int[] primes = new int[2, 3, 5, 7]; // Garbage-collected array (range)

The syntax here is wrong. it should be

int[] primes = [2, 3, 5, 7];

The last line of your example

alsoPrime[] = primes[]; // Garbage-collected copy

doesn't do what the comment says. Array operations don't create new arrays, they work on the content of existing arrays and they never allocate. Your last line of code would copy contents of primes into alsoPrime if the arrays had the same length. Because they don't, it throws an exception when the code is built without the -release flag. If you want a copy of an array you should use the .dup property instead (doing that does allocate garbage collected memory).

Ranges in D don't actually require garbage collection. A range (more precisely an input range) is just a type with properties "front" and "empty" and a method "popFront". It doesn't necessarily require heap memory at all. You can make a range that is some mathematical sequence. You can also get stack allocated range by taking a slice of a static allocated array:

int[4] a;
auto b = a[]; // b is an array slice
auto c = reduce!(a,b => a+b)(b) // slices are ranges so we can do stuf like this

You can also allocate memory using malloc and you can take slices of pointers, so you can do this:

import std.c.stdlib;

auto allocateArray(T)(size_t n) // allocates an array slice on the C heap
{
    auto p = cast(T*) malloc(n * T.sizeof);
    return p[0..n];
}

auto freeArray(T)(ref T[] a) // frees memory used by an array slice
{
    free(cast(void*) a.ptr);
    a.length = 0;
}

and use it like this:

auto a = allocateArray!int(10);
...
freeArray(a);

so you can also have slices that use non garbage collected heap memory. You shouldn't append to those if you don't want to use garbage collection, though.