Rollup merge of #127017 - mu001999-contrib:dead/enhance, r=pnkfelix

Extend rules of dead code analysis for impls for adts to impls for types refer to adts

The rules of dead code analysis for impl blocks can be extended to self types which refer to adts.

So that we can lint the following unused struct and trait:
```rust
struct Foo; //~ ERROR struct `Foo` is never constructed

trait Trait { //~ ERROR trait `Trait` is never used
    fn foo(&self) {}
}

impl Trait for &Foo {}
```

r? `@pnkfelix`

0 files changed, 0 insertions, 0 deletions