Eager multiple entities across relations

A{ ToMany<B> list; }

B{ ToOne<C> c; }

C{ ... }

The relationship of ABC is 1:N:1
store.boxFor(A.class).query().eager(A_.list).build().find()
Using the above method, I cannot immediately fill in the contents of C.

store.boxFor(A.class).query().eager(A_.list,B_.c).build().find()
This will give an error
A cannot be cast to B

Question:
With eager, how can I get all the data of the associated table？

首先复现 issue 中所示的 A→B→C 1:N:1 关系和两个 eager 查询。检查 eager loading 的入口点，以及产生 “A cannot be cast to B” 错误的关系遍历过程。当一个受支持的查询可以通过 B 对 C 执行 eager loading，或明确记录该限制时，即表示完成。