Don't import Link from pip._internal.index

src/pip/_internal/req/req_install.py

@@ -90,7 +90,6 @@ class InstallRequirement(object):
         if link is not None:
             self.link = self.original_link = link
         else:
-            from pip._internal.index import Link
             self.link = self.original_link = req and req.url and Link(req.url)
 
         if extras:
@@ -205,8 +204,6 @@ class InstallRequirement(object):
         """Creates an InstallRequirement from a name, which might be a
         requirement, directory containing 'setup.py', filename, or URL.
         """
-        from pip._internal.index import Link
-
         if is_url(name):
             marker_sep = '; '
         else:
@@ -1043,8 +1040,6 @@ def parse_editable(editable_req):
         .[some_extra]
     """
 
-    from pip._internal.index import Link
-
     url = editable_req
 
     # If a file path is specified with extras, strip off the extras.

tests/unit/test_download.py

@@ -14,7 +14,7 @@ from pip._internal.download import (
     unpack_file_url, unpack_http_url, url_to_path,
 )
 from pip._internal.exceptions import HashMismatch
-from pip._internal.index import Link
+from pip._internal.models.link import Link
 from pip._internal.utils.hashes import Hashes
 from tests.lib import create_file