Improve handling of constraints on requirements with extras

src/pip/_internal/resolution/resolvelib/factory.py

@@ -465,7 +465,6 @@ def _make_requirements_from_install_req(
                 ireq.name,
                 ireq.markers,
             )
-            yield from ()
         elif not ireq.link:
             if ireq.extras and ireq.req is not None and ireq.req.specifier:
                 yield SpecifierWithoutExtrasRequirement(ireq)

tests/unit/resolution_resolvelib/test_requirement.py

@@ -109,5 +109,5 @@ def test_new_resolver_full_resolve(factory: Factory, provider: PipProvider) -> N
     reqs = list(factory.make_requirements_from_spec("simplewheel", comes_from=None))
     assert len(reqs) == 1
     r: Resolver[Requirement, Candidate, str] = Resolver(provider, BaseReporter())
-    result = r.resolve([reqs[0]])
+    result = r.resolve(reqs)
     assert set(result.mapping.keys()) == {"simplewheel"}