diff --git a/test_regress/t/t_castdyn.out b/test_regress/t/t_castdyn.out
index 8f9e32b5e..14761e02a 100644
--- a/test_regress/t/t_castdyn.out
+++ b/test_regress/t/t_castdyn.out
@@ -1,9 +1,29 @@
-%Error-UNSUPPORTED: t/t_castdyn.v:12:11: Unsupported: $cast. Suggest try static cast.
+%Error-UNSUPPORTED: t/t_castdyn.v:28:11: Unsupported: $cast. Suggest try static cast.
                                        : ... In instance t
-   12 |       i = $cast(a, b);
+   28 |       i = $cast(ao, a);
       |           ^~~~~
-%Error-UNSUPPORTED: t/t_castdyn.v:14:7: Unsupported: $cast. Suggest try static cast.
+%Error-UNSUPPORTED: t/t_castdyn.v:32:7: Unsupported: $cast. Suggest try static cast.
                                       : ... In instance t
-   14 |       $cast(a, b);
+   32 |       $cast(ao, a);
       |       ^~~~~
+%Error-UNSUPPORTED: t/t_castdyn.v:35:11: Unsupported: $cast. Suggest try static cast.
+                                       : ... In instance t
+   35 |       i = $cast(ao, 2.1 * 3.7);
+      |           ^~~~~
+%Error-UNSUPPORTED: t/t_castdyn.v:39:11: Unsupported: $cast. Suggest try static cast.
+                                       : ... In instance t
+   39 |       i = $cast(bo, null);
+      |           ^~~~~
+%Error-UNSUPPORTED: t/t_castdyn.v:45:11: Unsupported: $cast. Suggest try static cast.
+                                       : ... In instance t
+   45 |       i = $cast(bao, b);
+      |           ^~~~~
+%Error-UNSUPPORTED: t/t_castdyn.v:51:11: Unsupported: $cast. Suggest try static cast.
+                                       : ... In instance t
+   51 |       i = $cast(bbo, b);
+      |           ^~~~~
+%Error-UNSUPPORTED: t/t_castdyn.v:57:11: Unsupported: $cast. Suggest try static cast.
+                                       : ... In instance t
+   57 |       i = $cast(bao, b);
+      |           ^~~~~
 %Error: Exiting due to
diff --git a/test_regress/t/t_castdyn.v b/test_regress/t/t_castdyn.v
index 3fd235e82..2d788ca51 100644
--- a/test_regress/t/t_castdyn.v
+++ b/test_regress/t/t_castdyn.v
@@ -4,14 +4,59 @@
 // any use, without warranty, 2020 by Wilson Snyder.
 // SPDX-License-Identifier: CC0-1.0
 
+class Base;
+endclass
+class BasedA extends Base;
+endclass
+class BasedB extends Base;
+endclass
+
 module t (/*AUTOARG*/);
    int i;
    int a;
-   int b;
+   int ao;
+
+   Base b;
+   Base bo;
+   BasedA ba;
+   BasedA bao;
+   BasedB bb;
+   BasedB bbo;
+
    initial begin
-      i = $cast(a, b);
+      a = 1234;
+      i = $cast(ao, a);
       if (i != 1) $stop;
-      $cast(a, b);
+      if (ao != 1234) $stop;
+      a = 12345;
+      $cast(ao, a);
+      if (ao != 12345) $stop;
+
+      i = $cast(ao, 2.1 * 3.7);
+      if (i != 1) $stop;
+      if (ao != 8) $stop;
+
+      i = $cast(bo, null);
+      if (i != 1) $stop;
+      if (bo != null) $stop;
+
+      ba = new;
+      b = ba;
+      i = $cast(bao, b);
+      if (i != 1) $stop;
+      if (b != ba) $stop;
+
+      bb = new;
+      b = bb;
+      i = $cast(bbo, b);
+      if (i != 1) $stop;
+      if (b != bb) $stop;
+
+      bb = new;
+      b = b;
+      i = $cast(bao, b);
+      if (i != 0) $stop;
+
       $write("*-* All Finished *-*\n");
       $finish;
    end
diff --git a/test_regress/t/t_castdyn_bad.out b/test_regress/t/t_castdyn_bad.out
new file mode 100644
index 000000000..030a8b1ac
--- /dev/null
+++ b/test_regress/t/t_castdyn_bad.out
@@ -0,0 +1,9 @@
+%Error-UNSUPPORTED: t/t_castdyn_bad.v:20:11: Unsupported: $cast. Suggest try static cast.
+                                           : ... In instance t
+   20 |       i = $cast(c, b);
+      |           ^~~~~
+%Error-UNSUPPORTED: t/t_castdyn_bad.v:23:7: Unsupported: $cast. Suggest try static cast.
+                                          : ... In instance t
+   23 |       $cast(c, b);   
+      |       ^~~~~
+%Error: Exiting due to
diff --git a/test_regress/t/t_castdyn_bad.pl b/test_regress/t/t_castdyn_bad.pl
new file mode 100755
index 000000000..2ad4a887d
--- /dev/null
+++ b/test_regress/t/t_castdyn_bad.pl
@@ -0,0 +1,23 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2020 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(simulator => 1);
+
+compile(
+    fails => $Self->{vlt_all},
+    expect_filename => $Self->{golden_filename},
+    );
+
+execute(
+    check_finished => 1,
+    ) if !$Self->{vlt_all};
+
+ok(1);
+1;
diff --git a/test_regress/t/t_castdyn_bad.v b/test_regress/t/t_castdyn_bad.v
new file mode 100644
index 000000000..37fe1ec74
--- /dev/null
+++ b/test_regress/t/t_castdyn_bad.v
@@ -0,0 +1,28 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2020 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+class Base;
+endclass
+class C;
+endclass
+
+module t (/*AUTOARG*/);
+   int i;
+
+   Base b;
+   C c;
+
+   initial begin
+      b = new;
+      i = $cast(c, b);
+      if (i != 0) $stop;
+
+      $cast(c, b);  // Bad at runtime
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+endmodule