From d406efdcf966218bbce0bc4834e6fde306f4cf53 Mon Sep 17 00:00:00 2001
From: jalcim <alcim.dev@gmail.com>
Date: Mon, 2 Mar 2026 15:15:34 -0500
Subject: [PATCH] Fix recursive constant function in $unit scope (#7174)
 (#7178)

---
 docs/CONTRIBUTORS                       |  1 +
 src/V3Scope.cpp                         |  1 +
 test_regress/t/t_func_unit_recursive.py | 18 ++++++++++++
 test_regress/t/t_func_unit_recursive.v  | 38 +++++++++++++++++++++++++
 4 files changed, 58 insertions(+)
 create mode 100755 test_regress/t/t_func_unit_recursive.py
 create mode 100644 test_regress/t/t_func_unit_recursive.v

diff --git a/docs/CONTRIBUTORS b/docs/CONTRIBUTORS
index 5ac1958e1..de64a9a88 100644
--- a/docs/CONTRIBUTORS
+++ b/docs/CONTRIBUTORS
@@ -99,6 +99,7 @@ Ivan Vnučec
 Iztok Jeras
 Jake Merdich
 Jakub Wasilewski
+jalcim
 James Bailey
 James Hanlon
 James Hutchinson
diff --git a/src/V3Scope.cpp b/src/V3Scope.cpp
index b10ac4999..29c3cc534 100644
--- a/src/V3Scope.cpp
+++ b/src/V3Scope.cpp
@@ -259,6 +259,7 @@ class ScopeVisitor final : public VNVisitor {
             clonep = nodep->cloneTree(false);
         }
         nodep->user2p(clonep);
+        clonep->user2p(clonep);  // For recursive self-references after cloneTree
         m_scopep->addBlocksp(clonep);
         // We iterate under the *clone*
         iterateChildren(clonep);
diff --git a/test_regress/t/t_func_unit_recursive.py b/test_regress/t/t_func_unit_recursive.py
new file mode 100755
index 000000000..8a938befd
--- /dev/null
+++ b/test_regress/t/t_func_unit_recursive.py
@@ -0,0 +1,18 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of either the GNU Lesser General Public License Version 3
+# or the Perl Artistic License Version 2.0.
+# SPDX-FileCopyrightText: 2026 Wilson Snyder
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+import vltest_bootstrap
+
+test.scenarios('simulator')
+
+test.compile()
+
+test.execute()
+
+test.passes()
diff --git a/test_regress/t/t_func_unit_recursive.v b/test_regress/t/t_func_unit_recursive.v
new file mode 100644
index 000000000..40096c953
--- /dev/null
+++ b/test_regress/t/t_func_unit_recursive.v
@@ -0,0 +1,38 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain.
+// SPDX-FileCopyrightText: 2026 jalcim
+// SPDX-License-Identifier: CC0-1.0
+
+// Recursive constant function defined at file scope ($unit).
+// Without the V3Scope.cpp fix, this triggers:
+//   %Error: Internal Error: V3Scope.cpp: No clone for package function
+
+function automatic integer gate_depth;
+  input integer way;
+  integer d1, d2, sc, n1, n2;
+  begin
+    if (way <= 1) gate_depth = 0;
+    else if (way <= 4) gate_depth = 1;
+    else begin
+      sc = $clog2(way);
+      n1 = 1 << (sc - 1);
+      n2 = way - n1;
+      d1 = gate_depth(n1);
+      d2 = gate_depth(n2);
+      gate_depth = ((d1 > d2) ? d1 : d2) + 1;
+    end
+  end
+endfunction
+
+module t;
+  localparam D5 = gate_depth(5);
+  localparam D8 = gate_depth(8);
+
+  initial begin
+    if (D5 !== 2) $stop;
+    if (D8 !== 2) $stop;
+    $write("*-* All Finished *-*\n");
+    $finish;
+  end
+endmodule