returns (uint256) is not implicitly convertible to expected type uint256

Question

I try to compile the following (in Solidity) ...

contract InfoFeed {
    function info() payable returns (uint ret) { return 42; }
}

contract Consumer {
  uint attribut = 0;
  InfoFeed feed;
  function setFeed(address addr) { feed = InfoFeed(addr); }
  function callFeed() { attribut = feed.info.value(10).gas(800); }  
}

but what I get is an error message (in MIST's deploy contract):

Type function () returns (uint256) is not implicitly convertible to expected type uint256.
  function callFeed() { attribut = feed.info.value(10).gas(800); }  
                                   ^--------------------------^

how can uint256 not be convertible to uint256, and what to do about it, please?

Answer 1

Try adding a pair of brackets after gas(800):

feed.info.value(10).gas(800)

becomes

feed.info.value(10).gas(800)()

What the error message is trying to tell you is that you're telling it to assign a function - one which returns (uint256) to be specific - to a uint called attribut, when what you need to do is call that function, and assign the result of calling it to the uint called attribut.