# T303

> type name is not UpperCamelCase

**Severity** Error

User type names must start with an uppercase letter and use UpperCamelCase, such as `LiqCluster` or `SwingPoint`. This keeps types visually distinct from values, which are written in lowerCamelCase.

Rename the type and every place it is used.

## Failing example

```flowscope
script "Liquidation clusters"
data (
  chart = subscribe(data.ohlcv)
  liq = subscribe(data.liquidations)
)
type liq_cluster {
  price: float
  usd: float
}
state biggest: liq_cluster? = null
on chart.close {
  let total = liq.total ?? 0.0
  let b = biggest
  if b == null || total > b.usd {
    biggest = liq_cluster { price: chart.close ?? 0.0, usd: total }
  }
}
```

## Fixed example

```flowscope
script "Liquidation clusters"
data (
  chart = subscribe(data.ohlcv)
  liq = subscribe(data.liquidations)
)
type LiqCluster {
  price: float
  usd: float
}
state biggest: LiqCluster? = null
on chart.close {
  let total = liq.total ?? 0.0
  let b = biggest
  if b == null || total > b.usd {
    biggest = LiqCluster { price: chart.close ?? 0.0, usd: total }
  }
}
```

## Related

- [T005](/docs/scripting/reference/diagnostics/t005)