case ir.OAS2:
		tcAssignList(n.(*ir.AssignListStmt))
		return n

	case ir.OBREAK,
		ir.OCONTINUE,
		ir.ODCL,
		ir.OGOTO,
		ir.OFALL:
		return n

	case ir.OBLOCK:
		n := n.(*ir.BlockStmt)
		Stmts(n.List)
		return n

	case ir.OLABEL:
		if n.Sym().IsBlank() {
			// Empty identifier is valid but useless.
			// Eliminate now to simplify life later.
			// See issues 7538, 11589, 11593.

		default:
			base.Fatalf("order.stmt: %v", r.Op())
		}

		o.as2ok(n)
		o.popTemp(t)

	// Special: does not save n onto out.
	case ir.OBLOCK:
		n := n.(*ir.BlockStmt)
		o.stmtList(n.List)

	// Special: n->left is not an expression; save as is.
	case ir.OBREAK,
		ir.OCONTINUE,
		ir.ODCL,
		ir.OFALL,
		ir.OGOTO,
		ir.OLABEL,
		ir.OTAILCALL:

			u.node(node.Results)
		}
	case *ast.FieldList:
		for _, field := range node.List {
			u.node(field)
		}
	case *ast.Field:
		u.node(node.Type)

	// statements

	case *ast.BlockStmt:
		defer u.scoped()()
		for _, stmt := range node.List {
			u.node(stmt)
		}
	case *ast.DeclStmt:
		u.node(node.Decl)
	case *ast.IfStmt:
		if node.Init != nil {
			u.node(node.Init)
		}