                     // OK
const int a = 1;     enum class A { x = a };
                     enum class B { x = 1 };

                     // Disallowed
                     enum class C { x = 0.5 };
                     enum class D { x = float(1) };
                     enum class E { x = 1.0 };
uniform float f;     enum class F { x = f };
const float g = 1.0; enum class G { x = g };
uniform int h;       enum class H { x = h };