Macro make_trait_castable_decl

macro_rules! make_trait_castable_decl {
    ($($source:ty => ($($target:path),* $(,)?)),+$(,)?) => { ... };
}

Declarative macro for automatic implementation of TraitcastableAny (and TraitcastableTo). Generally not for direct invocation, but rather used by the proc-macro make_trait_castable.

Syntax: <concrete struct/enum/union> => (<target traits>, ...)

Usage

make_trait_castable_decl! {
    SrcStruct1 => (DstTrait1, DstTrait2),
    SrcStruct2 => (DstTrait3, DstTrait4),
}