix resolving single struct argument

accounts/abi/argument.go

@@ -137,7 +137,7 @@ func (arguments Arguments) copyAtomic(v interface{}, marshalledValues interface{
 	dst := reflect.ValueOf(v).Elem()
 	src := reflect.ValueOf(marshalledValues)
 
-	if dst.Kind() == reflect.Struct && src.Kind() != reflect.Struct {
+	if dst.Kind() == reflect.Struct {
 		return set(dst.Field(0), src)
 	}
 	return set(dst, src)

accounts/abi/bind/bind_test.go

@@ -1785,6 +1785,77 @@ var bindTests = []struct {
 		nil,
 		nil,
 	},
+	// Test resolving single struct argument
+	{
+		`NewSingleStructArgument`,
+		`
+		 pragma solidity ^0.8.0;
+
+		 contract NewSingleStructArgument {
+			 struct MyStruct{
+				 uint256 a;
+				 uint256 b;
+			 }
+			 event StructEvent(MyStruct s);
+			 function TestEvent() public {
+				 emit StructEvent(MyStruct({a: 1, b: 2}));
+			 }
+		 }
+	   `,
+		[]string{"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"},
+		[]string{`[{"anonymous":false,"inputs":[{"components":[{"internalType":"uint256","name":"a","type":"uint256"},{"internalType":"uint256","name":"b","type":"uint256"}],"indexed":false,"internalType":"struct Test.MyStruct","name":"s","type":"tuple"}],"name":"StructEvent","type":"event"},{"inputs":[],"name":"TestEvent","outputs":[],"stateMutability":"nonpayable","type":"function"}]`},
+		`
+			"math/big"
+
+			"github.com/ethereum/go-ethereum/accounts/abi/bind"
+			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
+			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/crypto"
+			"github.com/ethereum/go-ethereum/eth/ethconfig"
+	   `,
+		`
+			var (
+				key, _  = crypto.GenerateKey()
+				user, _ = bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
+				sim     = backends.NewSimulatedBackend(core.GenesisAlloc{user.From: {Balance: big.NewInt(1000000000000000000)}}, ethconfig.Defaults.Miner.GasCeil)
+			)
+			defer sim.Close()
+
+			_, _, d, err := DeployNewSingleStructArgument(user, sim)
+			if err != nil {
+				t.Fatalf("Failed to deploy contract %v", err)
+			}
+			sim.Commit()
+
+			_, err = d.TestEvent(user)
+			if err != nil {
+				t.Fatalf("Failed to call contract %v", err)
+			}
+			sim.Commit()
+
+			it, err := d.FilterStructEvent(nil)
+			if err != nil {
+				t.Fatalf("Failed to filter contract event %v", err)
+			}
+			var count int
+			for it.Next() {
+				if it.Event.S.A.Cmp(big.NewInt(1)) != 0 {
+					t.Fatal("Unexpected contract event")
+				}
+				if it.Event.S.B.Cmp(big.NewInt(2)) != 0 {
+					t.Fatal("Unexpected contract event")
+				}
+				count += 1
+			}
+			if count != 1 {
+				t.Fatal("Unexpected contract event number")
+			}
+	   `,
+		nil,
+		nil,
+		nil,
+		nil,
+	},
 }
 
 // Tests that packages generated by the binder can be successfully compiled and

accounts/abi/unpack_test.go

@@ -762,20 +762,24 @@ func TestUnpackTuple(t *testing.T) {
 	buff.Write(common.Hex2Bytes("ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff")) // ret[b] = -1
 
 	// If the result is single tuple, use struct as return value container directly.
-	v := struct {
+	type v struct {
 		A *big.Int
 		B *big.Int
-	}{new(big.Int), new(big.Int)}
+	}
+	type r struct {
+		Result v
+	}
+	var ret0 = new(r)
+	err = abi.UnpackIntoInterface(ret0, "tuple", buff.Bytes())
 
-	err = abi.UnpackIntoInterface(&v, "tuple", buff.Bytes())
 	if err != nil {
 		t.Error(err)
 	} else {
-		if v.A.Cmp(big.NewInt(1)) != 0 {
-			t.Errorf("unexpected value unpacked: want %x, got %x", 1, v.A)
+		if ret0.Result.A.Cmp(big.NewInt(1)) != 0 {
+			t.Errorf("unexpected value unpacked: want %x, got %x", 1, ret0.Result.A)
 		}
-		if v.B.Cmp(big.NewInt(-1)) != 0 {
-			t.Errorf("unexpected value unpacked: want %x, got %x", -1, v.B)
+		if ret0.Result.B.Cmp(big.NewInt(-1)) != 0 {
+			t.Errorf("unexpected value unpacked: want %x, got %x", -1, ret0.Result.B)
 		}
 	}