fix: improve error for transfer argument mixup (#2445)

src/ape/api/accounts.py

@@ -18,6 +18,7 @@
 from ape.exceptions import (
     AccountsError,
     AliasAlreadyInUseError,
+    ConversionError,
     MethodNonPayableError,
     MissingDeploymentBytecodeError,
     SignatureError,
@@ -220,8 +221,18 @@ def transfer(
         Returns:
             :class:`~ape.api.transactions.ReceiptAPI`
         """
+        if isinstance(account, int):
+            raise AccountsError(
+                "Cannot use integer-type for the `receiver` argument in the "
+                "`.transfer()` method (this protects against accidentally passing "
+                "the `value` as the `receiver`)."
+            )
+
+        try:
+            receiver = self.conversion_manager.convert(account, AddressType)
+        except ConversionError as err:
+            raise AccountsError(f"Invalid `receiver` value: '{account}'.") from err
 
-        receiver = self.conversion_manager.convert(account, AddressType)
         txn = self.provider.network.ecosystem.create_transaction(
             sender=self.address, receiver=receiver, **kwargs
         )

tests/functional/test_accounts.py

@@ -240,6 +240,27 @@ def test_transfer_value_of_0(sender, receiver):
     assert receiver.balance == initial_balance
 
 
+def test_transfer_mixed_up_sender_and_value(sender, receiver):
+    """
+    Testing the case where the user mixes up the argument order,
+    it should show a nicer error than it was previously, as this is
+    a common and easy mistake.
+    """
+    expected = (
+        r"Cannot use integer-type for the `receiver` "
+        r"argument in the `\.transfer\(\)` method \(this "
+        r"protects against accidentally passing the "
+        r"`value` as the `receiver`\)."
+    )
+    with pytest.raises(AccountsError, match=expected):
+        sender.transfer(123, receiver)
+
+    # Similarly show using currency-str (may fail for different error).
+    expected = r"Invalid `receiver` value: '123 wei'\."
+    with pytest.raises(AccountsError, match=expected):
+        sender.transfer("123 wei", receiver)
+
+
 def test_deploy(owner, contract_container, clean_contract_caches):
     contract = owner.deploy(contract_container, 0)
     assert contract.address