fix(metadata): `setClassMetadata` names `Inject` / `Optional` / tokens whose imports OXC removed (ReferenceError under TestBed overrides)

Start in crates/oxc_angular_compiler/src/component/import_elision.rs, then trace class_metadata/builders.rs, especially the constructor-parameter import collection and metadata builder named in the issue. Run the supplied TestBed override reproduction with metadata enabled; done means the generated module retains imports needed by ɵsetClassMetadata and the override no longer raises ReferenceError.

OXC removes the imports of Angular's constructor parameter decorators (Inject, Optional, Self, SkipSelf, Host, Attribute) and of tokens used only inside @Inject(...). The factory doesn't need them (it uses i0. / i1. namespace imports). But ɵsetClassMetadata, which is emitted by default, still names them as bare identifiers in its ctorParameters callback. Those names no longer exist in the module.

The callback is lazy, so a normal app works. It throws as soon as Angular reads ctorParameters, for example when TestBed.overrideComponent / overrideDirective / overridePipe / overrideModule recompiles the class in JIT (reflectDependencies → ReflectionCapabilities.parameters → ctorParameters()).

ngtsc keeps these imports.

Repro

// tokens.ts
import {InjectionToken} from '@angular/core';
export const TOKEN = new InjectionToken<unknown>('TOKEN');

// test.ts
import {Component, Inject, Optional} from '@angular/core';
import {TOKEN} from './tokens';
@Component({selector: 'c', template: ''})
export class C {
  constructor(@Optional() @Inject(TOKEN) x: unknown) {}
}

// spec (plain node, @angular/core 22.1.7)
TestBed.initTestEnvironment(BrowserTestingModule, platformBrowserTesting());
TestBed.configureTestingModule({imports: [C], providers: [{provide: TOKEN, useValue: 1}, C]});
TestBed.overrideComponent(C, {set: {template: 'overridden'}});
TestBed.inject(C);

OXC (#504 tip and main, same output)

import { Component } from "@angular/core";       // Inject, Optional: gone
import * as i0 from '@angular/core';
import * as i1 from './tokens';                   // `import {TOKEN}`: gone
export class C {
  static ɵfac = function C_Factory(__ngFactoryType__) {
    return new (__ngFactoryType__ || C)(i0.ɵɵdirectiveInject(i1.TOKEN,8));
  };
  ...
}
(() =>{
  (((typeof ngDevMode === "undefined") || ngDevMode) && i0.ɵsetClassMetadata(C,[{type:Component,
      args:[{selector:"c",template:""}]}],() =>[{type:undefined,decorators:[{type:Optional},
      {type:Inject,args:[TOKEN]}]}],null));
})();

Spec result: ReferenceError: Optional is not defined (without the overrideComponent line: ok).

ngtsc 22.1.7

import { Component, Inject, Optional } from '@angular/core';
import { TOKEN } from './tokens';
import * as i0 from "@angular/core";
...
(() => { (typeof ngDevMode === "undefined" || ngDevMode) && i0.ɵsetClassMetadata(C, [{
        type: Component,
        args: [{ selector: 'c', template: '' }]
    }], () => [{ type: undefined, decorators: [{
                type: Optional
            }, {
                type: Inject,
                args: [TOKEN]
            }] }], null); })();

Spec result: ok.

The same happens in an @NgModule / @Directive / @Pipe / @Injectable constructor, and with a token declared in the same file (then only Inject / Optional dangle).

When it runs

• emitClassMetadata defaults to true in the Vite plugin (vite-plugin/index.ts ~L124 / L255) and in the NAPI options (src/lib.rs ~L262).
• The call is behind (typeof ngDevMode === "undefined" || ngDevMode). The Vite plugin sets ngDevMode: 'false' only for production builds (angular-build-optimizer-plugin.ts, which also strips ɵsetClassMetadata). So it runs in dev serve and in tests (vitest + TestBed).

Where

crates/oxc_angular_compiler/src/component/import_elision.rs: PARAM_DECORATORS (~L53) and collect_ctor_param_decorator_only_imports / collect_uses_from_constructor_params (tip ~L331 / ~L512, main ~L329 / ~L500) mark these imports for removal without checking whether class metadata will still reference them. The metadata is built in class_metadata/builders.rs (build_ctor_params_metadata, ~L323) with the original bare names.

On main?

Yes.

Direction

Keep these imports whenever class metadata is emitted (emit_class_metadata && !advanced_optimizations), like ngtsc. Only remove them when no setClassMetadata is emitted.