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new lint ptr_to_temporary 
1 parent cda13a8 commit 0762b75

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+152
-13
lines changed

‎CHANGELOG.md‎

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@@ -5088,6 +5088,7 @@ Released 2018-09-13
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[`ptr_cast_constness`]: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_cast_constness
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[`ptr_eq`]: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_eq
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[`ptr_offset_with_cast`]: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_offset_with_cast
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[`ptr_to_temporary`]: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_to_temporary
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[`pub_enum_variant_names`]: https://rust-lang.github.io/rust-clippy/master/index.html#pub_enum_variant_names
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[`pub_use`]: https://rust-lang.github.io/rust-clippy/master/index.html#pub_use
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[`question_mark`]: https://rust-lang.github.io/rust-clippy/master/index.html#question_mark

‎clippy_lints/src/casts/mod.rs‎

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@@ -18,6 +18,7 @@ mod fn_to_numeric_cast_any;
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mod fn_to_numeric_cast_with_truncation;
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mod ptr_as_ptr;
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mod ptr_cast_constness;
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mod ptr_to_temporary;
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mod unnecessary_cast;
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mod utils;
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@@ -657,6 +658,28 @@ declare_clippy_lint! {
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"casting a known floating-point NaN into an integer"
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}
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declare_clippy_lint! {
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/// ### What it does
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/// Checks for raw pointers that point to temporary values.
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///
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/// ### Why is this bad?
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/// It will result in Undefined Behavior, as the pointer will stop pointing to valid stack
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/// memory once the temporary is dropped.
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///
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/// ### Example
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/// ```rust,ignore
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/// let _: (0.0_f32 / 0.0) as u64;
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/// ```
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/// Use instead:
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/// ```rust,ignore
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/// let _: = 0_u64;
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/// ```
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#[clippy::version = "1.72.0"]
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pub PTR_TO_TEMPORARY,
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correctness,
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"casting a known floating-point NaN into an integer"
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}
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pub struct Casts {
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msrv: Msrv,
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}
@@ -691,6 +714,7 @@ impl_lint_pass!(Casts => [
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CAST_SLICE_FROM_RAW_PARTS,
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AS_PTR_CAST_MUT,
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CAST_NAN_TO_INT,
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PTR_TO_TEMPORARY,
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]);
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impl<'tcx> LateLintPass<'tcx> for Casts {
@@ -736,6 +760,7 @@ impl<'tcx> LateLintPass<'tcx> for Casts {
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}
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as_underscore::check(cx, expr, cast_to_hir);
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ptr_to_temporary::check(cx, expr, cast_expr, cast_to_hir);
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if self.msrv.meets(msrvs::BORROW_AS_PTR) {
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borrow_as_ptr::check(cx, expr, cast_expr, cast_to_hir);

‎clippy_lints/src/casts/ptr_to_temporary.rs‎

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@@ -0,0 +1,34 @@
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use clippy_utils::diagnostics::span_lint_and_help;
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use rustc_hir::{BorrowKind, Expr, ExprKind, Ty, TyKind};
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use rustc_lint::LateContext;
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use rustc_middle::ty::adjustment::Adjust;
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use super::PTR_TO_TEMPORARY;
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pub(super) fn check<'tcx>(
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cx: &LateContext<'tcx>,
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expr: &'tcx Expr<'_>,
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cast_expr: &'tcx Expr<'_>,
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cast_to: &'tcx Ty<'_>,
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) {
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if matches!(cast_to.kind, TyKind::Ptr(_))
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&& let ExprKind::AddrOf(BorrowKind::Ref, _, e) = cast_expr.kind
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{
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// rustc's criteria of a "temporary value", so this should be 100% accurate
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if !e.is_place_expr(|base| {
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cx.typeck_results()
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.adjustments()
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.get(base.hir_id)
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.is_some_and(|x| x.iter().any(|adj| matches!(adj.kind, Adjust::Deref(_))))
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}) {
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span_lint_and_help(
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cx,
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PTR_TO_TEMPORARY,
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expr.span,
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"raw pointer to a temporary value",
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None,
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"this causes Undefined Behavior; create a local binding to make it longer lived",
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);
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}
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}
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}

‎clippy_lints/src/declared_lints.rs‎

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@@ -94,6 +94,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
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crate::casts::FN_TO_NUMERIC_CAST_WITH_TRUNCATION_INFO,
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crate::casts::PTR_AS_PTR_INFO,
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crate::casts::PTR_CAST_CONSTNESS_INFO,
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crate::casts::PTR_TO_TEMPORARY_INFO,
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crate::casts::UNNECESSARY_CAST_INFO,
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crate::checked_conversions::CHECKED_CONVERSIONS_INFO,
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crate::cognitive_complexity::COGNITIVE_COMPLEXITY_INFO,

‎tests/ui/borrow_deref_ref.fixed‎

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@@ -1,7 +1,7 @@
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//@run-rustfix
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//@aux-build: proc_macros.rs
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#![allow(dead_code, unused_variables)]
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#![allow(clippy::ptr_to_temporary, dead_code, unused_variables)]
55

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extern crate proc_macros;
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use proc_macros::with_span;

‎tests/ui/borrow_deref_ref.rs‎

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@@ -1,7 +1,7 @@
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//@run-rustfix
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//@aux-build: proc_macros.rs
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4-
#![allow(dead_code, unused_variables)]
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#![allow(clippy::ptr_to_temporary, dead_code, unused_variables)]
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extern crate proc_macros;
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use proc_macros::with_span;

‎tests/ui/cast_alignment.rs‎

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@@ -9,7 +9,8 @@ extern crate libc;
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clippy::no_effect,
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clippy::unnecessary_operation,
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clippy::cast_lossless,
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clippy::borrow_as_ptr
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clippy::borrow_as_ptr,
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clippy::ptr_to_temporary
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)]
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fn main() {

‎tests/ui/cast_alignment.stderr‎

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@@ -1,25 +1,25 @@
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error: casting from `*const u8` to a more-strictly-aligned pointer (`*const u16`) (1 < 2 bytes)
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--> $DIR/cast_alignment.rs:19:5
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--> $DIR/cast_alignment.rs:20:5
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|
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LL | (&1u8 as *const u8) as *const u16;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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|
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= note: `-D clippy::cast-ptr-alignment` implied by `-D warnings`
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error: casting from `*mut u8` to a more-strictly-aligned pointer (`*mut u16`) (1 < 2 bytes)
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--> $DIR/cast_alignment.rs:20:5
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--> $DIR/cast_alignment.rs:21:5
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|
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LL | (&mut 1u8 as *mut u8) as *mut u16;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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error: casting from `*const u8` to a more-strictly-aligned pointer (`*const u16`) (1 < 2 bytes)
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--> $DIR/cast_alignment.rs:23:5
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--> $DIR/cast_alignment.rs:24:5
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|
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LL | (&1u8 as *const u8).cast::<u16>();
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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error: casting from `*mut u8` to a more-strictly-aligned pointer (`*mut u16`) (1 < 2 bytes)
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--> $DIR/cast_alignment.rs:24:5
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--> $DIR/cast_alignment.rs:25:5
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|
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LL | (&mut 1u8 as *mut u8).cast::<u16>();
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

‎tests/ui/ptr_to_temporary.rs‎

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#![allow(clippy::explicit_auto_deref, clippy::unnecessary_cast, clippy::useless_vec)]
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use std::ptr::addr_of;
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fn a() -> i32 {
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0
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}
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struct Vec3 {
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x: f32,
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y: f32,
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z: f32,
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}
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fn main() {
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let _p = &0 as *const i32;
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let _p = &a() as *const i32;
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let vec = vec![1];
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let _p = &vec.len() as *const usize;
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let x = &(1 + 2) as *const i32;
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let x = &(x as *const i32) as *const *const i32;
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// Do not lint...
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let ptr = &Vec3 { x: 1.0, y: 2.0, z: 3.0 };
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let some_variable = 1i32;
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let x = &(*ptr).x as *const f32;
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let x = &(some_variable) as *const i32;
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// ...As `addr_of!` does not report anything out of the ordinary
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let ptr = &Vec3 { x: 1.0, y: 2.0, z: 3.0 };
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let some_variable = 1i32;
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let x = addr_of!((*ptr).x) as *const f32;
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let x = addr_of!(some_variable);
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}

‎tests/ui/ptr_to_temporary.stderr‎

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error: raw pointer to a temporary value
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--> $DIR/ptr_to_temporary.rs:16:14
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|
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LL | let _p = &0 as *const i32;
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| ^^^^^^^^^^^^^^^^
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|
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= help: this causes Undefined Behavior; create a local binding to make it longer lived
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= note: `#[deny(clippy::ptr_to_temporary)]` on by default
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error: raw pointer to a temporary value
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--> $DIR/ptr_to_temporary.rs:17:14
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|
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LL | let _p = &a() as *const i32;
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| ^^^^^^^^^^^^^^^^^^
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|
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= help: this causes Undefined Behavior; create a local binding to make it longer lived
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18+
error: raw pointer to a temporary value
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--> $DIR/ptr_to_temporary.rs:19:14
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|
21+
LL | let _p = &vec.len() as *const usize;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^
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|
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= help: this causes Undefined Behavior; create a local binding to make it longer lived
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error: raw pointer to a temporary value
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--> $DIR/ptr_to_temporary.rs:20:13
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|
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LL | let x = &(1 + 2) as *const i32;
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| ^^^^^^^^^^^^^^^^^^^^^^
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|
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= help: this causes Undefined Behavior; create a local binding to make it longer lived
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error: raw pointer to a temporary value
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--> $DIR/ptr_to_temporary.rs:21:13
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|
37+
LL | let x = &(x as *const i32) as *const *const i32;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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|
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= help: this causes Undefined Behavior; create a local binding to make it longer lived
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error: aborting due to 5 previous errors
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