Incorrect interface

A contract interface defines functions with a different type signature than the implementation, causing two different method id's to be created. As a result, when the interface is called, the fallback method will be executed.

Vulnerability

The vulnerability here is that the interface could be incorrectly defined.

let's see an example:

Alice.set(uint) 

takes an uint in Bob.sol but

Alice.set(int) 

a int in Alice.sol.

The two interfaces will produce two differents method IDs. As a result, Bob will call the fallback function of Alice rather than the set function of Alice.

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