diff --git a/src/vector2d.cpp b/src/vector2d.cpp
index 7c06f9d99..8bb81de3c 100644
--- a/src/vector2d.cpp
+++ b/src/vector2d.cpp
@@ -75,8 +75,8 @@ Vector2D Vector2D::Round(float step) const {
 	return Vector2D(floorf(x / step + .5f) * step, floorf(y / step + .5f) * step);
 }
 
-Vector2D::operator unspecified_bool_type() const {
-	return *this == Vector2D() ? nullptr : &Vector2D::x;
+Vector2D::operator bool() const {
+	return *this != Vector2D();
 }
 
 std::string Vector2D::PStr(char sep) const {
diff --git a/src/vector2d.h b/src/vector2d.h
index 41811c709..3f353434e 100644
--- a/src/vector2d.h
+++ b/src/vector2d.h
@@ -28,7 +28,6 @@
 class Vector2D {
 	float x, y;
 
-	typedef float Vector2D::*unspecified_bool_type;
 public:
 	float X() const { return x; }
 	float Y() const { return y; }
@@ -42,7 +41,7 @@ public:
 
 	bool operator ==(const Vector2D r) const { return x == r.x && y == r.y; }
 	bool operator !=(const Vector2D r) const { return x != r.x || y != r.y; }
-	operator unspecified_bool_type() const;
+	explicit operator bool() const;
 
 	Vector2D operator -() const { return Vector2D(-x, -y); }
 	Vector2D operator +(const Vector2D r) const { return Vector2D(x + r.x, y + r.y); }