/unsafe-check

Check a file for unsafe code issues and potential safety violations.

Usage

/unsafe-check [file]

Parameters

file (optional): Path to the Rust file to check. If not provided, checks the current file or prompts for input.

Workflow

Read the file to identify all unsafe blocks and unsafe fn
Load unsafe-checker skill rules
Check each unsafe block against relevant rules:
- SAFETY comment present? (safety-09)
- Pointer validity verified? (ptr-*)
- Panic safety considered? (safety-01)
- FFI rules followed? (ffi-*)
Report findings with rule references and fix suggestions

Checks Performed

Safety Comments

Every unsafe block should have // SAFETY: comment
Comment should explain invariants, not just say "this is safe"

Pointer Operations

Null checks before dereference
Alignment verification
Bounds checking
No aliasing violations

FFI

Types have #[repr(C)]
Panics caught at boundary
String handling correct
Memory ownership clear

Send/Sync

Manual implementations are sound
No data races possible

Example Output

Checking: src/lib.rs

Found 3 unsafe blocks:

1. Line 42: unsafe { ptr.read() }
   - [WARN] Missing SAFETY comment (safety-09)
   - [WARN] No null check for ptr (ptr-01)
   Suggestion: Add SAFETY comment and verify ptr is non-null

2. Line 87: unsafe impl Send for MyType {}
   - [WARN] Missing Safety docs (safety-10)
   - [OK] Type analysis shows no !Send fields
   Suggestion: Add /// # Safety documentation

3. Line 123: extern "C" fn callback() { ... }
   - [WARN] No catch_unwind (ffi-04)
   Suggestion: Wrap body in std::panic::catch_unwind