case *ast.CompositeLit:
		walkBeforeAfter(&n.Type, before, after)
		walkBeforeAfter(&n.Elts, before, after)
	case *ast.ParenExpr:
		walkBeforeAfter(&n.X, before, after)
	case *ast.SelectorExpr:
		walkBeforeAfter(&n.X, before, after)
	case *ast.IndexExpr:
		walkBeforeAfter(&n.X, before, after)
		walkBeforeAfter(&n.Index, before, after)
	case *ast.IndexListExpr:
		walkBeforeAfter(&n.X, before, after)

			// ignore - error reported before
		case novalue:
			check.errorf(&x, NotAType, "%s used as type", &x)
		default:
			check.errorf(&x, NotAType, "%s is not a type", &x)
		}

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

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

	//
	Implicits map[syntax.Node]Object

	// Selections maps selector expressions (excluding qualified identifiers)
	// to their corresponding selections.
	Selections map[*syntax.SelectorExpr]*Selection

	// Scopes maps syntax.Nodes to the scopes they define. Package scopes are not
	// associated with a specific node but with all files belonging to a package.

	}

	if ident == nil {
		ident = p.parseIdent()
	}

	if p.tok == token.PERIOD {
		// ident is a package name
		p.next()
		sel := p.parseIdent()
		return &ast.SelectorExpr{X: ident, Sel: sel}
	}

	return ident
}

// "[" has already been consumed, and lbrack is its position.
// If len != nil it is the already consumed array length.

			wrapperFn.WrappedFunc = wrapped.Func
		}

		visit(&call.Fun)
		visitList(call.Args)

	case ir.OCALLINTER:
		call := call.(*ir.CallExpr)
		argps = append(argps, &call.Fun.(*ir.SelectorExpr).X) // must be first for OCHECKNIL; see below
		visitList(call.Args)

	case ir.OAPPEND, ir.ODELETE, ir.OPRINT, ir.OPRINTLN, ir.ORECOVERFP:
		call := call.(*ir.CallExpr)
		visitList(call.Args)
		visit(&call.RType)

	// expression, or the blank identifier. Operands may be parenthesized."
	switch x.mode {
	case invalid:
		return Typ[Invalid]
	case variable, mapindex:
		// ok
	default:
		if sel, ok := x.expr.(*ast.SelectorExpr); ok {
			var op operand
			check.expr(nil, &op, sel.X)
			if op.mode == mapindex {
				check.errorf(&x, UnaddressableFieldAssign, "cannot assign to struct field %s in map", ExprString(x.expr))
				return Typ[Invalid]

		case invalid:
			// ignore - error reported before
		case novalue:
			check.errorf(&x, NotAType, "%s used as type", &x)
		default:
			check.errorf(&x, NotAType, "%s is not a type", &x)
		}

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

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

	// expression, or the blank identifier. Operands may be parenthesized."
	switch x.mode {
	case invalid:
		return Typ[Invalid]
	case variable, mapindex:
		// ok
	default:
		if sel, ok := x.expr.(*syntax.SelectorExpr); ok {
			var op operand
			check.expr(nil, &op, sel.X)
			if op.mode == mapindex {
				check.errorf(&x, UnaddressableFieldAssign, "cannot assign to struct field %s in map", ExprString(x.expr))
				return Typ[Invalid]

	// Expressions.
	case *ast.Ident:
		r.resolve(n, true)

	case *ast.FuncLit:
		r.openScope(n.Pos())
		defer r.closeScope()
		r.walkFuncType(n.Type)
		r.walkBody(n.Body)

	case *ast.SelectorExpr:
		ast.Walk(r, n.X)
		// Note: don't try to resolve n.Sel, as we don't support qualified
		// resolution.

	case *ast.StructType:
		r.openScope(n.Pos())
		defer r.closeScope()

		x = p.operand(keep_parens)
	}

loop:
	for {
		pos := p.pos()
		switch p.tok {
		case _Dot:
			p.next()
			switch p.tok {
			case _Name:
				// pexpr '.' sym
				t := new(SelectorExpr)
				t.pos = pos
				t.X = x
				t.Sel = p.name()
				x = t

			case _Lparen:
				p.next()
				if p.got(_Type) {
					t := new(TypeSwitchGuard)