import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)

    @Suppress("unused")
    private
    abstract class Receiver {
        @Adding
        abstract fun lambdaRequired(x: Int, configure: Receiver.() -> Unit): Receiver

        @Adding
        abstract fun lambdaOptional(x: Int, configure: Receiver.() -> Unit = { }): Receiver

        @Adding
        abstract fun lambdaNotAllowed(x: Int): Receiver
    }

package org.gradle.internal.declarativedsl.demo.demoPlugins

import org.gradle.declarative.dsl.model.annotations.Adding
import org.gradle.declarative.dsl.model.annotations.Builder
import org.gradle.declarative.dsl.model.annotations.Configuring
import org.gradle.declarative.dsl.model.annotations.HasDefaultValue
import org.gradle.declarative.dsl.model.annotations.Restricted


class TopLevelScope {
    @get:Restricted
    val plugins = PluginsBlock()

 * will be considered equivalent.
 *
 * Line ending normalization is only supported with ASCII encoding and its supersets (i.e.
 * UTF-8, ISO-8859-1, etc).  Other encodings (e.g. UTF-16) will be treated as binary files
 * and will not be subject to line ending normalization.
 *
 * <p>This annotation should be attached to the getter method in Java or the property in Groovy.

    execution failed for task :tooling-api:gradle3.5.1CrossVersionTest'.
    > No tests found for given includes: [org.gradle.integtests.tooling.r81.LogLevelConfigCrossVersionSpec](--tests filter)`

You can fix it by adding `-PtestJavaVersion=8` to the build.

This is due to the fact that Gradle 4.6 and older don't support Java 11 and newer, which is checked before the test filter is applied.

Adding test task to project ':project-a'

import org.gradle.api.Action;
import org.gradle.api.artifacts.dsl.RepositoryHandler;
import org.gradle.api.initialization.ConfigurableIncludedPluginBuild;
import org.gradle.declarative.dsl.model.annotations.Adding;
import org.gradle.declarative.dsl.model.annotations.Configuring;
import org.gradle.declarative.dsl.model.annotations.Restricted;
import org.gradle.internal.HasInternalProtocol;

import org.gradle.testing.base.TestingExtension;

/**
 * Utility class intended for use only when the {@link org.gradle.api.plugins.JavaPlugin JavaPlugin} is applied.
 *
 * This class exists to avoid adding these methods to the plugin itself,
 * and thus avoids adding these methods to the public API.
 */
public class JavaPluginHelper {

    private JavaPluginHelper() {
        // Private to prevent instantiation.
    }

    /**

        when:
        newBase.addInterface(stablePublicInterface)

        then:
        noViolation(rule)
    }

    def 'adding an #type interface can be reported'() {
        given:
        newBase.addInterface(interfaces[type])

        when:
        Violation violation = rule.maybeViolation(apiClass)

        then:

project :producer FAILED
\--- runtimeClasspath

project :producer FAILED
\--- runtimeClasspath

project :producer FAILED
\--- runtimeClasspath

A web-based, searchable dependency report is available by adding the --scan option.

BUILD SUCCESSFUL in 0s