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openzeppelin-contracts/certora/specs/ERC1155Supply.spec

89 lines
2.6 KiB

methods {
totalSupply(uint256) returns uint256 envfree
balanceOf(address, uint256) returns uint256 envfree
exists_wrapper(uint256) returns bool envfree
}
/// given two different token ids, if totalSupply for one changes, then
/// totalSupply for other should not
rule token_totalSupply_independence(method f)
filtered {
f -> f.selector != _burnBatch(address,uint256[],uint256[]).selector
&& f.selector != _mintBatch(address,uint256[],uint256[],bytes).selector
&& f.selector != safeBatchTransferFrom(address,address,uint256[],uint256[],bytes).selector
}
{
uint256 token1; uint256 token2;
require token1 != token2;
uint256 token1_before = totalSupply(token1);
uint256 token2_before = totalSupply(token2);
env e; calldataarg args;
f(e, args);
uint256 token1_after = totalSupply(token1);
uint256 token2_after = totalSupply(token2);
assert token1_after != token1_before => token2_after == token2_before,
"methods must not change the total supply of more than one token";
}
/******************************************************************************/
ghost mapping(uint256 => mathint) sumOfBalances;
hook Sstore _balances[KEY uint256 token][KEY address user] uint256 newValue (uint256 oldValue) STORAGE {
sumOfBalances[token] = sumOfBalances[token] + newValue - oldValue;
}
// status: not passing, because mint and burn are the same as transferring to/from
// the 0 address.
invariant total_supply_is_sum_of_balances(uint256 token)
sumOfBalances[token] == totalSupply(token) + balanceOf(0, token)
rule total_supply_is_sum_of_balances_as_rule {
uint256 token;
require sumOfBalances[token] == totalSupply(token) + balanceOf(0, token);
mathint sum_before = sumOfBalances[token];
method f; calldataarg arg; env e;
f(e, arg);
mathint sum_after = sumOfBalances[token];
assert sumOfBalances[token] == totalSupply(token) + balanceOf(0, token);
}
/******************************************************************************/
// if a user has a token, then the token should exist
/*
hook Sload _balances[...] {
require balance <= totalSupply
}
*/
rule held_tokens_should_exist {
address user; uint256 token;
// This assumption is safe because of total_supply_is_sum_of_balances
require balanceOf(user, token) <= totalSupply(token);
assert balanceOf(user, token) > 0 => exists_wrapper(token),
"if a user's balance for a token is positive, the token must exist";
}
/******************************************************************************/
rule sanity {
method f; env e; calldataarg args;
f(e, args);
assert false;
}