The compiler keeps track of how a declaration has been referenced
using absolute module imports and from which path the absolute module
should be resolved from. There was a bug in how the .d.ts metadata
extraction would incorrectly use the .d.ts file itself as resolution
context for symbols that had been imported using a relative module
specifier. This could result in module resolution failures.
For example, when extracting NgModule metadata from
`/node_modules/lib/index.d.ts` that looks like
```
import {LibDirective} from './dir';
@NgModule({
declarations: [LibDirective],
exports: [LibDirective],
})
export class LibModule {}
```
and `/app.module.ts` that contains
```
import {LibModule} from 'lib';
@NgModule({
imports: [LibModule],
})
export class AppModule {}
```
then `AppModule` would have recorded a reference to `LibModule` using
the `'lib'` module specifier. When extracting the NgModule metadata from
the `/node_modules/lib/index.d.ts` file the relative import into `./dir`
should also be assumed to be importable from `'lib'` (according to APF
where symbols need to be exported from a single entry-point)
so the reference to `LibDirective` should have `'lib'` as absolute
module specifier, but it would incorrectly have
`/node_modules/lib/index.d.ts` as resolution context path. The latter is
incorrect as `'lib'` needs to be resolved from `/app.module.ts` and not
from within the library itself.
Fixes#42810
PR Close#42879
ed9cfb674f