[StackOverflow/rust] Is it possible to have a vec of a struct with generic phantom data in rust?

### ROOT CAUSE The issue arises from misunderstanding how generics and `PhantomData` work in Rust. A generic struct with `PhantomData` still requires a concrete type parameter to be specified for the struct instance. Rust's type system does not allow mixing different generic parameters in a single vector unless using trait objects or an enum, which complicates the design. ### CODE FIX To create a vector of a struct with generic phantom data, use a concrete type parameter. For example: ```rust use std::marker::PhantomData; struct MyStruct { value: i32, _phantom: PhantomData, } fn main() { let vec: Vec> = vec![ MyStruct { value: 10, _phantom: PhantomData, }, MyStruct { value: 20, _phantom: PhantomData, }, ]; } ``` If heterogeneity is required, use trait objects: ```rust trait Trait {} impl Trait for MyStruct {} fn main() { let vec: Vec> = vec![ Box::new(MyStruct { value: 10, _phantom: PhantomData::, }), Box::new(MyStruct { value: 20, _phantom: PhantomData::, }), ]; } ```