Add lint error on importing package within a class (#5634) (#5679)

docs/CONTRIBUTORS

@@ -159,6 +159,7 @@ Nandu Raj
 Nathan Graybeal
 Nathan Kohagen
 Nathan Myers
+Nick Brereton
 Nolan Poe
 Oleh Maksymenko
 Patrick Stewart

src/V3LinkParse.cpp

@@ -893,6 +893,13 @@ class LinkParseVisitor final : public VNVisitor {
         }
         iterateChildren(nodep);
     }
+    void visit(AstPackageImport* nodep) override {
+        cleanFileline(nodep);
+        if (m_modp && !m_ftaskp && VN_IS(m_modp, Class)) {
+            nodep->v3error("Import statement directly within a class scope is illegal");
+        }
+        iterateChildren(nodep);
+    }
 
     void visit(AstNode* nodep) override {
         // Default: Just iterate

test_regress/t/t_class_scope_import.out

@@ -0,0 +1,4 @@
+%Error: t/t_class_scope_import.v:11:14: Import statement directly within a class scope is illegal
+   11 |    import pkg::*;
+      |              ^~
+%Error: Exiting due to

test_regress/t/t_class_scope_import.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2025 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_scope_import.v

@@ -0,0 +1,15 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2025 by Wilson Snyder
+// SPDX-License-Identifier: CC0-1.0
+
+package pkg;
+endpackage
+
+class genericClass;
+   import pkg::*;
+endclass
+
+module tb_top();
+endmodule

test_regress/t/t_queue_unknown_sel.v

@@ -262,23 +262,22 @@ interface z_if;
                      );
 endinterface
 class z_txn_class;
-   import z_pkg::*;
-   rand txn_type_t   req_txn_type;
-   rand cid_t        cid;
-   rand sid_t        sid;
-   rand ctag_t       ctag;
-   rand stag_t       stag;
-   rand size_t       size;
-   rand address_t    address;
-   rand state_t   state1;
-   rand state_t   state2;
-   rand state_t   state3;
+   rand z_pkg::txn_type_t   req_txn_type;
+   rand z_pkg::cid_t        cid;
+   rand z_pkg::sid_t        sid;
+   rand z_pkg::ctag_t       ctag;
+   rand z_pkg::stag_t       stag;
+   rand z_pkg::size_t       size;
+   rand z_pkg::address_t    address;
+   rand z_pkg::state_t      state1;
+   rand z_pkg::state_t      state2;
+   rand z_pkg::state_t      state3;
    rand logic               f1;
    rand logic               f2;
    rand logic               f3;
    rand logic               f4;
-   data_t            data[];
-   mask_t            mask[];
+   z_pkg::data_t            data[];
+   z_pkg::mask_t            mask[];
    bit                      corrupt[];
    logic [2:0]              req_opcode;
 endclass