Proposal for explict keyword for non constructor functions

[TheIdeasMan]

So we have the explicit specifier for constructors, would it be better if we could have explicit for any type of callable functions as well. At the moment we can use a template function where the template parameters are set to a specific type:

template <typename T = double>
T f(T) {
// ...
}

I would also like to avoid using RTTI for this purpose.

So I think it would be better to have the syntatic sugar, this usage meaning that all the parameters have to be explicit:

explicit void f(double input) {
// ...
}

Going further, we could have the explicit being optional for some of the function parameters:

void f(explicit double input, float other) {
// ...
}

While we are at it, I propose to have a way of turning off implicit type conversion, maybe with a #pragma and/or a compiler option? The #pragma would be for Translation Unit level control, while the compiler option would be global. Implicit type conversions are the source of many errors according to Jason Turner.

Any thoughts?

[Ganado]

Can you explain the difference in behavior on the calling side?

Edit: Ah, you mean, if foo was explicit, this would not compile:

void foo(double bar) { }

int main() {    
    foo((char)42);
}

Seems like a good proposal to me, but if you're serious about trying to get a new proposal into the language,
you should look at https://isocpp.org/std/submit-a-proposal