Solvedangular Generics do not correctly infer in template pipe usage

I'm submitting a...

[x] Bug report  

Current behavior

Please take a look at the minimal example below:

@Pipe({name: 'map'})
export class MapPipe implements PipeTransform {
  transform<T, R>(value: T[], func: (value: T) => R): R[] {
    return value ? value.map(func) : [];
  }
}

// the component
interface InData {
  foo: string;
}

interface OutData {
  bar: string;
}

@Component({
  selector: 'app-test',
  template: `
    <span *ngFor="let item of items | map: _mapper">
      {{item.bar}}
    </span>
  `,
})
export class TestComponent {
  @Input() items: InData[];

  _mapper(item: InData): OutData {
    return {
      bar: item.foo,
    };
  }
}

Angular language service (v5.0.2) gives me an error:
Error:(7, 9) Angular: Identifier 'bar' is not defined. 'R' does not contain such a member

Expected behavior

Should infer the type as TypeScript would.

From angular/vscode-ng-language-service#196

The Ivy Language Service is currently under construction. I pasted this example into a running IDE with it.

We're able to infer the generic arguments to MapPipe.transform:

which flows through to the type of item in the *ngFor:

Any news? I'm using vscode extension and its basically unusable. A lot of errors everywhere.

I am having same issue with built-in slice pipe.

For instance:

<div *ngFor="let item of (items | slice : 0 : 5)">

The type of item is lost. item.id starts giving error:

Identifier 'id' is not defined. 'T' does not contain such a member"

Would love to see a fix or workaround for this. Let us know if we can help. I thought I had made a mistake fixing up my template variable types. I didn't notice it was compiling despite the warnings in VS Code.

It is almost 2 years after this bug is first added and still with Angular 8.2.7 this issue is not fixed. I do understand that TypeScript 3 may have an issue with this, but i also think that the Angular Pipe should have a solution for this. It is not always possible or wanted to do stuff like slining outsite of the template. otherwise i could do some like this.trips = this.trips.slice(this.start,this.end);