As a TypeScript developer, I have become too used to \"Duplicate identifier\" issues when working with .d.ts
files.
Most recently, this occurred because
There is no official tool to flatten .d.ts
files or any other I'm aware of. There are many reported issues for your (or similar) problem:
Angular team is working on the issue.
As a workaround, I would simply comment out ///<reference>
comments that cause your errors and wait for a bugfix.