// result is assignable if n is.
func safeExpr(n ir.Node, init *ir.Nodes) ir.Node {
	if n == nil {
		return nil
	}

	if len(n.Init()) != 0 {
		walkStmtList(n.Init())
		init.Append(ir.TakeInit(n)...)
	}

	switch n.Op() {
	case ir.ONAME, ir.OLITERAL, ir.ONIL, ir.OLINKSYMOFFSET:
		return n

	case ir.OLEN, ir.OCAP:
		n := n.(*ir.UnaryExpr)
		l := safeExpr(n.X, init)
		if l == n.X {
			return n

	res := typecheck.Expr(ir.NewUnaryExpr(n.Pos(), ir.OSPTR, slice))
	res.SetType(n.Type())
	return walkExpr(res, init)
}

func walkUnsafeSlice(n *ir.BinaryExpr, init *ir.Nodes) ir.Node {
	ptr := safeExpr(n.X, init)
	len := safeExpr(n.Y, init)
	sliceType := n.Type()

	lenType := types.Types[types.TINT64]
	unsafePtr := typecheck.Conv(ptr, types.Types[types.TUNSAFEPTR])

		}
	}
	and := func(cond ir.Node) {
		if expr == nil {
			expr = cond
		} else {
			expr = ir.NewLogicalExpr(base.Pos, andor, expr, cond)
		}
	}
	cmpl = safeExpr(cmpl, init)
	cmpr = safeExpr(cmpr, init)
	if t.IsStruct() {
		conds, _ := compare.EqStruct(t, cmpl, cmpr)
		if n.Op() == ir.OEQ {
			for _, cond := range conds {
				and(cond)
			}
		} else {

	return o.copyExpr(n)
}

// safeExpr returns a safe version of n.
// The definition of safe is that n can appear multiple times
// without violating the semantics of the original program,
// and that assigning to the safe version has the same effect
// as assigning to the original n.
//
// The intended use is to apply to x when rewriting x += y into x = x + y.
func (o *orderState) safeExpr(n ir.Node) ir.Node {
	switch n.Op() {

			arg = ir.NewStarExpr(pos, addr)
			arg.SetType(argType)
		}
		args = []ir.Node{arg}
	}
	call := ir.NewCallExpr(base.Pos, ir.OCALL, fn, nil)
	call.Args = args
	return safeExpr(walkExpr(typecheck.Expr(call), init), init)
}

// walkBytesRunesToString walks an OBYTES2STR or ORUNES2STR node.
func walkBytesRunesToString(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
	a := typecheck.NodNil()

		mapAppend = right.(*ir.CallExpr)
		if !ir.SameSafeExpr(left, mapAppend.Args[0]) {
			base.Fatalf("not same expressions: %v != %v", left, mapAppend.Args[0])
		}
	}

	left = walkExpr(left, init)
	left = safeExpr(left, init)
	if mapAppend != nil {
		mapAppend.Args[0] = left
	}

	if n.Op() == ir.OASOP {
		// Rewrite x op= y into x = x op y.