warn impl Deref

[cathaysia]

What it does

deref is usually implemented for transparent types such as pointers, but some people use it for other purposes, such as polymorphism, etc.

Without the help of lsp, it is difficult for the reader to know where this method comes from.

• deref anti-pattern

Advantage

More clear code.

Drawbacks

If possible, we should warn users when they implement deref

Example

struct Parent {}

impl Parent {

   fn some_op(&self) {}
}

struct Child {
    parent: Parent 
}

impl Deref<Parent> for Child {
       // ^ warning: DON'T implement Deref
  // ...
}

Could be written as:

struct Parent {}

impl Parent {

   fn some_op(&self) {}
}

struct Child {
    parent: Parent 
}

impl Child {
    fn some_op(&self) {
       self.parent.some_op(&self)
   }
}