PR Checklist

Closes #

When a service is imported only for use as a constructor DI token, the analog compiler's single-file type-elision pass marks the import as type-only and erases it. The constructor DI extractor then sees the missing token and emits ɵɵinvalidFactory(), causing Error: This constructor was not compatible with Dependency Injection at runtime.

Affected scope

• Primary scope: angular-compiler
• Secondary scopes:

Recommended merge strategy for maintainer [optional]

• Squash merge
• Rebase merge
• Other

Commit preservation note [optional]

What is the new behavior?

type-elision.ts runs a pre-pass that walks every decorated class declaration, finds its constructor, and marks parameter type names as value-referenced before the type-elision walk. The import is preserved, extractConstructorDeps sees the runtime token, and ɵfac correctly emits i0.ɵɵdirectiveInject(MyService).

Before

import { MyService } from './my-service';
@Component({...})
export class FooComponent {
  constructor(private svc: MyService) {}
}

Compiled to:

// import erased
export class FooComponent {
  constructor(private svc: MyService) {}
  static ɵfac = function FooComponent_Factory(...) { i0.ɵɵinvalidFactory(); };
  static ɵcmp = ...;
}

Runtime: Error: This constructor was not compatible with Dependency Injection

After

import { MyService } from './my-service';
export class FooComponent {
  constructor(private svc: MyService) {}
  static ɵfac = (__ngFactoryType__) => new (__ngFactoryType__ || FooComponent)(i0.ɵɵdirectiveInject(MyService));
  static ɵcmp = ...;
}

Edge cases handled

• Plain constructor(svc: Foo) parameters
• TSParameterProperty (constructor(private svc: Foo))
• Generic type arguments (constructor(svc: Service<Bar>))
• Union/intersection types
• Non-decorated classes still get correct type-only elision (no false negatives)

Test plan

• npx vitest run packages/angular-compiler/src/lib/type-elision.spec.ts — 48 tests pass (3 new)
• npx vitest run packages/angular-compiler — 534 tests pass, 0 failures
• npx nx e2e analog-app-e2e — 11/11 pass
• pnpm build
• pnpm test

Does this PR introduce a breaking change?

• Yes
• No

This only adds preservation — no imports that were previously preserved are now elided. Pre-existing behavior for non-decorated classes is unchanged.

Other information

The bug only affects projects using the older constructor DI pattern (constructor(private svc: MyService)). Modern Angular code that uses inject() in field initializers wasn't affected because MyService appears in a value position (call argument) and was correctly preserved. This is why the bug didn't surface in analog-app (which uses inject() everywhere).

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