moduleResolution "bundler" breaks type inference in RxJS 7.4.0

[john8329]

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

upgrade

Is this a regression?

Yes

Description

After upgrading to Angular 19, one of the migrations was to set "moduleResolution": "bundler", in tsconfig.json. This broke basic type inference in all RxJS Observables. The only reasonable solution I found was to upgrade to the unsupported version "rxjs": "~7.5.0",. Perhaps Angular should recommend that in the documentation?

Oddly I didn't find anything related to this anywhere. I can reproduce this systematically just by changing rxjs' version. Perhaps it could be also due to some other setting in tsconfig, so I'm adding it too.
Thanks

Please provide a link to a minimal reproduction of the bug

No response

Please provide the exception or error you saw

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

Angular CLI: 19.2.15
Node: 22.15.0
Package Manager: yarn 4.6.0
OS: darwin arm64

Angular: 19.2.14
... animations, common, compiler, compiler-cli, core, forms
... language-service, platform-browser, platform-browser-dynamic
... router, service-worker

Package                      Version
------------------------------------------------------
@angular-devkit/architect    0.1802.20
@angular-devkit/core         18.2.20
@angular-devkit/schematics   19.2.15
@angular/build               19.2.15
@angular/cdk                 18.2.14
@angular/cli                 19.2.15
@schematics/angular          19.2.15
rxjs                         7.4.0
typescript                   5.8.3
zone.js                      0.15.1

Anything else?

{
  "compileOnSave": false,
  "compilerOptions": {
    "baseUrl": "./",
    "forceConsistentCasingInFileNames": true,
    "strict": true,
    "noImplicitReturns": true,
    "esModuleInterop": true,
    "noImplicitAny": false,
    "noFallthroughCasesInSwitch": false,
    "sourceMap": true,
    "declaration": false,
    "experimentalDecorators": true,
    "inlineSources": true,
    "resolveJsonModule": true,
    "moduleResolution": "bundler",
    "importHelpers": true,
    "target": "ES2022",
    "module": "esnext",
    "lib": [
      "ES2022",
      "dom"
    ],
    "paths": {},
    "useDefineForClassFields": false
  },
  "exclude": [
    "**/*.spec.ts",
    "src/**/*.e2e.ts"
  ],
  "angularCompilerOptions": {
    "strictInjectionParameters": true,
    "strictInputAccessModifiers": true,
    "strictTemplates": true,
    "trace": false
  }
}

[alan-agius4]

As per the shared link of the documentation RXJS version 7.5.0 is supported.

[john8329]

I understand it implicitly says minor versions are supported, but the minimum should be 7.5.0 nevertheless otherwise it's buggy.