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

	case *Ellipsis:
		if n.Elt != nil {
			Walk(v, n.Elt)
		}

	case *FuncLit:
		Walk(v, n.Type)
		Walk(v, n.Body)

	case *CompositeLit:
		if n.Type != nil {
			Walk(v, n.Type)
		}
		walkList(v, n.Elts)

	case *ParenExpr:
		Walk(v, n.X)

	case *SelectorExpr:
		Walk(v, n.X)
		Walk(v, n.Sel)

	mimeTypesLower.Store(extLower, mimeType)

	extensionsMu.Lock()
	defer extensionsMu.Unlock()
	var exts []string
	if ei, ok := extensions.Load(justType); ok {
		exts = ei.([]string)
	}
	for _, v := range exts {
		if v == extLower {
			return nil
		}
	}
	extensions.Store(justType, append(exts, extLower))
	return nil

}

// Stop implements Interface
func (w emptyWatch) Stop() {
}

// ResultChan implements Interface
func (w emptyWatch) ResultChan() <-chan Event {
	return chan Event(w)
}

// FakeWatcher lets you test anything that consumes a watch.Interface; threadsafe.
type FakeWatcher struct {
	result  chan Event
	stopped bool
	sync.Mutex
}

func NewFake() *FakeWatcher {
	return &FakeWatcher{

}

func (c *nowritebarrierrecChecker) check() {
	// We walk the call graph as late as possible so we can
	// capture all calls created by lowering, but this means we
	// only get to see the obj.LSyms of calls. symToFunc lets us
	// get back to the ODCLFUNCs.
	symToFunc := make(map[*obj.LSym]*ir.Func)
	// funcs records the back-edges of the BFS call graph walk. It
	// maps from the ODCLFUNC of each function that must not have