Can't resolve all parameters for .... This will become an error in Angular v6.x

[FrancescoBorzi]

I'm submitting a...

[ ] Regression (a behavior that used to work and stopped working in a new release)
[x] Bug report  
[ ] Performance issue
[ ] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question
[ ] Other... Please describe:

I have 4 classes:

• Class A, @Injectable
• Class B, abstract, NON injectable, extends A
• Class C, @Injectable, extends B
• Class D, @Injectable, extends B

classes A, C and D are used as Services and correctly added to the providers list of my module. Class B is NOT used as a service.

Current behavior

Everything works fine but I got this warning:

Can't resolve all parameters for ClassBService in /path/to/class-b.service.ts: ([object Object], ?). This will become an error in Angular v6.x

Expected behavior

Not sure if some action on my side is required or this warning should not be displayed.

Demo

Clone the repository, run npm install and then ng build --prod. You'll see the warning.

https://github.com/ShinDarth/angular-test/

FrancescoBorzi/angular-test@4101bc5

Environment

Angular CLI: 1.7.4
Node: 8.10.0
OS: linux x64
Angular: 5.2.11
... animations, common, compiler, compiler-cli, core, forms
... http, language-service, platform-browser
... platform-browser-dynamic, router

@angular/cli: 1.7.4
@angular-devkit/build-optimizer: 0.3.2
@angular-devkit/core: 0.3.2
@angular-devkit/schematics: 0.3.2
@ngtools/json-schema: 1.2.0
@ngtools/webpack: 1.10.2
@schematics/angular: 0.3.2
@schematics/package-update: 0.3.2
typescript: 2.6.2
webpack: 3.11.0

[FrancescoBorzi]

@trotyl I would appreciate to know how I can improve my issue report.

[trotyl]

Please provide a reproduction via https://stackblitz.com/

[FrancescoBorzi]

@trotyl I got the warning when compiling, but in the web app everything is fine. As I said, this is my setup:

I have 4 classes:

Class A, @Injectable
Class B, abstract, NON injectable, extends A
Class C, @Injectable, extends B
Class D, @Injectable, extends B
classes A, C and D are used as Services and correctly added to the providers list of my module. Class B is NOT used as a service.

not sure how I can reproduce the compile warning here.

[trotyl]

@ShinDarth Then you could create a brand new Angular CLI application to repro this problem.

[mlc-mlapis]

@ShinDarth ... we don't know what are the constructors of all 4 classes also.

[FrancescoBorzi]

@trotyl @mlc-mlapis here's a very small Angular app which reproduces the issue:

https://github.com/ShinDarth/angular-test/

FrancescoBorzi/angular-test@4101bc5

[trotyl]

Duplicate of #19797, #22153

[FrancescoBorzi]

@trotyl no it is not. I've already checked those issues. The main difference is that in their case the service which is triggering the warning has the @Injectable annotation (and they solve the warning by simply removing it).

In my case, Service B has NO @Injectable (as I wrote in the issue report).

[trotyl]

@ShinDarth The linked issue above doesn't have an @Injectable() either, you can check the source code. It's exact same except string/enum difference.