zig fmt: error set decls

std/zig/parser.zig

@@ -4110,14 +4110,30 @@ pub const Parser = struct {
                     },
                     ast.Node.Id.ErrorSetDecl => {
                         const err_set_decl = @fieldParentPtr(ast.Node.ErrorSetDecl, "base", base);
-                        try stream.print("error ");
+
+                        const decls = err_set_decl.decls.toSliceConst();
+                        if (decls.len == 0) {
+                            try stream.write("error{}");
+                            continue;
+                        }
+
+                        if (decls.len == 1) blk: {
+                            const node = decls[0];
+                            if (node.same_line_comment != null or node.doc_comments != null) break :blk;
+
+                            try stream.write("error{");
+                            try stack.append(RenderState { .Text = "}" });
+                            try stack.append(RenderState { .Expression = node });
+                            continue;
+                        }
+
+                        try stream.write("error{");
 
                         try stack.append(RenderState { .Text = "}"});
                         try stack.append(RenderState.PrintIndent);
                         try stack.append(RenderState { .Indent = indent });
                         try stack.append(RenderState { .Text = "\n"});
 
-                        const decls = err_set_decl.decls.toSliceConst();
                         var i = decls.len;
                         while (i != 0) {
                             i -= 1;
@@ -4142,7 +4158,6 @@ pub const Parser = struct {
                             });
                         }
                         try stack.append(RenderState { .Indent = indent + indent_delta});
-                        try stack.append(RenderState { .Text = "{"});
                     },
                     ast.Node.Id.MultilineStringLiteral => {
                         const multiline_str_literal = @fieldParentPtr(ast.Node.MultilineStringLiteral, "base", base);

std/zig/parser_test.zig

@@ -1,5 +1,35 @@
-test "zig fmt: union(enum(u32)) with assigned enum values" {
+test "zig fmt: error set declaration" {
       try testCanonical(
+        \\const E = error{
+        \\    A,
+        \\    B,
+        \\
+        \\    C,
+        \\};
+        \\
+        \\const Error = error{
+        \\    /// no more memory
+        \\    OutOfMemory,
+        \\};
+        \\
+        \\const Error = error{
+        \\    /// no more memory
+        \\    OutOfMemory,
+        \\
+        \\    /// another
+        \\    Another,
+        \\
+        \\    // end
+        \\};
+        \\
+        \\const Error = error{OutOfMemory};
+        \\const Error = error{};
+        \\
+    );
+}
+
+test "zig fmt: union(enum(u32)) with assigned enum values" {
+    try testCanonical(
         \\const MultipleChoice = union(enum(u32)) {
         \\    A = 20,
         \\    B = 40,
@@ -23,7 +53,7 @@ test "zig fmt: labeled suspend" {
 
 test "zig fmt: comments before error set decl" {
     try testCanonical(
-        \\const UnexpectedError = error {
+        \\const UnexpectedError = error{
         \\    /// The Operating System returned an undocumented error code.
         \\    Unexpected,
         \\    // another
@@ -601,18 +631,6 @@ test "zig fmt: union declaration" {
     );
 }
 
-test "zig fmt: error set declaration" {
-      try testCanonical(
-        \\const E = error {
-        \\    A,
-        \\    B,
-        \\
-        \\    C,
-        \\};
-        \\
-    );
-}
-
 test "zig fmt: arrays" {
     try testCanonical(
         \\test "test array" {