What happened?

Fallow's unused-class-members analyzer recognises a method call routed through Angular's single-instance decorator queries (@ViewChild, @ContentChild) but misses the equivalent calls routed through:

1. The four modern signal-based query factories — viewChild(), viewChildren(), contentChild(), contentChildren().
2. The two plural decorator queries that produce a QueryList<T> — @ViewChildren, @ContentChildren — when the methods are invoked through QueryList.forEach(c => c.method()).

All of these are first-class, idiomatic Angular APIs that produce the same runtime behaviour as @ViewChild: a property holding a child-component reference (or a list of references) whose methods are called from the parent.

Reproduction

1. Create the four files below in an empty directory.

   package.json

   {
     "name": "fallow-repro-angular-queries",
     "version": "0.0.0",
     "private": true,
     "dependencies": {
       "@angular/core": "^20.0.0",
       "@angular/platform-browser": "^20.0.0"
     }
   }

   tsconfig.json

   {
     "compilerOptions": {
       "target": "ES2022",
       "module": "ESNext",
       "moduleResolution": "Bundler",
       "strict": true,
       "experimentalDecorators": true,
       "emitDecoratorMetadata": true,
       "skipLibCheck": true
     },
     "include": ["src/**/*.ts"]
   }

   .fallowrc.json

   {
     "entry": ["src/main.ts"]
   }

   src/child.component.ts

   import { Component } from '@angular/core';
   
   @Component({ selector: 'app-child', template: '<ng-content />' })
   export class ChildComponent {
     refreshViewChild(): void {
       console.log('called via viewChild()');
     }
   
     refreshViewChildren(): void {
       console.log('called via viewChildren()');
     }
   
     refreshContentChild(): void {
       console.log('called via contentChild()');
     }
   
     refreshContentChildren(): void {
       console.log('called via contentChildren()');
     }
   
     refreshDecoratorViewChild(): void {
       console.log('called via @ViewChild');
     }
   
     refreshDecoratorViewChildren(): void {
       console.log('called via @ViewChildren');
     }
   
     refreshDecoratorContentChild(): void {
       console.log('called via @ContentChild');
     }
   
     refreshDecoratorContentChildren(): void {
       console.log('called via @ContentChildren');
     }
   }

   src/parent.component.ts

   import {
     Component,
     ContentChild,
     ContentChildren,
     QueryList,
     ViewChild,
     ViewChildren,
     contentChild,
     contentChildren,
     viewChild,
     viewChildren
   } from '@angular/core';
   
   import { ChildComponent } from './child.component';
   
   @Component({
     selector: 'app-parent',
     imports: [ChildComponent],
     template: `
       <app-child #vc />
       <app-child #vcs />
       <app-child #dvc />
       <app-child #dvcs />
       <ng-content />
     `
   })
   export class ParentComponent {
     // Modern signal queries
     readonly vc = viewChild<ChildComponent>('vc');
     readonly vcs = viewChildren<ChildComponent>('vcs');
     readonly cc = contentChild<ChildComponent>(ChildComponent);
     readonly ccs = contentChildren<ChildComponent>(ChildComponent);
   
     // Legacy decorator queries
     @ViewChild('dvc') readonly dvc?: ChildComponent;
     @ViewChildren('dvcs') readonly dvcs?: QueryList<ChildComponent>;
     @ContentChild(ChildComponent) readonly dcc?: ChildComponent;
     @ContentChildren(ChildComponent) readonly dccs?: QueryList<ChildComponent>;
   
     triggerRefresh(): void {
       // Signal-based call sites
       this.vc()?.refreshViewChild();
       this.vcs().forEach((c) => c.refreshViewChildren());
       this.cc()?.refreshContentChild();
       this.ccs().forEach((c) => c.refreshContentChildren());
   
       // Decorator-based call sites
       this.dvc?.refreshDecoratorViewChild();
       this.dvcs?.forEach((c) => c.refreshDecoratorViewChildren());
       this.dcc?.refreshDecoratorContentChild();
       this.dccs?.forEach((c) => c.refreshDecoratorContentChildren());
     }
   }

   src/main.ts

   import { bootstrapApplication } from '@angular/platform-browser';
   
   import { ParentComponent } from './parent.component';
   
   bootstrapApplication(ParentComponent);

2. Run fallow dead-code from the project root.

3. Output (fallow 2.63.0, compact format):

   unused-class-member:src/child.component.ts:5:ChildComponent.refreshViewChild
   unused-class-member:src/child.component.ts:9:ChildComponent.refreshViewChildren
   unused-class-member:src/child.component.ts:13:ChildComponent.refreshContentChild
   unused-class-member:src/child.component.ts:17:ChildComponent.refreshContentChildren
   unused-class-member:src/child.component.ts:25:ChildComponent.refreshDecoratorViewChildren
   unused-class-member:src/child.component.ts:33:ChildComponent.refreshDecoratorContentChildren
   unused-class-member:src/parent.component.ts:40:ParentComponent.triggerRefresh
   

   Tabulating which of the eight call sites in triggerRefresh are traced:

   Pattern	Method on ChildComponent	Traced?
   viewChild()	refreshViewChild	❌
   viewChildren()	refreshViewChildren	❌
   contentChild()	refreshContentChild	❌
   contentChildren()	refreshContentChildren	❌
   @ViewChild	refreshDecoratorViewChild	✅
   @ViewChildren	refreshDecoratorViewChildren	❌
   @ContentChild	refreshDecoratorContentChild	✅
   @ContentChildren	refreshDecoratorContentChildren	❌

   ParentComponent.triggerRefresh is a separate noise issue — bootstrapped-component lifecycle/event-handler members have no static caller; not the focus of this report.

Expected behavior

The four signal-query factories (viewChild, viewChildren, contentChild, contentChildren) and the two plural decorator queries (@ViewChildren, @ContentChildren) should be treated equivalently to the already-supported @ViewChild / @ContentChild decorators. A method call reachable from any of the following expressions should count as a reference to that method on the parameterised component type:

• this.<prop>()?.method() — single-instance signal query
• this.<prop>().forEach(c => c.method()) and similar QueryList/Signal<readonly T[]> iteration helpers — plural signal query
• this.<prop>?.forEach(c => c.method()) — QueryList<T> from @ViewChildren / @ContentChildren

Fallow version

fallow 2.63.0

Operating system

macOS

Configuration

default