From ee9fc54cd032b6ac0fcaa422aa9c2826fa370bfa Mon Sep 17 00:00:00 2001
From: Veikka Tuominen <git@vexu.eu>
Date: Thu, 8 Dec 2022 22:21:49 +0200
Subject: [PATCH] TypedValue: fix handling of tuples represented as
 empty_struct_value

---
 src/TypedValue.zig           | 16 ++++------------
 src/type.zig                 |  1 -
 test/behavior.zig            |  1 +
 test/behavior/bugs/13785.zig | 12 ++++++++++++
 4 files changed, 17 insertions(+), 13 deletions(-)
 create mode 100644 test/behavior/bugs/13785.zig

diff --git a/src/TypedValue.zig b/src/TypedValue.zig
index 10ab88b866..3c1972c78d 100644
--- a/src/TypedValue.zig
+++ b/src/TypedValue.zig
@@ -142,12 +142,10 @@ pub fn print(
         .extern_options_type => return writer.writeAll("std.builtin.ExternOptions"),
         .type_info_type => return writer.writeAll("std.builtin.Type"),
 
-        .empty_struct_value => return writer.writeAll(".{}"),
-        .aggregate => {
+        .empty_struct_value, .aggregate => {
             if (level == 0) {
                 return writer.writeAll(".{ ... }");
             }
-            const values = val.castTag(.aggregate).?;
             if (ty.zigTypeTag() == .Struct) {
                 try writer.writeAll(".{");
                 const max_len = std.math.min(ty.structFieldCount(), max_aggregate_items);
@@ -161,13 +159,7 @@ pub fn print(
                     }
                     try print(.{
                         .ty = ty.structFieldType(i),
-                        .val = switch (ty.containerLayout()) {
-                            .Packed => values.data[i],
-                            else => ty.structFieldValueComptime(i) orelse b: {
-                                const vals = values.data;
-                                break :b vals[i];
-                            },
-                        },
+                        .val = val.fieldValue(ty, i),
                     }, writer, level - 1, mod);
                 }
                 if (ty.structFieldCount() > max_aggregate_items) {
@@ -184,7 +176,7 @@ pub fn print(
 
                     var i: u32 = 0;
                     while (i < max_len) : (i += 1) {
-                        buf[i] = std.math.cast(u8, values.data[i].toUnsignedInt(target)) orelse break :str;
+                        buf[i] = std.math.cast(u8, val.fieldValue(ty, i).toUnsignedInt(target)) orelse break :str;
                     }
 
                     const truncated = if (len > max_string_len) " (truncated)" else "";
@@ -199,7 +191,7 @@ pub fn print(
                     if (i != 0) try writer.writeAll(", ");
                     try print(.{
                         .ty = elem_ty,
-                        .val = values.data[i],
+                        .val = val.fieldValue(ty, i),
                     }, writer, level - 1, mod);
                 }
                 if (len > max_aggregate_items) {
diff --git a/src/type.zig b/src/type.zig
index f587bdc490..1aefa8f7a1 100644
--- a/src/type.zig
+++ b/src/type.zig
@@ -5670,7 +5670,6 @@ pub const Type = extern union {
         switch (ty.tag()) {
             .@"struct" => {
                 const struct_obj = ty.castTag(.@"struct").?.data;
-                assert(struct_obj.layout != .Packed);
                 const field = struct_obj.fields.values()[index];
                 if (field.is_comptime) {
                     return field.default_val;
diff --git a/test/behavior.zig b/test/behavior.zig
index 64ffcb7a44..e4a04bbccb 100644
--- a/test/behavior.zig
+++ b/test/behavior.zig
@@ -120,6 +120,7 @@ test {
     _ = @import("behavior/bugs/13435.zig");
     _ = @import("behavior/bugs/13664.zig");
     _ = @import("behavior/bugs/13714.zig");
+    _ = @import("behavior/bugs/13785.zig");
     _ = @import("behavior/byteswap.zig");
     _ = @import("behavior/byval_arg_var.zig");
     _ = @import("behavior/call.zig");
diff --git a/test/behavior/bugs/13785.zig b/test/behavior/bugs/13785.zig
new file mode 100644
index 0000000000..cef117f486
--- /dev/null
+++ b/test/behavior/bugs/13785.zig
@@ -0,0 +1,12 @@
+const builtin = @import("builtin");
+const std = @import("std");
+
+const S = packed struct { a: u0 = 0 };
+test {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
+
+    var a: u8 = 0;
+    try std.io.null_writer.print("\n{} {}\n", .{ a, S{} });
+}