Specifying lib: DOM and WebWorker should not be mutually exclusive

I got myself into a situation similar to #11093.

My project is designed to work either in the "main thread", with access to DOM, or as a WebWorker, where a different behavior kicks in. This was done for compatibility reasons and to have only one distributable js file and it's been working fine for the last two years.

In all this time I never specified the lib compiler option, only target ES5.

Today, as I'm experimenting some ES2015 stuff, I see that if I specify targets DOM,ES5,WebWorker,ES2015.Promise all hell breaks loose with errors. - Duplicate identifier, Subsequent variable declarations must have the same type.

Shouldn't this kind of mix be allowed in a project?

まず、lib 設定 DOM,ES5,WebWorker,ES2015.Promise で報告されたエラーを再現し、次に TypeScript がライブラリ宣言をどのように処理して組み合わせているかを追跡します。メインスレッド用ライブラリと WebWorker 用ライブラリを、重複した識別子や互換性のない変数宣言のエラーなしに一緒に指定できれば完了です。