diff --git a/topdown/topdown.go b/topdown/topdown.go
index 0a32adb1ba..ca80b5b709 100644
--- a/topdown/topdown.go
+++ b/topdown/topdown.go
@@ -2214,23 +2214,20 @@ func indexBuildLazy(t *Topdown, ref ast.Ref) (storage.Index, error) {
 	}
 
 	// Ignore refs against virtual docs.
-	tmp := ast.Ref{ref[0], ref[1]}
-	r := t.Compiler.GetRulesExact(tmp)
-	if r != nil {
-		return nil, nil
-	}
-
-	for _, p := range ref[2:] {
+	node := t.Compiler.RuleTree.Child(ref[0].Value)
 
-		if !p.Value.IsGround() {
+	for i := 1; i < len(ref); i++ {
+		if node == nil || !ref[i].IsGround() {
 			break
 		}
-
-		tmp = append(tmp, p)
-		r := t.Compiler.GetRulesExact(tmp)
-		if r != nil {
-			return nil, nil
+		if len(node.Values) > 0 {
+			break
 		}
+		node = node.Child(ref[i].Value)
+	}
+
+	if node != nil {
+		return nil, nil
 	}
 
 	index, err := t.Store.Build(t.Context, t.txn, ref)
diff --git a/topdown/topdown_test.go b/topdown/topdown_test.go
index 26a21bb0d0..2730fd84c7 100644
--- a/topdown/topdown_test.go
+++ b/topdown/topdown_test.go
@@ -777,6 +777,12 @@ p = true { input.foo }`,
 
 p = true { false }`,
 
+		`package topdown.virtual.constants
+
+		p = 1
+		q = 2
+		r = 1`,
+
 		// Define virtual docs that we can query to obtain merged result.
 		`package topdown
 
@@ -787,7 +793,10 @@ s = data.topdown.no { true }
 t = data.topdown.a.b.c.undefined1 { true }
 u = data.topdown.missing.input.value { true }
 v = data.topdown.g { true }
-w = data.topdown.set { true }`,
+w = data.topdown.set { true }
+
+iterate_ground[x] { data.topdown.virtual.constants[x] = 1 }
+`,
 	})
 
 	store := inmem.NewFromObject(data)
@@ -835,6 +844,7 @@ w = data.topdown.set { true }`,
 	assertTopDownWithPath(t, compiler, store, "base/virtual: undefined", []string{"topdown", "t"}, "{}", "{}")
 	assertTopDownWithPath(t, compiler, store, "base/virtual: undefined-2", []string{"topdown", "v"}, "{}", `{"h": {"k": [1,2,3]}}`)
 	assertTopDownWithPath(t, compiler, store, "base/virtual: missing input value", []string{"topdown", "u"}, "{}", "")
+	assertTopDownWithPath(t, compiler, store, "iterate ground", []string{"topdown", "iterate_ground"}, "{}", `["p", "r"]`)
 }
 
 func TestTopDownNestedReferences(t *testing.T) {