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Auto merge of #8648 - Jarcho:transmute_collection_7706, r=xFrednet

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Fix `unsound_collection_transmute`

fixes #7706

changelog: Better check size and alignment requirements in `unsound_collection_transmute`
This commit is contained in:
bors 2022-04-08 21:43:26 +00:00
commit b029a86c6b
2 changed files with 11 additions and 12 deletions
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18
clippy_lints/src/transmute/utils.rs
View File

@ -1,10 +1,9 @@
use clippy_utils::last_path_segment;
use clippy_utils::source::snippet;
use clippy_utils::ty::is_normalizable;
use if_chain::if_chain;
use rustc_hir::{Expr, GenericArg, QPath, TyKind};
use rustc_lint::LateContext;
use rustc_middle::ty::{self, cast::CastKind, Ty};
use rustc_middle::ty::{cast::CastKind, Ty};
use rustc_span::DUMMY_SP;
use rustc_typeck::check::{cast::CastCheck, FnCtxt, Inherited};
@ -34,15 +33,12 @@ pub(super) fn get_type_snippet(cx: &LateContext<'_>, path: &QPath<'_>, to_ref_ty
// check if the component types of the transmuted collection and the result have different ABI,
// size or alignment
pub(super) fn is_layout_incompatible<'tcx>(cx: &LateContext<'tcx>, from: Ty<'tcx>, to: Ty<'tcx>) -> bool {
let empty_param_env = ty::ParamEnv::empty();
// check if `from` and `to` are normalizable to avoid ICE (#4968)
if !(is_normalizable(cx, empty_param_env, from) && is_normalizable(cx, empty_param_env, to)) {
return false;
}
let from_ty_layout = cx.tcx.layout_of(empty_param_env.and(from));
let to_ty_layout = cx.tcx.layout_of(empty_param_env.and(to));
if let (Ok(from_layout), Ok(to_layout)) = (from_ty_layout, to_ty_layout) {
from_layout.size != to_layout.size || from_layout.align != to_layout.align || from_layout.abi != to_layout.abi
if let Ok(from) = cx.tcx.try_normalize_erasing_regions(cx.param_env, from)
&& let Ok(to) = cx.tcx.try_normalize_erasing_regions(cx.param_env, to)
&& let Ok(from_layout) = cx.tcx.layout_of(cx.param_env.and(from))
&& let Ok(to_layout) = cx.tcx.layout_of(cx.param_env.and(to))
{
from_layout.size != to_layout.size || from_layout.align.abi != to_layout.align.abi
} else {
// no idea about layout, so don't lint
false

5
tests/ui/transmute_collection.rs
View File

@ -1,7 +1,7 @@
#![warn(clippy::unsound_collection_transmute)]
use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, VecDeque};
use std::mem::transmute;
use std::mem::{transmute, MaybeUninit};
fn main() {
unsafe {
@ -43,5 +43,8 @@ fn main() {
// wrong layout
let _ = transmute::<_, HashMap<u8, u32>>(HashMap::<u8, [u8; 4]>::new());
let _ = transmute::<_, HashMap<u32, u32>>(HashMap::<[u8; 4], u32>::new());
let _ = transmute::<_, Vec<u8>>(Vec::<MaybeUninit<u8>>::new());
let _ = transmute::<_, Vec<*mut u32>>(Vec::<Box<u32>>::new());
}
}