Don't lint useless_transmute on types with erased regions
This commit is contained in:
Jason Newcomb
parent
2466a0507c
commit
9c9cca3e66
@ -4,7 +4,7 @@
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use rustc_errors::Applicability;
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use rustc_hir::Expr;
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use rustc_lint::LateContext;
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use rustc_middle::ty::{self, Ty};
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use rustc_middle::ty::{self, Ty, TypeFoldable};
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/// Checks for `useless_transmute` lint.
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/// Returns `true` if it's triggered, otherwise returns `false`.
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@ -16,7 +16,7 @@ pub(super) fn check<'tcx>(
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arg: &'tcx Expr<'_>,
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) -> bool {
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match (&from_ty.kind(), &to_ty.kind()) {
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_ if from_ty == to_ty => {
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_ if from_ty == to_ty && !from_ty.has_erased_regions() => {
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span_lint(
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cx,
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USELESS_TRANSMUTE,
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@ -26,28 +26,31 @@ pub(super) fn check<'tcx>(
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true
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},
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(ty::Ref(_, rty, rty_mutbl), ty::RawPtr(ptr_ty)) => {
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span_lint_and_then(
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cx,
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USELESS_TRANSMUTE,
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e.span,
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"transmute from a reference to a pointer",
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|diag| {
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if let Some(arg) = sugg::Sugg::hir_opt(cx, arg) {
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let rty_and_mut = ty::TypeAndMut {
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ty: *rty,
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mutbl: *rty_mutbl,
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};
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// No way to give the correct suggestion here. Avoid linting for now.
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if !rty.has_erased_regions() {
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span_lint_and_then(
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cx,
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USELESS_TRANSMUTE,
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e.span,
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"transmute from a reference to a pointer",
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|diag| {
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if let Some(arg) = sugg::Sugg::hir_opt(cx, arg) {
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let rty_and_mut = ty::TypeAndMut {
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ty: *rty,
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mutbl: *rty_mutbl,
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};
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let sugg = if *ptr_ty == rty_and_mut {
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arg.as_ty(to_ty)
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} else {
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arg.as_ty(cx.tcx.mk_ptr(rty_and_mut)).as_ty(to_ty)
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};
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let sugg = if *ptr_ty == rty_and_mut {
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arg.as_ty(to_ty)
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} else {
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arg.as_ty(cx.tcx.mk_ptr(rty_and_mut)).as_ty(to_ty)
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};
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diag.span_suggestion(e.span, "try", sugg.to_string(), Applicability::Unspecified);
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}
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},
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);
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diag.span_suggestion(e.span, "try", sugg.to_string(), Applicability::Unspecified);
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}
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},
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);
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}
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true
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},
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(ty::Int(_) | ty::Uint(_), ty::RawPtr(_)) => {
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@ -16,7 +16,8 @@ fn my_vec() -> MyVec<i32> {
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#[allow(clippy::needless_lifetimes, clippy::transmute_ptr_to_ptr)]
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#[warn(clippy::useless_transmute)]
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unsafe fn _generic<'a, T, U: 'a>(t: &'a T) {
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let _: &'a T = core::intrinsics::transmute(t);
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// FIXME: should lint
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// let _: &'a T = core::intrinsics::transmute(t);
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let _: &'a U = core::intrinsics::transmute(t);
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@ -48,6 +49,22 @@ fn useless() {
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let _ = (1 + 1_usize) as *const usize;
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}
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unsafe fn _f<'a, 'b>(x: &'a u32) -> &'b u32 {
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std::mem::transmute(x)
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}
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unsafe fn _f2<'a, 'b>(x: *const (dyn Iterator<Item = u32> + 'a)) -> *const (dyn Iterator<Item = u32> + 'b) {
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std::mem::transmute(x)
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}
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unsafe fn _f3<'a, 'b>(x: fn(&'a u32)) -> fn(&'b u32) {
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std::mem::transmute(x)
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}
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unsafe fn _f4<'a, 'b>(x: std::borrow::Cow<'a, str>) -> std::borrow::Cow<'b, str> {
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std::mem::transmute(x)
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}
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}
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struct Usize(usize);
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@ -1,73 +1,67 @@
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error: transmute from a type (`&T`) to itself
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--> $DIR/transmute.rs:19:20
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error: transmute from a reference to a pointer
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--> $DIR/transmute.rs:24:23
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LL | let _: &'a T = core::intrinsics::transmute(t);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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LL | let _: *const T = core::intrinsics::transmute(t);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `t as *const T`
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= note: `-D clippy::useless-transmute` implied by `-D warnings`
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error: transmute from a reference to a pointer
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--> $DIR/transmute.rs:23:23
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LL | let _: *const T = core::intrinsics::transmute(t);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `t as *const T`
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error: transmute from a reference to a pointer
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--> $DIR/transmute.rs:25:21
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--> $DIR/transmute.rs:26:21
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LL | let _: *mut T = core::intrinsics::transmute(t);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `t as *const T as *mut T`
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error: transmute from a reference to a pointer
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--> $DIR/transmute.rs:27:23
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--> $DIR/transmute.rs:28:23
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LL | let _: *const U = core::intrinsics::transmute(t);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `t as *const T as *const U`
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error: transmute from a type (`std::vec::Vec<i32>`) to itself
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--> $DIR/transmute.rs:33:27
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--> $DIR/transmute.rs:34:27
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LL | let _: Vec<i32> = core::intrinsics::transmute(my_vec());
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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error: transmute from a type (`std::vec::Vec<i32>`) to itself
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--> $DIR/transmute.rs:35:27
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--> $DIR/transmute.rs:36:27
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LL | let _: Vec<i32> = core::mem::transmute(my_vec());
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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error: transmute from a type (`std::vec::Vec<i32>`) to itself
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--> $DIR/transmute.rs:37:27
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--> $DIR/transmute.rs:38:27
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LL | let _: Vec<i32> = std::intrinsics::transmute(my_vec());
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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error: transmute from a type (`std::vec::Vec<i32>`) to itself
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--> $DIR/transmute.rs:39:27
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--> $DIR/transmute.rs:40:27
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LL | let _: Vec<i32> = std::mem::transmute(my_vec());
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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error: transmute from a type (`std::vec::Vec<i32>`) to itself
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--> $DIR/transmute.rs:41:27
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--> $DIR/transmute.rs:42:27
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LL | let _: Vec<i32> = my_transmute(my_vec());
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| ^^^^^^^^^^^^^^^^^^^^^^
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error: transmute from an integer to a pointer
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--> $DIR/transmute.rs:43:31
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--> $DIR/transmute.rs:44:31
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LL | let _: *const usize = std::mem::transmute(5_isize);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `5_isize as *const usize`
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error: transmute from an integer to a pointer
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--> $DIR/transmute.rs:47:31
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--> $DIR/transmute.rs:48:31
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LL | let _: *const usize = std::mem::transmute(1 + 1usize);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `(1 + 1usize) as *const usize`
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error: transmute from a type (`*const Usize`) to the type that it points to (`Usize`)
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--> $DIR/transmute.rs:62:24
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--> $DIR/transmute.rs:79:24
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LL | let _: Usize = core::intrinsics::transmute(int_const_ptr);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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@ -75,25 +69,25 @@ LL | let _: Usize = core::intrinsics::transmute(int_const_ptr);
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= note: `-D clippy::crosspointer-transmute` implied by `-D warnings`
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error: transmute from a type (`*mut Usize`) to the type that it points to (`Usize`)
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--> $DIR/transmute.rs:64:24
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--> $DIR/transmute.rs:81:24
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LL | let _: Usize = core::intrinsics::transmute(int_mut_ptr);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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error: transmute from a type (`Usize`) to a pointer to that type (`*const Usize`)
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--> $DIR/transmute.rs:66:31
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--> $DIR/transmute.rs:83:31
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LL | let _: *const Usize = core::intrinsics::transmute(my_int());
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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error: transmute from a type (`Usize`) to a pointer to that type (`*mut Usize`)
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--> $DIR/transmute.rs:68:29
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--> $DIR/transmute.rs:85:29
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LL | let _: *mut Usize = core::intrinsics::transmute(my_int());
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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error: transmute from a `u32` to a `char`
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--> $DIR/transmute.rs:74:28
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--> $DIR/transmute.rs:91:28
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LL | let _: char = unsafe { std::mem::transmute(0_u32) };
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::char::from_u32(0_u32).unwrap()`
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@ -101,13 +95,13 @@ LL | let _: char = unsafe { std::mem::transmute(0_u32) };
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= note: `-D clippy::transmute-int-to-char` implied by `-D warnings`
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error: transmute from a `i32` to a `char`
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--> $DIR/transmute.rs:75:28
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--> $DIR/transmute.rs:92:28
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LL | let _: char = unsafe { std::mem::transmute(0_i32) };
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::char::from_u32(0_i32 as u32).unwrap()`
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error: transmute from a `u8` to a `bool`
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--> $DIR/transmute.rs:84:28
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--> $DIR/transmute.rs:101:28
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LL | let _: bool = unsafe { std::mem::transmute(0_u8) };
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| ^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `0_u8 != 0`
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@ -115,7 +109,7 @@ LL | let _: bool = unsafe { std::mem::transmute(0_u8) };
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= note: `-D clippy::transmute-int-to-bool` implied by `-D warnings`
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error: transmute from a `u32` to a `f32`
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--> $DIR/transmute.rs:90:31
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--> $DIR/transmute.rs:107:31
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LL | let _: f32 = unsafe { std::mem::transmute(0_u32) };
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `f32::from_bits(0_u32)`
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@ -123,25 +117,25 @@ LL | let _: f32 = unsafe { std::mem::transmute(0_u32) };
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= note: `-D clippy::transmute-int-to-float` implied by `-D warnings`
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error: transmute from a `i32` to a `f32`
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--> $DIR/transmute.rs:91:31
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--> $DIR/transmute.rs:108:31
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LL | let _: f32 = unsafe { std::mem::transmute(0_i32) };
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `f32::from_bits(0_i32 as u32)`
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error: transmute from a `u64` to a `f64`
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--> $DIR/transmute.rs:92:31
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--> $DIR/transmute.rs:109:31
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LL | let _: f64 = unsafe { std::mem::transmute(0_u64) };
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `f64::from_bits(0_u64)`
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error: transmute from a `i64` to a `f64`
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--> $DIR/transmute.rs:93:31
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--> $DIR/transmute.rs:110:31
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LL | let _: f64 = unsafe { std::mem::transmute(0_i64) };
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `f64::from_bits(0_i64 as u64)`
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error: transmute from a `u8` to a `[u8; 1]`
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--> $DIR/transmute.rs:113:30
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--> $DIR/transmute.rs:130:30
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LL | let _: [u8; 1] = std::mem::transmute(0u8);
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| ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `to_ne_bytes()`: `0u8.to_ne_bytes()`
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@ -149,85 +143,85 @@ LL | let _: [u8; 1] = std::mem::transmute(0u8);
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= note: `-D clippy::transmute-num-to-bytes` implied by `-D warnings`
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error: transmute from a `u32` to a `[u8; 4]`
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--> $DIR/transmute.rs:114:30
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--> $DIR/transmute.rs:131:30
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LL | let _: [u8; 4] = std::mem::transmute(0u32);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `to_ne_bytes()`: `0u32.to_ne_bytes()`
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error: transmute from a `u128` to a `[u8; 16]`
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--> $DIR/transmute.rs:115:31
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--> $DIR/transmute.rs:132:31
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LL | let _: [u8; 16] = std::mem::transmute(0u128);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `to_ne_bytes()`: `0u128.to_ne_bytes()`
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error: transmute from a `i8` to a `[u8; 1]`
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--> $DIR/transmute.rs:116:30
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--> $DIR/transmute.rs:133:30
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|
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LL | let _: [u8; 1] = std::mem::transmute(0i8);
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| ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `to_ne_bytes()`: `0i8.to_ne_bytes()`
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error: transmute from a `i32` to a `[u8; 4]`
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--> $DIR/transmute.rs:117:30
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--> $DIR/transmute.rs:134:30
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|
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LL | let _: [u8; 4] = std::mem::transmute(0i32);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `to_ne_bytes()`: `0i32.to_ne_bytes()`
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error: transmute from a `i128` to a `[u8; 16]`
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--> $DIR/transmute.rs:118:31
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--> $DIR/transmute.rs:135:31
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|
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LL | let _: [u8; 16] = std::mem::transmute(0i128);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `to_ne_bytes()`: `0i128.to_ne_bytes()`
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error: transmute from a `f32` to a `[u8; 4]`
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--> $DIR/transmute.rs:119:30
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--> $DIR/transmute.rs:136:30
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|
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LL | let _: [u8; 4] = std::mem::transmute(0.0f32);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `to_ne_bytes()`: `0.0f32.to_ne_bytes()`
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error: transmute from a `f64` to a `[u8; 8]`
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--> $DIR/transmute.rs:120:30
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--> $DIR/transmute.rs:137:30
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|
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LL | let _: [u8; 8] = std::mem::transmute(0.0f64);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `to_ne_bytes()`: `0.0f64.to_ne_bytes()`
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error: transmute from a `u8` to a `[u8; 1]`
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--> $DIR/transmute.rs:125:30
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--> $DIR/transmute.rs:142:30
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|
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LL | let _: [u8; 1] = std::mem::transmute(0u8);
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| ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `to_ne_bytes()`: `0u8.to_ne_bytes()`
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error: transmute from a `u32` to a `[u8; 4]`
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--> $DIR/transmute.rs:126:30
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--> $DIR/transmute.rs:143:30
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|
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LL | let _: [u8; 4] = std::mem::transmute(0u32);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `to_ne_bytes()`: `0u32.to_ne_bytes()`
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error: transmute from a `u128` to a `[u8; 16]`
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--> $DIR/transmute.rs:127:31
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--> $DIR/transmute.rs:144:31
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|
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LL | let _: [u8; 16] = std::mem::transmute(0u128);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `to_ne_bytes()`: `0u128.to_ne_bytes()`
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error: transmute from a `i8` to a `[u8; 1]`
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--> $DIR/transmute.rs:128:30
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--> $DIR/transmute.rs:145:30
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|
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LL | let _: [u8; 1] = std::mem::transmute(0i8);
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| ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `to_ne_bytes()`: `0i8.to_ne_bytes()`
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error: transmute from a `i32` to a `[u8; 4]`
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--> $DIR/transmute.rs:129:30
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--> $DIR/transmute.rs:146:30
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|
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LL | let _: [u8; 4] = std::mem::transmute(0i32);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `to_ne_bytes()`: `0i32.to_ne_bytes()`
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error: transmute from a `i128` to a `[u8; 16]`
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--> $DIR/transmute.rs:130:31
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--> $DIR/transmute.rs:147:31
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|
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LL | let _: [u8; 16] = std::mem::transmute(0i128);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `to_ne_bytes()`: `0i128.to_ne_bytes()`
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error: transmute from a `&[u8]` to a `&str`
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--> $DIR/transmute.rs:140:28
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--> $DIR/transmute.rs:157:28
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LL | let _: &str = unsafe { std::mem::transmute(B) };
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::str::from_utf8(B).unwrap()`
|
||||
@ -235,16 +229,16 @@ LL | let _: &str = unsafe { std::mem::transmute(B) };
|
||||
= note: `-D clippy::transmute-bytes-to-str` implied by `-D warnings`
|
||||
|
||||
error: transmute from a `&mut [u8]` to a `&mut str`
|
||||
--> $DIR/transmute.rs:141:32
|
||||
--> $DIR/transmute.rs:158:32
|
||||
|
|
||||
LL | let _: &mut str = unsafe { std::mem::transmute(mb) };
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::str::from_utf8_mut(mb).unwrap()`
|
||||
|
||||
error: transmute from a `&[u8]` to a `&str`
|
||||
--> $DIR/transmute.rs:142:30
|
||||
--> $DIR/transmute.rs:159:30
|
||||
|
|
||||
LL | const _: &str = unsafe { std::mem::transmute(B) };
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::str::from_utf8_unchecked(B)`
|
||||
|
||||
error: aborting due to 39 previous errors
|
||||
error: aborting due to 38 previous errors
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user