Questions tagged [solidity]
Solidity is a contract-oriented, high-level language whose syntax is similar to that of JavaScript and it is designed for writing smart contracts in Ethereum to run on the EVM. Solidity is statically typed, supports inheritance, libraries and complex user-defined types among other features.
17,412
questions
0
votes
0
answers
13
views
Adding Uniswap interface to a ERC20 token smart contract
I just started learning Solidity, as browse through various smart contracts for tokens listen on Uniswap, I notice that most of them use IUniswapV2Factory and IUniswapV2Router02 and a small amount don'...
- 1
0
votes
0
answers
7
views
Cannot import correctly uniswap's permit2
Hello i am trying to import the permit2 following the official uniswap's guide but i cannot manage to import it correctly since it lacks of the structs and more things even if i don't get any error ...
0
votes
0
answers
5
views
The function runs external, but not internal
mapping(string => mapping(uint256 => Order[])) buyOrders;
mapping(string => mapping(uint256 => Order[])) sellOrders;
function placeBuyOrder(string memory stockName, uint256 price, uint32 ...
- 1
0
votes
0
answers
4
views
USdt ERC20 1006
I am confused about this "Usdt erc20 1006" . In a website for withdrawal it is written "your Usdt Erc20 1006"..
This is certainly address but which type of address is this.
- 1
0
votes
0
answers
10
views
ERC20 Multisend works on Sepolia Testnet but Fails on Mainnet
I've got a smart contract function that takes an erc20 contract address, an array of addresses and an array of amounts and then sends the each amount to each address of the specified token. I've got ...
0
votes
0
answers
6
views
Redeploy safe with same address on OP
I deployed the Safe on Ethereum using this factory: 0xa6B71E26C5e0845f74c812102Ca7114b6a896AB2. Now, I'd like to deploy the same Safe address on Optimism. Could you please provide guidance on the ...
0
votes
0
answers
13
views
Brownie Request for Random number (Mock VRF) reverts
Using chainlink tutorial and concept for testing a random request locally, Request Randomness fails to execute in brownie for VRFCoordinatorV2Mock, however, I tested the same code in remix IDE and it ...
0
votes
0
answers
9
views
Solidity assembly: `target_slot`. Is it an opcode or other stuff?
I found this strange variable or opcode in inline assembly, but I'm not sure: target_ slot. I couldn't find its definition in the contract. I prefer it to be an opcode, but I didn't seem to find it ...
- 61
0
votes
2
answers
35
views
How to Import OpenZeppelin Contracts with Node.js Environment
I'm having an issue. I'm attempting to compile my contract with Node.js inside of a VSCode terminal, but my openzeppelin imports aren't being seen, and I'm not sure how to handle them with Node.js. ...
0
votes
1
answer
21
views
Rebasing tokenomics
I have the following variables where all values are multiplied by 1e18 to represent fixed-point numbers on the EVM:
uint totalShares = 100;
uint sharesAlice = 20;
uint sharesBob = 30;
uint ...
- 711
1
vote
1
answer
14
views
How works refund ReentrancyGuard library for solidity
When I was reading the library code, I came across the following comment: "the values being non-zero value makes deployment a bit more expensive, but in exchange the refund on every call to ...
- 11
0
votes
1
answer
16
views
Creating a token for my personal dapp use only
I want to store the money in a smart contract from my user as long the user wants and pay back the user once he asks i will not charge for this service
if I store ether in it and the value of Ethereum ...
0
votes
1
answer
10
views
GoFundMe Contract: Minting "Thanks" over time vs all at once & "Thanks" token value
I was assigned to write a smart contract for class (to be deployed on a test-net), which, upon receiving ETH, returns to the sender some amount of tokens with symbol "Thanks". I want this ...
- 101
0
votes
1
answer
36
views
What's the cheapest way to store a large amount of data into a smart contract?
I'm working on a smart contract in which we need to store some addresses along with their pending rewards periodically,
so the most first approach is to have a mapping of addresses to an int, like ...
- 11
1
vote
0
answers
21
views
Foundry or Hardhat: I'm really confused about which one should I use?
Hello everyone
I'm new in the smart contract and Dapp development and I'm so confused about choosing a framework. my questions are dumb but I couldn't find the answers by myself. Here is my problem:
I ...
- 21
0
votes
1
answer
10
views
Staking pool for native coins
I wanna build a staking pool for native coins like trx to test my skills as an engineer and yet due to my limited knowledge I don't know how to make a staking platform without creating a new token. Is ...
- 43
0
votes
0
answers
13
views
Verify signature from dApp on contract
I am creating a signed message using a user address, nonce and number (amount of eth to send) like this:
const ammount = 1;
const userAddr = await otherAccount.address
const nonce = ...
- 23
1
vote
0
answers
14
views
How can this be a bytes32[] method? _merkleProof.verifyCalldata(root, leaf)
Code: https://www.contractreader.io/contract/mainnet/0x0C7D4bdA40CF78F9F1BAf6e3D5774f1E22c9CC4B
My question is about this verifyCalldata() call:
function verifyAddress(
uint256 _projectId,
...
- 111
0
votes
1
answer
28
views
removeLiquidity function in a smart contract, getting execution reverted due to ds-math-sub-underflow
i'm trying to create a smart contract which removes user's lp share from the pool doing these steps:
calculates the current user's balance of LP tokens for a particular pair
removes their liquidity ...
- 129
0
votes
1
answer
12
views
What is the reason for this assembly code?
I am looking at the following contract, specifically the following assembly code....I think I decoded that it means make sure that if the contents of slot 0 equals 2, then store 3980109478 (which is ...
- 41
0
votes
1
answer
15
views
What is the purpose of the import statement in Solidity?
Could someone explain to me what the pupose of the import statement is, in Solidity? Is it the similar to inheriting from another contract where you have access to the state variables and function of ...
- 43
0
votes
1
answer
11
views
Chainlink fulfillRequest is not able to call another contract
I am working on a project that includes Chainlink Functions (for off-chain API calls) and CCIP (to transfer tokens cross-chain).
My project includes 3 main contracts:
FunctionConsumer.sol: Chainlink ...
0
votes
1
answer
15
views
gas estimation error because of reverted
here is a situation I have: a user came to my platform to buy mytoken and he paid 44 matic for it and 266,087 | 263,663 (99.09%) which reverted because of the gas out. is there any solution to add gas ...
- 15
0
votes
1
answer
18
views
Are multiplications after division UNSAFE?
I have a smart contract which essentially does this:
uint256 tokenRate = _pair.a2 * PRECISION_FACTOR / _pair.a1;
uint256 toSend = _amount * tokenRate / PRECISION_FACTOR;
uint256 feeToOwner2 = toSend ...
- 640
0
votes
1
answer
14
views
How can I get a defi site source code?
I'm trying to expose a defi scam website which copycats a famous platform on TRX blockchain. I have their transaction address, but no source code or website's contract address. I was wondering if ...
- 43
2
votes
1
answer
26
views
Assembly 'create2' and 'new' with salt not determining the same address
Since solidity 0.8.0, we can now specify the salt for contract creation using new keyword
Using 'new'
bytes32 _salt = bytes32("0x4");
address addr = address(new DummyContract{salt: _salt}());...
- 127
0
votes
0
answers
12
views
Why are you able to swap eth to token lesser than specified amount in amountOutMinimum?
I am using Dai as an example for token address in constructor so when you call this function it should swap ether to Dai.
My question is why sending ether lesser than amountOutMinimum. It still able ...
- 65
0
votes
0
answers
26
views
Swap functions seems to not swap?
I have deployed a smart contract on a local network and I am trying to do swaps from a metamask account. I have allocated a quantity of tokens to the smart contract so it can use it using the approve ...
- 1
0
votes
1
answer
20
views
Whats in the mempool? Was wondering if there are listed properties that anyone can view it
If you send a transaction and it is in the mempool, what are the properties in the transaction of the memool?
I was wondering if you can get the address of the sender in the mempool. What else can be ...
- 65
0
votes
1
answer
13
views
Inline assembly loop doesn't update memory
I want to copy in inline assembly from calldata the last two bytes of every 32 byte slices to the lower half of the first free memory slot(32 bytes).
free = free memory pointer + 14 (bytes)
moffset = ...
1
vote
2
answers
65
views
Trying to create a soulbound token. Keep getting two errors
I'm trying to create a soulbound (non-transferable NFT) token on Solidity. Here is my code so far.
// SPDX-License-Identifier: MIT
pragma solidity >=0.4.17 <0.9.0;
import "@openzeppelin/...
- 11
0
votes
1
answer
14
views
How can I fetch the current dollar price of BNB in a Solidity smart contract?
How can I fetch the current dollar price of BNB in a Solidity smart contract? Are there any recommended APIs or secure, decentralized methodologies for this?Is there a way to fetch the dollar price ...
0
votes
1
answer
10
views
How do you deal with relative imports in a contract you depend on?
Goal
I am attempting to create a smart contract that uses contracts from the iden3 library. I am using the Remix IDE.
Problem
My issue is that the contract I need (IdentityBase.sol) has several ...
1
vote
0
answers
20
views
How to I solve fetch has been blocked by CORS policy when fetch data from contract
I'm trying to fetch campaign data and display it to the user. I'm using Nextjs in the front-end and solidity & hardhat in the back-end. The contract data seems to be fetched but when being ...
- 11
0
votes
1
answer
20
views
Bought a scam token, trying to understand what part of the code should I check next time to prevent that
Contract code - https://etherscan.io/token/0x67bcd18a484a88f073097a18b0462eb7c44d3178#code
Ownership renounce at 08:17 UTC https://etherscan.io/tx/...
- 1
0
votes
1
answer
26
views
Decoding Chainlink Function Response in Solidity Contract and Handling Nested JSON Objects
I'm dealing with a problem regarding the decoding of data obtained from a Chainlink function in my Solidity code. Specifically, I'm using a Chainlink custom function that sends an HTTP GET request to ...
0
votes
1
answer
15
views
Trying to issue ERC 3475 tokens
I'm trying to issue ERC 3475 tokens from a relatively simple contract using Remix. The contract compiles and deploys when gas is optimized, but when I try to issue the tokens I get an error of "...
- 1
0
votes
0
answers
18
views
Kill a smart contract where my funds are currently stuck inside
I am the owner of the contract however I didnt write it but have some funds stuck inside, when i try to withdraw or run the contract the remix IDE tells me that "Gas estimation errored with the ...
- 1
0
votes
1
answer
9
views
Reliably disassamble bytecode to opcodes across various evm versions
Is there a reliable way of disassembling bytecode into opcodes across different EVM versions, to make it agnostic to the EVM version used during compilation?
As the second best option - is there a ...
- 61
0
votes
1
answer
37
views
Invalid implicit conversion from enum to enum
My question is how is it possible to have such error:
Error (9553): Invalid type for argument in function call. Invalid implicit conversion from enum CoinType to enum CoinType requested.
--> test/...
- 65
3
votes
1
answer
53
views
How do old smart contracts that contain certain opcodes behave when those opcodes get deprecated/removed in hard fork upgrades?
For example say a contract with a compiler version of 0.7.5 (pragma solidity 0.7.5) contained selfdestruct(payable(address))
what happens to the contract when the self destruct opcode gets deprecated ...
- 43
0
votes
2
answers
29
views
How to pass blockNumber to viem call?
I'm trying to view the owner of a certain NFT at a specific blockNumber, when I make the viem call without the blockNumber parameter it works perfectly, however, once I try to pass a blockNumber with ...
- 1,408
0
votes
1
answer
29
views
I want to call a contract method using my safe wallet address
I made a safe wallet in my panel safe wallet which is 2/3 signers. I want to use it in my access control for an admin role and use it for calling a transfer method with it only. The problem is when I ...
- 15
0
votes
2
answers
21
views
Object has no member 'call' when reading smart contract in geth console
I'm following the Storage contract example from the Geth site (https://geth.ethereum.org/docs/interacting-with-geth/javascript-console-contracts)
I am unable to call a 'retrieve' function on the ...
- 101
0
votes
1
answer
25
views
How to exchange one nft for another from a different contract?
I have 2 ERC1155 contracts, and am looking to transfer nft2 into nft1's wallet upon checking wallet holds nft1, but not sure what I'm doing wrong.
This is my nft1 contract:
import "./NFT2.sol&...
- 1
0
votes
1
answer
24
views
Ethers is not decoding the indexed parameters
I want to get the value from the first indexed parameter of the TokensTransferred event from the transaction logs which can look like this. You can see that the TokensTransferred event has the first ...
0
votes
1
answer
12
views
importing other contract in remix gone wrong despite write file name or path [closed]
import "./filename.sol"
output
Error: not found SimpleStorage.sol
0
votes
0
answers
21
views
Malicious ERC20 blocking batch withdrawals of tokens (e.g. ERC777)
I was wondering whether the following attack vector is possible in practice.
There's a batch transfer function that is intended to batch transfer the tokens owned by the contract. That function ...
- 264
0
votes
1
answer
38
views
Error (9322): No matching declaration found after argument-dependent lookup
Here is the file which i try to run test through foundry.
//Imports
import "forge-std/Test.sol";
import {Portal} from "../src/Portal.sol";
import {IERC20} from "@openzeppelin/...
1
vote
1
answer
73
views
Byte32 Array is not emitted as array from events
I have created this demo contract. It has a function called convertText which converts a string text into bytes32 and stores it into bytes32[] public storedData.
You can see when you call convertText()...