WEBASSEMBLY · LEAN 4 · VALIDATION
A small boundary.
A meaningful check.
An exported tag must point to a tag that exists. This contribution adds that check to Talos and records the edge cases in eight Lean regression theorems.
01 / EXPLORE THE BOUNDARY
One index space. Imports first.
Explorer limits: 0–8 tags of each kind; indices 0–4,294,967,295. Whole numbers only.
Illustrative browser model · evaluates index bounds only. This page does not execute Lean or validate a complete Wasm module.
02 / THE CHANGE
Check the right space.
Check every export.
Talos is Cajal's WebAssembly interpreter written in Lean. In this patch, Module.checkInterface now walks through tag exports and rejects an index when no corresponding tag exists.
Imports occupy the first positions; local tag declarations follow. A function at index 0 cannot supply a missing tag at index 0. Two distinct export names may point to the same existing tag.
Inspect the interface check ↗03 / PUBLIC EVIDENCE
Eight cases, made explicit.
The patch's regression source is the primary evidence. Each theorem states a concrete result and closes with Lean's cbv proof tactic.
A precise claim, with a precise scope.
The imported-and-local positive case exercises decoding followed by checkInterface. It does not establish success across every validation path. These regressions pin the behavior of this patch; they are not a proof of complete WebAssembly correctness.
This is a public contribution on Alok's fork. No upstream merge or public CI result is claimed here.