Fix interface parameters used in loop generate constructs (#4664) (#4665)

src/V3Param.cpp

@@ -1313,6 +1313,10 @@ class ParamVisitor final : public VNVisitor {
             // so process here rather than at the generate to avoid iteration problems
             UINFO(9, "  BEGIN " << nodep << endl);
             UINFO(9, "  GENFOR " << forp << endl);
+            // Visit child nodes before unrolling
+            iterateAndNextNull(forp->initsp());
+            iterateAndNextNull(forp->condp());
+            iterateAndNextNull(forp->incsp());
             V3Width::widthParamsEdit(forp);  // Param typed widthing will NOT recurse the body
             // Outer wrapper around generate used to hold genvar, and to ensure genvar
             // doesn't conflict in V3LinkDot resolution with other genvars

test_regress/t/t_interface_param_genblk.out

@@ -0,0 +1,24 @@
+-Info: t/t_interface_param_genblk.v:35:9: correct
+                                        : ... note: In instance 't.i_sub'
+   35 |         $info("correct");
+      |         ^~~~~
+-Info: t/t_interface_param_genblk.v:44:13: i = 98, j = 2
+                                         : ... note: In instance 't.i_sub'
+   44 |             $info("i = %0d, j = %0d", i, j);
+      |             ^~~~~
+-Info: t/t_interface_param_genblk.v:44:13: i = 98, j = 1
+                                         : ... note: In instance 't.i_sub'
+   44 |             $info("i = %0d, j = %0d", i, j);
+      |             ^~~~~
+-Info: t/t_interface_param_genblk.v:44:13: i = 100, j = 2
+                                         : ... note: In instance 't.i_sub'
+   44 |             $info("i = %0d, j = %0d", i, j);
+      |             ^~~~~
+-Info: t/t_interface_param_genblk.v:44:13: i = 100, j = 1
+                                         : ... note: In instance 't.i_sub'
+   44 |             $info("i = %0d, j = %0d", i, j);
+      |             ^~~~~
+-Info: t/t_interface_param_genblk.v:50:26: correct
+                                         : ... note: In instance 't.i_sub'
+   50 |         intf.B * 50:     $info("correct");
+      |                          ^~~~~

test_regress/t/t_interface_param_genblk.pl

@@ -0,0 +1,18 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 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(linter => 1);
+
+lint(
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;

test_regress/t/t_interface_param_genblk.v

@@ -0,0 +1,54 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2023 by Anthony Donlon.
+// SPDX-License-Identifier: CC0-1.0
+
+// See #4664
+
+interface intf #(
+    parameter A = 10
+);
+    localparam B = A / A + 1; // 2
+
+    logic [A/10-1:0] sig;
+endinterface
+
+module t;
+    intf #(
+        .A(100)
+    ) intf();
+
+    sub i_sub (
+        .intf
+    );
+endmodule
+
+module sub (
+    intf intf
+);
+
+    if (intf.A == 10) begin
+        $error("incorrect");
+    end else if (intf.A / intf.B == 50) begin
+    // end else if (intf.A / $bits(intf.sig) == 10) begin // TODO: support this
+        $info("correct");
+    end else begin
+        $error("incorrect");
+    end
+
+    for (genvar i = intf.A - 2; i < intf.A + 1; i += intf.B) begin
+        for (genvar j = intf.B; j > intf.A - 100; j--) begin
+            if (i < intf.A - 2) $error("error");
+            if (i > intf.A)     $error("error");
+            $info("i = %0d, j = %0d", i, j);
+        end
+    end
+
+    case (intf.A)
+        10, intf.A - 10: $error("incorrect");
+        intf.B * 50:     $info("correct");
+        30:              $error("incorrect");
+        default:         $error("incorrect");
+    endcase
+endmodule