Rust: various unsafe traits/functions meant for gencode in public API

Description

fn main() {
    let ptr: &&u8 = flatbuffers::follow_cast_ref(&[1, 2, 3, 4, 5, 6, 7, 8], 0);
    println!("{}", **ptr);
}

Contributor guide

Tech stack

rust

Domain

backend

Issue type

bug

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

4

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

1-2 days

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

active

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

mostly clear

Prerequisites

Rust programmingunderstanding of unsafe codeknowledge of flatbuffers internals

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

30

Research direction

Investigate the unsafe functions `follow cast ref` and related traits in the Rust flatbuffers source (likely in `rust/flatbuffers/src/lib.rs`). The issue demonstrates a segfault when calling `follow cast ref` on a byte slice. The problem is that the function assumes the referenced data is valid for the type `T`, but the input is not properly aligned or sized. Check how `follow cast ref` is implemented and whether it should be marked unsafe. Look at the discussion in issue #6627 for additional context and any proposed fixes.