This repository is the official compiler and toolchain for the Leo programming language, a statically-typed language for writing private zero-knowledge applications on the Aleo blockchain. The codebase implements a full compilation pipeline from Leo source to Aleo bytecode, including parsing (with a lossless rowan-based parser), type checking, static analysis, multiple optimization passes (constant propagation, loop unrolling, dead code elimination, common subexpression elimination, SSA formation, function inlining, flattening, destructuring, storage lowering, option lowering, peephole optimization), and code generation targeting snarkVM. Beyond the compiler, it provides a complete development environment: a CLI with commands for building, testing, deploying, executing, and querying the Aleo network; a Language Server Protocol (LSP) implementation with diagnostics, goto-definition, references, rename, and semantic tokens; a standalone formatter; a package manager supporting local, git, network, and workspace dependencies with lock files; and an ABI generation and compatibility checker. The architecture is a multi-crate Rust workspace with clear separation of concerns, extensive test coverage (unit, integration, and expectation-based compiler tests), and CI/CD pipelines. The codebase demonstrates high craftsmanship with reusable patterns such as a generic directed graph with cycle detection, a canonicalization trait for structural equality, an intern-based type system, and a pass-based compiler architecture.