# `semantic.standard_operation_qualification`

Standard-library operation is called without its namespace.

Area 1, [Project layout and modules](../topics/project-layout-and-modules.md); not declinable; the next step is usually the agent's.

```jadpo
type DueAt = Instant {}

type HomeZone = Zone {}

type DueTime = ZonedTime {}

function local_due(at: DueAt, zone: HomeZone) -> DueTime {
    var local: ZonedTime = in_zone(at, zone)
    return DueTime(local)
}
```

```text
error: `in_zone` is a standard-library operation
 --> main.jadpo:8:28
  |
8 |     var local: ZonedTime = in_zone(at, zone)
  |                            ^^^^^^^ needs its namespace
  reason: The standard library is always called through its namespace, so the dot says who owns the operation.
  next: Call `temporal.in_zone(...)` (agent)
  rule: semantic.standard_operation_qualification
  help: https://jadpo.dev/docs/errors/semantic.standard_operation_qualification

check failed: 1 error, 1 file
```