From 8d1805f81c97a0b773772e86aa39f26c894b7985 Mon Sep 17 00:00:00 2001
From: Jacob Young <jacobly0@users.noreply.github.com>
Date: Sat, 29 Jul 2023 05:51:33 -0400
Subject: [PATCH] behavior: add coverage for no longer reproducing issue

Closes #14305
---
 test/behavior.zig              |  1 +
 test/behavior/packed-union.zig | 40 ++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)
 create mode 100644 test/behavior/packed-union.zig

diff --git a/test/behavior.zig b/test/behavior.zig
index 249d3191e6..fe2856649a 100644
--- a/test/behavior.zig
+++ b/test/behavior.zig
@@ -193,6 +193,7 @@ test {
     _ = @import("behavior/optional.zig");
     _ = @import("behavior/packed-struct.zig");
     _ = @import("behavior/packed_struct_explicit_backing_int.zig");
+    _ = @import("behavior/packed-union.zig");
     _ = @import("behavior/pointers.zig");
     _ = @import("behavior/popcount.zig");
     _ = @import("behavior/prefetch.zig");
diff --git a/test/behavior/packed-union.zig b/test/behavior/packed-union.zig
new file mode 100644
index 0000000000..ceb22e1ba9
--- /dev/null
+++ b/test/behavior/packed-union.zig
@@ -0,0 +1,40 @@
+const std = @import("std");
+const builtin = @import("builtin");
+const expectEqual = std.testing.expectEqual;
+
+test "flags in packed union" {
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
+
+    const FlagBits = packed struct(u8) {
+        enable_1: bool = false,
+        enable_2: bool = false,
+        enable_3: bool = false,
+        enable_4: bool = false,
+        other_flags: packed union {
+            flags: packed struct(u4) {
+                enable_1: bool = true,
+                enable_2: bool = false,
+                enable_3: bool = false,
+                enable_4: bool = false,
+            },
+            bits: u4,
+        } = .{ .flags = .{} },
+    };
+    var test_bits: FlagBits = .{};
+
+    try expectEqual(false, test_bits.enable_1);
+    try expectEqual(true, test_bits.other_flags.flags.enable_1);
+
+    test_bits.enable_1 = true;
+
+    try expectEqual(true, test_bits.enable_1);
+    try expectEqual(true, test_bits.other_flags.flags.enable_1);
+
+    test_bits.other_flags.flags.enable_1 = false;
+
+    try expectEqual(true, test_bits.enable_1);
+    try expectEqual(false, test_bits.other_flags.flags.enable_1);
+}