diff --git a/src/pip/_internal/req/constructors.py b/src/pip/_internal/req/constructors.py
index edc6c36f9..7e57f22f7 100644
--- a/src/pip/_internal/req/constructors.py
+++ b/src/pip/_internal/req/constructors.py
@@ -218,7 +218,7 @@ def parse_req_from_editable(editable_req):
 
 def install_req_from_editable(
     editable_req,  # type: str
-    comes_from=None,  # type: Optional[str]
+    comes_from=None,  # type: Optional[Union[InstallRequirement, str]]
     use_pep517=None,  # type: Optional[bool]
     isolated=False,  # type: bool
     options=None,  # type: Optional[Dict[str, Any]]
@@ -231,7 +231,9 @@ def install_req_from_editable(
     source_dir = parts.link.file_path if parts.link.scheme == 'file' else None
 
     return InstallRequirement(
-        parts.requirement, comes_from, source_dir=source_dir,
+        parts.requirement,
+        comes_from=comes_from,
+        source_dir=source_dir,
         editable=True,
         link=parts.link,
         constraint=constraint,
diff --git a/src/pip/_internal/resolution/resolvelib/candidates.py b/src/pip/_internal/resolution/resolvelib/candidates.py
index b78201a34..db750823f 100644
--- a/src/pip/_internal/resolution/resolvelib/candidates.py
+++ b/src/pip/_internal/resolution/resolvelib/candidates.py
@@ -60,10 +60,7 @@ def make_install_req_from_editable(link, parent):
     assert parent.editable, "parent not editable"
     return install_req_from_editable(
         link.url,
-        # HACK: install_req_from_editable accepts Optional[str] here, but
-        # parent.comes_from is Union[str, InstallRequirement, None]. How do
-        # we fix the type hint conflicts?
-        comes_from=parent.comes_from,  # type: ignore
+        comes_from=parent.comes_from,
         use_pep517=parent.use_pep517,
         isolated=parent.isolated,
         constraint=parent.constraint,