Why doesn't C++ support range based for loop for dynamic arrays?

Question

Why doesn't C++ support range based for loop over dynamic arrays? That is, something like this:

int* array = new int[len];
for[] (int i : array) {};

I just invented the for[] statement to rhyme with new[] and delete[]. As far as I understand, the runtime has the size of the array available (otherwise delete[] could not work) so in theory, range based for loop could also be made to work. What is the reason that it's not made to work?

Answer 1

What is the reason that it's not made to work?

A range based loop like

 for(auto a : y) {
     // ...
 }

is just syntactic sugar for the following expression

 auto endit = std::end(y);
 for(auto it = std::begin(y); it != endit; ++it) {
     auto a = *it;
     // ...
 }

Since std::begin() and std::end() cannot be used with a plain pointer, this can't be applied with a pointer allocated with new[].

As far as I understand, the runtime has the size of the array available (otherwise delete[] could not work)

How delete[] keeps track of the memory block that was allocated with new[] (which isn't necessarily the same size as was specified by the user), is a completely different thing and the compiler most probably doesn't even know how exactly this is implemented.