From 631714c50a99b5bb96387d3d74b82c99fdf59efd Mon Sep 17 00:00:00 2001
From: Igor Zaworski <izaworski@internships.antmicro.com>
Date: Thu, 21 Aug 2025 12:26:30 +0200
Subject: [PATCH] Fix expression type comparison (#6316)

---
 src/V3Width.cpp                             | 15 +++++----
 test_regress/t/t_type_expression_compare.py | 18 +++++++++++
 test_regress/t/t_type_expression_compare.v  | 36 +++++++++++++++++++++
 3 files changed, 63 insertions(+), 6 deletions(-)
 create mode 100755 test_regress/t/t_type_expression_compare.py
 create mode 100644 test_regress/t/t_type_expression_compare.v

diff --git a/src/V3Width.cpp b/src/V3Width.cpp
index 694dc36e0..7ce8d1477 100644
--- a/src/V3Width.cpp
+++ b/src/V3Width.cpp
@@ -1832,8 +1832,11 @@ class WidthVisitor final : public VNVisitor {
             break;
         }
         case VAttrType::TYPEID:
-            // Soon to be handled in AstEqT
-            nodep->dtypeSetSigned32();
+            if (AstNodeDType* dtypep = VN_CAST(nodep->fromp(), NodeDType)) {
+                nodep->dtypep(dtypep);
+            } else {
+                nodep->dtypep(VN_AS(nodep->fromp(), NodeExpr)->dtypep());
+            }
             break;
         case VAttrType::VAR_BASE:
             // Soon to be handled in V3LinkWidth SEL generation, under attrp() and newSubLsbOf
@@ -5199,7 +5202,7 @@ class WidthVisitor final : public VNVisitor {
         // Deal with case(type(data_type))
         if (AstAttrOf* const exprap = VN_CAST(nodep->exprp(), AttrOf)) {
             if (exprap->attrType() == VAttrType::TYPEID) {
-                AstNodeDType* const exprDtp = VN_AS(exprap->fromp(), NodeDType);
+                const AstNodeDType* const exprDtp = exprap->dtypep();
                 UINFO(9, "case type exprDtp " << exprDtp);
                 // V3Param may have a pointer to this case statement, and we need
                 // dotted references to remain properly named, so rather than
@@ -5218,7 +5221,7 @@ class WidthVisitor final : public VNVisitor {
                                 condp->v3error(
                                     "Case(type) statement requires items that have type() items");
                             } else {
-                                AstNodeDType* const condDtp = VN_AS(condAttrp->fromp(), NodeDType);
+                                AstNodeDType* const condDtp = condAttrp->dtypep();
                                 if (AstNode::computeCastable(exprDtp, condDtp, nodep)
                                     == VCastable::SAMEISH) {
                                     hit = true;
@@ -7021,8 +7024,8 @@ class WidthVisitor final : public VNVisitor {
                         "Type compare expects type reference");
             UASSERT_OBJ(rhsap->attrType() == VAttrType::TYPEID, rhsap,
                         "Type compare expects type reference");
-            AstNodeDType* const lhsDtp = VN_AS(lhsap->fromp(), NodeDType);
-            AstNodeDType* const rhsDtp = VN_AS(rhsap->fromp(), NodeDType);
+            const AstNodeDType* const lhsDtp = lhsap->dtypep();
+            const AstNodeDType* const rhsDtp = rhsap->dtypep();
             UINFO(9, "==type lhsDtp " << lhsDtp);
             UINFO(9, "==type rhsDtp " << lhsDtp);
             const bool invert = VN_IS(nodep, NeqT);
diff --git a/test_regress/t/t_type_expression_compare.py b/test_regress/t/t_type_expression_compare.py
new file mode 100755
index 000000000..f989a35fb
--- /dev/null
+++ b/test_regress/t/t_type_expression_compare.py
@@ -0,0 +1,18 @@
+#!/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.execute()
+
+test.passes()
diff --git a/test_regress/t/t_type_expression_compare.v b/test_regress/t/t_type_expression_compare.v
new file mode 100644
index 000000000..d94e9fc70
--- /dev/null
+++ b/test_regress/t/t_type_expression_compare.v
@@ -0,0 +1,36 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2025 by Antmicro.
+// SPDX-License-Identifier: CC0-1.0
+
+typedef int Int_T;
+
+module t;
+  initial begin
+    Int_T value1 = 7;
+    int value2 = 13;
+    real r;
+    if (type(value1) != type(value2)) $stop;
+    if (type(value1 + value2) != type(value2 + 18)) $stop;
+    case (type(value1))
+      type(value2): ;
+      type(r): $stop;
+      type(chandle): $stop;
+      type(logic): $stop;
+      default: $stop;
+    endcase
+    case (type(value1 + value2 + 13))
+      type(type(value2 + 18 - 40)): ;
+      type(r): $stop;
+      type(chandle): $stop;
+      default: $stop;
+    endcase
+    if (type(value1) == type(value2) && type(value1 + value2) == type(value2 + 18)) begin
+      $write("*-* All Finished *-*\n");
+      $finish;
+    end else begin
+      $stop;
+    end
+  end
+endmodule