Angular update 8.1 to 8.2 I get many “Cannot read property 'ngInjectableDef' of undefined”

问题

After updating from 8.1 to 8.2 I get many errors like this

MyComponent.html:6 ERROR TypeError: Cannot read property 'ngInjectableDef' of undefined
    at getInjectableDef (core.js:361)
    at resolveNgModuleDep (core.js:30377)
    at NgModuleRef_.get (core.js:31578)
    at injectInjectorOnly (core.js:734)
    at ɵɵinject (core.js:744)
    at injectArgs (core.js:837)
    at core.js:16346
    at _callFactory (core.js:30486)
    at _createProviderInstance (core.js:30429)
    at resolveNgModuleDep (core.js:30388)```

回答1:

I found one reason...

I had many places like this

export class AbstractSth {
    constructor(protected service: SomeService) {}
}

export class SpecialSth extends AbstractSth {
    // ... special stuff (no constructor needed in 8.1)
}

Well it turned out that with 8.2 the SpecialSth class needs its own constructor with a super() call, because somehow now only the child class gets the needed properties injected and with no constructor nothing is injected and the inherited parent constructor seems to be ignored in the injection logic.

So this fixes the problem:

export class SpecialSth extends AbstractSth {
    constructor(protected service: SomeService) {
        super(service);
    }
    // ... special stuff
}

来源：https://stackoverflow.com/questions/59271316/angular-update-8-1-to-8-2-i-get-many-cannot-read-property-nginjectabledef-of