Compiling @Injectable abstract class fails when constructor params cannot be resolved

🐞 bug report

Affected Package

This is caused by package @angular/compiler

Is this a regression?

Kind-of - abstract classes didn’t require @Injectable or @Directive annotations until v10

Description

Adding @Injectable annotation to an abstract class, with "strictInjectionParameters": true, fails compilation if the compiler can’t resolve constructor parameter injection tokens for the abstract class constructor. This should not fail, because the abstract class constructor isn’t called by the angular injector at runtime.

🔬 Minimal Reproduction

I’ve attempted to reproduce it in stackblitz, but it seems that stackblitz doesn’t respect the tsconfig "strictInjectionParameters": true. The code is here: https://stackblitz.com/edit/angular-ivy-vwamit

Here’s a minimal repro on an ng new --strict --minimal: https://github.com/johncrim/ng10-abstract-injectable/commit/a10be0eca1f4225a91946f65acdc46130a2da2b5

🔥 Exception or Error

ERROR in src/app/abstract.service.ts:6:24 - error NG2003: No suitable injection token for parameter 'name' of class 'AbstractService'.
Found string

6   constructor(readonly name: string) { }
                         ~~~~

🌍 Your Environment

Angular Version:

Angular CLI: 10.0.1
Node: 14.4.0
OS: win32 x64

Angular: 10.0.2
... animations, common, compiler, compiler-cli, core, forms
... platform-browser, platform-browser-dynamic, router
Ivy Workspace: Yes

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.1000.1
@angular-devkit/build-angular     0.1000.1
@angular-devkit/build-optimizer   0.1000.1
@angular-devkit/build-webpack     0.1000.1
@angular-devkit/core              10.0.1
@angular-devkit/schematics        10.0.1
@angular/cli                      10.0.1
@ngtools/webpack                  10.0.1
@schematics/angular               10.0.1
@schematics/update                0.1000.1
rxjs                              6.5.5
typescript                        3.9.6
webpack                           4.43.0

Anything else relevant? See: https://github.com/angular/angular/pull/32987

It appears that a fix for this issue was added for the @Directive decorator (allowing abstract constructors to not be injectable), but not for @Injectable.

[sergidt]

@pheinicke Providing a provider for any abstract class could be a solution, but is not the best solution. Any developer should be able to extend any abstract class passing parameters, is a OOP rule, without resolving via Dependency Injector.

In my product with thousands of files, I cannot resolve this kind of error declaring providers. In my opinion is a bug with high priority!!

[JoostK]

Thank you for the excellent bug report, this is indeed an issue.