From f7a6d64ffb77db10d8f61effe0e7f6d1bc6d84cd Mon Sep 17 00:00:00 2001
From: Jacob Young <jacobly@ziglang.org>
Date: Fri, 14 Aug 2026 00:08:19 -0400
Subject: [PATCH] Dwarf2: fix incremental test failure when a file becomes
 unreferenced

---
 src/link/Dwarf2.zig | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/link/Dwarf2.zig b/src/link/Dwarf2.zig
index 657a07821d49a195e5057bf2e472c1984596a438..05071d246b2783e2e482d7619f0011029ecb602a 100644
--- a/src/link/Dwarf2.zig
+++ b/src/link/Dwarf2.zig
@@ -1847,7 +1847,8 @@ pub fn genDebugLineHeader(
     for (unit.files.keys()) |zfi| {
         const zf = zcu.fileByIndex(zfi);
         try dwarf.strp(&dwarf.debug_line_str, dlh_nw, zf.sub_file_path);
-        const di = unit.dirs.getIndex(dwarf.getUnit(zf.mod.?)).?;
+        const di =
+            if (zcu.alive_files.contains(zfi)) unit.dirs.getIndex(dwarf.getUnit(zf.mod.?)).? else 0;
         switch (directory_index_form) {
             else => unreachable,
             .data1 => try dlhw.writeByte(@intCast(di)),
-- 
2.54.0