Sieve

import std.algorithm : sum, until;
import std.range : take, array;

assert(Sieve!int(50).until!(n => n >= 50).sum == 328);
assert(Sieve!int(nthPrimeUpperBound(50)).take(50).sum == 5117);
assert(Sieve!int(30).fixed.array == [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]);
assert(Sieve!int(0).fixed.array == []);

// this causes compilation to take about 9s and 2 GB of memory.
// static assert(Sieve!ulong(2_000_000).fixed.sum = 142913828922);

auto ps = Sieve!int();
assert(ps.front == 2);
ps.popFront();
assert(ps.front == 3);