childType

pub fn childType(self: Type, builder: *const Builder) Type {
    const item = builder.type_items.items[@intFromEnum(self)];
    return switch (item.tag) {
        .vector,
        .scalable_vector,
        .small_array,
        => builder.typeExtraData(Type.Vector, item.data).child,
        .array => builder.typeExtraData(Type.Array, item.data).child,
        .named_structure => builder.typeExtraData(Type.NamedStructure, item.data).body,
        else => unreachable,
    };
}