F.40 : "Use a lambda.." : incorrect assertion that function objects don't overload?

[jmarathe1]

The text says:
"On the other hand, lambdas and function objects don't overload; if you need to overload, prefer a function..".

I was confused by this. The operator() for a "function object" is overloadable. e.g:

struct foo {
void operator()(int) { std::cout << "first" << std::endl; }
void operator()(double) { std::cout << "second" << std::endl; }
};

Can the text be clarified?

[MikeGitb]

I guess this is about multiple different function objects. So you can do

//foo1.h:
void foo(int i);

//foo2.h:
void foo(std::string s);

//bar.cpp
#include "foo1.h"
#include "foo2.h"

foo(5);
foo("Hello");

but not

//foo1.h:
struct foo { void operator()(int);  };

//foo2.h:
struct foo { void operator()(string);  };

//bar.cpp
#include "foo1.h"
#include "foo2.h"

foo{}(5);
foo{}("Hello");

[AxelStrem]

I think the point is "Don't define non-local non-generic lambdas that capture nothing", but the wording is very unclear.

As a sidenote, please fix the issue title - it's F.50