|  | // Copyright 2018 The Go Authors. All rights reserved. | 
|  | // Use of this source code is governed by a BSD-style | 
|  | // license that can be found in the LICENSE file. | 
|  |  | 
|  | // Package pragma provides types that can be embedded into a struct to | 
|  | // statically enforce or prevent certain language properties. | 
|  | package pragma | 
|  |  | 
|  | import "sync" | 
|  |  | 
|  | // NoUnkeyedLiterals can be embedded in a struct to prevent unkeyed literals. | 
|  | type NoUnkeyedLiterals struct{} | 
|  |  | 
|  | // DoNotImplement can be embedded in an interface to prevent trivial | 
|  | // implementations of the interface. | 
|  | // | 
|  | // This is useful to prevent unauthorized implementations of an interface | 
|  | // so that it can be extended in the future for any protobuf language changes. | 
|  | type DoNotImplement interface{ ProtoInternal(DoNotImplement) } | 
|  |  | 
|  | // DoNotCompare can be embedded in a struct to prevent comparability. | 
|  | type DoNotCompare [0]func() | 
|  |  | 
|  | // DoNotCopy can be embedded in a struct to help prevent shallow copies. | 
|  | // This does not rely on a Go language feature, but rather a special case | 
|  | // within the vet checker. | 
|  | // | 
|  | // See https://golang.org/issues/8005. | 
|  | type DoNotCopy [0]sync.Mutex |