diff --git a/parse.y b/parse.y
index cc87a0f34..d160c3725 100644
--- a/parse.y
+++ b/parse.y
@@ -5550,9 +5550,9 @@ parameter_assign_list
   ;
 
 parameter_assign
-  : IDENTIFIER initializer_opt parameter_value_ranges_opt
+  : IDENTIFIER dimensions_opt initializer_opt parameter_value_ranges_opt
       { pform_set_parameter(@1, lex_strings.make($1), param_is_local,
-			    param_is_type, param_data_type, $2, $3);
+			    param_is_type, param_data_type, $2, $3, $4);
 	delete[]$1;
       }
   ;
diff --git a/pform.cc b/pform.cc
index b1fd68b1e..3be307d85 100644
--- a/pform.cc
+++ b/pform.cc
@@ -2896,8 +2896,8 @@ static void pform_set_type_parameter(const struct vlltype&loc, perm_string name,
 
 void pform_set_parameter(const struct vlltype&loc,
 			 perm_string name, bool is_local, bool is_type,
-			 data_type_t*data_type, PExpr*expr,
-			 LexicalScope::range_t*value_range)
+			 data_type_t*data_type, list<pform_range_t>*udims,
+			 PExpr*expr, LexicalScope::range_t*value_range)
 {
       LexicalScope*scope = lexical_scope;
       if (is_compilation_unit(scope) && !gn_system_verilog()) {
@@ -2925,6 +2925,13 @@ void pform_set_parameter(const struct vlltype&loc,
 	    return;
       }
 
+      if (udims) {
+	    if (pform_requires_sv(loc, "unpacked array parameter")) {
+		  VLerror(loc, "sorry: unpacked array parameters are not supported yet.");
+	    }
+	    return;
+      }
+
       bool overridable = !is_local;
 
       if (scope == pform_cur_generate && !is_local) {
diff --git a/pform.h b/pform.h
index 127f503f1..64e23972b 100644
--- a/pform.h
+++ b/pform.h
@@ -1,7 +1,7 @@
 #ifndef IVL_pform_H
 #define IVL_pform_H
 /*
- * Copyright (c) 1998-2021 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 1998-2024 Stephen Williams (steve@icarus.com)
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -403,7 +403,7 @@ extern LexicalScope::range_t* pform_parameter_value_range(bool exclude_flag,
 extern void pform_set_parameter(const struct vlltype&loc,
 				perm_string name,
 				bool is_local, bool is_type,
-				data_type_t*data_type,
+				data_type_t*data_type, std::list<pform_range_t>*udims,
 				PExpr*expr, LexicalScope::range_t*value_range);
 extern void pform_set_specparam(const struct vlltype&loc,
 				 perm_string name,