# Experimental source preview

Preview limited local Swift source patterns without a build or Index Store. This workflow produces review candidates; it does not provide compiler-backed source-scan coverage.

## Inspect the available patterns

```sh
"$ANALYZER" experimental-scan --list-rules
```

The documented executable lists 13 preview rules. Use the listed string ID with `--rule`; a catalog condition ID such as `V-PERF-04` is not the CLI selector. [CLI reference](https://docs.swift-analyzer.com/reference/cli/#experimental-scan) includes the exact help.

## Scan source text

Replace `/path/to/source` with a Swift file or directory:

```sh
"$ANALYZER" experimental-scan /path/to/source \
  --rule performance.array-fifo-shifts --format json
```

Repeat `--rule` to select more patterns. With no rule filter, the registered preview rules are selected. Review each candidate's assumptions, file issues, report limitations and status. It does not build or execute the analyzed code.

## Interpret the boundary

A source-text pattern can miss effects hidden by calls, aliases, generated code, dynamic behavior or build conditions. A candidate is a reason to inspect the code. No candidate does not prove absence of a semantic defect. Its `complete` status describes this preview operation, not whole-program completeness or source-scan support.


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Language: en
Canonical: https://docs.swift-analyzer.com/guides/experimental/
Product revision: 524fa07e0ae4153c84ac12ae9eb6559df89ec2be
Catalog revision: 4558458d
Documentation digest: 1f17ba58ab08627e0de898f1442067b09e960b48cd5605d6529e9275f8930d68
Channel: pre-prod; maturity: experimental; access: owner-provided checkout.