From c6a7682f0466df21b5890d2ef0ee1393675d2dec Mon Sep 17 00:00:00 2001
From: Patrick Martin <me@psm.pm>
Date: Sun, 28 Sep 2025 16:30:16 -0400
Subject: [PATCH] translate-c: demote structs with opaque fields to opaque

---
 lib/compiler/translate-c/Translator.zig | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lib/compiler/translate-c/Translator.zig b/lib/compiler/translate-c/Translator.zig
index b630584eb308..abf289fe074f 100644
--- a/lib/compiler/translate-c/Translator.zig
+++ b/lib/compiler/translate-c/Translator.zig
@@ -527,6 +527,13 @@ fn transRecordDecl(t: *Translator, scope: *Scope, record_qt: QualType) Error!voi
                 break :init ZigTag.opaque_literal.init();
             }
 
+            // Demote record to opaque if it contains an opaque field
+            if (t.typeWasDemotedToOpaque(field.qt)) {
+                try t.opaque_demotes.put(t.gpa, base.qt, {});
+                try t.warn(scope, field_loc, "{s} demoted to opaque type - has opaque field", .{container_kind_name});
+                break :init ZigTag.opaque_literal.init();
+            }
+
             var field_name = field.name.lookup(t.comp);
             if (field.name_tok == 0) {
                 field_name = try std.fmt.allocPrint(t.arena, "unnamed_{d}", .{unnamed_field_count});