From da043ca16d74d67f6b23f4c2a76496d294cadb58 Mon Sep 17 00:00:00 2001
From: Ryszard Rozak <rrozak@antmicro.com>
Date: Fri, 7 Jul 2023 13:20:23 +0200
Subject: [PATCH] Fix comparison of class objects (#4346)

---
 include/verilated_types.h        | 10 ++++++++--
 test_regress/t/t_class_compare.v |  9 +++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/include/verilated_types.h b/include/verilated_types.h
index 5d5c41db2..6a77768c3 100644
--- a/include/verilated_types.h
+++ b/include/verilated_types.h
@@ -1508,8 +1508,14 @@ public:
     // For 'if (ptr)...'
     operator bool() const { return m_objp; }
     // In SV A == B iff both are handles to the same object (IEEE 1800-2017 8.4)
-    bool operator==(const VlClassRef& rhs) const { return m_objp == rhs.m_objp; };
-    bool operator!=(const VlClassRef& rhs) const { return m_objp != rhs.m_objp; };
+    template <typename T_OtherClass>
+    bool operator==(const VlClassRef<T_OtherClass>& rhs) const {
+        return m_objp == rhs.m_objp;
+    };
+    template <typename T_OtherClass>
+    bool operator!=(const VlClassRef<T_OtherClass>& rhs) const {
+        return m_objp != rhs.m_objp;
+    };
 };
 
 template <typename T, typename U>
diff --git a/test_regress/t/t_class_compare.v b/test_regress/t/t_class_compare.v
index ee4826725..bcbb1842a 100644
--- a/test_regress/t/t_class_compare.v
+++ b/test_regress/t/t_class_compare.v
@@ -14,13 +14,22 @@ class Cls;
    int i;
 endclass
 
+class ExtendCls extends Cls;
+endclass
+
 module t;
    initial begin
       Cls a = new;
       Cls b = new;
+      ExtendCls ext = new;
       `check_ne(a, b)
+      `check_ne(a, ext)
+      `check_ne(ext, a)
       a = b;
       `check_eq(a, b)
+      a = ext;
+      `check_eq(a, ext)
+      `check_eq(ext, a)
       $write("*-* All Finished *-*\n");
       $finish;
    end