--- /dev/null
+// Copyright 2020 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.
+
+// +build no
+
+package a
+
+// want +1 `misplaced \+build comment`
+// +build toolate
+
+// want +1 `misplaced //go:build comment`
+//go:build toolate
+
+var _ = `
+// +build notacomment
+`