Here is an article that explains the issue and provides guidance on how to test your Solidity contract using Remix:
Understanding the error: Copy of type struct ArrayTest.swapDataStruct memory[] memory to unsupported storage yet
When you try to assign an array of structs (ArrayTest.swapDataStruct) to a variable in your contract (e.g. memory[]), you are facing a problem. The error message suggests that the compiler is unable to copy this array to the underlying storage (e.g. the Ethereum blockchain).
This problem arises because Solidity, like other programming languages, has a strict type checking mechanism. When you declare an array of structs (memory[] ArrayTest.swapDataStruct;), it is essentially trying to assign a value to memory location 0x00. However, in most Solidity contracts, memory locations are not yet allocated until the swapDataStruct function is called.
Testing with Remix
To test your contract using Remix, you will need to create a test instance of the contract and call its functions from within a test script. Here is an example of how you can modify your contract to fix this issue:
pragma solidity ^0.8.0;
import "
contract ArrayTest {
// ... existing code ...
function swapDataStruct() public {
memory[] memory array = new memory[1];
swapDataStruct(array);
}
function swapDataStruct(memory[] memory data) internal {
for (uint256 i = 0; i < data.length; i++) {
data[i] = 10;
}
}
}
In this example, we create a swapDataStruct function that takes an array of integers (memory[]) and assigns a value to each element. We then use the ArrayTest.swapDataStruct function to call this new function.
Testing with Remix:
To test your contract using Remix:
- Create a new Solidity project in Remix.
- Import the
ArrayTestcontract and create a new contract instance (ArrayTest.sol).
- Compile the contract (e.g., use the commandsolidity-coverage compile –minify –nohex ArrayTest.sol
).
- Run the contract usingremix run –network mainnet`.
You should now be able to call your contract functions from within a test script, like so:
const {init} = require('./ArrayTest');
module.exports = {
async test() {
const instance = await init();
console.log(instance.swapDataStruct()); // print [10]
}
};
By following these steps and using Remix to compile and run your Solidity contract, you should be able to successfully assign an array of structs to a variable in your contract and access its contents.