This test exists to validate that ngtsc, when compiling an application where Ivy would otherwise require a circular dependency, uses "remote scoping" via the setComponentScope function instead.

How it works

There are two files, index.ts and trigger.ts. index.ts contains the NgModule and a simple component (<dep>).

trigger.ts contains a component TriggerComponent that uses <dep> in its template. Normally, Ivy would want DepComponent to be listed in TriggerComponent's definition. However, this requires adding an import from trigger.ts -> index.ts, and there's already an import from index.ts to trigger.ts (for the NgModule).

In this case, ngtsc decides to set the directives in TriggerComponent's definition via a different mechanism: remote scoping. Alongside the NgModule (in index.ts) a call to setComponentScope is generated which sets up TriggerComponent's definition correctly, without introducing any imports. This call is not tree-shakeable, but does not create a cycle.

The symbol test here verifies that setComponentScope is used, and the e2e spec verifies that the application works correctly.