import (
	"fmt"
	"go/build/constraint"
	"io"
	"strconv"
	"strings"
)

const debug = false
const trace = false

type parser struct {
	file  *PosBase
	errh  ErrorHandler
	mode  Mode
	pragh PragmaHandler
	scanner

	base      *PosBase // current position base
	first     error    // first error encountered
	errcnt    int      // number of errors encountered
	pragma    Pragma   // pragmas

		var src string
		if test.fileVersion != "" {
			src = "//go:build " + test.fileVersion + "\n"
		}
		src += "package p"

		conf := Config{GoVersion: test.goVersion}
		versions := make(map[*syntax.PosBase]string)
		var info Info
		info.FileVersions = versions
		mustTypecheck(src, &conf, &info)

		n := 0
		for _, v := range info.FileVersions {
			want := test.wantVersion
			if v != want {