diff --git a/piptools/_compat/pip_compat.py b/piptools/_compat/pip_compat.py
index f5d8d1be1..3d190d9c2 100644
--- a/piptools/_compat/pip_compat.py
+++ b/piptools/_compat/pip_compat.py
@@ -36,8 +36,8 @@ def do_import(module_path, subimport=None, old_path=None):
 FAVORITE_HASH = do_import("utils.hashes", "FAVORITE_HASH")
 path_to_url = do_import("utils.urls", "path_to_url", old_path="download")
 url_to_path = do_import("utils.urls", "url_to_path", old_path="download")
-PackageFinder = do_import("index", "PackageFinder")
-FormatControl = do_import("index", "FormatControl")
+PackageFinder = do_import("index.package_finder", "PackageFinder", old_path="index")
+FormatControl = do_import("models.format_control", "FormatControl", old_path="index")
 InstallCommand = do_import("commands.install", "InstallCommand")
 Wheel = do_import("wheel", "Wheel")
 cmdoptions = do_import("cli.cmdoptions", old_path="cmdoptions")
diff --git a/piptools/repositories/pypi.py b/piptools/repositories/pypi.py
index 588a8dc23..9a81ec9fe 100644
--- a/piptools/repositories/pypi.py
+++ b/piptools/repositories/pypi.py
@@ -226,9 +226,16 @@ def resolve_reqs(self, download_dir, ireq, wheel_cache):
                 reqset = RequirementSet()
                 ireq.is_direct = True
                 reqset.add_requirement(ireq)
+
                 resolver = PipResolver(**resolver_kwargs)
-                resolver.require_hashes = False
-                results = resolver._resolve_one(reqset, ireq)
+                require_hashes = False
+                if PIP_VERSION < (19, 4):
+                    resolver.require_hashes = require_hashes
+                    results = resolver._resolve_one(reqset, ireq)
+                else:  # pragma: no cover
+                    # TODO remove pragma after pip==19.4 being released
+                    results = resolver._resolve_one(reqset, ireq, require_hashes)
+
                 reqset.cleanup_files()
 
         return set(results)