C++17: std::is_same_v fails unexpectedly

Question

Can someone explain to me, why this code fails to compile

friend
std::ostream& operator<<(std::ostream& os, const Matrix<T> &matrix) {
    os << matrix.rows();
    os << "x";
    os << matrix.cols();
    os << std::endl;
    for (int i = 0; i < matrix.M * matrix.N; ++i) {
        float value;
        if constexpr (std::is_same_v<T, half>) {
            value = __half2float(matrix.dataOnCPU[i]);
        } else {
            value = matrix.dataOnCPU[i];
        }

        if ( (i + 1) % matrix.N == 0 ) {
            os << value;
            os << std::endl;
        } else {
            os << value << ",";
        }
    }
    return os;
}

with internal error: assertion failed at: "statements.c", line 4170 in if_statement but this code compiles fine

friend
std::ostream& operator<<(std::ostream& os, const Matrix<T> &matrix) {
    for (int i = 0; i < matrix.M * matrix.N; ++i) {
        float value;
        if constexpr (std::is_same_v<T, half>) {
            value = __half2float(matrix.dataOnCPU[i]);
        } else {
            value = matrix.dataOnCPU[i];
        }

        if ( (i + 1) % matrix.N == 0 ) {
            os << value;
            os << std::endl;
        } else {
            os << value << ",";
        }
    }
    return os;
}