Redundant cast in generated component

I have a redundant cast in one of my generated component implementations: this.provideFooProvider = DoubleCheck.provider((Provider) provideRealFooProvider); where Foo is an interface and RealFoo is the concrete type.

@Module public abstract class FooModule {
  @AppScope @Provides static RealFoo provideRealFoo() {
    return Foo.create();
  }

  @AppScope @Binds abstract Foo provideFoo(RealFoo realFoo);
}

This is such a minor thing, and it doesn’t end up in the bytecode. Totally close this if it’s uninteresting.

[TWiStErRob]

@ronshapiro @gk5885 I just ran into this while upgrading from 2.16 to 2.23.2. If you’re not going to go with ? extends would it make sense to at least @SuppressWarnings("cast") on that method so we can use -Werror on our codebases?

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By the way, if someone find this issue, the TL;DR workaround is to open up the visibility of the implementation (so that the generated component can access it):

package a;
@Module
public class MyModule {
    @Binds
    Interface bind(Implementation impl);
}

package a;
public interface Interface {}

package a;
-class Implementation implements Interface {}
+public class Implementation implements Interface {}

package b;
import a.MyModule;
@Component(modules = {MyModule.class})

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Exact error message that lead me here for SEO:

> Task :app:compileDebugJavaWithJavac
C:\dev\app\build\generated\source\kapt\debug\a\DaggerAppComponent.java:5986:
warning: [cast] redundant cast to Provider
        this.bindProvider = DoubleCheck.provider((Provider) implementationProvider);

[NightlyNexus]

Yes, my component is in a different package, and those are my fields.

Oh, that makes sense. Thank you for the fantastic explanation! I appreciate it! I was super curious about the cause. 🌟