no-empty-interface should not fail on an interface with multiple parents

[HamletDRC]

Bug Report

• TSLint version: 4.3.0
• TypeScript version: 2.1.4
• Running TSLint via: grunt tslint

TypeScript code being linted

            interface MyInterface extends First, Second {
            }

An interface with two parents is not empty. It is a common way to merge disparate attributes into a meaningful composition.

For example, we use this by having three interfaces: HasWidth, HasHeight, and a 3rd called HasDimensions that implements the first two. Then there are functions that operate on the appropriate abstraction.

[mohsen1]

Isn't it cleaner to use intersection to merge those types instead of extending them with an empty Interface?

[mohsen1]

type MyInterface = First & Second 

[HamletDRC]

Whether or not an alternative is cleaner does not change the fact that an interface with two parents is not empty. The preference for intersection types that you describe may be a valid preference, but it is a different tslint rule that should enforce that.