Safety property verification for transpiled Rust code.

Verifies memory safety, type safety, and other Rust safety guarantees.

Unsafe Code Auditing

This module provides comprehensive auditing of unsafe blocks in generated Rust code:

• Detection and counting of all unsafe blocks
• Confidence scoring for elimination potential
• Suggestions for safer alternatives
• Unsafe density metrics (<5 per 1000 LOC target)

Example

use decy_verify::{UnsafeAuditor, audit_rust_code};

let rust_code = r#"
    fn example() {
        unsafe {
            let ptr = std::ptr::null_mut();
        }
    }
"#;

let report = audit_rust_code(rust_code).expect("Failed to audit");
println!("Unsafe blocks found: {}", report.unsafe_blocks.len());
println!("Unsafe density: {:.2}%", report.unsafe_density_percent);

What's New in 2.0

Release Date: January 2025

• 99.9% Test Pass Rate - 1,391 tests passing
• 95% Code Coverage - Comprehensive test suite
• DECY-220: Fixed malloc cast expression handling ((int*)malloc(n) → Vec<T>)
• Portable Tests: All test paths use CARGO_MANIFEST_DIR
• System Include Discovery: Automatic detection of stdlib.h, string.h

cargo install decy

Quick Start

# Transpile a C file to Rust
decy transpile input.c -o output.rs

# Transpile an entire project
decy transpile-project src/ -o rust_output/

# Audit unsafe code
decy audit output.rs

Example:

// input.c
int add(int a, int b) {
    return a + b;
}

decy transpile input.c

// Generated Rust (no unsafe!)
fn add(a: i32, b: i32) -> i32 {
    a + b
}

Quality Metrics (PMAT)

Run quality analysis:

pmat rust-project-score
pmat repo-score
pmat analyze complexity

Installation

From crates.io (Recommended)

cargo install decy

From Source

git clone https://github.com/paiml/decy.git
cd decy
make install   # Installs Rust + LLVM/Clang
cargo install --path crates/decy

Requirements

• Rust: 1.70+ (stable)
• LLVM/Clang: 14+ (for C parsing)
• Platform: Linux, macOS, Windows (WSL2)

Features

Core Transpilation

# Single file
decy transpile input.c -o output.rs

# Project with caching (10-20x faster on unchanged files)
decy transpile-project src/ -o rust_output/
decy cache-stats src/

Debug & Visualization

# Visualize C AST
decy debug --visualize-ast input.c

# Visualize ownership inference
decy debug --visualize-ownership input.c

# Step-through debugging
decy debug --step-through input.c

Safety Analysis

# Audit unsafe blocks
decy audit output.rs --verbose

# Generate verification book
decy verify --book-output ./book

MCP Integration

# Start MCP server for Claude Code
decy mcp-server --port 3000

Architecture

C Source → Parser → HIR → Analyzer → Ownership → Codegen → Rust
             │         │       │          │          │
           clang    Rust-IR  Types   &T/&mut T    Safe code

Crates

Unsafe Minimization

Decy uses a 4-phase approach to minimize unsafe code:

Target: <5 unsafe blocks per 1000 LOC

Development

EXTREME TDD Workflow

# RED: Write failing tests
git commit -m "[RED] DECY-XXX: Add failing tests"

# GREEN: Minimal implementation
git commit -m "[GREEN] DECY-XXX: Implement feature"

# REFACTOR: Meet quality gates
git commit -m "[REFACTOR] DECY-XXX: Clean up"

Quality Gates

make quality-gates   # Run all checks
make test            # Run tests
make coverage        # Generate coverage report

Running Tests

cargo test --workspace          # All tests
cargo test -p decy-ownership    # Single crate
cargo llvm-cov --workspace      # Coverage

Documentation

• Getting Started - Developer guide
• Specification - Technical spec
• Unsafe Strategy - How we reduce unsafe
• Roadmap - Development plan

License

MIT OR Apache-2.0

Acknowledgments

• C2Rust - Mozilla's C-to-Rust transpiler
• PMAT - Quality metrics toolkit
• Toyota Production System - Quality principles