Warn about supertrait bound duplicated in function trait bound (where Self: Supertrait)

[jendrikw]

Summary

This could be covered under trait_duplication_in_bounds.

Lint Name

trait_duplication_in_bounds

Reproducer

I tried this code: play

#![warn(clippy::style, clippy::pedantic)]
trait T: Default {
    fn f() where Self: Default;
}

I expected to see this happen:
warning: this trait bound is already specified in the where clause

Instead, this happened:
no warning.

Version

rustc 1.57.0 (f1edd0429 2021-11-29)
binary: rustc
commit-hash: f1edd0429582dd29cccacaf50fd134b05593bd9c
commit-date: 2021-11-29
host: x86_64-unknown-linux-gnu
release: 1.57.0
LLVM version: 13.0.0