Add 'x/' from commit 'a10a11b9d371f36b7c3510da32a1d70b74e27bd1'

git-subtree-dir: x
git-subtree-mainline: 7d05a6ee8f
git-subtree-split: a10a11b9d3

x/types/structs/structs.go

@@ -0,0 +1,15 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Package structs contains the Incomparable type.
+package structs
+
+// Incomparable is a zero-width incomparable type. If added as the
+// first field in a struct, it marks that struct as not comparable
+// (can't do == or be a map key) and usually doesn't add any width to
+// the struct (unless the struct has only small fields).
+//
+// By making a struct incomparable, you can prevent misuse (prevent
+// people from using ==), but also you can shrink generated binaries,
+// as the compiler can omit equality funcs from the binary.
+type Incomparable [0]func()