# N003

> null needs an explicit type

**Severity** Error

A bare `null` was used where no type can be inferred from context, for example `state peak = null` or `let x = null`. The compiler cannot tell whether it is meant to be a `float?`, a `time?` or something else.

Add a type annotation (`state peak: float? = null`), or use the `null` where the expected type is known, such as a typed parameter or the other branch of a ternary.

## Failing example

```flowscope
script "Swing memory"
data chart = subscribe(data.ohlcv)
state lastPivot = null
plot level = plot.line(title: "Last pivot high", style: linestyle.step)
on chart.close {
  let p = ta.pivotHigh(chart.high, 3, 3)
  if p != null {
    lastPivot = p
  }
  level.plot(lastPivot)
}
```

## Fixed example

```flowscope
script "Swing memory"
data chart = subscribe(data.ohlcv)
state lastPivot: float? = null
plot level = plot.line(title: "Last pivot high", style: linestyle.step)
on chart.close {
  let p = ta.pivotHigh(chart.high, 3, 3)
  if p != null {
    lastPivot = p
  }
  level.plot(lastPivot)
}
```

## Related

- [N001](/docs/scripting/reference/diagnostics/n001)
- [T208](/docs/scripting/reference/diagnostics/t208)