Parser: Move 'virtual class' block unsupported messages down out of parser

src/V3AstNodes.h

@@ -301,6 +301,7 @@ class AstClass : public AstNodeModule {
     // MEMBERS
     MemberNameMap m_members;  // Members or method children
     AstClassPackage* m_packagep;  // Class package this is under
+    bool m_virtual;  // Virtual class
     void insertCache(AstNode* nodep);
 
 public:
@@ -333,6 +334,8 @@ public:
         MemberNameMap::const_iterator it = m_members.find(name);
         return (it == m_members.end()) ? NULL : it->second;
     }
+    bool isVirtual() const { return m_virtual; }
+    void isVirtual(bool flag) { m_virtual = flag; }
 };
 
 class AstClassExtends : public AstNode {

src/V3Width.cpp

@@ -1962,6 +1962,7 @@ private:
     virtual void visit(AstClass* nodep) VL_OVERRIDE {
         if (nodep->didWidthAndSet()) return;
         userIterateChildren(nodep, NULL);  // First size all members
+        if (nodep->isVirtual()) nodep->v3warn(E_UNSUPPORTED, "Unsupported: virtual class");
         nodep->repairCache();
     }
     virtual void visit(AstClassRefDType* nodep) VL_OVERRIDE {

src/verilog.y

@@ -5804,6 +5804,7 @@ class_declaration<nodep>:	// ==IEEE: part of class_declaration
 classFront<classp>:		// IEEE: part of class_declaration
 		classVirtualE yCLASS lifetimeE idAny/*class_identifier*/
 			{ $$ = new AstClass($2, *$4);
+			  $$->isVirtual($1);
 			  $$->lifetime($3);
 			  SYMP->pushNew($<classp>$); }
 	//			// IEEE: part of interface_class_declaration
@@ -5814,9 +5815,9 @@ classFront<classp>:		// IEEE: part of class_declaration
 			  BBUNSUP($2, "Unsupported: interface classes");  }
 	;
 
-classVirtualE:
-		/* empty */				{ }
-	|	yVIRTUAL__CLASS				{ BBUNSUP($1, "Unsupported: virtual classes"); }
+classVirtualE<cbool>:
+		/* empty */				{ $$ = false; }
+	|	yVIRTUAL__CLASS				{ $$ = true; }
 	;
 
 classExtendsE<nodep>:		// IEEE: part of class_declaration

test_regress/t/t_class_unsup_bad.out

@@ -22,9 +22,6 @@
 %Error-UNSUPPORTED: t/t_class_unsup_bad.v:29:4: Unsupported: extern class method prototype
    29 |    extern task exttask;
       |    ^~~~~~
-%Error-UNSUPPORTED: t/t_class_unsup_bad.v:32:1: Unsupported: virtual classes
-   32 | virtual class VC;
-      | ^~~~~~~
 %Error-UNSUPPORTED: t/t_class_unsup_bad.v:42:4: Unsupported: virtual class member qualifier
    42 |    virtual function uvm_root get_root();
       |    ^~~~~~~

test_regress/t/t_class_virtual.out

@@ -0,0 +1,4 @@
+%Error-UNSUPPORTED: t/t_class_virtual.v:7:9: Unsupported: virtual class
+    7 | virtual class VC;
+      |         ^~~~~
+%Error: Exiting due to

test_regress/t/t_class_virtual.pl

@@ -0,0 +1,19 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2020 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(vlt => 1);
+
+lint(
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;

test_regress/t/t_class_virtual.v

@@ -0,0 +1,8 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2019 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+virtual class VC;
+endclass

test_regress/t/t_class_vparam_unsup.out

@@ -1,6 +1,3 @@
-%Error-UNSUPPORTED: t/t_class_vparam_unsup.v:12:1: Unsupported: virtual classes
-   12 | virtual class vclass #(type CTYPE_t = arg_class_t);
-      | ^~~~~~~
 %Error-UNSUPPORTED: t/t_class_vparam_unsup.v:13:58: Unsupported: Parameter classes
    13 |    pure virtual function void funcname(paramed_class_t #(CTYPE_t) v);
       |                                                          ^~~~~~~