From 052aeee4150eba68051311982d883688670f6ca4 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Thu, 19 Feb 2026 22:06:44 -0800
Subject: [PATCH] std.zon.Serializer: slightly more helpful message

when a type is unserializable
---
 lib/std/zon/Serializer.zig | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/std/zon/Serializer.zig b/lib/std/zon/Serializer.zig
index c30c0e09d8051c0eafab2e8e4ba2a85d46aa1db2..9839129e316906fd20110f47ae40c28d193f8ec4 100644
--- a/lib/std/zon/Serializer.zig
+++ b/lib/std/zon/Serializer.zig
@@ -122,7 +122,7 @@ pub fn valueMaxDepth(self: *Serializer, val: anytype, options: ValueOptions, dep
 
 /// Serialize a value, similar to `serializeArbitraryDepth`.
 pub fn valueArbitraryDepth(self: *Serializer, val: anytype, options: ValueOptions) Error!void {
-    comptime assert(canSerializeType(@TypeOf(val)));
+    comptime assertCanSerializeType(@TypeOf(val));
     switch (@typeInfo(@TypeOf(val))) {
         .int, .comptime_int => if (options.emit_codepoint_literals.emitAsCodepoint(val)) |c| {
             self.codePoint(c) catch |err| switch (err) {
@@ -321,7 +321,7 @@ pub fn tupleArbitraryDepth(
 }
 
 fn tupleImpl(self: *Serializer, val: anytype, options: ValueOptions) Error!void {
-    comptime assert(canSerializeType(@TypeOf(val)));
+    comptime assertCanSerializeType(@TypeOf(val));
     switch (@typeInfo(@TypeOf(val))) {
         .@"struct" => {
             var container = try self.beginTuple(.{ .whitespace_style = .{ .fields = val.len } });
@@ -814,6 +814,10 @@ test checkValueDepth {
     try expectValueDepthEquals(3, @as([]const []const u8, &.{&.{ 1, 2, 3 }}));
 }
 
+inline fn assertCanSerializeType(T: type) void {
+    if (!canSerializeType(T)) @compileError("cannot serialize: " ++ @typeName(T));
+}
+
 inline fn canSerializeType(T: type) bool {
     comptime return canSerializeTypeInner(T, &.{}, false);
 }
-- 
2.54.0