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fix(transmute_ptr_to_ptr): add parens if transmute is receiver of a projection #15724

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fix(transmute_ptr_to_ptr): add parens if transmute is receiver of a projection #15724

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14 changes: 12 additions & 2 deletions clippy_lints/src/transmute/transmute_ref_to_ref.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@ use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_and_then};
use clippy_utils::source::snippet;
use clippy_utils::{std_or_core, sugg};
use rustc_errors::Applicability;
use rustc_hir::{Expr, Mutability};
use rustc_hir::{Expr, ExprKind, Mutability, Node};
use rustc_lint::LateContext;
use rustc_middle::ty::{self, Ty};

Expand Down Expand Up @@ -58,11 +58,21 @@ pub(super) fn check<'tcx>(
let sugg_paren = arg
.as_ty(Ty::new_ptr(cx.tcx, ty_from, from_mutbl))
.as_ty(Ty::new_ptr(cx.tcx, ty_to, to_mutbl));
let sugg = if to_mutbl == Mutability::Mut {
let mut sugg = if to_mutbl == Mutability::Mut {
sugg_paren.mut_addr_deref()
} else {
sugg_paren.addr_deref()
};
// If the expression is a receiver of some kind of a projection, we'll need to wrap the
// replacement in parens
if let Node::Expr(parent) = cx.tcx.parent_hir_node(e.hir_id)
&& let ExprKind::Index(recv, ..)
| ExprKind::Field(recv, _)
| ExprKind::MethodCall(_, recv, ..) = parent.kind
&& recv.hir_id == e.hir_id
{
sugg = sugg.maybe_paren();
}
diag.span_suggestion(e.span, "try", sugg, Applicability::Unspecified);
}
},
Expand Down
29 changes: 28 additions & 1 deletion tests/ui/transmute_ptr_to_ptr.fixed
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Original file line number Diff line number Diff line change
@@ -1,5 +1,12 @@
#![warn(clippy::transmute_ptr_to_ptr)]
#![allow(clippy::borrow_as_ptr, clippy::missing_transmute_annotations)]
#![allow(
clippy::borrow_as_ptr,
clippy::missing_transmute_annotations,
clippy::let_unit_value,
clippy::unnecessary_mut_passed,
mutable_transmutes,
invalid_reference_casting
)]

use std::mem::transmute;

Expand Down Expand Up @@ -117,4 +124,24 @@ fn msrv_1_65(ptr: *const u8, mut_ptr: *mut u8) {
}
}

fn issue15003(bs: &[u8]) {
unsafe {
(&mut *(bs as *const [u8] as *mut [u8]))[4] = 42;
//~^ transmute_ptr_to_ptr
let _ = (&mut *(bs as *const [u8] as *mut [u8])).len();
//~^ transmute_ptr_to_ptr
// NOTE: need to transmute into something we can then index into
let _ = (&mut *(bs as *const [u8] as *mut (u8, [u8]))).0;
//~^ transmute_ptr_to_ptr

// Don't add parens if the expression is not the receiver
struct S;
impl S {
fn foo(self, _: &mut [u8]) {}
}
let _ = S.foo(&mut *(bs as *const [u8] as *mut [u8]));
//~^ transmute_ptr_to_ptr
}
}

fn main() {}
29 changes: 28 additions & 1 deletion tests/ui/transmute_ptr_to_ptr.rs
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Original file line number Diff line number Diff line change
@@ -1,5 +1,12 @@
#![warn(clippy::transmute_ptr_to_ptr)]
#![allow(clippy::borrow_as_ptr, clippy::missing_transmute_annotations)]
#![allow(
clippy::borrow_as_ptr,
clippy::missing_transmute_annotations,
clippy::let_unit_value,
clippy::unnecessary_mut_passed,
mutable_transmutes,
invalid_reference_casting
)]

use std::mem::transmute;

Expand Down Expand Up @@ -117,4 +124,24 @@ fn msrv_1_65(ptr: *const u8, mut_ptr: *mut u8) {
}
}

fn issue15003(bs: &[u8]) {
unsafe {
transmute::<&[u8], &mut [u8]>(bs)[4] = 42;
//~^ transmute_ptr_to_ptr
let _ = transmute::<&[u8], &mut [u8]>(bs).len();
//~^ transmute_ptr_to_ptr
// NOTE: need to transmute into something we can then index into
let _ = transmute::<&[u8], &mut (u8, [u8])>(bs).0;
//~^ transmute_ptr_to_ptr

// Don't add parens if the expression is not the receiver
struct S;
impl S {
fn foo(self, _: &mut [u8]) {}
}
let _ = S.foo(transmute::<&[u8], &mut [u8]>(bs));
//~^ transmute_ptr_to_ptr
}
}

fn main() {}
58 changes: 41 additions & 17 deletions tests/ui/transmute_ptr_to_ptr.stderr
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
error: transmute from a pointer to a pointer
--> tests/ui/transmute_ptr_to_ptr.rs:32:29
--> tests/ui/transmute_ptr_to_ptr.rs:39:29
|
LL | let _: *const f32 = transmute(ptr);
| ^^^^^^^^^^^^^^
Expand All @@ -13,7 +13,7 @@ LL + let _: *const f32 = ptr.cast::<f32>();
|

error: transmute from a pointer to a pointer
--> tests/ui/transmute_ptr_to_ptr.rs:35:27
--> tests/ui/transmute_ptr_to_ptr.rs:42:27
|
LL | let _: *mut f32 = transmute(mut_ptr);
| ^^^^^^^^^^^^^^^^^^
Expand All @@ -25,37 +25,37 @@ LL + let _: *mut f32 = mut_ptr.cast::<f32>();
|

error: transmute from a reference to a reference
--> tests/ui/transmute_ptr_to_ptr.rs:39:23
--> tests/ui/transmute_ptr_to_ptr.rs:46:23
|
LL | let _: &f32 = transmute(&1u32);
| ^^^^^^^^^^^^^^^^ help: try: `&*(&1u32 as *const u32 as *const f32)`

error: transmute from a reference to a reference
--> tests/ui/transmute_ptr_to_ptr.rs:42:23
--> tests/ui/transmute_ptr_to_ptr.rs:49:23
|
LL | let _: &f32 = transmute(&1f64);
| ^^^^^^^^^^^^^^^^ help: try: `&*(&1f64 as *const f64 as *const f32)`

error: transmute from a reference to a reference
--> tests/ui/transmute_ptr_to_ptr.rs:47:27
--> tests/ui/transmute_ptr_to_ptr.rs:54:27
|
LL | let _: &mut f32 = transmute(&mut 1u32);
| ^^^^^^^^^^^^^^^^^^^^ help: try: `&mut *(&mut 1u32 as *mut u32 as *mut f32)`

error: transmute from a reference to a reference
--> tests/ui/transmute_ptr_to_ptr.rs:50:37
--> tests/ui/transmute_ptr_to_ptr.rs:57:37
|
LL | let _: &GenericParam<f32> = transmute(&GenericParam { t: 1u32 });
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&*(&GenericParam { t: 1u32 } as *const GenericParam<u32> as *const GenericParam<f32>)`

error: transmute from a reference to a reference
--> tests/ui/transmute_ptr_to_ptr.rs:54:27
--> tests/ui/transmute_ptr_to_ptr.rs:61:27
|
LL | let u8_ref: &u8 = transmute(u64_ref);
| ^^^^^^^^^^^^^^^^^^ help: try: `&*(u64_ref as *const u64 as *const u8)`

error: transmute from a pointer to a pointer
--> tests/ui/transmute_ptr_to_ptr.rs:57:29
--> tests/ui/transmute_ptr_to_ptr.rs:64:29
|
LL | let _: *const u32 = transmute(mut_ptr);
| ^^^^^^^^^^^^^^^^^^
Expand All @@ -67,7 +67,7 @@ LL + let _: *const u32 = mut_ptr.cast_const();
|

error: transmute from a pointer to a pointer
--> tests/ui/transmute_ptr_to_ptr.rs:60:27
--> tests/ui/transmute_ptr_to_ptr.rs:67:27
|
LL | let _: *mut u32 = transmute(ptr);
| ^^^^^^^^^^^^^^
Expand All @@ -79,7 +79,7 @@ LL + let _: *mut u32 = ptr.cast_mut();
|

error: transmute from a pointer to a pointer
--> tests/ui/transmute_ptr_to_ptr.rs:72:14
--> tests/ui/transmute_ptr_to_ptr.rs:79:14
|
LL | unsafe { transmute(v) }
| ^^^^^^^^^^^^
Expand All @@ -91,7 +91,7 @@ LL + unsafe { v as *const &() }
|

error: transmute from a pointer to a pointer
--> tests/ui/transmute_ptr_to_ptr.rs:87:28
--> tests/ui/transmute_ptr_to_ptr.rs:94:28
|
LL | let _: *const i8 = transmute(ptr);
| ^^^^^^^^^^^^^^
Expand All @@ -103,7 +103,7 @@ LL + let _: *const i8 = ptr as *const i8;
|

error: transmute from a pointer to a pointer
--> tests/ui/transmute_ptr_to_ptr.rs:95:28
--> tests/ui/transmute_ptr_to_ptr.rs:102:28
|
LL | let _: *const i8 = transmute(ptr);
| ^^^^^^^^^^^^^^
Expand All @@ -115,7 +115,7 @@ LL + let _: *const i8 = ptr.cast::<i8>();
|

error: transmute from a pointer to a pointer
--> tests/ui/transmute_ptr_to_ptr.rs:103:26
--> tests/ui/transmute_ptr_to_ptr.rs:110:26
|
LL | let _: *mut u8 = transmute(ptr);
| ^^^^^^^^^^^^^^
Expand All @@ -127,7 +127,7 @@ LL + let _: *mut u8 = ptr as *mut u8;
|

error: transmute from a pointer to a pointer
--> tests/ui/transmute_ptr_to_ptr.rs:105:28
--> tests/ui/transmute_ptr_to_ptr.rs:112:28
|
LL | let _: *const u8 = transmute(mut_ptr);
| ^^^^^^^^^^^^^^^^^^
Expand All @@ -139,7 +139,7 @@ LL + let _: *const u8 = mut_ptr as *const u8;
|

error: transmute from a pointer to a pointer
--> tests/ui/transmute_ptr_to_ptr.rs:113:26
--> tests/ui/transmute_ptr_to_ptr.rs:120:26
|
LL | let _: *mut u8 = transmute(ptr);
| ^^^^^^^^^^^^^^
Expand All @@ -151,7 +151,7 @@ LL + let _: *mut u8 = ptr.cast_mut();
|

error: transmute from a pointer to a pointer
--> tests/ui/transmute_ptr_to_ptr.rs:115:28
--> tests/ui/transmute_ptr_to_ptr.rs:122:28
|
LL | let _: *const u8 = transmute(mut_ptr);
| ^^^^^^^^^^^^^^^^^^
Expand All @@ -162,5 +162,29 @@ LL - let _: *const u8 = transmute(mut_ptr);
LL + let _: *const u8 = mut_ptr.cast_const();
|

error: aborting due to 16 previous errors
error: transmute from a reference to a reference
--> tests/ui/transmute_ptr_to_ptr.rs:129:9
|
LL | transmute::<&[u8], &mut [u8]>(bs)[4] = 42;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `(&mut *(bs as *const [u8] as *mut [u8]))`

error: transmute from a reference to a reference
--> tests/ui/transmute_ptr_to_ptr.rs:131:17
|
LL | let _ = transmute::<&[u8], &mut [u8]>(bs).len();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `(&mut *(bs as *const [u8] as *mut [u8]))`

error: transmute from a reference to a reference
--> tests/ui/transmute_ptr_to_ptr.rs:134:17
|
LL | let _ = transmute::<&[u8], &mut (u8, [u8])>(bs).0;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `(&mut *(bs as *const [u8] as *mut (u8, [u8])))`

error: transmute from a reference to a reference
--> tests/ui/transmute_ptr_to_ptr.rs:142:23
|
LL | let _ = S.foo(transmute::<&[u8], &mut [u8]>(bs));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&mut *(bs as *const [u8] as *mut [u8])`

error: aborting due to 20 previous errors