if err != nil {
		t.Fatalf("error opening src inline_hot.go: %v", err)
	}
	defer src.Close()

	dst, err := os.Create(filepath.Join(dir, "inline_hot.go"))
	if err != nil {
		t.Fatalf("error creating dst inline_hot.go: %v", err)
	}
	defer dst.Close()

	if _, err := io.WriteString(dst, `// Autogenerated
// Lines
`); err != nil {

	unlock, err := r.mu.Lock()
	if err != nil {
		return "", err
	}
	defer unlock()

	return "", vcsErrorf("vcs %s: RecentTag: %w", r.cmd.vcs, errors.ErrUnsupported)
}

func (r *vcsRepo) DescendsFrom(ctx context.Context, rev, tag string) (bool, error) {
	unlock, err := r.mu.Lock()
	if err != nil {
		return false, err
	}
	defer unlock()

	zipfile, err := DownloadZip(ctx, mod)
	if err != nil {
		return "", err
	}

	unlock, err := lockVersion(ctx, mod)
	if err != nil {
		return "", err
	}
	defer unlock()

	ctx, span = trace.StartSpan(ctx, "unzip "+zipfile)
	defer span.Done()

	// Check whether the directory was populated while we were waiting on the lock.
	_, dirErr := DownloadDir(ctx, mod)
	if dirErr == nil {
		return dir, nil
	}

	}

	// Sort normal variables before open-coded-defer slots, so that the
	// latter are grouped together and near the top of the frame (to
	// minimize varint encoding of their varp offset).
	if a.OpenDeferSlot() != b.OpenDeferSlot() {
		return a.OpenDeferSlot()
	}

	// If a and b are both open-coded defer slots, then order them by
	// index in descending order, so they'll be laid out in the frame in

# Defers

The last wrinkle is handling defer statements. If we have

	for range f {
		defer print("A")
	}

we cannot rewrite that into

	f(func() {
		defer print("A")
	})

because the deferred code will run at the end of the iteration, not
the end of the containing function. To fix that, the runtime provides
a special hook that lets us obtain a defer "token" representing the

	if check.conf.Trace {
		check.trace(x.Pos(), "-- instantiating type %s with %s", x, xlist)
		check.indent++
		defer func() {
			check.indent--
			// Don't format the underlying here. It will always be nil.
			check.trace(x.Pos(), "=> %s", res)
		}()
	}

	defer func() {
		setDefType(def, res)
	}()

	var cause string
	gtyp := check.genericType(x, &cause)
	if cause != "" {

		t.Run(name, func(t *testing.T) {
			t.Parallel()
			StartProxy()

			workdir, err := os.MkdirTemp(testTmpDir, name)
			if err != nil {
				t.Fatal(err)
			}
			if !*testWork {
				defer removeAll(workdir)
			}

			s, err := script.NewState(tbContext(ctx, t), workdir, env)
			if err != nil {
				t.Fatal(err)
			}

			// Unpack archive.
			a, err := txtar.ParseFile(file)

	// Confirm that when Reader panics, the empty buffer remains empty
	var buf2 Buffer
	defer func() {
		recover()
		check(t, "TestReadFromPanicReader (2)", &buf2, "")
	}()
	buf2.ReadFrom(panicReader{panic: true})
}

func TestReadFromNegativeReader(t *testing.T) {
	var b Buffer
	defer func() {
		switch err := recover().(type) {
		case nil:
			t.Fatal("bytes.Buffer.ReadFrom didn't panic")

			fmt.Println() // empty line between top-level objects for readability
		}
		check.trace(obj.Pos(), "-- checking %s (%s, objPath = %s)", obj, obj.color(), pathString(check.objPath))
		check.indent++
		defer func() {
			check.indent--
			check.trace(obj.Pos(), "=> %s (%s)", obj, obj.color())
		}()
	}

	// Checking the declaration of obj means inferring its type
	// (and possibly its value, for constants).

		return n
	}

	// TODO(rfindley): if n.check is non-nil we can avoid locking here, since
	// type-checking is not concurrent. Evaluate if this is worth doing.
	n.mu.Lock()
	defer n.mu.Unlock()

	if n.state() >= resolved {
		return n
	}

	if n.inst != nil {
		assert(n.underlying == nil) // n is an unresolved instance