I'm starting to read the Ethereum ressources and started with this article. I'm struggling to understand what the fallback will do in the following contract:

pragma solidity ^0.6.4;

contract MyContract {
  event Log(address addr);

  fallback() external payable{
    emit Log(address(this));

  function add(uint256 a, uint256 b) public pure returns (uint256) {
    return a + b;

I understand what an event is. From the documentation:"this(current contract’s type):the current contract, explicitly convertible to Address". My understanding is that the fallback will always log the same address (the address of MyContract). Is it correct ?

  • Yes............... Apr 1, 2020 at 7:13
  • Thank you for your reply (it doesn't change the anser but I wrongly updated the contract; it shouldn't be a falllback function but a constructor.)
    – Caladay
    Apr 1, 2020 at 7:34
  • Same answer. The expression address(this) will always evaluate to the same value in every function of a given instance of the contract (i.e., if you call the same function but from different instances of the contract, you will get different results). Apr 1, 2020 at 7:40

1 Answer 1


The expression address(this) will evaluate to the same value in every function which uses it, when called on a given instance of the contract.

Of course, when such function is called on different instances of the contract, this expression will evaluate to a different value for each instance.

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