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// SPDX-License-Identifier: MIT | |
pragma solidity ^0.8.21; | |
contract MemorySafetyExample { | |
function unsafeAssembly() public pure returns (uint) { | |
uint x; | |
uint y = 1; | |
assembly { | |
// Directly manipulate memory in an unsafe manner | |
x := mload(0x40) // Load from the free memory pointer | |
mstore(x, y) // Store y at location x | |
mstore(add(x, 0x20), 2) // Deliberately create a memory safety issue | |
} | |
return x; | |
} | |
} | |
contract MemorySafetyTest { | |
MemorySafetyExample example; | |
function setUp() public { | |
example = new MemorySafetyExample(); | |
} | |
function testIsOne() public view returns (uint x) { | |
// x should be 1, this call may fail or lead | |
// to undefined behavior due to memory safety issues | |
x = example.unsafeAssembly(); | |
} | |
function assertIsOne() public view { | |
// x should be 1, this call may fail or lead | |
// to undefined behavior due to memory safety issues | |
require(example.unsafeAssembly() == 1, "unexpected"); | |
} | |
} | |
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