From a9ef4b3ff1d137324be4b97b2402fcb86e03efa8 Mon Sep 17 00:00:00 2001
From: Luca Colagrande <bigcola.96@gmail.com>
Date: Wed, 17 Dec 2025 00:08:49 +0100
Subject: [PATCH] Fix nested struct within parameter port list (#6818) (#6824)

---
 src/V3LinkParse.cpp            |  8 +++++---
 test_regress/t/t_param_type5.v | 23 +++++++++++++++++------
 2 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/src/V3LinkParse.cpp b/src/V3LinkParse.cpp
index 24330dacd..e748ddcab 100644
--- a/src/V3LinkParse.cpp
+++ b/src/V3LinkParse.cpp
@@ -583,16 +583,18 @@ class LinkParseVisitor final : public VNVisitor {
             UINFO(9, "Reused impltypedef " << nodep << "  -->  " << defp);
         } else {
             // Definition must be inserted right after the variable (etc) that needed it
-            // AstVar, AstTypedef, AstNodeFTask are common containers
+            // AstVar, AstTypedef, AstNodeFTask, AstParamTypeDType are common containers
             AstNode* backp = nodep->backp();
             for (; backp; backp = backp->backp()) {
-                if (VN_IS(backp, Var) || VN_IS(backp, Typedef) || VN_IS(backp, NodeFTask)) break;
+                if (VN_IS(backp, Var) || VN_IS(backp, Typedef) || VN_IS(backp, NodeFTask)
+                    || VN_IS(backp, ParamTypeDType))
+                    break;
             }
             UASSERT_OBJ(backp, nodep,
                         "Implicit enum/struct type created under unexpected node type");
             AstNodeDType* const dtypep = nodep->childDTypep();
             dtypep->unlinkFrBack();
-            if (VN_IS(backp, Typedef)) {
+            if (VN_IS(backp, Typedef) || VN_IS(backp, ParamTypeDType)) {
                 // A typedef doesn't need us to make yet another level of typedefing
                 // For typedefs just remove the AstRefDType level of abstraction
                 nodep->replaceWith(dtypep);
diff --git a/test_regress/t/t_param_type5.v b/test_regress/t/t_param_type5.v
index cd73625c7..3744262e4 100644
--- a/test_regress/t/t_param_type5.v
+++ b/test_regress/t/t_param_type5.v
@@ -7,20 +7,31 @@
 class ParamClass #(string P = "ABC", R = "GDF");
 endclass
 
-module t #(parameter int A = 0, B = 1, C = 2, type D = int, E = string);
-   parameter bit F = 1'b0, G = 1'b1;
-   parameter type H = int, I = string;
+module t #(
+   parameter int A = 0, B = 1, C = 2, type D = int, E = string, F =
+      struct packed {
+         struct packed {
+            logic a;
+         } b;
+      }
+);
+   parameter bit G = 1'b0, H = 1'b1;
+   parameter type I = int, J = string;
    E str1 = "abc";
-   I str2 = "";
+   J str2 = "";
+
+   F struct1;
+   assign struct1.b.a = 1'b1;
+
    initial begin
       automatic ParamClass param_class = new;
       if ($typename(B) != "int") $stop;
       if ($typename(C) != "int") $stop;
       if (str1.len() != 3) $stop;
-      if ($typename(G) != "bit") $stop;
+      if ($typename(H) != "bit") $stop;
       if (str2.len() != 0) $stop;
       if ($typename(param_class.R) != "string") $stop;
-
+      if ($typename(struct1.b.a) != "MEMBERDTYPE 'a'") $stop;
       $write("*-* All Finished *-*\n");
       $finish;
    end