Remove duplicate trait bound or where clause

[aldhsu]

What it does

This lint warns about repetitions of the same trait in trait bounds or where clauses.

Lint Name

repetition_where_clause_or_trait_bound

Category

pedantic

Advantage

Leaving duplicate trait bounds is less readable.

Drawbacks

None

Example

pub fn foo<T: Copy + Copy>(t: T) {}

Could be written as:

pub fn foo<T: Copy>(t: T) {}

OR

pub fn foo<T>(t: T) where T: Copy + Copy {}

Could be written as:

pub fn foo<T>(t: T) where T: Copy {}

[aldhsu]

I saw there is an existing lint that compares where clauses and trait bounds for duplicates. This could be an extension of that lint.

[aldhsu]

Closed by #8703.