@switch exhaustiveness does not work for @for loop nad @if variables #67406
Description
Which @angular/* package(s) are the source of the bug?
compiler
Is this a regression?
No
Description
Summary
@switch exhaustiveness checks do not work when switching on a variable introduced by @for or @if.
Example
@for (nested of nesteds; track nested) {
@switch (nested.type) {
@case ('alpha') {
<span>{{ nested.alpha }}</span>
}
@case ('beta') {
<span>{{ nested.beta }}</span>
}
@default never;
}
}
@if (optional.maybe; as union) {
@switch (union.type) {
@case ('alpha') {
<span>{{ union.alpha }}</span>
}
@case ('beta') {
<span>{{ union.beta }}</span>
}
@default never;
}
}Expected behavior
@switch exhaustiveness should work for @for loop / @if variables (including their discriminant fields), the same way it works for direct const references, when the switched value is a finite/discriminated union.
Actual behavior
The compilator reports an error.
Please provide a link to a minimal reproduction of the bug
https://stackblitz.com/edit/stackblitz-starters-4ticm6ar
Please provide the exception or error you saw
✘ [ERROR] TS2322: Type 'any' is not assignable to type 'never'. [plugin angular-compiler]
✘ [ERROR] TS2339: Property 'kind' does not exist on type 'never'. [plugin angular-compiler]
Please provide the environment you discovered this bug in (run ng version)
_ _ ____ _ ___
/ \ _ __ __ _ _ _| | __ _ _ __ / ___| | |_ _|
/ △ \ | '_ \ / _` | | | | |/ _` | '__| | | | | | |
/ ___ \| | | | (_| | |_| | | (_| | | | |___| |___ | |
/_/ \_\_| |_|\__, |\__,_|_|\__,_|_| \____|_____|___|
|___/
Angular CLI : 21.2.0
Angular : 21.2.0
Node.js : 24.13.0
Package Manager : bun 1.3.10
Operating System : darwin arm64
┌──────────────────────────────────┬───────────────────┬───────────────────┐
│ Package │ Installed Version │ Requested Version │
├──────────────────────────────────┼───────────────────┼───────────────────┤
│ @angular-devkit/build-angular │ 21.2.0 │ 21.2.0 │
│ @angular-devkit/core │ 21.2.0 │ 21.2.0 │
│ @angular-devkit/schematics │ 21.2.0 │ 21.2.0 │
│ @angular/animations │ 21.2.0 │ 21.2.0 │
│ @angular/cdk │ 21.2.0 │ 21.2.0 │
│ @angular/cli │ 21.2.0 │ 21.2.0 │
│ @angular/common │ 21.2.0 │ 21.2.0 │
│ @angular/compiler │ 21.2.0 │ 21.2.0 │
│ @angular/compiler-cli │ 21.2.0 │ 21.2.0 │
│ @angular/core │ 21.2.0 │ 21.2.0 │
│ @angular/elements │ 21.2.0 │ 21.2.0 │
│ @angular/forms │ 21.2.0 │ 21.2.0 │
│ @angular/language-service │ 21.2.0 │ 21.2.0 │
│ @angular/localize │ 21.2.0 │ 21.2.0 │
│ @angular/material │ 21.2.0 │ 21.2.0 │
│ @angular/material-luxon-adapter │ 21.2.0 │ 21.2.0 │
│ @angular/material-moment-adapter │ 21.2.0 │ 21.2.0 │
│ @angular/platform-browser │ 21.2.0 │ 21.2.0 │
│ @angular/platform-server │ 21.2.0 │ 21.2.0 │
│ @angular/router │ 21.2.0 │ 21.2.0 │
│ @angular/service-worker │ 21.2.0 │ 21.2.0 │
│ @schematics/angular │ 21.2.0 │ 21.2.0 │
│ ng-packagr │ 21.2.0 │ 21.2.0 │
│ rxjs │ 7.8.2 │ 7.8.2 │
│ typescript │ 5.9.3 │ 5.9.3 │
│ vitest │ 4.0.18 │ 4.0.18 │
└──────────────────────────────────┴───────────────────┴───────────────────┘
Anything else?
No response