Fallback function - why revert?

Question

Just wrote and tested the following on http://remix.ethereum.org

Same happens on Ropsten network.

If I run without sending any value it works, but I can't deploy the Test contract if I put any value > 0 to send because it reverts, but why?

pragma solidity ^0.5.0;

contract Test
{
    uint public m_ReceivedWei;

    function()
        external payable
    {
        m_ReceivedWei += msg.value;
    }

}

Answer 1

There is no constructor, so you can't fund the contract in the deploy because by default constructor is not payable. You can add the following line:

constructor() public payable {}

About Constructor:

A constructor is an optional function declared with the constructor keyword which is executed upon contract creation, and where you can run contract initialisation code. [...] If there is no constructor, the contract will assume the default constructor, which is equivalent to constructor() public {}.

Fallback function works fine.

About Fallback function:

A contract can have exactly one unnamed function. This function cannot have arguments, cannot return anything and has to have external visibility. It is executed on a call to the contract if none of the other functions match the given function identifier (or if no data was supplied at all).

Answer 2

As you might know the constructor is executed once the smart contract is deployed thus when you deploy with value you need to define a payable constructor as follows:

    constructor() public {        
 m_ReceivedWei += msg.value;
 } .