rust-lang/rust-clippy

[lint idea] dangerous transmutes

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#546 opened on Jan 13, 2016

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 (11 comments) (0 reactions) (0 assignees)Rust (10,406 stars) (1,391 forks)batch import
A-lintT-middlegood first issue

Description

Along the lines of useless_transmute, it seems plausible to warn on transmute::<X, Y>(x) where X and Y aren't both primitive types or marked #[repr(C)], since as @ubsan keeps reminding us this is likely to cause UB.

Contributor guide

Tech stack
rust
Domain
tooling
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Rust programmingClippy internalstransmute semantics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50
Research direction
Look at the existing `useless transmute` lint in the clippy source code (likely in `clippy lints/src/transmute.rs`) to understand the pattern. Identify where to add a new lint check for transmutes where both types are not primitive or `#[repr(C)]`. The issue comments may contain additional context, such as concerns about false positives. Also, review the clippy lint registration and testing guidelines in the repository documentation.
[lint idea] dangerous transmutes · rust-lang/rust-clippy#546 | Good First Issue