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))
diff --git a/src/librustc_lint/builtin.rs b/src/librustc_lint/builtin.rs
index 8216008..ce7681c 100644
--- a/src/librustc_lint/builtin.rs
+++ b/src/librustc_lint/builtin.rs
@@ -1876,16 +1876,70 @@
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 @@
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 @@
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 @@
})
})
}
+ // 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();
}
}
}
diff --git a/src/test/ui/consts/const-eval/ub-nonnull.rs b/src/test/ui/consts/const-eval/ub-nonnull.rs
index 431ff35..9edae19 100644
--- a/src/test/ui/consts/const-eval/ub-nonnull.rs
+++ b/src/test/ui/consts/const-eval/ub-nonnull.rs
@@ -1,5 +1,5 @@
#![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;
diff --git a/src/test/ui/consts/const-eval/ub-ref.rs b/src/test/ui/consts/const-eval/ub-ref.rs
index 0d8f301..bbab85c 100644
--- a/src/test/ui/consts/const-eval/ub-ref.rs
+++ b/src/test/ui/consts/const-eval/ub-ref.rs
@@ -1,6 +1,6 @@
// 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;
diff --git a/src/test/ui/consts/const-eval/ub-upvars.rs b/src/test/ui/consts/const-eval/ub-upvars.rs
index 0a427cd..baab14d 100644
--- a/src/test/ui/consts/const-eval/ub-upvars.rs
+++ b/src/test/ui/consts/const-eval/ub-upvars.rs
@@ -1,5 +1,5 @@
#![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;
diff --git a/src/test/ui/lint/uninitialized-zeroed.rs b/src/test/ui/lint/uninitialized-zeroed.rs
index d816479..5cf62b8 100644
--- a/src/test/ui/lint/uninitialized-zeroed.rs
+++ b/src/test/ui/lint/uninitialized-zeroed.rs
@@ -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 @@
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 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 @@
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();
}
}
diff --git a/src/test/ui/lint/uninitialized-zeroed.stderr b/src/test/ui/lint/uninitialized-zeroed.stderr
index 1b15fc2..a36a32a 100644
--- a/src/test/ui/lint/uninitialized-zeroed.stderr
+++ b/src/test/ui/lint/uninitialized-zeroed.stderr
@@ -1,5 +1,5 @@
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 @@
= 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 @@
= 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 @@
| 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 @@
| 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 @@
= 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 @@
= 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 @@
= 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 @@
= 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 @@
= 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 @@
= 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 @@
= 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 @@
= 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 @@
| 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 @@
| 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 @@
= 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 @@
= 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 @@
| 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 @@
| 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 @@
| 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 @@
| 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 @@
| 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 @@
| 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
