# Plan #106

**Source:** Dart SDK 3.0.0
**Category:** Deprecation
**Relevance Score:** 5
**Detected APIs:** BidirectionalIterator, Removed

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## Release Note Entry

> - Removed the deprecated [`BidirectionalIterator`][] class.
>
> Context: Existing bidirectional iterators can still work, they just don't have

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## Migration Analysis

### What Changed

An API has been deprecated. Users still using the old API should migrate to the recommended replacement.

### APIs Involved

- `BidirectionalIterator`
- `Removed`

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## Proposed Lint Rule

**Rule Type:** `deprecation_migration`
**Estimated Difficulty:** medium

### Detection Strategy

Detect usage of the deprecated API via AST method/property invocation nodes

**Relevant AST nodes:**
- `MethodInvocation`
- `PropertyAccess`
- `PrefixedIdentifier`
- `SimpleIdentifier`

### Fix Strategy

Replace with the recommended alternative API

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## Implementation Checklist

- [ ] Verify the API change in Flutter/Dart SDK source
- [ ] Determine minimum SDK version requirement
- [ ] Write detection logic (AST visitor)
- [ ] Write quick-fix replacement
- [ ] Create test fixture with bad/good examples
- [ ] Add unit tests
- [ ] Register rule in `all_rules.dart`
- [ ] Add to tier in `tiers.dart`
- [ ] Update ROADMAP.md
- [ ] Update CHANGELOG.md

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**Status:** Not started
**Generated:** From Dart SDK v3.0.0 release notes
