// We could use a temporary directory outside $GOROOT instead,
	// but it is easier to debug on failure if the files are in a known location.
	workspace := pathf("%s/pkg/bootstrap", goroot)
	xremoveall(workspace)
	xatexit(func() { xremoveall(workspace) })
	base := pathf("%s/src/bootstrap", workspace)
	xmkdirall(base)

	// Copy source code into $GOROOT/pkg/bootstrap and rewrite import paths.

	"strconv"
	"sync"
)

var buildInitStarted = false

func BuildInit() {
	if buildInitStarted {
		base.Fatalf("go: internal error: work.BuildInit called more than once")
	}
	buildInitStarted = true
	base.AtExit(closeBuilders)

	modload.Init()
	instrumentInit()
	buildModeInit()
	if err := fsys.Init(base.Cwd()); err != nil {
		base.Fatal(err)
	}

	// Make sure -pkgdir is absolute, because we run commands

	if cfg.DebugTrace == "" {
		return pctx
	}

	ctx, close, err := trace.Start(pctx, cfg.DebugTrace)
	if err != nil {
		base.Fatalf("failed to start trace: %v", err)
	}
	base.AtExit(func() {
		if err := close(); err != nil {
			base.Fatalf("failed to stop trace: %v", err)
		}
	})

	return ctx
}

// handleChdirFlag handles the -C flag before doing anything else.

			f.walk(&n.Type, ctxEmbedType, visit)
		} else {
			f.walk(&n.Type, ctxType, visit)
		}
	case *ast.FieldList:
		for _, field := range n.List {
			f.walk(field, context, visit)
		}
	case *ast.BadExpr:
	case *ast.Ident:
	case *ast.Ellipsis:
		f.walk(&n.Elt, ctxType, visit)
	case *ast.BasicLit:
	case *ast.FuncLit:
		f.walk(n.Type, ctxType, visit)
		f.walk(n.Body, ctxStmt, visit)
	case *ast.CompositeLit:

		a.apply(n, "Type", nil, n.Type)
		a.apply(n, "Tag", nil, n.Tag)
		a.apply(n, "Comment", nil, n.Comment)

	case *ast.FieldList:
		a.applyList(n, "List")

	// Expressions
	case *ast.BadExpr, *ast.Ident, *ast.BasicLit:
		// nothing to do

	case *ast.Ellipsis:
		a.apply(n, "Elt", nil, n.Elt)

	case *ast.FuncLit:
		a.apply(n, "Type", nil, n.Type)
		a.apply(n, "Body", nil, n.Body)

		walkBeforeAfter(&n.Type, before, after)
		walkBeforeAfter(&n.Tag, before, after)
	case *ast.FieldList:
		for _, field := range n.List {
			walkBeforeAfter(field, before, after)
		}
	case *ast.BadExpr:
	case *ast.Ident:
	case *ast.Ellipsis:
		walkBeforeAfter(&n.Elt, before, after)
	case *ast.BasicLit:
	case *ast.FuncLit:
		walkBeforeAfter(&n.Type, before, after)
		walkBeforeAfter(&n.Body, before, after)

				check.trace(e0.Pos(), "=> %s // %s", T, goTypeName(T))
			} else {
				check.trace(e0.Pos(), "=> %s (under = %s) // %s", T, under, goTypeName(T))
			}
		}()
	}

	switch e := e0.(type) {
	case *syntax.BadExpr:
		// ignore - error reported before

	case *syntax.Name:
		var x operand
		check.ident(&x, e, def, true)

		switch x.mode {
		case typexpr:
			typ := x.typ
			setDefType(def, typ)

	// already held it's assumed that the first caller exits the program
	// so other calls can hang forever without an issue.
	lock(&raceFiniLock)

	// __tsan_fini will run C atexit functions and C++ destructors,
	// which can theoretically call back into Go.
	// Tell the scheduler we entering external code.
	entersyscall()

	// We're entering external code that may call ExitProcess on

				check.trace(e0.Pos(), "=> %s // %s", T, goTypeName(T))
			} else {
				check.trace(e0.Pos(), "=> %s (under = %s) // %s", T, under, goTypeName(T))
			}
		}()
	}

	switch e := e0.(type) {
	case *ast.BadExpr:
		// ignore - error reported before

	case *ast.Ident:
		var x operand
		check.ident(&x, e, def, true)

		switch x.mode {
		case typexpr:
			typ := x.typ
			setDefType(def, typ)

	old, found := check.untyped[x]
	if !found {
		return // nothing to do
	}

	// update operands of x if necessary
	switch x := x.(type) {
	case *ast.BadExpr,
		*ast.FuncLit,
		*ast.CompositeLit,
		*ast.IndexExpr,
		*ast.SliceExpr,
		*ast.TypeAssertExpr,
		*ast.StarExpr,
		*ast.KeyValueExpr,
		*ast.ArrayType,
		*ast.StructType,
		*ast.FuncType,