diff --git a/django/db/models/sql/compiler.py b/django/db/models/sql/compiler.py
index 0e483dc4f649..14603d57733e 100644
--- a/django/db/models/sql/compiler.py
+++ b/django/db/models/sql/compiler.py
@@ -228,6 +228,13 @@ def collapse_group_by(self, expressions, having):
             ]
         return expressions
 
+    @classmethod
+    def get_select_from_parent(cls, klass_info):
+        for ki in klass_info["related_klass_infos"]:
+            if ki["from_parent"]:
+                ki["select_fields"] = klass_info["select_fields"] + ki["select_fields"]
+            cls.get_select_from_parent(ki)
+
     def get_select(self, with_col_aliases=False):
         """
         Return three values:
@@ -300,15 +307,7 @@ def get_select(self, with_col_aliases=False):
             related_klass_infos = self.get_related_selections(select, select_mask)
             klass_info["related_klass_infos"] = related_klass_infos
 
-            def get_select_from_parent(klass_info):
-                for ki in klass_info["related_klass_infos"]:
-                    if ki["from_parent"]:
-                        ki["select_fields"] = (
-                            klass_info["select_fields"] + ki["select_fields"]
-                        )
-                    get_select_from_parent(ki)
-
-            get_select_from_parent(klass_info)
+            self.get_select_from_parent(klass_info)
 
         ret = []
         col_idx = 1
diff --git a/tests/bulk_create/tests.py b/tests/bulk_create/tests.py
index 8ab918fff57d..7b77ffed3d0c 100644
--- a/tests/bulk_create/tests.py
+++ b/tests/bulk_create/tests.py
@@ -889,19 +889,27 @@ def test_db_default_primary_key(self):
 class BulkCreateTransactionTests(TransactionTestCase):
     available_apps = ["bulk_create"]
 
+    def get_unused_country_id(self):
+        # Find a serial ID that hasn't been used already and has enough of a
+        # buffer for the following `bulk_create` call without an explicit pk
+        # not to conflict.
+        return getattr(Country.objects.last(), "id", 10) + 100
+
     def test_no_unnecessary_transaction(self):
+        unused_id = self.get_unused_country_id()
         with self.assertNumQueries(1):
             Country.objects.bulk_create(
-                [Country(id=1, name="France", iso_two_letter="FR")]
+                [Country(id=unused_id, name="France", iso_two_letter="FR")]
             )
         with self.assertNumQueries(1):
             Country.objects.bulk_create([Country(name="Canada", iso_two_letter="CA")])
 
     def test_objs_with_and_without_pk(self):
+        unused_id = self.get_unused_country_id()
         with self.assertNumQueries(4):
             Country.objects.bulk_create(
                 [
-                    Country(id=10, name="France", iso_two_letter="FR"),
+                    Country(id=unused_id, name="France", iso_two_letter="FR"),
                     Country(name="Canada", iso_two_letter="CA"),
                 ]
             )
diff --git a/tests/select_related/tests.py b/tests/select_related/tests.py
index 41ed350cf3da..59d1270aa069 100644
--- a/tests/select_related/tests.py
+++ b/tests/select_related/tests.py
@@ -1,6 +1,9 @@
+import gc
+
 from django.core.exceptions import FieldError
 from django.db.models import FETCH_PEERS
 from django.test import SimpleTestCase, TestCase
+from django.test.utils import garbage_collect
 
 from .models import (
     Bookmark,
@@ -57,6 +60,17 @@ def setUpTestData(cls):
             "Amanita muscaria"
         )
 
+    def setup_gc_debug(self):
+        self.addCleanup(gc.set_debug, 0)
+        self.addCleanup(gc.enable)
+        gc.disable()
+        garbage_collect()
+        gc.set_debug(gc.DEBUG_SAVEALL)
+
+    def assert_no_memory_leaks(self):
+        garbage_collect()
+        self.assertEqual(gc.garbage, [])
+
     def test_access_fks_without_select_related(self):
         """
         Normally, accessing FKs doesn't fill in related objects
@@ -128,6 +142,11 @@ def test_select_related_with_extra(self):
         )
         self.assertEqual(s.id + 10, s.a)
 
+    def test_select_related_memory_leak(self):
+        self.setup_gc_debug()
+        list(Species.objects.select_related("genus"))
+        self.assert_no_memory_leaks()
+
     def test_certain_fields(self):
         """
         The optional fields passed to select_related() control which related