Add error when accessing a non-static class field from a static function (#6948)

src/V3Width.cpp

@@ -2770,6 +2770,12 @@ class WidthVisitor final : public VNVisitor {
                                               << nodep->prettyNameQ()
                                               << " (IEEE 1800-2023 6.20.6)");
         }
+        if (nodep->varp()->isClassMember() && !nodep->varp()->isFuncLocal()
+            && !nodep->varp()->lifetime().isStatic() && m_ftaskp && m_ftaskp->isStatic()) {
+            nodep->v3error("Cannot access non-static member variable "
+                           << nodep->prettyNameQ() << " from a static method "
+                           << m_ftaskp->prettyNameQ() << " without object (IEEE 1800-2023 8.10)");
+        }
         nodep->didWidth(true);
     }
 
@@ -3309,6 +3315,10 @@ class WidthVisitor final : public VNVisitor {
     void visit(AstThisRef* nodep) override {
         if (nodep->didWidthAndSet()) return;
         nodep->dtypep(iterateEditMoveDTypep(nodep, nodep->childDTypep()));
+        if (m_ftaskp && m_ftaskp->isStatic()) {
+            nodep->v3error("Cannot use 'this' in a static method "
+                           << m_ftaskp->prettyNameQ() << " (IEEE 1800-2023 8.10-8.11)");
+        }
     }
     void visit(AstClassRefDType* nodep) override {
         if (nodep->didWidthAndSet()) return;

test_regress/t/t_class_static_member_bad.out

@@ -0,0 +1,8 @@
+%Error: t/t_class_static_member_bad.v:10:11: Cannot access non-static member variable 'mb' from a static method 'foo' without object (IEEE 1800-2023 8.10)
+   10 |     void'(mb.try_put(this));
+      |           ^~
+        ... See the manual at https://verilator.org/verilator_doc.html?v=latest for more assistance.
+%Error: t/t_class_static_member_bad.v:10:22: Cannot use 'this' in a static method 'foo' (IEEE 1800-2023 8.10-8.11)
+   10 |     void'(mb.try_put(this));
+      |                      ^~~~
+%Error: Exiting due to

test_regress/t/t_class_static_member_bad.py

@@ -0,0 +1,16 @@
+#!/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('linter')
+
+test.lint(fails=True, expect_filename=test.golden_filename)
+
+test.passes()

test_regress/t/t_class_static_member_bad.v

@@ -0,0 +1,12 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2026 by Antmicro.
+// SPDX-License-Identifier: CC0-1.0
+
+class Cls;
+  mailbox #(Cls) mb = new();
+  static task foo();
+    void'(mb.try_put(this));
+  endtask
+endclass