From 2b6589bd3b2d529c56220d762c6a95b7609ea768 Mon Sep 17 00:00:00 2001
From: Kendall Condon <goon.pri.low@gmail.com>
Date: Tue, 29 Jul 2025 09:25:41 -0400
Subject: [PATCH] zig fmt: fix error sets with empty line before comma

---
 lib/std/zig/Ast/Render.zig  |  7 ++++++-
 lib/std/zig/parser_test.zig | 16 ++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/lib/std/zig/Ast/Render.zig b/lib/std/zig/Ast/Render.zig
index ffb4f2bfb847c648f94d97111152e283352b3c49..121586a3bbd25f35f11580fd3422fad0941e2da4 100644
--- a/lib/std/zig/Ast/Render.zig
+++ b/lib/std/zig/Ast/Render.zig
@@ -748,8 +748,13 @@ fn renderExpression(r: *Render, node: Ast.Node.Index, space: Space) Error!void {
                 try renderToken(r, lbrace, .newline);
                 var i = lbrace + 1;
                 while (i < rbrace) : (i += 1) {
+                    const tag = tree.tokenTag(i);
+                    if (tag == .comma) {
+                        assert(tree.tokenTag(i - 1) == .identifier);
+                        continue;
+                    }
                     if (i > lbrace + 1) try renderExtraNewlineToken(r, i);
-                    switch (tree.tokenTag(i)) {
+                    switch (tag) {
                         .doc_comment => try renderToken(r, i, .newline),
                         .identifier => {
                             try ais.pushSpace(.comma);
diff --git a/lib/std/zig/parser_test.zig b/lib/std/zig/parser_test.zig
index 53b3cf8eb879a0aa141fab3f1acb0d081dd4b0a7..b98207f904d5684ad900258cc38416a5fef6adb4 100644
--- a/lib/std/zig/parser_test.zig
+++ b/lib/std/zig/parser_test.zig
@@ -6822,6 +6822,22 @@ test "zig fmt: canonicalize stray backslashes in identifiers" {
     );
 }
 
+test "zig fmt: error set with extra newline before comma" {
+    try testTransform(
+        \\const E = error{
+        \\    A
+        \\
+        \\    ,
+        \\};
+        \\
+    ,
+        \\const E = error{
+        \\    A,
+        \\};
+        \\
+    );
+}
+
 test "recovery: top level" {
     try testError(
         \\test "" {inline}
-- 
2.54.0