Attribute Macro stored 

#[stored]

Attribute macro for simplifying storage type definitions with consistent field-based bounding.

Derives the implementation of Encode, Decode, DecodeWithMemTracking, MaxEncodedLen, Clone, PartialEq, Eq, Debug and `TypeInfo.

Automatically extracts field types and applies derives with bounds on those fields, ensuring consistent behavior across all traits. Supports both structs and enums.

Directly recursive types are not supported.

Example

#[frame_support::stored]
pub struct Foo<F, F2> {
    f: F,
    f2: Vec<F2>,
}

In this example, the macro will automatically apply field-based bounds to F and F2 (requiring them to implement Clone, Eq, PartialEq, Debug, TypeInfo, Codec, etc.) without requiring the user to manually specify them on the generic parameters.

For pallet storage, you can of course still use generics, in this example bound T::Balance and not T as the bounds are applied to the fields.

#[frame_support::stored]
pub struct AccountData<T: ABCD> {
    pub free: T::Balance,
    pub reserved: T::Balance,
}

By default the type params are skipped, because they are rarely used. But to not skip them an attribute can used as follows:

#[frame_support::stored(no_skip_type_params)]
pub struct Bar<T>(T);