Someone requested it back in the TSLint days at palantir/tslint#3652 , i'm interested in it now

not following the template since it seems to be geared for issues with existing rules.

It would be nice to have a check for enums where two keys have the same value, at least for literal enums (this wouldn't work with enums that have dynamic values, but i don't use any of those, so it's fine with me). I don't have any use for that kind of enum in my codebase and it opens the potential for confusing behavior if it is present.

I haven't made a rule fresh before but I'll try giving it a go if maintainers are cool with this idea.

// bad
enum Foo {
  A = "A",
  B = "A"
}

// good
enum Foo {
  A = "A",
  B = "B"
}