Verify that projections work with subqueries.

Interface-based projections used to NOT work when the query had a subquery in it. But with the new query parser, it already handles it. So this simply captures the test providing that corner case.

See #2008
Original Pull Request: #420

spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/UserRepositoryFinderTests.java

@@ -315,4 +315,15 @@ class UserRepositoryFinderTests {
 	void executesNamedQueryWithConstructorExpression() {
 		userRepository.findByNamedQueryWithConstructorExpression();
 	}
+
+	@Test // DATAJPA-1713, GH-2008
+	public void selectProjectionWithSubselect() {
+
+		List<UserRepository.NameOnly> dtos = userRepository.findProjectionBySubselect();
+
+		assertThat(dtos).flatExtracting(UserRepository.NameOnly::getFirstname) //
+				.containsExactly("Dave", "Carter", "Oliver August");
+		assertThat(dtos).flatExtracting(UserRepository.NameOnly::getLastname) //
+				.containsExactly("Matthews", "Beauford", "Matthews");
+	}
 }

spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/sample/UserRepository.java

@@ -718,6 +718,10 @@ public interface UserRepository extends JpaRepository<User, Integer>, JpaSpecifi
 			nativeQuery = true)
 	int mergeNativeStatement();
 
+	// DATAJPA-1713, GH-2008
+	@Query("select u from User u where u.firstname >= (select Min(u0.firstname) from User u0)")
+	List<NameOnly> findProjectionBySubselect();
+
 	interface RolesAndFirstname {
 
 		String getFirstname();