From ed268805ceaa4bf6cc6c64c5f5bb9d467d3bf317 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Fri, 27 Nov 2020 19:53:04 -0500
Subject: [PATCH] Lint check for pure virtual in non-virtual class.

---
 src/V3WidthCommit.h                         |  9 +++++++++
 test_regress/t/t_class_virtual_pure.out     |  7 -------
 test_regress/t/t_class_virtual_pure_bad.out |  4 ++++
 test_regress/t/t_class_virtual_pure_bad.pl  | 19 +++++++++++++++++++
 test_regress/t/t_class_virtual_pure_bad.v   |  9 +++++++++
 5 files changed, 41 insertions(+), 7 deletions(-)
 delete mode 100644 test_regress/t/t_class_virtual_pure.out
 create mode 100644 test_regress/t/t_class_virtual_pure_bad.out
 create mode 100755 test_regress/t/t_class_virtual_pure_bad.pl
 create mode 100644 test_regress/t/t_class_virtual_pure_bad.v

diff --git a/src/V3WidthCommit.h b/src/V3WidthCommit.h
index 3abe211ba..52344c197 100644
--- a/src/V3WidthCommit.h
+++ b/src/V3WidthCommit.h
@@ -205,6 +205,15 @@ private:
         nodep->virtRefDTypep(editOneDType(nodep->virtRefDTypep()));
         nodep->virtRefDType2p(editOneDType(nodep->virtRefDType2p()));
     }
+    virtual void visit(AstNodeFTask* nodep) override {
+        iterateChildren(nodep);
+        editDType(nodep);
+        if (nodep->classMethod() && nodep->pureVirtual() && VN_IS(m_modp, Class)
+            && !VN_CAST(m_modp, Class)->isVirtual()) {
+            nodep->v3error(
+                "Illegal to have 'pure virtual' in non-virtual class (IEEE 1800-2017 8.21)");
+        }
+    }
     virtual void visit(AstNodeVarRef* nodep) override {
         iterateChildren(nodep);
         editDType(nodep);
diff --git a/test_regress/t/t_class_virtual_pure.out b/test_regress/t/t_class_virtual_pure.out
deleted file mode 100644
index ec7ef63ac..000000000
--- a/test_regress/t/t_class_virtual_pure.out
+++ /dev/null
@@ -1,7 +0,0 @@
-%Error-UNSUPPORTED: t/t_class_virtual_pure.v:8:22: Unsupported: 'virtual' class method
-    8 |    pure virtual task hello();
-      |                      ^~~~~
-%Error-UNSUPPORTED: t/t_class_virtual_pure.v:7:9: Unsupported: virtual class
-    7 | virtual class VC;
-      |         ^~~~~
-%Error: Exiting due to
diff --git a/test_regress/t/t_class_virtual_pure_bad.out b/test_regress/t/t_class_virtual_pure_bad.out
new file mode 100644
index 000000000..067482f2b
--- /dev/null
+++ b/test_regress/t/t_class_virtual_pure_bad.out
@@ -0,0 +1,4 @@
+%Error: t/t_class_virtual_pure_bad.v:8:22: Illegal to have 'pure virtual' in non-virtual class (IEEE 1800-2017 8.21)
+    8 |    pure virtual task pure_task;
+      |                      ^~~~~~~~~
+%Error: Exiting due to
diff --git a/test_regress/t/t_class_virtual_pure_bad.pl b/test_regress/t/t_class_virtual_pure_bad.pl
new file mode 100755
index 000000000..009248fc5
--- /dev/null
+++ b/test_regress/t/t_class_virtual_pure_bad.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;
diff --git a/test_regress/t/t_class_virtual_pure_bad.v b/test_regress/t/t_class_virtual_pure_bad.v
new file mode 100644
index 000000000..7b3754db3
--- /dev/null
+++ b/test_regress/t/t_class_virtual_pure_bad.v
@@ -0,0 +1,9 @@
+// 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
+
+class VBase;
+   pure virtual task pure_task;
+endclass