You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: buildtag.go
    path of file: ./repos/gccrs/libgo/go/golang.org/x/tools/go/analysis/passes/buildtag
    
    the code of the file until where you have to start completion: // 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.

//go:build go1.16
// +build go1.16

// Package buildtag defines an Analyzer that checks build tags.
package buildtag

import (
	"
    
func checkGoFile(pass *analysis.Pass, f *ast.File) {
	var check checker
	check.init(pass)
	defer check.finish()

	for _, group := range f.Comments {
		// A +build comment is ignored after or adjoining the package declaration.
		if group.End()+1 >= f.Package {
			check.plusBuildOK = false
		}
		// A //go:build comment is ignored after the package declaration
		// (but adjoining it is OK, in contrast to +build comments).
		if group.Pos() >= f.Package {
			check.goBuildOK = false
		}

		// Check each line of a //-comment.
		for _, c := range group.List {
			// "+build" is ignored within or after a /*...*/ comment.
			if !strings.HasPrefix(c.Text, "//") {
				check.plusBuildOK = false
			}
			check.comment(c.Slash, c.Text)
		}
	}
}