error: expected type-specifier before 'Vector2' overloading type casts

Question

I have been working on a C++ library for a while and im running into this problem:

arlib/math/la/Vector.h:163:12: error: expected type-specifier before 'Vector3'

operator Vector3() const { return Vector3(x, y, 0); }

Im trying to overload a typecast from a Vector2 to a Vector3.

Edit: This is the surrounding code:

bool operator == (Vector2 vec) const
{ return x == vec.x && y == vec.y; }
bool operator != (Vector2 vec) const
{ return !(vec == *this); }
bool operator > (Vector2 vec) const
{ return Magnitude() > vec.Magnitude(); }
bool operator < (Vector2 vec) const
{ return Magnitude() < vec.Magnitude(); }
bool operator <= (Vector2 vec) const
{ return Magnitude() <= vec.Magnitude(); }
bool operator >= (Vector2 vec) const
{ return Magnitude() >= vec.Magnitude(); }
operator Vector() const
{ return Vector(new float[2] {x, y}, 2); }
operator Vector3() const
{ return Vector3(x, y, 0); }
operator float() const
{ return Magnitude(); }