Fix reference to extended class in parameterized class (#4466).

Changes

@@ -32,6 +32,7 @@ Verilator 5.015 devel
 * Fix internal error on real conversion (#4447). [vdhotre-ventana]
 * Fix lifetime unknown error on enum.name (#4448). [jwoutersymatra]
 * Fix error on enum with VARHIDDEN of cell (#4482). [Michail Rontionov]
+* Fix reference to extended class in parameterized class (#4466).
 * Fix display %x formatting of real.
 * Fix mis-warning on #() in classes' own functions.
 

src/V3LinkDot.cpp

@@ -2251,6 +2251,15 @@ private:
         if (baseClassp->isInterfaceClass()) importImplementsClass(nodep, srcp, baseClassp);
         if (!cextp->isImplements()) m_curSymp->importFromClass(m_statep->symsp(), srcp);
     }
+    void classExtendImport(AstClass* nodep) {
+        // A class reference might be to a class that is later in Ast due to
+        // e.g. parmaeterization or referring to a "class (type T) extends T"
+        // Resolve it so later Class:: references into its base classes work
+        VL_RESTORER(m_ds);
+        VSymEnt* const srcp = m_statep->getNodeSym(nodep);
+        m_ds.init(srcp);
+        iterate(nodep);
+    }
     bool checkPinRef(AstPin* pinp, VVarType refVarType) {
         // In instantiations of modules/ifaces, we shouldn't connect port pins to submodule's
         // parameters or vice versa
@@ -2901,12 +2910,14 @@ private:
         if (nodep->classOrPackagep()) {
             m_pinSymp = m_statep->getNodeSym(nodep->classOrPackagep());
         }
+        AstClass* const refClassp = VN_CAST(nodep->classOrPackagep(), Class);
+        // Make sure any extends() are properly imported within referenced class
+        if (refClassp && !m_statep->forPrimary()) classExtendImport(refClassp);
+
         m_ds.init(m_curSymp);
         UINFO(4, "(Backto) Link ClassOrPackageRef: " << nodep << endl);
-
         iterateChildren(nodep);
 
-        AstClass* const refClassp = VN_CAST(nodep->classOrPackagep(), Class);
         AstClass* const modClassp = VN_CAST(m_modp, Class);
         if (m_statep->forPrimary() && refClassp && !nodep->paramsp()
             && nodep->classOrPackagep()->hasGParam()
@@ -3511,6 +3522,8 @@ private:
                     // Already converted. Update symbol table to link unlinked members.
                     // Base class has to be visited in a case if its extends statement
                     // needs to be handled. Recursive inheritance was already checked.
+                    // Must be here instead of in LinkDotParam to handle
+                    // "class (type T) extends T".
                     if (baseClassp == nodep) {
                         cextp->v3error("Attempting to extend class " << nodep->prettyNameQ()
                                                                      << " from itself");

test_regress/t/t_class_param_extends3.pl

@@ -0,0 +1,21 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2023 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
+
+scenarios(simulator => 1);
+
+compile(
+    );
+
+execute(
+    check_finished => 1,
+    );
+
+ok(1);
+1;

test_regress/t/t_class_param_extends3.v

@@ -0,0 +1,63 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2023 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+package u_pkg;
+   typedef class u_report_object;
+   typedef class u_callback;
+
+   virtual class u_object;
+   endclass
+
+   class u_queue #(type T=int) extends u_object;
+      int m_value = 6;
+   endclass
+
+   class u_callbacks_base extends u_object;
+      typedef u_callbacks_base this_type;
+   endclass
+
+   class u_typed_callbacks#(type T=u_object) extends u_callbacks_base;
+      typedef u_typed_callbacks#(T) this_type;
+      static this_type m_t_inst;
+      static u_queue#(u_callback) m_tw_cb_q;
+   endclass
+
+   class u_callbacks #(type T=u_object, type CB=u_callback)
+      extends u_typed_callbacks#(T);
+      static function bit m_register_pair();
+      endfunction
+      static function void add(u_callback cb);
+         u_queue#(u_callback) qr;
+         qr = u_callbacks#(u_report_object,u_callback)::m_t_inst.m_tw_cb_q;  //<<<<
+         if (qr.m_value != 6) $stop;
+      endfunction
+   endclass
+
+   class u_callback extends u_object;
+   endclass
+
+   virtual class u_report_catcher extends u_callback;
+      static local bit m_register_cb_u_report_catcher = u_callbacks#(u_report_object,u_report_catcher)::m_register_pair();
+   endclass
+
+   // Having this class (versus using #(u_object) is needed to hit the bug
+   class u_report_object extends u_object;
+   endclass
+
+endpackage
+
+module t;
+
+   u_pkg::u_callback cb;
+
+   initial begin
+      cb = new;
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+
+endmodule