Creating and debugging in Rust

--- description: Fix Rust build errors, borrow checker issues, and dependency problems incrementally. Invokes the rust-build-resolver agent for minimal, surgical fixes. --- # Rust Build and Fix This command invokes the rust-build-resolver agent to incrementally fix Rust build errors with minimal changes. ## What This Command Does 1. Run Diagnostics: Execute cargo check, cargo clippy, cargo fmt --check 2. Parse Errors: Identify error codes and affected files 3. Fix Incrementally: One error at a time 4. Verify Each Fix: Re-run cargo check after each change 5. Report Summary: Show what was fixed and what remains ## When to Use Use /rust-build when: - cargo build or cargo check fails with errors - cargo clippy reports warnings - Borrow checker or lifetime errors block compilation - Cargo dependency resolution fails - After pulling changes that break the build ## Diagnostic Commands Run ``bash # Primary build check cargo check 2>&1 # Lints and suggestions cargo clippy -- -D warnings 2>&1 # Formatting check cargo fmt --check 2>&1 # Dependency issues cargo tree --duplicates # Security audit (if available) if command -v cargo-audit >/dev/null; then cargo audit; else echo "cargo-audit not installed"; fi ` ## Example Session ``text User: /rust-build Agent: # Rust Build Resolution ## Initial Diagnostics `bash $ cargo check error[E0502]: cannot borrow map as mutable because it is also borrowed as immutable --> src/service/cache.rs:25:5 error[E0308]: mismatched types --> src/handler/api.rs:42:12 error[E0425]: cannot find value db in this scope --> src/handler/api.rs:58:9 ` Errors found: 3 ## Fix 1: Borrow Checker Error File: src/service/cache.rs:25 Error: E0502 : cannot borrow map as mutable because also borrowed as immutable Cause: Immutable borrow still active during mutable insert `rust // Changed: restructured to end immutable borrow before mutable access if !map.contains_key("key") { map.insert("key".into(), default); } ` `bash $ cargo check # 2 errors remaining ` ## Fix 2: Type Mismatch File: src/handler/api.rs:42 Error: E0308 : mismatched types: expected usize, found &str `rust // Changed let count = params.get("count"); // To let count: usize = params.get("count") .and_then(|s| s.parse().ok()) .unwrap_or(0); ` `bash $ cargo check # 1 error remaining ` ## Fix 3: Unresolved Name File: src/handler/api.rs:58 Error: E0425 : cannot find value db in this scope Cause: Missing import `rust // Added use crate::db; ` `bash $ cargo check # Build successful! ` ## Final Verification `bash $ cargo clippy -- -D warnings # No warnings $ cargo test running 6 tests test service::cache::tests::test_insert ... ok test service::cache::tests::test_get ... ok test handler::api::tests::test_parse_count ... ok test handler::api::tests::test_missing_count ... ok test handler::api::tests::test_db_import ... ok test handler::api::tests::test_response ... ok test result: ok. 6 passed; 0 failed; 0 ignored ` ## Summary | Metric | Count | |--------|-------| | Build errors fixed | 3 | | Clippy warnings fixed | 0 | | Files modified | 2 | | Remaining issues | 0 | Build Status: SUCCESS `` ## Common Errors Fixed | Error | Typical Fix | |-------|-------------| | cannot borrow as mutable | Restructure to end immutable borrow first; clone only if justified | | does not live long enough | Use owned type or add lifetime annotation | | cannot move out of | Restructure to take ownership; clone only as last resort | | mismatched types | Add .into(), as, or explicit conversion | | trait X not implemented | Add #[derive(Trait)] or implement manually | | unresolved import | Add to Cargo.toml or fix use path | | cannot find value | Add import or fix path | ## Fix Strategy 1. **Build errors first** - Code must compile 2. **Clippy warnings second** - Fix suspicious constructs 3. **Formatting third** - cargo fmt compliance 4. **One fix at a time** - Verify each change 5. **Minimal changes** - Don't refactor, just fix ## Stop Conditions The agent will stop and report if: - Same error persists after 3 attempts - Fix introduces more errors - Requires architectural changes - Borrow checker error requires redesigning data ownership ## Related Commands - /rust-test - Run tests after build succeeds - /rust-review - Review code quality - verification-loop skill - Full verification loop ## Related - Agent: agents/rust-build-resolver.md - Skill: skills/rust-patterns/`