diff --git a/test_regress/t/t_func_nba.py b/test_regress/t/t_func_nba.py
new file mode 100755
index 000000000..70066470e
--- /dev/null
+++ b/test_regress/t/t_func_nba.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: 2024 Wilson Snyder
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+import vltest_bootstrap
+
+test.scenarios("simulator")
+
+test.compile(timing_loop=True, verilator_flags2=["--trace", "--timing"])
+
+test.execute()
+
+test.passes()
diff --git a/test_regress/t/t_func_nba.v b/test_regress/t/t_func_nba.v
new file mode 100644
index 000000000..5c5dd10c2
--- /dev/null
+++ b/test_regress/t/t_func_nba.v
@@ -0,0 +1,72 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain.
+// SPDX-FileCopyrightText: 2026 Wilson Snyder
+// SPDX-License-Identifier: CC0-1.0
+
+
+interface intf
+(
+    input logic clk
+);
+    logic       blargh /*verilator isolate_assignments*/;
+    int data;
+    modport sink (
+        input   clk,
+        output  blargh,
+        input   data
+    );
+    modport source (
+        input clk, blargh,
+        output data
+    );
+endinterface
+
+module sub
+(
+    intf.sink intf_a,
+    intf.source  intf_b
+);
+    function automatic logic ident_func(logic arg);
+        return arg;
+    endfunction
+    function automatic logic other_func();
+    endfunction
+    wire bar /* verilator public */;
+    always_ff @(posedge intf_a.clk) begin
+            intf_a.blargh <= '1;
+            if (other_func()) begin
+            end
+            if (ident_func(intf_a.data[0])) begin
+                intf_b.data <= '1;
+                intf_a.blargh <= '0;
+            end
+    end
+endmodule
+
+module t();
+    logic clk;
+    intf intf_b (.*);
+    intf intf_a (.*);
+    sub the_sub (.*);
+
+    initial begin
+        clk = '0;
+        #10;
+        clk = ~clk;
+        #10;
+        if (!intf_a.blargh) $stop;
+        clk = ~clk;
+        intf_a.data = '1;
+        #10;
+        clk = ~clk;
+        #10;
+        clk = ~clk;
+        #10;
+        if (intf_a.blargh) $stop;
+        clk = ~clk;
+        #10;
+            $write("*-* All Finished *-*\n");
+            $finish;
+    end
+endmodule