--- /dev/null
+// Copyright 2013 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.
+
+// This file contains tests for the buildtag checker.
+
+// +builder // want `possible malformed \+build comment`
+// +build !ignore
+
+// Mention +build // want `possible malformed \+build comment`
+
+// +build nospace // want "build comment must appear before package clause and be followed by a blank line"
+package a
+
+// +build toolate // want "build comment must appear before package clause and be followed by a blank line$"
+
+var _ = 3
+
+var _ = `
+// +build notacomment
+`