# V0008 nesting_limit_exceeded

URL: /docs/errors/V0008
Markdown: /docs/errors/V0008.md

> Expressions, types, patterns or blocks nest deeper than the parser's limit (128).

An error from the `parse` phase. `sakura explain V0008` prints this explanation offline.

Expressions, types, patterns or blocks nest deeper than the parser's limit (128). The limit
keeps the compiler's stack bounded on malformed or adversarial input. Split the expression with
`let` bindings.

## Wrong program [#wrong-program]

[`compiler/tests/ui/V0008_nesting_limit.sakura`](https://github.com/icantcodefyi/sakuralang/blob/master/compiler/tests/ui/V0008_nesting_limit.sakura), which the compiler's ui suite runs through `sakura check`:

The program is 10022 bytes, too long to show here; open the file to read it.

`sakura check --json` reports this record (pretty-printed; `$DIR` is the fixture's directory):

```json
{
  "schema_version": "1.0",
  "kind": "diagnostic",
  "id": "d:53e1660d0c45dbbd",
  "code": "V0008",
  "severity": "error",
  "phase": "parse",
  "message": "nesting exceeds the limit of 128",
  "snapshot": "sha256:$SNAPSHOT",
  "symbol_id": "main::V0008_nesting_limit::deep",
  "spans": [
    {
      "uri": "file://$DIR/V0008_nesting_limit.sakura",
      "content_hash": "sha256:b0535cfc22662ebf15361d5ab0c56fe7b5f50a4fd0acf3139b95343829f66f54",
      "start_byte": 240,
      "end_byte": 241,
      "role": "primary"
    }
  ],
  "related_ids": [],
  "expected": null,
  "actual": null,
  "obligation": null,
  "counterexample": null,
  "explanation_uri": "sakura://explain/V0008",
  "fixes": []
}
```

## Fixed program [#fixed-program]

[`compiler/tests/ui/V0008_nesting_limit.fixed.sakura`](https://github.com/icantcodefyi/sakuralang/blob/master/compiler/tests/ui/V0008_nesting_limit.fixed.sakura), which `sakura check` accepts with no diagnostics:

```sakura
fn deep() -> Int {
  let inner = ((1))
  ((inner))
}
```