Fixed #30988 -- Deprecated the InvalidQuery exception.

It was barely documented without pointers at its defining location and
was abused to prevent misuse of the QuerySet field deferring feature.

tests/queries/test_deprecation.py

@@ -0,0 +1,30 @@
+from contextlib import contextmanager
+
+from django.core.exceptions import FieldDoesNotExist, FieldError
+from django.db.models.query_utils import InvalidQuery
+from django.test import SimpleTestCase
+from django.utils.deprecation import RemovedInDjango40Warning
+
+
+class InvalidQueryTests(SimpleTestCase):
+    @contextmanager
+    def assert_warns(self):
+        msg = (
+            'The InvalidQuery exception class is deprecated. Use '
+            'FieldDoesNotExist or FieldError instead.'
+        )
+        with self.assertWarnsMessage(RemovedInDjango40Warning, msg):
+            yield
+
+    def test_type(self):
+        self.assertIsInstance(InvalidQuery(), InvalidQuery)
+
+    def test_isinstance(self):
+        for exception in (FieldError, FieldDoesNotExist):
+            with self.assert_warns(), self.subTest(exception.__name__):
+                self.assertIsInstance(exception(), InvalidQuery)
+
+    def test_issubclass(self):
+        for exception in (FieldError, FieldDoesNotExist, InvalidQuery):
+            with self.assert_warns(), self.subTest(exception.__name__):
+                self.assertIs(issubclass(exception, InvalidQuery), True)