c++templatestemplate-argument-deductionconstructor-overloadingdeduction-guide

Disambiguating ambiguous function overloads because of converting constructor

Given a wrapper type

template <typename T>
struct Ptr
{
    Ptr(T*);
};

a class hierarchy

struct Base {};
struct Derived : Base {};

and a set of function overloads

void f(Ptr<Base>);
void f(Ptr<Derived>);

void g(Ptr<Base>);

is there a way to make the statements

f(new Base);
f(new Derived);
g(new Derived);

compile without changing the declarations of f or g or the call sites?

Demonstration of compilation error: https://godbolt.org/z/renKr7P1v

Solution

  • compile without changing the declarations of f or g or the call sites?

    I don't know if adding an extra overload break your requirements, but adding

    template <typename T>
void f(T* p)
{
    f(Ptr{p});
}

    makes code compile Demo