Fix VarRef lookup for module-level variables (#6741) (#6882)

src/V3Scope.cpp

@@ -53,7 +53,8 @@ class ScopeVisitor final : public VNVisitor {
     AstCell* m_aboveCellp = nullptr;  // Cell that instantiates this module
     AstScope* m_aboveScopep = nullptr;  // Scope that instantiates this scope
 
-    std::unordered_map<AstNodeModule*, AstScope*> m_packageScopes;  // Scopes for each package
+    std::unordered_map<AstNodeModule*, AstScope*>
+        m_classOrPackageScopes;  // Scopes for each class or package
     VarScopeMap m_varScopes;  // Varscopes created for each scope and var
     std::set<std::pair<AstVarRef*, AstScope*>>
         m_varRefScopes;  // Varrefs-in-scopes needing fixup when done
@@ -64,9 +65,12 @@ class ScopeVisitor final : public VNVisitor {
         for (const auto& itr : m_varRefScopes) {
             AstVarRef* const nodep = itr.first;
             AstScope* scopep = itr.second;
-            if (nodep->classOrPackagep()) {
-                const auto it2 = m_packageScopes.find(nodep->classOrPackagep());
-                UASSERT_OBJ(it2 != m_packageScopes.end(), nodep, "Can't locate package scope");
+            if (nodep->classOrPackagep()
+                && !VN_IS(nodep->classOrPackagep(),
+                          Module)) {  // Module scopes are not in m_classOrPackageScopes
+                const auto it2 = m_classOrPackageScopes.find(nodep->classOrPackagep());
+                UASSERT_OBJ(it2 != m_classOrPackageScopes.end(), nodep,
+                            "Can't locate class or package scope");
                 scopep = it2->second;
             }
             // Search up the scope hierarchy for the variable
@@ -114,7 +118,7 @@ class ScopeVisitor final : public VNVisitor {
             (m_aboveCellp ? static_cast<AstNode*>(m_aboveCellp) : static_cast<AstNode*>(nodep))
                 ->fileline(),
             nodep, scopename, m_aboveScopep, m_aboveCellp};
-        if (VN_IS(nodep, Package)) m_packageScopes.emplace(nodep, m_scopep);
+        if (VN_IS(nodep, Package)) m_classOrPackageScopes.emplace(nodep, m_scopep);
 
         // Get list of cells before we edit, to avoid excess visits (issue #6059)
         std::deque<AstCell*> cells;
@@ -180,7 +184,7 @@ class ScopeVisitor final : public VNVisitor {
             = (m_aboveCellp ? static_cast<AstNode*>(m_aboveCellp) : static_cast<AstNode*>(nodep));
         m_scopep
             = new AstScope{abovep->fileline(), m_modp, scopename, m_aboveScopep, m_aboveCellp};
-        m_packageScopes.emplace(nodep, m_scopep);
+        m_classOrPackageScopes.emplace(nodep, m_scopep);
 
         // Create scope for the current usage of this cell
         AstNode::user1ClearTree();

test_regress/t/t_randomize_module_var.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2026 by Wilson Snyder. 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-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+import vltest_bootstrap
+
+test.scenarios('simulator')
+
+if not test.have_solver:
+    test.skip("No constraint solver installed")
+
+test.compile()
+
+test.execute()
+
+test.passes()

test_regress/t/t_randomize_module_var.v

@@ -0,0 +1,43 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2026 by PlanV GmbH.
+// SPDX-License-Identifier: CC0-1.0
+
+
+module t_randomize_module_var;
+   int golden_queue[$];
+
+   class Cls;
+      rand bit deq;
+      constraint valid_enq {
+         if (golden_queue.size() == 0) {deq == 0;}
+      }
+   endclass
+
+   Cls tr;
+
+   initial begin
+      tr = new;
+
+      // Test 1: Empty queue - deq must be 0
+      if (tr.randomize() == 0) begin
+         $stop;
+      end
+      if (tr.deq != 0) begin
+         $display("Error: Expected deq=0 when queue is empty, got %0d", tr.deq);
+         $stop;
+      end
+
+      // Test 2: Non-empty queue - deq can be 0 or 1
+      golden_queue.push_back(42);
+      if (tr.randomize() == 0) begin
+         $stop;
+      end
+      // deq can be 0 or 1, both are valid
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+
+endmodule