[HHH-12969] Identifiable.getJavaType() returns IdClass member type rather than Entity class member type

hibernate-core/src/test/java/org/hibernate/test/metamodel/IdClassAssociationMetamodelTest.java

@@ -0,0 +1,50 @@
+package org.hibernate.test.metamodel;
+
+import java.io.Serializable;
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.IdClass;
+import javax.persistence.ManyToOne;
+import javax.persistence.metamodel.SingularAttribute;
+
+import org.hibernate.jpa.test.BaseEntityManagerFunctionalTestCase;
+
+import org.junit.Test;
+
+import static org.hibernate.testing.transaction.TransactionUtil.doInJPA;
+import static org.junit.Assert.assertEquals;
+
+public class IdClassAssociationMetamodelTest extends BaseEntityManagerFunctionalTestCase {
+
+	@Entity @IdClass(EntityType.EntityId.class) public static class EntityType {
+		@Id private Long key2;
+		@Id @ManyToOne
+		private SomeAssociationType key1;
+
+		public static class EntityId implements Serializable {
+			private Long key1, key2;
+		}
+	}
+
+	@Entity public static class SomeAssociationType {
+		@Id
+		private Long id;
+	}
+
+	@Override
+	protected Class<?>[] getAnnotatedClasses() {
+		return new Class<?>[] { EntityType.class, SomeAssociationType.class };
+	}
+
+	@Test
+	public void idClassAttributeIsProperlyRepresentedInMetamodelTest() {
+		doInJPA( this::entityManagerFactory, entityManager -> {
+			javax.persistence.metamodel.EntityType<EntityType> entity = entityManager.getMetamodel()
+					.entity( EntityType.class );
+
+			SingularAttribute<? super EntityType, ?> key1 = entity.getSingularAttribute( "key1" );
+			assertEquals( SomeAssociationType.class, key1.getJavaType() );
+			assertEquals( SomeAssociationType.class, key1.getType().getJavaType()  );
+		} );
+	}
+}