Error:
104 |
105 | //
106 | impl<T> Option<T> {
| ^ Cannot infer type for type parameter "T". Insufficient type information provided. Try annotating its type.
107 | // Querying the contained values
108 | //
|
My toolchain:
Installed toolchains
--------------------
latest-x86_64-unknown-linux-gnu (default)
nightly-x86_64-unknown-linux-gnu
nightly-2024-05-28-x86_64-unknown-linux-gnu
testnet-x86_64-unknown-linux-gnu
active toolchain
----------------
latest-x86_64-unknown-linux-gnu (default)
forc : 0.64.0
- forc-client
- forc-deploy : 0.64.0
- forc-run : 0.64.0
- forc-crypto : 0.64.0
- forc-debug : 0.64.0
- forc-doc : 0.64.0
- forc-fmt : 0.64.0
- forc-lsp : 0.64.0
- forc-tx : 0.64.0
- forc-wallet : 0.9.1
fuel-core : 0.36.0
fuel-core-keygen : 0.36.0
fuels versions
--------------
forc : 0.66
forc-wallet : 0.66.5
There won’t be any error if using forc 0.60.0+nightly.20240528.4fe6f1ed51, why though:
//fuel-toolchain.toml
[toolchain]
channel = "nightly-2024-05-28"
[components]
forc = "0.60.0+nightly.20240528.4fe6f1ed51"
fuel-core = "0.26.0"
My code:
script;
use libraries::{AMM, Exchange, data_structures::Asset, data_structures::PreviewSwapInfo };
/// Determines the type of input error.
enum InputError {
/// The number of assets in the swap is less than 2.
RouteTooShort: (),
}
/// Determines the type of swap error.
enum SwapError {
/// The amount bought is less than the minimum output amount.
ExcessiveSlippage: u64,
/// The exchange for this asset pair could not be found.
PairExchangeNotRegistered: (AssetId, AssetId),
}
configurable {
/// The ContractId of the AMM contract.
AMM_ID: b256 = 0x07b88ef9667910ca5b107df63ca2171b5dfffdcab8f07e219971876e46dce9de,
}
/// Swaps assets along a route by specifying exact output for each swap.
///
/// # Arguments
///
/// * `assets`: [Vec<AssetId>] - The assets along the swap route.
/// * `output_amount`: [u64] - The desired amount of the output asset.
/// * `maximum_input_amount`: [u64] - The maximum amount of the input asset.
/// * `deadline`: [u64] - The limit on block height for operation.
///
/// # Returns
///
/// * `u64`: The amount of the input asset that was sold.
///
/// # Reverts
///
/// * When `assets.len()` is less than two.
/// * When the exchange contract has not been registered in the AMM.
/// * When the amount of the sold asset is greater than `maximum_input_amount`.
fn main(
assets: Vec<AssetId>,
output_amount: Option<u64>,
maximum_input_amount: Option<u64>,
deadline: u64,
) -> u64 {
require(assets.len() >= 2, InputError::RouteTooShort);
let amm_contract = abi(AMM, AMM_ID);
let mut latest_sold_wrap: Option<u64> = output_amount;
let mut latest_sold = output_amount.unwrap();
if maximum_input_amount.is_some(){
require(
latest_sold <= maximum_input_amount.unwrap(),
SwapError::ExcessiveSlippage(latest_sold),
);
}
// start swapping by buying the last asset in the route.
let mut bought_asset_index = assets.len() - 1;
// swap subsequent asset pairs along route.
while bought_asset_index > 0 {
let asset_pair = (
assets.get(bought_asset_index - 1).unwrap(),
assets.get(bought_asset_index).unwrap(),
);
// get the exchange contract id of asset pair.
let exchange_contract_id = amm_contract.pool {
gas: 100_000,
}(asset_pair);
require(
exchange_contract_id
.is_some(),
SwapError::PairExchangeNotRegistered(asset_pair),
);
let exchange_contract = abi(Exchange, exchange_contract_id.unwrap().into());
let preview: PreviewSwapInfo = exchange_contract.preview_swap_exact_output(Asset::new(asset_pair.1, latest_sold));
let sell_amount = preview.other_asset.amount;
// swap by specifying the exact amount to buy.
latest_sold = exchange_contract.swap_exact_output {
gas: 10_000_000,
coins: sell_amount, // forward coins of asset to sell.
asset_id: asset_pair.0.into(), // identifier of asset to sell.
}(latest_sold_wrap, deadline);
bought_asset_index -= 1;
}
latest_sold
}
