Control flow schematic: ngFor + as syntax produces invalid code

[mattlewis92]

Which @angular/* package(s) are the source of the bug?

core

Is this a regression?

No

Description

Input:

<ng-container
  *ngFor="
      let item of list$ | async as list;
      trackBy: trackById;
      let index = index
    "
>
  Previous: {{ list[index - 1] }}
</ng-container>

Output:

@for (
  item of list$ | async as list; track trackById(index,
  item); let index = $index) {
  Previous: {{ list[index - 1] }}
}

I have never seen as + ngFor being used like this before, and we only have 1 case of it in our codebase. I can't see an obvious equivalent with @for, so maybe the solution here is just to print a warning and not attempt to migrate this style?

Please provide a link to a minimal reproduction of the bug

No response

Please provide the exception or error you saw

No response

Please provide the environment you discovered this bug in (run ng version)

Angular CLI: 17.0.3
Node: 20.9.0
Package Manager: pnpm 8.11.0
OS: darwin arm64

Angular: 17.1.0-next.1+sha-f1b7d40
... core

Package                             Version
-------------------------------------------------------------
@angular-devkit/architect           0.1700.1
@angular-devkit/build-angular       17.0.3
@angular-devkit/core                17.0.3
@angular-devkit/schematics          17.0.3
@angular/animations                 17.0.4
@angular/cdk                        17.0.1
@angular/cli                        17.0.3
@angular/common                     17.0.4
@angular/compiler                   17.0.4
@angular/compiler-cli               17.0.4
@angular/elements                   17.0.4
@angular/forms                      17.0.4
@angular/google-maps                15.2.9
@angular/language-service           17.0.4
@angular/localize                   17.0.4
@angular/platform-browser           17.0.4
@angular/platform-browser-dynamic   17.0.4
@angular/router                     17.0.4
@angular/service-worker             17.0.4
@schematics/angular                 17.0.3
ng-packagr                          17.0.2
rxjs                                7.8.0
typescript                          5.2.2
webpack                             5.88.2
zone.js                             0.14.2

Anything else?

Noting that I have installed the latest dev build against the main branch via "@angular/core": "angular/core-builds#17.1.0-next.1+f1b7d40", to get the latest fixes

[JoostK]

Yeah, this isn't supported. Also see #52184.

[jessicajaniuk]

The fix to add a warning in this case is in #53238.