ast -> linkers = {
    ['g|"X"|"Y"|"Z"'] = {src1, src2, src3},
    ['g|"X"|"Y"']     = {src4, src5, src6},
    ['g|"X"']         = {src7, src8, src9},
    ['l|7']           = {src10},
    ['l|7|"x"']       = {src11},
    ['l|11|"k"']      = {src12},
}

```lua
x.y.<?z?> = <!f!>

<?g?> = x.y.z

t.<!z!> = 1
x.y = t

x = {
    y = {
        <!z!> = 1
    }
}
```

expect:   'l|x|y|z'
forward:  'l|x|y|z' -> f
backward: 'l|x|y|z' -> g
last:     'l|x|y' + 'z'

expect:   'l|x|y' + '|z'
forward:  'l|t' + '|z' -> 'l|t|z' -> t.z
backward: nil
last:     'l|x' + '|y|z'

expect:   'l|x' + '|y|z'
forward:  'l|0' + '|y|z' -> 'l|0|y|z'
backward: nil
last:     nil

expect:   'l|0|y|z'
forward:  nil
backward: nil
last:     'l|0|y' + '|z'

expect:   'l|0|y' + '|z'
forward:  'l|1'+ '|z' -> 'l|1|z' -> field z
backward: nil
last:     'l|0' + '|y|z'


```lua
a = {
    b = {
        <?c?> = 1,
    }
}

print(a.b.<!c!>)
```

expect:   't|3|c'
forward:  nil
backward: nil
last:     't|3' + '|c'

expect:   't|3' + '|c'
forward:  nil
backward: 't|2|b' + '|c'
last:     nil

expect:   't|2|b|c'
forward:  nil
backward: 't|2|b' + '|c'
last:     nil

```lua
---@return <?A?>
local function f()
end

local <!x!> = f()
```

'd|A'
'f|1|#1'
'f|1' + '|#1'
'l|1' + '|#1'
's|1' + '|#1'

```lua
---@generic T
---@param a T
---@return T
local function f(a) end

local <?c?>

local <!v!> = f(c)
```

'l1'
'l2|@1'
'f|1|@1'
'f|1|#1'

```
---@generic T
---@param p T
---@return T
local function f(p) end

local <?r?> = f(<!k!>)
```

l:r
s:1#1 call
l:f#1 call
f:1#1 call -> f:1&T = l:k
l:f@1 --> 从保存的call信息里找到 f:1&T = l:k
l:k



```
---@generic T, V
---@param p T
---@return fun(V):T, V
local function f(p) end

local f2 = f(<!k!>)
local <?r?> = f2()
```

l:r
s:2|#1 call1
l:f2|#1 call1
f:2|#1 call1
s:1#1|#1 call2
f:1#1|#1 call2 -> f:1&T = l:k
dfun:1|#1
dn:V -> f:1&T = l:k