def libraryTable = project.component.find { it.@name == "libraryTable" }
        assert libraryTable

        def library = libraryTable.library.find { it.@name == libraryName }
        assert library: "Can't find $libraryName in ${libraryTable.library******@****.***(', ')}"

        def classesRoots = library.CLASSES.root
        assert classesRoots.size() == classesLibs.size()
        classesLibs.each {

                File scalaLibraryJar = findScalaJar(classpath, "library");
                File scala3LibraryJar = findScalaJar(classpath, "library_3");
                boolean isScala3 = scala3LibraryJar != null;
                if (scalaLibraryJar == null && scala3LibraryJar == null) {
                    throw new GradleException(String.format("Cannot infer Scala class path because no Scala library Jar was found. "

            parameters.getClasspath().from(getClasspath());
            parameters.getOutputDirectory().set(getDestinationDir());
            boolean isScala3 = ScalaRuntimeHelper.findScalaJar(getScalaClasspath(), "library_3") != null;
            parameters.getIsScala3().set(isScala3);
            if (isScala3) {
                parameters.getSources().from(getFilteredCompilationOutputs());
            } else {

    private static final int COMPILER_CLASSLOADER_CACHE_SIZE = 4;
    private static final String SCALA_3_COMPILER_ID = "scala3-compiler_3";
    private static final String SCALA_3_LIBRARY_ID = "scala3-library_3";
    private static final GuavaBackedClassLoaderCache<HashCode> CLASSLOADER_CACHE = new GuavaBackedClassLoaderCache<HashCode>(CLASSLOADER_CACHE_SIZE);
    private static final ClassLoaderCache COMPILER_CLASSLOADER_CACHE;

If you want to use Scala 3 instead of the `scala-library` dependency you should add the `scala3-library_3` dependency:

.Declaring a Scala 3 dependency for production code
====
include::sample[dir="snippets/scala/scala3/kotlin",files="build.gradle.kts"]
include::sample[dir="snippets/scala/scala3/groovy",files="build.gradle"]
====

/**
 * A classpath entry representing a library.
 */
public class Library extends AbstractLibrary {
    public Library(Node node, FileReferenceFactory fileReferenceFactory) {
        super(node, fileReferenceFactory);
        setSourcePath(fileReferenceFactory.fromPath((String) node.attribute("sourcepath")));
    }

    public Library(FileReference library) {
        super(library);
    }

    @Override

 */

package org.gradle.platform.base;

import org.gradle.api.Incubating;
import org.gradle.api.component.Component;

/**
 * A library that can be linked into or depended on by another software element.
 */
@Incubating
public interface Library extends Component {

package sym

import "cmd/internal/goobj"

type Library struct {
	Objref      string
	Srcref      string
	File        string
	Pkg         string
	Shlib       string
	Fingerprint goobj.FingerprintType
	Autolib     []goobj.ImportedPkg
	Imports     []*Library
	Main        bool
	Units       []*CompilationUnit

	Textp       []LoaderSym // text syms defined in this library

class Library {
    void function() {}

class Library {
    void function() {}