Commit 8d1805f81c

@@ -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);
+}

@@ -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");