From fac07970e631605abb77bc48c9351404c69cee70 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Sun, 12 Apr 2026 18:12:41 -0400
Subject: [PATCH] Improve too-small cast warning to show size

---
 src/V3Width.cpp                    | 2 +-
 test_regress/t/t_cast_size_bad.out | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/V3Width.cpp b/src/V3Width.cpp
index b9b0eb0c6..6a6213471 100644
--- a/src/V3Width.cpp
+++ b/src/V3Width.cpp
@@ -2631,7 +2631,7 @@ class WidthVisitor final : public VNVisitor {
         if (m_vup->prelim()) {
             int width = nodep->rhsp()->toSInt();
             if (width < 1) {
-                nodep->v3error("Size-changing cast to zero or negative size");
+                nodep->v3error("Size-changing cast to zero or negative size: " << width);
                 width = 1;
             }
             userIterateAndNext(nodep->lhsp(), WidthVP{SELF, PRELIM}.p());
diff --git a/test_regress/t/t_cast_size_bad.out b/test_regress/t/t_cast_size_bad.out
index 59bc68f3b..f0ecfdff7 100644
--- a/test_regress/t/t_cast_size_bad.out
+++ b/test_regress/t/t_cast_size_bad.out
@@ -1,4 +1,4 @@
-%Error: t/t_cast_size_bad.v:14:13: Size-changing cast to zero or negative size
+%Error: t/t_cast_size_bad.v:14:13: Size-changing cast to zero or negative size: -1
                                  : ... note: In instance 't'
    14 |     b = (-1)'(a);   
       |             ^