The compiler says "expected X, but found Y". I don't know how to interpret this: is the type of the thing underlined with "^^^" X or Y? "Expected" and "found" are just like "up" and "down" in space: they are meaningless if you don't know what the compiler expects (and why should it?).
What it needs to say is something along the lines of "a function f is defined with type X, but is given an argument of type Y": maybe the function should be defined differently, maybe the argument needs to change -- it's up to the programmer to decide.