ERC20 Interfaces overwriting ERC721 functions - Possible to adhere to standard?

Question

Is it possible to have a contract that both generates and manages its own NFT according to the ERC721 Standard, and is able to make calls to outside ERC20 contracts? My contract currently inherits the ERC20 interface or contract, so that it can calls an instance of ERC20

someCoin = ERCInterface(xxxxxx); 
myCoin.transferFrom();

However, the approve() and transferFrom() functions have the exact same number and types of arguments in both standards so the ERC721 functions get overwritten. Does anyone know of a workaround? Alternatively, can someone provide an example of how a direct contract call can be written? Thanks

Answer 1

One contract cannot simultaneously implement ERC-20 and ERC-721. You must design your system so that those are separate contracts (deployed at separate addresses).

Yes, you can have a ERC-721 contract make calls to an ERC-20 contracts. There is nothing that makes that a problem.

Answer 2

You don't have to inherit an interface in order to call its methods:

interface Foo {
  function doFoo () external;
}

contract Bar {
  function bar (Foo foo) public {
    foo.doFoo ();
  }
}

You need to inherit an interface only when you want you contract to implement this interface by itself:

contract MyFoo is Foo {
  function doFoo () public {
    // Do something useful here
  }
}