Command

serve

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

No response

Description

I recently started to notice that after introducing strictTemplates and strictNullChecks in my project, WebStorm still sometimes highlights types incompatibility. So I started investigating whether it's my IDE's problem or not.

Let's assume that we have a method in component, which accepts string as an argument. If we try to call it from a template with undefined or null explicitly, compiler would throw an error. However, this is not the case when library is involved. In my example is used along with (selectedChange).

$event can be null. And if I try to call that method with $event.toString(), compiler would not complain. Even something like $event?.toString() or $event?.toString() ?? undefined or $event?.toString() || undefined would still be fine for the compiler. At the same time something like '' || undefined will trigger a compilation error.

Here is the StackBlitz link. This is a fork from the official example.

Minimal Reproduction

• init strict application with strictTemplates & strictNullChecks
• create component with a method, which accepts string as a single argument
• call that method from the template using third-party library's component where $event can be null. E.g. myMethod($event.toString())

Exception or Error

This is what I would actually expect to see in such case, but no error was given.

Your Environment

Angular CLI: 18.2.1
Node: 18.20.3
Package Manager: npm 10.2.3
OS: linux x64

Angular: 18.2.2
... animations, cdk, common, compiler, compiler-cli, core, forms
... localize, material, material-moment-adapter
... platform-browser, platform-browser-dynamic, router

Package                         Version
---------------------------------------------------------
@angular-devkit/architect       0.1802.1
@angular-devkit/build-angular   18.2.1
@angular-devkit/core            18.2.1
@angular-devkit/schematics      18.2.1
@angular/cli                    18.2.1
@schematics/angular             18.2.1
rxjs                            7.4.0
typescript                      5.5.4
zone.js                         0.14.10

Anything else relevant?

No response