Method bindingMethodKeyType

java/dagger/internal/codegen/KeyFactory.java:214–236

(
      TypeMirror returnType,
      ExecutableElement method,
      ContributionType contributionType,
      Optional<TypeElement> frameworkType)

  }

  private TypeMirror bindingMethodKeyType(
      TypeMirror returnType,
      ExecutableElement method,
      ContributionType contributionType,
      Optional<TypeElement> frameworkType) {
    switch (contributionType) {
      case UNIQUE:
        return returnType;
      case SET:
        return setOf(returnType);
      case MAP:
        TypeMirror mapKeyType = mapKeyType(getMapKey(method).get(), types);
        return frameworkType.isPresent()
            ? mapOfFrameworkType(mapKeyType, frameworkType.get(), returnType)
            : mapOf(mapKeyType, returnType);
      case SET_VALUES:
        // TODO(gak): do we want to allow people to use "covariant return" here?
        checkArgument(SetType.isSet(returnType));
        return returnType;
      default:
        throw new AssertionError();
    }
  }

  /**
   * Returns the key for a binding associated with a {@link DelegateDeclaration}.