未验证 提交 a00b4f14 编写于 作者: M Mazdak Farrokhzad 提交者: GitHub

Rollup merge of #63657 - RalfJung:invalid_value, r=Centril

Crank up invalid value lint

* Warn against uninit `bool` and `char`.
* Warn against 0-init `NonNull` and friends
* Detect transmute-from-0 as zero-initialization ([seen in the wild](https://github.com/glium/glium/issues/1775#issuecomment-522144636))
......@@ -1876,16 +1876,70 @@ fn check_crate(&mut self, cx: &EarlyContext<'_>, _: &ast::Crate) {
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for InvalidValue {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &hir::Expr) {
const ZEROED_PATH: &[Symbol] = &[sym::core, sym::mem, sym::zeroed];
const UININIT_PATH: &[Symbol] = &[sym::core, sym::mem, sym::uninitialized];
#[derive(Debug, Copy, Clone, PartialEq)]
enum InitKind { Zeroed, Uninit };
/// Information about why a type cannot be initialized this way.
/// Contains an error message and optionally a span to point at.
type InitError = (String, Option<Span>);
/// Test if this constant is all-0.
fn is_zero(expr: &hir::Expr) -> bool {
use hir::ExprKind::*;
use syntax::ast::LitKind::*;
match &expr.node {
Lit(lit) =>
if let Int(i, _) = lit.node {
i == 0
} else {
false
},
Tup(tup) =>
tup.iter().all(is_zero),
_ =>
false
}
}
/// Determine if this expression is a "dangerous initialization".
fn is_dangerous_init(cx: &LateContext<'_, '_>, expr: &hir::Expr) -> Option<InitKind> {
const ZEROED_PATH: &[Symbol] = &[sym::core, sym::mem, sym::zeroed];
const UININIT_PATH: &[Symbol] = &[sym::core, sym::mem, sym::uninitialized];
// `transmute` is inside an anonymous module (the `extern` block?);
// `Invalid` represents the empty string and matches that.
const TRANSMUTE_PATH: &[Symbol] =
&[sym::core, sym::intrinsics, kw::Invalid, sym::transmute];
if let hir::ExprKind::Call(ref path_expr, ref args) = expr.node {
if let hir::ExprKind::Path(ref qpath) = path_expr.node {
let def_id = cx.tables.qpath_res(qpath, path_expr.hir_id).opt_def_id()?;
if cx.match_def_path(def_id, ZEROED_PATH) {
return Some(InitKind::Zeroed);
}
if cx.match_def_path(def_id, UININIT_PATH) {
return Some(InitKind::Uninit);
}
if cx.match_def_path(def_id, TRANSMUTE_PATH) {
if is_zero(&args[0]) {
return Some(InitKind::Zeroed);
}
}
// FIXME: Also detect `MaybeUninit::zeroed().assume_init()` and
// `MaybeUninit::uninit().assume_init()`.
}
}
None
}
/// Return `Some` only if we are sure this type does *not*
/// allow zero initialization.
fn ty_find_init_error<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Option<InitError> {
fn ty_find_init_error<'tcx>(
tcx: TyCtxt<'tcx>,
ty: Ty<'tcx>,
init: InitKind,
) -> Option<InitError> {
use rustc::ty::TyKind::*;
match ty.sty {
// Primitive types that don't like 0 as a value.
......@@ -1893,8 +1947,30 @@ fn ty_find_init_error<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Option<InitError
Adt(..) if ty.is_box() => Some((format!("`Box` must be non-null"), None)),
FnPtr(..) => Some((format!("Function pointers must be non-null"), None)),
Never => Some((format!("The never type (`!`) has no valid value"), None)),
// Recurse for some compound types.
// Primitive types with other constraints.
Bool if init == InitKind::Uninit =>
Some((format!("Booleans must be `true` or `false`"), None)),
Char if init == InitKind::Uninit =>
Some((format!("Characters must be a valid unicode codepoint"), None)),
// Recurse and checks for some compound types.
Adt(adt_def, substs) if !adt_def.is_union() => {
// First check f this ADT has a layout attribute (like `NonNull` and friends).
use std::ops::Bound;
match tcx.layout_scalar_valid_range(adt_def.did) {
// We exploit here that `layout_scalar_valid_range` will never
// return `Bound::Excluded`. (And we have tests checking that we
// handle the attribute correctly.)
(Bound::Included(lo), _) if lo > 0 =>
return Some((format!("{} must be non-null", ty), None)),
(Bound::Included(_), _) | (_, Bound::Included(_))
if init == InitKind::Uninit =>
return Some((
format!("{} must be initialized inside its custom valid range", ty),
None,
)),
_ => {}
}
// Now, recurse.
match adt_def.variants.len() {
0 => Some((format!("0-variant enums have no valid value"), None)),
1 => {
......@@ -1905,6 +1981,7 @@ fn ty_find_init_error<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Option<InitError
ty_find_init_error(
tcx,
field.ty(tcx, substs),
init,
).map(|(mut msg, span)| if span.is_none() {
// Point to this field, should be helpful for figuring
// out where the source of the error is.
......@@ -1918,57 +1995,48 @@ fn ty_find_init_error<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Option<InitError
})
})
}
// Multi-variant enums are tricky: if all but one variant are
// uninhabited, we might actually do layout like for a single-variant
// enum, and then even leaving them uninitialized could be okay.
_ => None, // Conservative fallback for multi-variant enum.
}
}
Tuple(..) => {
// Proceed recursively, check all fields.
ty.tuple_fields().find_map(|field| ty_find_init_error(tcx, field))
ty.tuple_fields().find_map(|field| ty_find_init_error(tcx, field, init))
}
// FIXME: Would be nice to also warn for `NonNull`/`NonZero*`.
// FIXME: *Only for `mem::uninitialized`*, we could also warn for `bool`,
// `char`, and any multivariant enum.
// Conservative fallback.
_ => None,
}
}
if let hir::ExprKind::Call(ref path_expr, ref _args) = expr.node {
if let hir::ExprKind::Path(ref qpath) = path_expr.node {
if let Some(def_id) = cx.tables.qpath_res(qpath, path_expr.hir_id).opt_def_id() {
if cx.match_def_path(def_id, &ZEROED_PATH) ||
cx.match_def_path(def_id, &UININIT_PATH)
{
// This conjures an instance of a type out of nothing,
// using zeroed or uninitialized memory.
// We are extremely conservative with what we warn about.
let conjured_ty = cx.tables.expr_ty(expr);
if let Some((msg, span)) = ty_find_init_error(cx.tcx, conjured_ty) {
let mut err = cx.struct_span_lint(
INVALID_VALUE,
expr.span,
&format!(
"the type `{}` does not permit {}",
conjured_ty,
if cx.match_def_path(def_id, &ZEROED_PATH) {
"zero-initialization"
} else {
"being left uninitialized"
}
),
);
err.span_label(expr.span,
"this code causes undefined behavior when executed");
err.span_label(expr.span, "help: use `MaybeUninit<T>` instead");
if let Some(span) = span {
err.span_note(span, &msg);
} else {
err.note(&msg);
}
err.emit();
}
}
if let Some(init) = is_dangerous_init(cx, expr) {
// This conjures an instance of a type out of nothing,
// using zeroed or uninitialized memory.
// We are extremely conservative with what we warn about.
let conjured_ty = cx.tables.expr_ty(expr);
if let Some((msg, span)) = ty_find_init_error(cx.tcx, conjured_ty, init) {
let mut err = cx.struct_span_lint(
INVALID_VALUE,
expr.span,
&format!(
"the type `{}` does not permit {}",
conjured_ty,
match init {
InitKind::Zeroed => "zero-initialization",
InitKind::Uninit => "being left uninitialized",
},
),
);
err.span_label(expr.span,
"this code causes undefined behavior when executed");
err.span_label(expr.span, "help: use `MaybeUninit<T>` instead");
if let Some(span) = span {
err.span_note(span, &msg);
} else {
err.note(&msg);
}
err.emit();
}
}
}
......
#![feature(rustc_attrs, const_transmute)]
#![allow(const_err)] // make sure we cannot allow away the errors tested here
#![allow(const_err, invalid_value)] // make sure we cannot allow away the errors tested here
use std::mem;
use std::ptr::NonNull;
......
// ignore-tidy-linelength
#![feature(const_transmute)]
#![allow(const_err)] // make sure we cannot allow away the errors tested here
#![allow(const_err, invalid_value)] // make sure we cannot allow away the errors tested here
use std::mem;
......
#![feature(const_transmute)]
#![allow(const_err)] // make sure we cannot allow away the errors tested here
#![allow(const_err, invalid_value)] // make sure we cannot allow away the errors tested here
use std::mem;
......
......@@ -2,11 +2,13 @@
// This test checks that calling `mem::{uninitialized,zeroed}` with certain types results
// in a lint.
#![feature(never_type)]
#![feature(never_type, rustc_attrs)]
#![allow(deprecated)]
#![deny(invalid_value)]
use std::mem::{self, MaybeUninit};
use std::ptr::NonNull;
use std::num::NonZeroU32;
enum Void {}
......@@ -16,6 +18,11 @@ enum Void {}
struct Wrap<T> { wrapped: T }
enum WrapEnum<T> { Wrapped(T) }
#[rustc_layout_scalar_valid_range_start(0)]
#[rustc_layout_scalar_valid_range_end(128)]
#[repr(transparent)]
pub(crate) struct NonBig(u64);
#[allow(unused)]
fn generic<T: 'static>() {
unsafe {
......@@ -29,6 +36,7 @@ fn generic<T: 'static>() {
fn main() {
unsafe {
// Things that cannot even be zero.
let _val: ! = mem::zeroed(); //~ ERROR: does not permit zero-initialization
let _val: ! = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
......@@ -56,11 +64,28 @@ fn main() {
let _val: Wrap<(RefPair, i32)> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
let _val: Wrap<(RefPair, i32)> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
// Some types that should work just fine.
let _val: NonNull<i32> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
let _val: NonNull<i32> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
// Things that can be zero, but not uninit.
let _val: bool = mem::zeroed();
let _val: bool = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
let _val: Wrap<char> = mem::zeroed();
let _val: Wrap<char> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
let _val: NonBig = mem::zeroed();
let _val: NonBig = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
// Transmute-from-0
let _val: &'static i32 = mem::transmute(0usize); //~ ERROR: does not permit zero-initialization
let _val: &'static [i32] = mem::transmute((0usize, 0usize)); //~ ERROR: does not permit zero-initialization
let _val: NonZeroU32 = mem::transmute(0); //~ ERROR: does not permit zero-initialization
// Some more types that should work just fine.
let _val: Option<&'static i32> = mem::zeroed();
let _val: Option<fn()> = mem::zeroed();
let _val: MaybeUninit<&'static i32> = mem::zeroed();
let _val: bool = mem::zeroed();
let _val: i32 = mem::zeroed();
}
}
error: the type `&'static T` does not permit zero-initialization
--> $DIR/uninitialized-zeroed.rs:22:32
--> $DIR/uninitialized-zeroed.rs:29:32
|
LL | let _val: &'static T = mem::zeroed();
| ^^^^^^^^^^^^^
......@@ -15,7 +15,7 @@ LL | #![deny(invalid_value)]
= note: References must be non-null
error: the type `&'static T` does not permit being left uninitialized
--> $DIR/uninitialized-zeroed.rs:23:32
--> $DIR/uninitialized-zeroed.rs:30:32
|
LL | let _val: &'static T = mem::uninitialized();
| ^^^^^^^^^^^^^^^^^^^^
......@@ -26,7 +26,7 @@ LL | let _val: &'static T = mem::uninitialized();
= note: References must be non-null
error: the type `Wrap<&'static T>` does not permit zero-initialization
--> $DIR/uninitialized-zeroed.rs:25:38
--> $DIR/uninitialized-zeroed.rs:32:38
|
LL | let _val: Wrap<&'static T> = mem::zeroed();
| ^^^^^^^^^^^^^
......@@ -35,13 +35,13 @@ LL | let _val: Wrap<&'static T> = mem::zeroed();
| help: use `MaybeUninit<T>` instead
|
note: References must be non-null (in this struct field)
--> $DIR/uninitialized-zeroed.rs:16:18
--> $DIR/uninitialized-zeroed.rs:18:18
|
LL | struct Wrap<T> { wrapped: T }
| ^^^^^^^^^^
error: the type `Wrap<&'static T>` does not permit being left uninitialized
--> $DIR/uninitialized-zeroed.rs:26:38
--> $DIR/uninitialized-zeroed.rs:33:38
|
LL | let _val: Wrap<&'static T> = mem::uninitialized();
| ^^^^^^^^^^^^^^^^^^^^
......@@ -50,13 +50,13 @@ LL | let _val: Wrap<&'static T> = mem::uninitialized();
| help: use `MaybeUninit<T>` instead
|
note: References must be non-null (in this struct field)
--> $DIR/uninitialized-zeroed.rs:16:18
--> $DIR/uninitialized-zeroed.rs:18:18
|
LL | struct Wrap<T> { wrapped: T }
| ^^^^^^^^^^
error: the type `!` does not permit zero-initialization
--> $DIR/uninitialized-zeroed.rs:32:23
--> $DIR/uninitialized-zeroed.rs:40:23
|
LL | let _val: ! = mem::zeroed();
| ^^^^^^^^^^^^^
......@@ -67,7 +67,7 @@ LL | let _val: ! = mem::zeroed();
= note: The never type (`!`) has no valid value
error: the type `!` does not permit being left uninitialized
--> $DIR/uninitialized-zeroed.rs:33:23
--> $DIR/uninitialized-zeroed.rs:41:23
|
LL | let _val: ! = mem::uninitialized();
| ^^^^^^^^^^^^^^^^^^^^
......@@ -78,7 +78,7 @@ LL | let _val: ! = mem::uninitialized();
= note: The never type (`!`) has no valid value
error: the type `(i32, !)` does not permit zero-initialization
--> $DIR/uninitialized-zeroed.rs:35:30
--> $DIR/uninitialized-zeroed.rs:43:30
|
LL | let _val: (i32, !) = mem::zeroed();
| ^^^^^^^^^^^^^
......@@ -89,7 +89,7 @@ LL | let _val: (i32, !) = mem::zeroed();
= note: The never type (`!`) has no valid value
error: the type `(i32, !)` does not permit being left uninitialized
--> $DIR/uninitialized-zeroed.rs:36:30
--> $DIR/uninitialized-zeroed.rs:44:30
|
LL | let _val: (i32, !) = mem::uninitialized();
| ^^^^^^^^^^^^^^^^^^^^
......@@ -100,7 +100,7 @@ LL | let _val: (i32, !) = mem::uninitialized();
= note: The never type (`!`) has no valid value
error: the type `Void` does not permit zero-initialization
--> $DIR/uninitialized-zeroed.rs:38:26
--> $DIR/uninitialized-zeroed.rs:46:26
|
LL | let _val: Void = mem::zeroed();
| ^^^^^^^^^^^^^
......@@ -111,7 +111,7 @@ LL | let _val: Void = mem::zeroed();
= note: 0-variant enums have no valid value
error: the type `Void` does not permit being left uninitialized
--> $DIR/uninitialized-zeroed.rs:39:26
--> $DIR/uninitialized-zeroed.rs:47:26
|
LL | let _val: Void = mem::uninitialized();
| ^^^^^^^^^^^^^^^^^^^^
......@@ -122,7 +122,7 @@ LL | let _val: Void = mem::uninitialized();
= note: 0-variant enums have no valid value
error: the type `&'static i32` does not permit zero-initialization
--> $DIR/uninitialized-zeroed.rs:41:34
--> $DIR/uninitialized-zeroed.rs:49:34
|
LL | let _val: &'static i32 = mem::zeroed();
| ^^^^^^^^^^^^^
......@@ -133,7 +133,7 @@ LL | let _val: &'static i32 = mem::zeroed();
= note: References must be non-null
error: the type `&'static i32` does not permit being left uninitialized
--> $DIR/uninitialized-zeroed.rs:42:34
--> $DIR/uninitialized-zeroed.rs:50:34
|
LL | let _val: &'static i32 = mem::uninitialized();
| ^^^^^^^^^^^^^^^^^^^^
......@@ -144,7 +144,7 @@ LL | let _val: &'static i32 = mem::uninitialized();
= note: References must be non-null
error: the type `Ref` does not permit zero-initialization
--> $DIR/uninitialized-zeroed.rs:44:25
--> $DIR/uninitialized-zeroed.rs:52:25
|
LL | let _val: Ref = mem::zeroed();
| ^^^^^^^^^^^^^
......@@ -153,13 +153,13 @@ LL | let _val: Ref = mem::zeroed();
| help: use `MaybeUninit<T>` instead
|
note: References must be non-null (in this struct field)
--> $DIR/uninitialized-zeroed.rs:13:12
--> $DIR/uninitialized-zeroed.rs:15:12
|
LL | struct Ref(&'static i32);
| ^^^^^^^^^^^^
error: the type `Ref` does not permit being left uninitialized
--> $DIR/uninitialized-zeroed.rs:45:25
--> $DIR/uninitialized-zeroed.rs:53:25
|
LL | let _val: Ref = mem::uninitialized();
| ^^^^^^^^^^^^^^^^^^^^
......@@ -168,13 +168,13 @@ LL | let _val: Ref = mem::uninitialized();
| help: use `MaybeUninit<T>` instead
|
note: References must be non-null (in this struct field)
--> $DIR/uninitialized-zeroed.rs:13:12
--> $DIR/uninitialized-zeroed.rs:15:12
|
LL | struct Ref(&'static i32);
| ^^^^^^^^^^^^
error: the type `fn()` does not permit zero-initialization
--> $DIR/uninitialized-zeroed.rs:47:26
--> $DIR/uninitialized-zeroed.rs:55:26
|
LL | let _val: fn() = mem::zeroed();
| ^^^^^^^^^^^^^
......@@ -185,7 +185,7 @@ LL | let _val: fn() = mem::zeroed();
= note: Function pointers must be non-null
error: the type `fn()` does not permit being left uninitialized
--> $DIR/uninitialized-zeroed.rs:48:26
--> $DIR/uninitialized-zeroed.rs:56:26
|
LL | let _val: fn() = mem::uninitialized();
| ^^^^^^^^^^^^^^^^^^^^
......@@ -196,7 +196,7 @@ LL | let _val: fn() = mem::uninitialized();
= note: Function pointers must be non-null
error: the type `Wrap<fn()>` does not permit zero-initialization
--> $DIR/uninitialized-zeroed.rs:50:32
--> $DIR/uninitialized-zeroed.rs:58:32
|
LL | let _val: Wrap<fn()> = mem::zeroed();
| ^^^^^^^^^^^^^
......@@ -205,13 +205,13 @@ LL | let _val: Wrap<fn()> = mem::zeroed();
| help: use `MaybeUninit<T>` instead
|
note: Function pointers must be non-null (in this struct field)
--> $DIR/uninitialized-zeroed.rs:16:18
--> $DIR/uninitialized-zeroed.rs:18:18
|
LL | struct Wrap<T> { wrapped: T }
| ^^^^^^^^^^
error: the type `Wrap<fn()>` does not permit being left uninitialized
--> $DIR/uninitialized-zeroed.rs:51:32
--> $DIR/uninitialized-zeroed.rs:59:32
|
LL | let _val: Wrap<fn()> = mem::uninitialized();
| ^^^^^^^^^^^^^^^^^^^^
......@@ -220,13 +220,13 @@ LL | let _val: Wrap<fn()> = mem::uninitialized();
| help: use `MaybeUninit<T>` instead
|
note: Function pointers must be non-null (in this struct field)
--> $DIR/uninitialized-zeroed.rs:16:18
--> $DIR/uninitialized-zeroed.rs:18:18
|
LL | struct Wrap<T> { wrapped: T }
| ^^^^^^^^^^
error: the type `WrapEnum<fn()>` does not permit zero-initialization
--> $DIR/uninitialized-zeroed.rs:53:36
--> $DIR/uninitialized-zeroed.rs:61:36
|
LL | let _val: WrapEnum<fn()> = mem::zeroed();
| ^^^^^^^^^^^^^
......@@ -235,13 +235,13 @@ LL | let _val: WrapEnum<fn()> = mem::zeroed();
| help: use `MaybeUninit<T>` instead
|
note: Function pointers must be non-null (in this enum field)
--> $DIR/uninitialized-zeroed.rs:17:28
--> $DIR/uninitialized-zeroed.rs:19:28
|
LL | enum WrapEnum<T> { Wrapped(T) }
| ^
error: the type `WrapEnum<fn()>` does not permit being left uninitialized
--> $DIR/uninitialized-zeroed.rs:54:36
--> $DIR/uninitialized-zeroed.rs:62:36
|
LL | let _val: WrapEnum<fn()> = mem::uninitialized();
| ^^^^^^^^^^^^^^^^^^^^
......@@ -250,13 +250,13 @@ LL | let _val: WrapEnum<fn()> = mem::uninitialized();
| help: use `MaybeUninit<T>` instead
|
note: Function pointers must be non-null (in this enum field)
--> $DIR/uninitialized-zeroed.rs:17:28
--> $DIR/uninitialized-zeroed.rs:19:28
|
LL | enum WrapEnum<T> { Wrapped(T) }
| ^
error: the type `Wrap<(RefPair, i32)>` does not permit zero-initialization
--> $DIR/uninitialized-zeroed.rs:56:42
--> $DIR/uninitialized-zeroed.rs:64:42
|
LL | let _val: Wrap<(RefPair, i32)> = mem::zeroed();
| ^^^^^^^^^^^^^
......@@ -265,13 +265,13 @@ LL | let _val: Wrap<(RefPair, i32)> = mem::zeroed();
| help: use `MaybeUninit<T>` instead
|
note: References must be non-null (in this struct field)
--> $DIR/uninitialized-zeroed.rs:14:16
--> $DIR/uninitialized-zeroed.rs:16:16
|
LL | struct RefPair((&'static i32, i32));
| ^^^^^^^^^^^^^^^^^^^
error: the type `Wrap<(RefPair, i32)>` does not permit being left uninitialized
--> $DIR/uninitialized-zeroed.rs:57:42
--> $DIR/uninitialized-zeroed.rs:65:42
|
LL | let _val: Wrap<(RefPair, i32)> = mem::uninitialized();
| ^^^^^^^^^^^^^^^^^^^^
......@@ -280,10 +280,102 @@ LL | let _val: Wrap<(RefPair, i32)> = mem::uninitialized();
| help: use `MaybeUninit<T>` instead
|
note: References must be non-null (in this struct field)
--> $DIR/uninitialized-zeroed.rs:14:16
--> $DIR/uninitialized-zeroed.rs:16:16
|
LL | struct RefPair((&'static i32, i32));
| ^^^^^^^^^^^^^^^^^^^
error: aborting due to 22 previous errors
error: the type `std::ptr::NonNull<i32>` does not permit zero-initialization
--> $DIR/uninitialized-zeroed.rs:67:34
|
LL | let _val: NonNull<i32> = mem::zeroed();
| ^^^^^^^^^^^^^
| |
| this code causes undefined behavior when executed
| help: use `MaybeUninit<T>` instead
|
= note: std::ptr::NonNull<i32> must be non-null
error: the type `std::ptr::NonNull<i32>` does not permit being left uninitialized
--> $DIR/uninitialized-zeroed.rs:68:34
|
LL | let _val: NonNull<i32> = mem::uninitialized();
| ^^^^^^^^^^^^^^^^^^^^
| |
| this code causes undefined behavior when executed
| help: use `MaybeUninit<T>` instead
|
= note: std::ptr::NonNull<i32> must be non-null
error: the type `bool` does not permit being left uninitialized
--> $DIR/uninitialized-zeroed.rs:72:26
|
LL | let _val: bool = mem::uninitialized();
| ^^^^^^^^^^^^^^^^^^^^
| |
| this code causes undefined behavior when executed
| help: use `MaybeUninit<T>` instead
|
= note: Booleans must be `true` or `false`
error: the type `Wrap<char>` does not permit being left uninitialized
--> $DIR/uninitialized-zeroed.rs:75:32
|
LL | let _val: Wrap<char> = mem::uninitialized();
| ^^^^^^^^^^^^^^^^^^^^
| |
| this code causes undefined behavior when executed
| help: use `MaybeUninit<T>` instead
|
note: Characters must be a valid unicode codepoint (in this struct field)
--> $DIR/uninitialized-zeroed.rs:18:18
|
LL | struct Wrap<T> { wrapped: T }
| ^^^^^^^^^^
error: the type `NonBig` does not permit being left uninitialized
--> $DIR/uninitialized-zeroed.rs:78:28
|
LL | let _val: NonBig = mem::uninitialized();
| ^^^^^^^^^^^^^^^^^^^^
| |
| this code causes undefined behavior when executed
| help: use `MaybeUninit<T>` instead
|
= note: NonBig must be initialized inside its custom valid range
error: the type `&'static i32` does not permit zero-initialization
--> $DIR/uninitialized-zeroed.rs:81:34
|
LL | let _val: &'static i32 = mem::transmute(0usize);
| ^^^^^^^^^^^^^^^^^^^^^^
| |
| this code causes undefined behavior when executed
| help: use `MaybeUninit<T>` instead
|
= note: References must be non-null
error: the type `&'static [i32]` does not permit zero-initialization
--> $DIR/uninitialized-zeroed.rs:82:36
|
LL | let _val: &'static [i32] = mem::transmute((0usize, 0usize));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| |
| this code causes undefined behavior when executed
| help: use `MaybeUninit<T>` instead
|
= note: References must be non-null
error: the type `std::num::NonZeroU32` does not permit zero-initialization
--> $DIR/uninitialized-zeroed.rs:83:32
|
LL | let _val: NonZeroU32 = mem::transmute(0);
| ^^^^^^^^^^^^^^^^^
| |
| this code causes undefined behavior when executed
| help: use `MaybeUninit<T>` instead
|
= note: std::num::NonZeroU32 must be non-null
error: aborting due to 30 previous errors
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