diff --git a/Changes b/Changes
index c243887f5..bc7597e37 100644
--- a/Changes
+++ b/Changes
@@ -50,7 +50,7 @@ Verilator 5.041 devel
 * Fix external function declarations with class typedef references (#6433).
 * Fix internal error on out-of-bounds real array access.
 * Fix pre/post increments in assertions (#6434).
-* Fix elaboration displays with `%m` (#6445). [Alex Solomatnikov]
+* Fix elaboration displays with `%m` and some `%p` (#6445) (#6451). [Alex Solomatnikov]
 * Fix false unique assertions on `else ;` (#6450). [Don Owen]
 
 
diff --git a/src/V3Const.cpp b/src/V3Const.cpp
index c00543b0f..b4b0e1308 100644
--- a/src/V3Const.cpp
+++ b/src/V3Const.cpp
@@ -3606,6 +3606,7 @@ class ConstVisitor final : public VNVisitor {
     //                $accessor_name, ...
     //                             # .castFoo is the test VN_IS(object,Foo)
     //                             # ,, gets replaced with a , rather than &&
+    //                DISABLE_BASE # Turnes off checking Ast's base class treeops
     //               }"            # bracket not paren
     //    ,"what to call"
     //
@@ -3920,6 +3921,7 @@ class ConstVisitor final : public VNVisitor {
     TREEOPA("AstPutcN{$lhsp.castConst, $rhsp.castConst, $thsp.castConst}",  "replaceConst(nodep)");
     TREEOPA("AstSubstrN{$lhsp.castConst, $rhsp.castConst, $thsp.castConst}",  "replaceConst(nodep)");
     TREEOPA("AstCvtPackString{$lhsp.castConst}", "replaceConstString(nodep, VN_AS(nodep->lhsp(), Const)->num().toString())");
+    TREEOP ("AstToStringN{DISABLE_BASE}", "DONE");  // Avoid uniop(const); use matchToStringNConst
     TREEOP ("AstToStringN{matchToStringNConst(nodep)}", "DONE");
     // Custom
     // Implied by AstIsUnbounded::numberOperate: V("AstIsUnbounded{$lhsp.castConst}", "replaceNum(nodep, 0)");
diff --git a/src/V3Width.cpp b/src/V3Width.cpp
index c99024b8c..a8a3691ec 100644
--- a/src/V3Width.cpp
+++ b/src/V3Width.cpp
@@ -4554,7 +4554,7 @@ class WidthVisitor final : public VNVisitor {
             } else if (nodep->name() == "atoreal") {
                 fmt = AstAtoN::ATOREAL;
             } else {
-                V3ERROR_NA;
+                nodep->v3fatalSrc("Bad case");
                 fmt = AstAtoN::ATOI;
             }  // dummy assignment to suppress compiler warning
             methodOkArguments(nodep, 0, 0);
diff --git a/src/astgen b/src/astgen
index 2f1140d0f..b0f14d728 100755
--- a/src/astgen
+++ b/src/astgen
@@ -21,6 +21,7 @@ class Node:
         self._subClasses = []  # Initially list, but tuple after completion
         self._allSuperClasses = None  # Computed on demand after completion
         self._allSubClasses = None  # Computed on demand after completion
+        self._disableBase = False  # Skip base class const checking
         self._typeId = None  # Concrete type identifier number for leaf classes
         self._typeIdMin = None  # Lowest type identifier number for class
         self._typeIdMax = None  # Highest type identifier number for class
@@ -47,6 +48,13 @@ class Node:
     def isCompleted(self):
         return isinstance(self._subClasses, tuple)
 
+    @property
+    def disableBase(self):
+        return self._disableBase
+
+    def disableBaseSet(self):
+        self._disableBase = True
+
     @property
     def file(self):
         return self._file
@@ -301,11 +309,15 @@ class Cpt:
                 mif = "m_doV"
             else:
                 self.error("Unknown flag: " + doflag)
+
             subnodes = re.sub(r',,', '__ESCAPEDCOMMA__', subnodes)
             for subnode in re.split(r'\s*,\s*', subnodes):
                 subnode = re.sub(r'__ESCAPEDCOMMA__', ',', subnode)
                 if re.match(r'^\$([a-zA-Z0-9]+)$', subnode):
                     continue  # "$lhs" is just a comment that this op has a lhs
+                if re.search(r'DISABLE_BASE', subnode):
+                    AstNodes[typen].disableBaseSet()
+                    return
                 subnodeif = subnode
                 subnodeif = re.sub(r'\$([a-zA-Z0-9]+)\.cast([A-Z][A-Za-z0-9]+)$',
                                    r'VN_IS(nodep->\1(),\2)', subnodeif)
@@ -464,7 +476,12 @@ class Cpt:
         for node in AstNodeList:
             out_for_type_sc = []
             out_for_type = []
-            classes = list(node.allSuperClasses)
+            if node.disableBase:
+                classes = []
+                out_for_type.extend("        // DISABLE_BASE\n")
+            else:
+                classes = list(node.allSuperClasses)
+
             classes.append(node)
             for base in classes:
                 base = base.name
diff --git a/test_regress/t/t_assert_elab_p.py b/test_regress/t/t_assert_elab_p.py
new file mode 100755
index 000000000..147fe6faf
--- /dev/null
+++ b/test_regress/t/t_assert_elab_p.py
@@ -0,0 +1,16 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2025 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
+
+import vltest_bootstrap
+
+test.scenarios('simulator')
+
+test.compile()
+
+test.passes()
diff --git a/test_regress/t/t_assert_elab_p.v b/test_regress/t/t_assert_elab_p.v
new file mode 100644
index 000000000..bf1248fdb
--- /dev/null
+++ b/test_regress/t/t_assert_elab_p.v
@@ -0,0 +1,39 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2025 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+// verilator lint_off WIDTH
+
+module pipe_id_match #(
+    parameter type ID_T = logic [4:0],
+    parameter ID_T STAGE_IDS[3:0][1:0] = '{default: 1}
+);
+  generate
+    $info("%m %s:%0d: 4=%0d 2=%0d STAGE_IDS=%p", "test.sv", 25, 4, 2, STAGE_IDS);
+  endgenerate
+endmodule
+
+module t #(
+    parameter type ID_T = logic [4:0]
+);
+  function automatic ID_T [3:0][1:0] gen_stage_ids();
+    for (int unsigned st = 0; st < 4; st++) begin
+      for (int unsigned id = 0; id < 2; id++) begin
+        gen_stage_ids[st][id] = 3 + ((st + 1) * 2) + id - (3 + ((st + 1) * 2) + id < 18 ? 0 : 18);
+      end
+    end
+  endfunction
+
+  localparam ID_T STAGE_IDS[3:0][1:0] = gen_stage_ids();
+
+  pipe_id_match #(
+      .ID_T(ID_T),
+      .STAGE_IDS(STAGE_IDS)
+  ) pipe (
+      .*);
+
+  initial $finish;
+
+endmodule