add struct field test

test_regress/t/t_class_lparam_struct_field_chain.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# 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-FileCopyrightText: 2026 Wilson Snyder
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+import vltest_bootstrap
+
+test.scenarios('simulator')
+
+test.compile(verilator_flags2=['--binary'])
+
+test.execute()
+
+test.passes()

test_regress/t/t_class_lparam_struct_field_chain.v

@@ -0,0 +1,65 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// Struct localparam field access via a class-scope Dot used in a cell
+// parameter pin (e.g. `CFG::cfg.jt.cam_type`), where CFG is a typedef
+// alias of a parameterized class.  V3LinkDot defers the `CFG::cfg` Dot
+// until post-V3Param; when the cell is deparameterized, resolveDotToTypedef
+// folds the class localparam to a Const and must then walk up the outer
+// `.field[.field...]` Dot chain, accumulating the packed-struct bit offset,
+// and replace the topmost Dot with a Sel(const, lsb, width) matching
+// V3Width::memberSelStruct.  Without this, the struct-field select on the
+// deferred class localparam cannot be constified for the cell pin.
+//
+// This file ONLY is placed under the Creative Commons Public Domain.
+// SPDX-FileCopyrightText: 2026 Wilson Snyder
+// SPDX-License-Identifier: CC0-1.0
+
+// verilog_format: off
+`define stop $stop
+`define checkh(gotv,expv) do if ((gotv) !== (expv)) begin $write("%%Error: %s:%0d:  got='h%x exp='h%x\n", `__FILE__,`__LINE__, (gotv), (expv)); `stop; end while(0)
+// verilog_format: on
+
+typedef struct packed {
+  logic [7:0] cam_type;
+  logic [7:0] depth;
+} inner_t;
+
+typedef struct packed {
+  inner_t     jt;
+  logic [7:0] tag;
+} cfg_t;
+
+class C #(parameter int W = 1);
+  // Struct localparam whose fields derive from the class parameter.
+  localparam cfg_t cfg = '{jt: '{cam_type: W[7:0], depth: W[7:0] + 8'd1},
+                           tag: W[7:0] + 8'd2};
+endclass
+
+module Sub #(parameter int WIDTH = 0) ();
+endmodule
+
+// Parameterized wrapper so the class specialization is deferred until
+// V3Param processes the cell instance.
+module Mid #(parameter int W = 8) ();
+  typedef C#(W) CFG;
+  // (1) single-level struct field access -> one loop iteration
+  Sub #(int'(CFG::cfg.tag)) u_tag ();
+  // (2) nested struct field access -> two loop iterations, lsb accumulation
+  Sub #(int'(CFG::cfg.jt.cam_type)) u_cam ();
+  Sub #(int'(CFG::cfg.jt.depth)) u_depth ();
+endmodule
+
+module t;
+  Mid #(.W(8)) u ();
+
+  initial begin
+    // cfg.tag = W + 2 = 10 (offset above the 16-bit jt struct)
+    `checkh(u.u_tag.WIDTH, 32'd10);
+    // cfg.jt.cam_type = W = 8 (nested, lsb 0)
+    `checkh(u.u_cam.WIDTH, 32'd8);
+    // cfg.jt.depth = W + 1 = 9 (nested, lsb 8)
+    `checkh(u.u_depth.WIDTH, 32'd9);
+    $write("*-* All Finished *-*\n");
+    $finish;
+  end
+endmodule