Clippy lints / Correctness
Clippy lint · Correctness · checked with Clippy 0.1.99
clippy::wrong_transmute: Checks for transmutes that can’t ever be correct on any architecture
What it meansChecks for transmutes that can’t ever be correct on any architecture. It is in the correctness group and denied by default (the build fails).
Does it matter?
It’s basically guaranteed to be undefined behavior.
Code that is almost certainly wrong. Denied by default: the build fails until you fix it or allow it.
How to fix it
Clippy does not fix this one automatically. Change the code by hand:
Flagged
let ptr: *const T = core::intrinsics::transmute('x')
Turn it off, or on
Allow it where it does not fit your code, as narrowly as you can:
On one item
#[allow(clippy::wrong_transmute)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
wrong_transmute = "allow"One run
cargo clippy -- -A clippy::wrong-transmuteThe [lints] table needs Rust 1.74 or newer. In a workspace, put it under [workspace.lints.clippy] and add [lints] workspace = true to each member.
Clippy's own documentation
What it does
Checks for transmutes that can’t ever be correct on any architecture.
Why is this bad?
It’s basically guaranteed to be undefined behavior.
Known problems
When accessing C, users might want to store pointer
sized objects in extradata arguments to save an allocation.
Example
let ptr: *const T = core::intrinsics::transmute('x')
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
Related lints
- useless_attributeChecks for extern crate and use items annotated with lint attributes. This lint permits lint attributes for lints emitted on the items themself. For use items these lints are: ambiguous_glob_reexports dead_code deprecated hidden_glob_reexports unreachable_pub unused unused_braces unused_import_braces clippy::disallowed_types clippy::enum_glob_use clippy::macro_use_imports clippy::module_name_repetitions clippy::redundant_pub_crate clippy::single_component_path_imports clippy::unsafe_removed_from_name clippy::wildcard_imports For extern crate items these lints are: unused_imports on items with #[macro_use]
- vec_resize_to_zeroFinds occurrences of Vec::resize(0, an_int)
- while_immutable_conditionvariables in the condition are not mutated in the loop body
- zst_offsetoffset calculation on zero-sized value
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
Up next
Related lintclippy::useless_attributeChecks for extern crate and use items annotated with lint attributes. This lint permits lint attributes for lints emitted on the items themself. For use items these lints are: ambiguous_glob_reexports dead_code deprecated hidden_glob_reexports unreachable_pub unused unused_braces unused_import_braces clippy::disallowed_types clippy::enum_glob_use clippy::macro_use_imports clippy::module_name_repetitions clippy::redundant_pub_crate clippy::single_component_path_imports clippy::unsafe_removed_from_name clippy::wildcard_imports For extern crate items these lints are: unused_imports on items with #[macro_use]Read it next →Did this answer your question?