E0206: Bad field attribute

A field attribute is a value (@Char{Max: 200}) written after its field, after the struct tag, on the field's line, on a field of a package-level struct type.

A generic struct's fields take attributes when it is live — it embeds ui.Live, or is a live .vuka.html shape: @ui.URL, @ui.Bind, @ui.Defer and the validate rules are written into its LiveSchema, a method of the generic type, so each instantiation (Table[Task], Table[User]) reads its own. Any other generic struct's attributes are an error: they are recorded for the type at package level (vuka.RegisterFields[T] at init, or a model's registration), which needs its type arguments. That covers plain value attributes such as @Char{Max: 200} and those of an orm model.

Wrong

type Post struct {
	Title string @Char{Max: 200} `json:"title"`
	@Char{}
	Body string
}

type Pair[K comparable, V any] struct {
	Key  K
	Note string @Char{Max: 50}
}

Right

type Post struct {
	Title string `json:"title"` @Char{Max: 200}
	Body  string @Char{}
}

type Table[T any] struct {
	ui.Live
	Rows []T
	page int @ui.URL("page").Default(1)
}