Add messages to replaced explicit bindings

[TWiStErRob]

Fix 3 TODOs and cover them with tests. Note: I missed mapOfLazyKey deliberately, see #159.

---

Here's the Dagger output for these issues:

integration-tests\src\main\java\com\example\MultibindingSetConflict.java:13:
error: [Dagger/DuplicateBindings] java.util.Set<java.lang.String> has incompatible bindings or declarations:
interface MultibindingSetConflict {
^
      Set bindings and declarations:
          @Provides @dagger.multibindings.IntoSet String com.example.MultibindingSetConflict.Module1.one()
          @Provides @dagger.multibindings.ElementsIntoSet Set<String> com.example.MultibindingSetConflict.Module1.three()
          @Provides @dagger.multibindings.IntoSet String com.example.MultibindingSetConflict.Module1.two()
      Unique bindings and declarations:
          @Provides Set<String> com.example.MultibindingSetConflict.Module1.explicit()
      java.util.Set<java.lang.String> is provided at
          com.example.MultibindingSetConflict.values()
1 error

integration-tests\src\main\java\com\example\MultibindingMapConflict.java:12:
error: [Dagger/DuplicateBindings] java.util.Map<java.lang.Integer,java.lang.String> has incompatible bindings or declarations:
interface MultibindingMapConflict {
^
      Map bindings and declarations:
          @Provides @dagger.multibindings.IntoMap @dagger.multibindings.IntKey(1) String com.example.MultibindingMapConflict.Module1.one()
          @Provides @dagger.multibindings.IntoMap @dagger.multibindings.IntKey(2) String com.example.MultibindingMapConflict.Module1.two()
      Unique bindings and declarations:
          @Provides Map<Integer,String> com.example.MultibindingMapConflict.Module1.explicit()
      java.util.Map<java.lang.Integer,java.lang.String> is provided at
          com.example.MultibindingMapConflict.values()
1 error

integration-tests\src\main\java\com\example\MultibindingMapProviderConflict.java:13:
error: [Dagger/DuplicateBindings] java.util.Map<java.lang.Integer,javax.inject.Provider<java.lang.String>> has incompatible bindings or declarations:
interface MultibindingMapProviderConflict {
^
      Map bindings and declarations:
          @Provides @dagger.multibindings.IntoMap @dagger.multibindings.IntKey(1) String com.example.MultibindingMapProviderConflict.Module1.one()
      Unique bindings and declarations:
          @Provides Map<Integer,Provider<String>> com.example.MultibindingMapProviderConflict.Module1.explicit()
      java.util.Map<java.lang.Integer,javax.inject.Provider<java.lang.String>> is provided at
          com.example.MultibindingMapProviderConflict.values()
1 error

[JakeWharton]

Scope shouldn't know anything about Dagger. Can we change these messages in a way to provide this information without encoding the implementation details of how Dagger contributes bindings into a set? Should the binding itself report this information in its toString() perhaps?

[TWiStErRob]

The Binding doesn't know it came from @IntoSet/@ElementsIntoSet/@IntoMap:

unless we look into method.declaredAnnotations.

I removed dagger.** class references and the dagger error code and fixed sentence comments in force push

[TWiStErRob]

Looking at Dagger output that's what's happening there too, happy to open a followup changing the toString of /(un)?linked(provides|binds)binding/ to include the full signature including annotations and parameters.

---

Did a quick test with:

  public String toString() {
    return "@Provides["
+        + Arrays.toString(method.getDeclaredAnnotations())
        + method.getDeclaringClass().getName() + '.' + method.getName() + "(…)]";
  }

  Set bindings and declarations:
    [single  ] @Binds[[@dagger.Binds(), @dagger.multibindings.IntoSet()]com.example.MultibindingSetConflict$Module1.three(…)]
    [single  ] @Provides[[@dagger.Provides(), @dagger.multibindings.IntoSet()]com.example.MultibindingSetConflict$Module1.one(…)]
    [multiple] @Provides[[@dagger.Provides(), @dagger.multibindings.ElementsIntoSet()]com.example.MultibindingSetConflict$Module1.two(…)]
    [multiple] @Binds[[@dagger.Binds(), @dagger.multibindings.ElementsIntoSet()]com.example.MultibindingSetConflict$Module1.four(…)]

I think I would need to remove the Binding's own annotation, and the noisy bits like () and known package names like dagger/dagger.mulitbindings/javax.inject to make it useful.

[JakeWharton]

You don't need to pull it from the method. We can supply an enum value or string at the time of binding creation which helps format this message.

[JakeWharton]

What about "instance" and "elements"? We can re-use terminology like "elements" which is in the API of Scope, I just don't want explicitly mechanisms of Dagger like @ElementsIntoSet (unless we sneak them into the Binding's toString(), then we can have as much Dagger-specific things as we like).