Ruchy v1.88.0+ Breaking Changes - Mutability Now Explicit

[noahgift]

Breaking Changes in Ruchy v1.88.0+

The rosetta-ruchy integration tests are reporting 95.5% breakage with Ruchy v1.88.0. The main issue identified:

Issue: Implicit Mutability No Longer Supported

Previous behavior (pre-v1.88.0):

let prev = 0;
let curr = 1;
prev = curr;  // Worked - implicit mutability

Current behavior (v1.88.0+):

let mut prev = 0;
let mut curr = 1;
prev = curr;  // Works - explicit mutability required

Impact

• All rosetta-ruchy algorithms use implicit mutability pattern
• Causes parse/compilation errors in for loops with reassignments
• Affects 21/22 algorithm implementations

Quick Fix

Add mut keyword to all variables that are reassigned:

• let prev = 0; → let mut prev = 0;
• let curr = 1; → let mut curr = 1;

New Features Working

• ✅ Explicit return statements fixed
• ✅ Array syntax [T; N] for function parameters
• ✅ Array initialization [value; size]
• ✅ Both fn and fun keywords supported

Ruchy is alpha software evolving rapidly. This change aligns with Rust's explicit mutability model for better code clarity and safety.