Language: C++

#ifndef ___CLASS_MATRIX
#define ___CLASS_MATRIX

#include <vector>
#include <cassert>
#include <cstddef>

template<class type>
class matrix {
private:
	size_t H, W;
	std::vector<type> mat;
public:
	matrix() : H(0), W(0), mat(std::vector<type>()) {};
	matrix(size_t N_) : H(N_), W(N_), mat(std::vector<type>(N_* N_)) {};
	matrix(size_t H_, size_t W_) : H(H_), W(W_), mat(std::vector<type>(H_* W_)) {};
	type& entry(size_t r, size_t c) { return mat[r * W + c]; }
	type entry(size_t r, size_t c) const { return mat[r * W + c]; }
	matrix& operator+=(const matrix& m) {
		assert(H == m.H && W == m.W);
		for (size_t i = 0; i < H; ++i) {
			for (size_t j = 0; j < W; ++j) {
				mat[i * W + j] += m.mat[i * W + j];
			}
		}
	}
	matrix& operator-=(const matrix& m) {
		assert(H == m.H && W == m.W);
		for (size_t i = 0; i < H; ++i) {
			for (size_t j = 0; j < W; ++j) {
				mat[i * W + j] -= m.mat[i * W + j];
			}
		}
	}
	matrix& operator*=(const matrix& m) {
		assert(W == m.H);
		matrix ans(H, m.W);
		for (size_t i = 0; i < H; ++i) {
			for (size_t j = 0; j < m.W; ++j) {
				for (size_t k = 0; k < W; ++k) {
					ans.mat[i * m.W + j] += mat[i * W + k] * m.mat[k * m.W + j];
				}
			}
		}
		return (*this) = ans;
	}
	matrix operator+(const matrix& m) const { return matrix(*this) += m; }
	matrix operator-(const matrix& m) const { return matrix(*this) -= m; }
	matrix operator*(const matrix& m) const { return matrix(*this) *= m; }
};

template<class type>
matrix<type> unit(int N) {
	matrix<type> ret(N);
	for (size_t i = 0; i < N; ++i) {
		ret.entry(i, i) = type(1);
	}
	return ret;
}

#endif // ___CLASS_MATRIX

#ifndef CLASS_FAST_MODINT
#define CLASS_FAST_MODINT

#include <cstdint>

static constexpr std::size_t digit_level = 8 * sizeof(std::uint32_t);
static constexpr std::uint32_t find_inv(std::uint32_t n, int d = 6, std::uint32_t x = 1) {
	return d == 0 ? x : find_inv(n, d - 1, x * (2 - x * n));
}
template <std::uint32_t mod> class fast_modint {
	// Fast Modulo Integer, Assertion: mod < 2^(bits of singlebit - 1) and mod is prime
private:
	singlebit n;
	static constexpr std::uint32_t r2 = (((std::uint64_t(1) << digit_level) % mod) << digit_level) % mod;
	static constexpr std::uint32_t ninv = std::uint32_t(-1) * find_inv(mod);
	std::uint32_t reduce(std::uint64_t x) const {
		singlebit res = (x + std::uint64_t(std::uint32_t(x) * ninv) * mod) >> digit_level;
		return res < mod ? res : res - mod;
	}
public:
	fast_modint() : n(0) {};
	fast_modint(std::uint32_t n_) { n = reduce(std::uint64_t(n_) * r2); };
	static constexpr std::uint32_t get_mod() { return mod; }
	std::uint32_t get() const { return reduce(n); }
	bool operator==(const fast_modint& x) const { return n == x.n; }
	bool operator!=(const fast_modint& x) const { return n != x.n; }
	fast_modint& operator+=(const fast_modint& x) { n += x.n; n -= (n < mod ? 0 : mod); return *this; }
	fast_modint& operator-=(const fast_modint& x) { n += mod - x.n; n -= (n < mod ? 0 : mod); return *this; }
	fast_modint& operator*=(const fast_modint& x) { n = reduce(std::uint64_t(n) * x.n); return *this; }
	fast_modint operator+(const fast_modint& x) const { return fast_modint(*this) += x; }
	fast_modint operator-(const fast_modint& x) const { return fast_modint(*this) -= x; }
	fast_modint operator*(const fast_modint& x) const { return fast_modint(*this) *= x; }
	fast_modint inv() const { return binpow(mod - 2); }
	fast_modint binpow(std::uint64_t b) const {
		fast_modint ans(1), cur(*this);
		while (b > 0) {
			if (b & 1) ans *= cur;
			cur *= cur;
			b >>= 1;
		}
		return ans;
	}
};

#endif // CLASS_FAST_MODINT

#include <vector>
#include <iostream>
#include <functional>
using namespace std;
using modulo = fast_modint<1000000007>;
const int limit = 1 << 20;
int main() {
	cin.tie(0);
	ios_base::sync_with_stdio(false);
	int N;
	cin >> N;
	vector<int> SA(N + 1);
	vector<vector<int> > G(limit);
	for (int i = 0; i < N; ++i) {
		cin >> SA[i + 1];
		SA[i + 1] ^= SA[i];
		G[SA[i]].push_back(i);
	}
	int sz = 1;
	while (sz < N) sz *= 2;
	vector<matrix<modulo> > seg(sz * 2, unit<modulo>(2));
	function<void(int, matrix<modulo>)> update = [&](int pos, matrix<modulo> d) {
		pos += sz;
		seg[pos] = d;
		while (pos > 1) {
			pos >>= 1;
			seg[pos] = seg[pos * 2] * seg[pos * 2 + 1];
		}
	};
	int cnt = 0;
	for (int i = 0; i < N; ++i) {
		if (SA[i] == 0) {
			matrix<modulo> mat(2);
			if (i != 0) mat = unit<modulo>(2);
			mat.entry(0, 1) = modulo(1);
			update(i, mat);
			++cnt;
		}
	}
	modulo ans = 0;
	if (SA[N] == 0) ans += modulo(2).pow(cnt - 1);
	for (int i = 1; i < limit; ++i) {
		if (SA[N] != 0 && SA[N] != i) continue;
		for (int j : G[i]) {
			matrix<modulo> mat = unit<modulo>(2);
			mat.entry(1, 0) = modulo(1);
			update(j, mat);
		}
		modulo sub = seg[1].entry(0, SA[N] == 0 ? 0 : 1);
		ans += sub;
		for (int j : G[i]) {
			update(j, unit<modulo>(2));
		}
	}
	cout << ans.get() << endl;
	return 0;
}

Compiler output:
a.cc:75:9: error: 'singlebit' does not name a type
   75 |         singlebit n;
      |         ^~~~~~~~~
a.cc: In member function 'uint32_t fast_modint<mod>::reduce(uint64_t) const':
a.cc:79:17: error: 'singlebit' was not declared in this scope
   79 |                 singlebit res = (x + std::uint64_t(std::uint32_t(x) * ninv) * mod) >> digit_level;
      |                 ^~~~~~~~~
a.cc:80:24: error: 'res' was not declared in this scope
   80 |                 return res < mod ? res : res - mod;
      |                        ^~~
a.cc: In constructor 'fast_modint<mod>::fast_modint()':
a.cc:83:25: error: class 'fast_modint<mod>' does not have any field named 'n'
   83 |         fast_modint() : n(0) {};
      |                         ^
a.cc: In constructor 'fast_modint<mod>::fast_modint(uint32_t)':
a.cc:84:41: error: 'n' was not declared in this scope; did you mean 'n_'?
   84 |         fast_modint(std::uint32_t n_) { n = reduce(std::uint64_t(n_) * r2); };
      |                                         ^
      |                                         n_
a.cc: In member function 'uint32_t fast_modint<mod>::get() const':
a.cc:86:51: error: 'n' was not declared in this scope
   86 |         std::uint32_t get() const { return reduce(n); }
      |                                                   ^
a.cc: In member function 'bool fast_modint<mod>::operator==(const fast_modint<mod>&) const':
a.cc:87:62: error: 'n' was not declared in this scope
   87 |         bool operator==(const fast_modint& x) const { return n == x.n; }
      |                                                              ^
a.cc: In member function 'bool fast_modint<mod>::operator!=(const fast_modint<mod>&) const':
a.cc:88:62: error: 'n' was not declared in this scope
   88 |         bool operator!=(const fast_modint& x) const { return n != x.n; }
      |                                                              ^
a.cc: In member function 'fast_modint<mod>& fast_modint<mod>::operator+=(const fast_modint<mod>&)':
a.cc:89:57: error: 'n' was not declared in this scope
   89 |         fast_modint& operator+=(const fast_modint& x) { n += x.n; n -= (n < mod ? 0 : mod); return *this; }
      |                                                         ^
a.cc: In member function 'fast_modint<mod>& fast_modint<mod>::operator-=(const fast_modint<mod>&)':
a.cc:90:57: error: 'n' was not declared in this scope
   90 |         fast_modint& operator-=(const fast_modint& x) { n += mod - x.n; n -= (n < mod ? 0 : mod); return *this; }
      |                                                         ^
a.cc: In member function 'fast_modint<mod>& fast_modint<mod>::operator*=(const fast_modint<mod>&)':
a.cc:91:57: error: 'n' was not declared in this scope
   91 |         fast_modint& operator*=(const fast_modint& x) { n = reduce(std::uint64_t(n) * x.n); return *this; }
      |                                                         ^
a.cc: In function 'int main()':
a.cc:149:42: error: 'using modulo = class fast_modint<1000000007>' {aka 'class fast_modint<1000000007>'} has no member named 'pow'
  149 |         if (SA[N] == 0) ans += modulo(2).pow(cnt - 1);
      |                                          ^~~