# V9002 phase_unavailable

URL: /docs/errors/V9002
Markdown: /docs/errors/V9002.md

> A compiler phase needed by this command is not implemented yet in this pre-alpha build.

An error from the `internal` phase. `sakura explain V9002` prints this explanation offline.

A compiler phase needed by this command is not implemented yet in this pre-alpha build. The
message names the missing piece (a backend feature, a `@contract_test` handler other than
`Effect.constructor()`, …). Rewrite the program to avoid it, use another command or target
(`sakura check` runs every front-end phase), or report it if the feature is documented as
available.

## Wrong program [#wrong-program]

[`compiler/tests/ui/V9002_contract_test_handler_unsupported.sakura`](https://github.com/icantcodefyi/sakuralang/blob/master/compiler/tests/ui/V9002_contract_test_handler_unsupported.sakura), which the compiler's ui suite runs through `sakura test --contracts`:

```sakura
@contract_test(handlers: [Log.captured(), 1])
pub fn half(x: Int) -> Int
  requires x > 0
{ x / 2 }
```

`sakura test --contracts` reports `V9002`.

## Fixed program [#fixed-program]

[`compiler/tests/ui/V9002_contract_test_handler_unsupported.fixed.sakura`](https://github.com/icantcodefyi/sakuralang/blob/master/compiler/tests/ui/V9002_contract_test_handler_unsupported.fixed.sakura), which `sakura test --contracts` accepts with no diagnostics:

```sakura
import std/log.{Log}

@contract_test(handlers: [Log.captured()])
pub fn half(x: Int) -> Int
  ! {Log}
  requires x > 0
{
  Log.event(Level.Info, "halving", [])
  x / 2
}
```