// DESCRIPTION: Verilator: Hierarchical interface pass-through with FUNCREF LPARAMs
//
// 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

// verilog_format: off
`define stop $stop
`define checkd(gotv,expv) do if ((gotv) !== (expv)) begin $write("%%Error: %s:%0d:  got=%0d exp=%0d (%s !== %s)\n", `__FILE__,`__LINE__, (gotv), (expv), `"gotv`", `"expv`"); `stop; end while(0);
// verilog_format: on

package pkg;
  function automatic int decode_width(int value);
    return (value > 0) ? value * 2 : 0;
  endfunction
endpackage

interface ifc #(
    parameter int WIDTH = 8
);
  localparam int DEPTH = $clog2(WIDTH);
  localparam int DECODED = pkg::decode_width(DEPTH);
endinterface

// Leaf module: uses interface LPARAM in a FUNCREF-based localparam
module leaf (
    ifc i
);
  localparam int BUF_SIZE = pkg::decode_width(i.DEPTH);
  localparam int OUT_W = i.DECODED + 1;
endmodule

// Intermediate wrapper: passes interface through to leaf
module wrapper (
    ifc i
);
  leaf u_leaf (.i);
endmodule

// Second level wrapper: adds another layer of hierarchy
module subsystem (
    ifc bus
);
  wrapper u_wrap (.i(bus));
endmodule

module t;
  ifc #(.WIDTH(64)) bus ();
  subsystem u_sub (.bus);

  initial begin
    // WIDTH=64, DEPTH=$clog2(64)=6, DECODED=decode_width(6)=12
    `checkd(u_sub.u_wrap.u_leaf.BUF_SIZE, 12);  // decode_width(6) = 12
    `checkd(u_sub.u_wrap.u_leaf.OUT_W, 13);  // 12 + 1 = 13
    $write("*-* All Finished *-*\n");
    $finish;
  end
endmodule