rust-borrow-checker

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name: rust-borrow-checker description: Debug Rust ownership, borrowing, and lifetime errors. Use when encountering borrow checker errors (E0382, E0502, E0597, etc.) or when code won't compile due to ownership issues.

<essential_principles> The Rust borrow checker enforces memory safety at compile time through three rules:

1. Each value has exactly one owner - When the owner goes out of scope, the value is dropped
2. You can have either one mutable reference OR any number of immutable references - Never both simultaneously
3. References must always be valid - No dangling references, lifetimes must be sufficient

Understanding these rules is the key to fixing borrow checker errors. </essential_principles>

1. Diagnose a borrow checker error (paste the error)
2. Fix a lifetime annotation issue
3. Fix an ownership transfer problem
4. Fix a mutable/immutable borrow conflict
5. Understand a specific error code

Paste the compiler error or describe the issue, then I'll route to the appropriate workflow.

<quick_fixes> Common solutions for frequent errors:

E0382 (use of moved value): Clone, use references, or restructure to avoid the move E0502 (cannot borrow as mutable, already borrowed as immutable): Separate the borrows into different scopes, or use interior mutability (RefCell, Mutex) E0499 (cannot borrow as mutable more than once): Split into separate scopes or use indices instead of references E0597 (borrowed value does not live long enough): Extend the lifetime of the owner, or use owned types instead E0506 (cannot assign, already borrowed): Complete borrow before assignment, or use Cell/RefCell </quick_fixes>

<reference_index> Domain knowledge in references/:

Core Rules:

• ownership-rules.md - The three ownership rules with examples
• borrowing-rules.md - Borrowing and reference rules
• lifetime-syntax.md - Lifetime annotation patterns and elision

Problem Solving:

• common-errors.md - Detailed breakdown of E0XXX errors
• patterns.md - Clone, Rc, Arc, RefCell, Cow patterns </reference_index>

<workflows_index>

<success_criteria> A fix is complete when:

• cargo check passes without borrow checker errors
• The solution doesn't introduce unnecessary cloning
• The fix maintains the original intent of the code
• Lifetimes are as simple as possible (rely on elision when possible) </success_criteria>