diff --git a/lib/spack/spack/spec.py b/lib/spack/spack/spec.py
index e6985b5bfe3..1f9ba1e530b 100644
--- a/lib/spack/spack/spec.py
+++ b/lib/spack/spack/spec.py
@@ -3783,8 +3783,11 @@ def __contains__(self, spec):
         # if anonymous or same name, we only have to look at the root
         if not spec.name or spec.name == self.name:
             return self.satisfies(spec)
-        else:
-            return any(s.satisfies(spec) for s in self.traverse(root=False))
+        try:
+            dep = self[spec.name]
+        except KeyError:
+            return False
+        return dep.satisfies(spec)
 
     def eq_dag(self, other, deptypes=True, vs=None, vo=None):
         """True if the full dependency DAGs of specs are equal."""
diff --git a/lib/spack/spack/test/spec_dag.py b/lib/spack/spack/test/spec_dag.py
index 7ee0f0a44fc..2b5a18e3ea2 100644
--- a/lib/spack/spack/test/spec_dag.py
+++ b/lib/spack/spack/test/spec_dag.py
@@ -933,6 +933,11 @@ def test_indexing_prefers_direct_or_transitive_link_deps():
     with pytest.raises(KeyError):
         root["a2"]
 
+    # Check consistency of __contains__ with __getitem__
+    assert "z3 +through_z1" in root
+    assert "z3 +through_a1" in a1
+    assert "a2" not in root
+
 
 def test_getitem_sticks_to_subdag():
     """Test that indexing on Spec by virtual does not traverse outside the dag, which happens in