Convert runtime array bounds checks to statically proven accesses in Lean 4.
npx skills add https://github.com/kim-em/lean-zip --skill proven-bounds
Please help me install this Agent Skill. Skill: proven-bounds Source: https://github.com/kim-em/lean-zip/tree/main/.claude/skills/proven-bounds Command: npx skills add https://github.com/kim-em/lean-zip --skill proven-bounds
This Skill helps developers safely convert runtime array bounds checks (xs[i]!) to statically proven accesses (xs[i]) in Lean 4, preventing runtime errors and improving code reliability.
if h : condition then to bind proof hypotheses for array bounds.for loops.data[pos]!, apply the techniques in this Skill to ensure pos < data.size is proven, allowing the ! to be removed.Use the proven-bounds skill to convert the data[pos]! access to data[pos] by adding an if h : pos < data.size guard.
High-intent search queries and answers about installing and using this skill.
To convert runtime array bounds checks in Lean 4, introduce an `if h : condition then` guard to bind proof hypotheses like `pos < data.size`, enabling the removal of the `!` operator for safe array indexing.
The Lean 4 proof system handles array bounds checking by requiring a statically proven hypothesis like `pos < data.size` to use safe indexing `data[pos]`, replacing runtime checks with compile-time proof obligations.
Yes, you can capture loop index bounds for safe array access within Lean 4 `for` loops. The Skill provides guidance on binding these bounds to prove accesses and avoid speculative conversion pitfalls.
The best way to refactor opaque loops for proof-friendly array access is replacing them with well-founded recursion. This structural change allows Lean 4 to properly capture loop bounds and verify safe indexing.
Removing the exclamation mark from array access in Lean 4 causes proof repair issues because the compiler requires a valid proof of `pos < data.size`. Without proper guard capture, speculative conversion fails to verify bounds.
fmhallProvide Lean 4 tactics for simplifying proofs with simp only failures.
fmhallGuide constructing well-founded recursion proofs in Lean 4.
fmhallConvert runtime bounds checks to proven bounds in Lean 4 code.
huialiWrite Rust const functions and const generics for compile-time computation.