b2MouseJoint::InitVelocityConstraints initializes mass variable but never uses it

[cugone]

I compile all projects in Warning Level 4 with treat warnings as errors turned on. The following function returns a warning as an error where the variable mass is initialized but never used.

void b2MouseJoint::InitVelocityConstraints(const b2SolverData& data)
{
    m_indexB = m_bodyB->m_islandIndex;
    m_localCenterB = m_bodyB->m_sweep.localCenter;
    m_invMassB = m_bodyB->m_invMass;
    m_invIB = m_bodyB->m_invI;

    b2Vec2 cB = data.positions[m_indexB].c;
    float aB = data.positions[m_indexB].a;
    b2Vec2 vB = data.velocities[m_indexB].v;
    float wB = data.velocities[m_indexB].w;

    b2Rot qB(aB);

    //mass variable initialized but never used!
    float mass = m_bodyB->GetMass();

    float d = m_damping;
    float k = m_stiffness;

    // magic formulas
    // gamma has units of inverse mass.
    // beta has units of inverse time.
    float h = data.step.dt;
    m_gamma = h * (d + h * k);
    if (m_gamma != 0.0f)
    {
        m_gamma = 1.0f / m_gamma;
    }
    m_beta = h * k * m_gamma;

    // Compute the effective mass matrix.
    m_rB = b2Mul(qB, m_localAnchorB - m_localCenterB);

    // K    = [(1/m1 + 1/m2) * eye(2) - skew(r1) * invI1 * skew(r1) - skew(r2) * invI2 * skew(r2)]
    //      = [1/m1+1/m2     0    ] + invI1 * [r1.y*r1.y -r1.x*r1.y] + invI2 * [r1.y*r1.y -r1.x*r1.y]
    //        [    0     1/m1+1/m2]           [-r1.x*r1.y r1.x*r1.x]           [-r1.x*r1.y r1.x*r1.x]
    b2Mat22 K;
    K.ex.x = m_invMassB + m_invIB * m_rB.y * m_rB.y + m_gamma;
    K.ex.y = -m_invIB * m_rB.x * m_rB.y;
    K.ey.x = K.ex.y;
    K.ey.y = m_invMassB + m_invIB * m_rB.x * m_rB.x + m_gamma;

    m_mass = K.GetInverse();

    m_C = cB + m_rB - m_targetA;
    m_C *= m_beta;

    // Cheat with some damping
    wB *= 0.98f;

    if (data.step.warmStarting)
    {
        m_impulse *= data.step.dtRatio;
        vB += m_invMassB * m_impulse;
        wB += m_invIB * b2Cross(m_rB, m_impulse);
    }
    else
    {
        m_impulse.SetZero();
    }

    data.velocities[m_indexB].v = vB;
    data.velocities[m_indexB].w = wB;
}