This might be supplanted by other features, but it would be helpful to have some form of basic enum syntax to declare integer constants. A very basic strawman is below:

enum BlendMode {
    Normal = 1,
    Add,
    Subtract,
    Multiply,
    Overlay,
    HardLight,
};

struct BlendParams {
    blend_mode: BlendMode, // the same size as a u32,
};

Alternatively, if we had support for user namespaces, we could use const statements to declare u32 variables inside a namespace; this loses the ability to have enums as a separate "type" that can be embedded in structs and passed to functions, but it would be OK to start with.