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

core

Is this a regression?

No

Description

When using signals with a type that requires an initial value, I must set it to null or undefined (e.g., signal<User | null>(null)). In the template, I guard access with @if (currentUser()) { ... }. However, it still reports a type error when accessing properties like currentUser().name unless I use the safe navigation operator ?..

This means the null check in @if is ignored for type narrowing.

Example:

currentUser = signal<User>();

It requires an initial value. Since you don’t have a user yet, you must initialize it with null or undefined:

currentUser = signal<User | null>(null);

In the template, when you try:

@if (currentUser()) { <!-- Ignored -->
  <p>{{ currentUser().name }}</p> <!-- Type error -->
}

The @if directive is ignored for type narrowing, so you get a type error on currentUser().name. You have to write it like this:

@if (currentUser()) {
  <p>{{ currentUser()?.name }}</p>
}

This works and is acceptable, but it feels verbose and redundant.

Now, when you have a dumb component where the user input is required:

user = input.required<User>();

You are sure the user will always be provided, so you want to avoid unnecessary null checks. But in the template:

@if (currentUser()) { <!-- Ignored -->
  <show-user [user]="currentUser()" /> <!-- Type error -->
}

You still get a type error because the @if directive does not narrow the type properly. To avoid this, you have to accept null in the input as well:

user = input.required<User | null>();

This forces you to write many unnecessary null checks even when you are sure the data is present.

The root cause is that the @if directive ignores type narrowing on signals, leading to awkward template code and type errors even where data is guaranteed to be non-null.

Please provide a link to a minimal reproduction of the bug

No response

Please provide the exception or error you saw

X [ERROR] NG1: Object is possibly 'null'

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

Angular CLI: 20.0.3
Node: 22.13.1
Package Manager: npm 11.4.1
OS: win32 x64

Angular: 20.0.4
... common, compiler, compiler-cli, core, forms
... platform-browser, router

Package                      Version
------------------------------------------------------
@angular-devkit/architect    0.2000.3
@angular-devkit/core         20.0.3
@angular-devkit/schematics   20.0.3
@angular/build               20.0.3
@angular/cdk                 20.0.3
@angular/cli                 20.0.3
@angular/material            20.0.3
@schematics/angular          20.0.3
rxjs                         7.8.2
typescript                   5.8.3

Anything else?

No response