more testing

src/V3Param.cpp

@@ -1311,26 +1311,47 @@ class ParamProcessor final {
                     AstNodeDType* curDTypep = varp->dtypep();
                     AstNode* topp = dotp;
                     AstDot* outerDotp = VN_CAST(dotp->backp(), Dot);
-                    // On any mismatch (non-ParseRef rhs, non-packed-struct dtype, or
-                    // unknown field name) leave the outer Dots intact so V3Width can
-                    // emit the proper user-facing diagnostic.
-                    while (outerDotp && outerDotp->lhsp() == topp) {
+                    const auto errorRecover = [&](AstDot* const badp, const string& msg) {
+                        badp->v3error(msg);
+                        badp->replaceWith(new AstConst{badp->fileline(), AstConst::Signed32{}, 0});
+                        VL_DO_DANGLING(badp->deleteTree(), badp);
+                    };
+                    bool errored = false;
+                    while (outerDotp && outerDotp->lhsp() == topp) {  // LCOV_EXCL_BR_LINE
                         const AstParseRef* const fieldRefp = VN_CAST(outerDotp->rhsp(), ParseRef);
-                        if (!fieldRefp) break;
-                        AstNodeDType* const skippedp = curDTypep ? curDTypep->skipRefp() : nullptr;
+                        if (!fieldRefp) {
+                            errorRecover(outerDotp, "Malformed dotted select in parameter value");
+                            errored = true;
+                            break;
+                        }
+                        UASSERT_OBJ(curDTypep, outerDotp,
+                                    "curDTypep null in struct field chain walk");
+                        AstNodeDType* const skippedp = curDTypep->skipRefp();
                         AstNodeUOrStructDType* const structp
                             = VN_CAST(skippedp, NodeUOrStructDType);
-                        if (!structp) break;
+                        if (!structp) {
+                            errorRecover(outerDotp,
+                                         "Dotted member select on non-struct parameter value");
+                            errored = true;
+                            break;
+                        }
                         AstMemberDType* const foundMemp = VN_CAST(
                             m_memberMap.findMember(structp, fieldRefp->name()), MemberDType);
-                        UASSERT_OBJ(foundMemp, outerDotp, "member not found in struct/union");
-                        if (!foundMemp->subDTypep()) break;
+                        if (!foundMemp) {
+                            errorRecover(outerDotp, "Member " + fieldRefp->prettyNameQ()
+                                                        + " not found in structure");
+                            errored = true;
+                            break;
+                        }
+                        UASSERT_OBJ(foundMemp->subDTypep(), outerDotp,
+                                    "member has null subDTypep");
                         totalLsb += foundMemp->lsb();
                         sliceWidth = foundMemp->width();
                         curDTypep = foundMemp->subDTypep();
                         topp = outerDotp;
                         outerDotp = VN_CAST(outerDotp->backp(), Dot);
                     }
+                    if (errored) return;
                     if (topp == dotp) {
                         dotp->replaceWith(constp->cloneTree(false));
                         VL_DO_DANGLING(dotp->deleteTree(), dotp);

test_regress/t/t_class_lparam_struct_field_chain.v

@@ -35,6 +35,12 @@ class C #(parameter int W = 1);
                            tag: W[7:0] + 8'd2};
 endclass
 
+// Wrapper class containing the use of another class
+class D #(parameter int W = 1);
+  typedef C#(W) CC;
+  localparam int q = int'(CC::cfg.tag) + 100;
+endclass
+
 module Sub #(parameter int WIDTH = 0) ();
 endmodule
 
@@ -47,6 +53,9 @@ module Mid #(parameter int W = 8) ();
   // (2) nested struct field access -> two loop iterations, lsb accumulation
   Sub #(int'(CFG::cfg.jt.cam_type)) u_cam ();
   Sub #(int'(CFG::cfg.jt.depth)) u_depth ();
+  // (3) nested struct-field Dot buried in a wrapper class's lparam value
+  typedef D#(W) DD;
+  Sub #(int'(DD::q)) u_q ();
 endmodule
 
 module t;
@@ -59,6 +68,8 @@ module t;
     `checkh(u.u_cam.WIDTH, 32'd8);
     // cfg.jt.depth = W + 1 = 9 (nested, lsb 8)
     `checkh(u.u_depth.WIDTH, 32'd9);
+    // q = cfg.tag + 100 = 10 + 100 = 110
+    `checkh(u.u_q.WIDTH, 32'd110);
     $write("*-* All Finished *-*\n");
     $finish;
   end

test_regress/t/t_class_lparam_struct_field_chain_bad.out

@@ -0,0 +1,14 @@
+%Error: t/t_class_lparam_struct_field_chain_bad.v:37:25: Malformed dotted select in parameter value
+                                                       : ... note: In instance 't.u'
+   37 |   Sub #(int'(CFG::cfg.jt.cam_type[0])) u_fieldref ();
+      |                         ^
+        ... See the manual at https://verilator.org/verilator_doc.html?v=latest for more assistance.
+%Error: t/t_class_lparam_struct_field_chain_bad.v:39:26: Dotted member select on non-struct parameter value
+                                                       : ... note: In instance 't.u'
+   39 |   Sub #(int'(CFG::cfg.tag.bogus)) u_nonstruct ();
+      |                          ^
+%Error: t/t_class_lparam_struct_field_chain_bad.v:41:25: Member 'nosuchfield' not found in structure
+                                                       : ... note: In instance 't.u'
+   41 |   Sub #(int'(CFG::cfg.jt.nosuchfield)) u_nomember ();
+      |                         ^
+%Error: Exiting due to

test_regress/t/t_class_lparam_struct_field_chain_bad.py

@@ -0,0 +1,16 @@
+#!/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: 2026 Wilson Snyder
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+import vltest_bootstrap
+
+test.scenarios('linter')
+
+test.lint(fails=True, expect_filename=test.golden_filename)
+
+test.passes()

test_regress/t/t_class_lparam_struct_field_chain_bad.v

@@ -0,0 +1,46 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// Negative test for the struct-localparam field-access folding in V3Param
+// (resolveDotToTypedef).  Malformed outer `.field` chains on a class
+// localparam value must produce clean user-facing errors, NOT an internal
+// error or a crash in the following width pass.  Exercises the three
+// mismatch guards in the field-chain walk:
+//   (1) outer Dot rhs is not a plain field identifier (bit-select)
+//   (2) `.field` applied to a non-struct value
+//   (3) field name not a member of the struct
+//
+// This file ONLY is placed under the Creative Commons Public Domain.
+// SPDX-FileCopyrightText: 2026 Wilson Snyder
+// SPDX-License-Identifier: CC0-1.0
+
+typedef struct packed {
+  logic [7:0] cam_type;
+  logic [7:0] depth;
+} inner_t;
+
+typedef struct packed {
+  inner_t     jt;
+  logic [7:0] tag;
+} cfg_t;
+
+class C #(parameter int W = 1);
+  localparam cfg_t cfg = '{jt: '{cam_type: W[7:0], depth: W[7:0] + 8'd1},
+                           tag: W[7:0] + 8'd2};
+endclass
+
+module Sub #(parameter int WIDTH = 0) ();
+endmodule
+
+module Mid #(parameter int W = 8) ();
+  typedef C#(W) CFG;
+  // (1) bit-select after the field chain: outer Dot rhs is not a ParseRef
+  Sub #(int'(CFG::cfg.jt.cam_type[0])) u_fieldref ();
+  // (2) `.bogus` on the scalar field `tag`: dotting into a non-struct
+  Sub #(int'(CFG::cfg.tag.bogus)) u_nonstruct ();
+  // (3) `.nosuchfield` not a member of struct `jt`
+  Sub #(int'(CFG::cfg.jt.nosuchfield)) u_nomember ();
+endmodule
+
+module t;
+  Mid #(.W(8)) u ();
+endmodule