diff options
| -rw-r--r-- | compiler/rustc_lint/messages.ftl | 4 | ||||
| -rw-r--r-- | compiler/rustc_lint/src/autorefs.rs | 153 | ||||
| -rw-r--r-- | compiler/rustc_lint/src/lib.rs | 3 | ||||
| -rw-r--r-- | compiler/rustc_lint/src/lints.rs | 20 | ||||
| -rw-r--r-- | library/alloc/src/vec/mod.rs | 2 | ||||
| -rw-r--r-- | tests/ui/lint/implicit_autorefs.fixed | 99 | ||||
| -rw-r--r-- | tests/ui/lint/implicit_autorefs.rs | 99 | ||||
| -rw-r--r-- | tests/ui/lint/implicit_autorefs.stderr | 219 |
8 files changed, 598 insertions, 1 deletions
diff --git a/compiler/rustc_lint/messages.ftl b/compiler/rustc_lint/messages.ftl index 60c183bd56b..a6499b07fe2 100644 --- a/compiler/rustc_lint/messages.ftl +++ b/compiler/rustc_lint/messages.ftl @@ -360,6 +360,10 @@ lint_impl_trait_overcaptures = `{$self_ty}` will capture more lifetimes than pos lint_impl_trait_redundant_captures = all possible in-scope parameters are already captured, so `use<...>` syntax is redundant .suggestion = remove the `use<...>` syntax +lint_implicit_unsafe_autorefs = implicit autoref creates a reference to the dereference of a raw pointer + .note = creating a reference requires the pointer target to be valid and imposes aliasing requirements + .suggestion = try using a raw pointer method instead; or if this reference is intentional, make it explicit + lint_improper_ctypes = `extern` {$desc} uses type `{$ty}`, which is not FFI-safe .label = not FFI-safe .note = the type is defined here diff --git a/compiler/rustc_lint/src/autorefs.rs b/compiler/rustc_lint/src/autorefs.rs new file mode 100644 index 00000000000..5dd26854c95 --- /dev/null +++ b/compiler/rustc_lint/src/autorefs.rs @@ -0,0 +1,153 @@ +use rustc_ast::{BorrowKind, UnOp}; +use rustc_hir::{Expr, ExprKind, Mutability}; +use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, OverloadedDeref}; +use rustc_session::{declare_lint, declare_lint_pass}; +use rustc_span::sym; + +use crate::lints::{ImplicitUnsafeAutorefsDiag, ImplicitUnsafeAutorefsSuggestion}; +use crate::{LateContext, LateLintPass, LintContext}; + +declare_lint! { + /// The `dangerous_implicit_autorefs` lint checks for implicitly taken references + /// to dereferences of raw pointers. + /// + /// ### Example + /// + /// ```rust + /// unsafe fn fun(ptr: *mut [u8]) -> *mut [u8] { + /// &raw mut (*ptr)[..16] + /// // ^^^^^^ this calls `IndexMut::index_mut(&mut ..., ..16)`, + /// // implicitly creating a reference + /// } + /// ``` + /// + /// {{produces}} + /// + /// ### Explanation + /// + /// When working with raw pointers it's usually undesirable to create references, + /// since they inflict additional safety requirements. Unfortunately, it's possible + /// to take a reference to the dereference of a raw pointer implicitly, which inflicts + /// the usual reference requirements. + /// + /// If you are sure that you can soundly take a reference, then you can take it explicitly: + /// + /// ```rust + /// unsafe fn fun(ptr: *mut [u8]) -> *mut [u8] { + /// &raw mut (&mut *ptr)[..16] + /// } + /// ``` + /// + /// Otherwise try to find an alternative way to achive your goals using only raw pointers: + /// + /// ```rust + /// use std::slice; + /// + /// unsafe fn fun(ptr: *mut [u8]) -> *mut [u8] { + /// slice::from_raw_parts_mut(ptr.cast(), 16) + /// } + /// ``` + pub DANGEROUS_IMPLICIT_AUTOREFS, + Warn, + "implicit reference to a dereference of a raw pointer", + report_in_external_macro +} + +declare_lint_pass!(ImplicitAutorefs => [DANGEROUS_IMPLICIT_AUTOREFS]); + +impl<'tcx> LateLintPass<'tcx> for ImplicitAutorefs { + fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { + // This logic has mostly been taken from + // <https://github.com/rust-lang/rust/pull/103735#issuecomment-1370420305> + + // 5. Either of the following: + // a. A deref followed by any non-deref place projection (that intermediate + // deref will typically be auto-inserted). + // b. A method call annotated with `#[rustc_no_implicit_refs]`. + // c. A deref followed by a `&raw const` or `&raw mut`. + let mut is_coming_from_deref = false; + let inner = match expr.kind { + ExprKind::AddrOf(BorrowKind::Raw, _, inner) => match inner.kind { + ExprKind::Unary(UnOp::Deref, inner) => { + is_coming_from_deref = true; + inner + } + _ => return, + }, + ExprKind::Index(base, _, _) => base, + ExprKind::MethodCall(_, inner, _, _) + if let Some(def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id) + && cx.tcx.has_attr(def_id, sym::rustc_no_implicit_autorefs) => + { + inner + } + ExprKind::Field(inner, _) => inner, + _ => return, + }; + + let typeck = cx.typeck_results(); + let adjustments_table = typeck.adjustments(); + + if let Some(adjustments) = adjustments_table.get(inner.hir_id) + // 4. Any number of automatically inserted deref/derefmut calls. + && let adjustments = peel_derefs_adjustments(&**adjustments) + // 3. An automatically inserted reference (might come from a deref). + && let [adjustment] = adjustments + && let Some(borrow_mutbl) = has_implicit_borrow(adjustment) + && let ExprKind::Unary(UnOp::Deref, dereferenced) = + // 2. Any number of place projections. + peel_place_mappers(inner).kind + // 1. Deref of a raw pointer. + && typeck.expr_ty(dereferenced).is_raw_ptr() + { + cx.emit_span_lint( + DANGEROUS_IMPLICIT_AUTOREFS, + expr.span.source_callsite(), + ImplicitUnsafeAutorefsDiag { + suggestion: ImplicitUnsafeAutorefsSuggestion { + mutbl: borrow_mutbl.ref_prefix_str(), + deref: if is_coming_from_deref { "*" } else { "" }, + start_span: inner.span.shrink_to_lo(), + end_span: inner.span.shrink_to_hi(), + }, + }, + ) + } + } +} + +/// Peels expressions from `expr` that can map a place. +fn peel_place_mappers<'tcx>(mut expr: &'tcx Expr<'tcx>) -> &'tcx Expr<'tcx> { + loop { + match expr.kind { + ExprKind::Index(base, _idx, _) => expr = &base, + ExprKind::Field(e, _) => expr = &e, + _ => break expr, + } + } +} + +/// Peel derefs adjustments until the last last element. +fn peel_derefs_adjustments<'a>(mut adjs: &'a [Adjustment<'a>]) -> &'a [Adjustment<'a>] { + while let [Adjustment { kind: Adjust::Deref(_), .. }, end @ ..] = adjs + && !end.is_empty() + { + adjs = end; + } + adjs +} + +/// Test if some adjustment has some implicit borrow. +/// +/// Returns `Some(mutability)` if the argument adjustment has implicit borrow in it. +fn has_implicit_borrow(Adjustment { kind, .. }: &Adjustment<'_>) -> Option<Mutability> { + match kind { + &Adjust::Deref(Some(OverloadedDeref { mutbl, .. })) => Some(mutbl), + &Adjust::Borrow(AutoBorrow::Ref(mutbl)) => Some(mutbl.into()), + Adjust::NeverToAny + | Adjust::Pointer(..) + | Adjust::ReborrowPin(..) + | Adjust::Deref(None) + | Adjust::Borrow(AutoBorrow::RawPtr(..)) => None, + } +} diff --git a/compiler/rustc_lint/src/lib.rs b/compiler/rustc_lint/src/lib.rs index 212368bea82..79c984cb634 100644 --- a/compiler/rustc_lint/src/lib.rs +++ b/compiler/rustc_lint/src/lib.rs @@ -36,6 +36,7 @@ mod async_closures; mod async_fn_in_trait; +mod autorefs; pub mod builtin; mod context; mod dangling; @@ -83,6 +84,7 @@ mod utils; use async_closures::AsyncClosureUsage; use async_fn_in_trait::AsyncFnInTrait; +use autorefs::*; use builtin::*; use dangling::*; use default_could_be_derived::DefaultCouldBeDerived; @@ -200,6 +202,7 @@ late_lint_methods!( PathStatements: PathStatements, LetUnderscore: LetUnderscore, InvalidReferenceCasting: InvalidReferenceCasting, + ImplicitAutorefs: ImplicitAutorefs, // Depends on referenced function signatures in expressions UnusedResults: UnusedResults, UnitBindings: UnitBindings, diff --git a/compiler/rustc_lint/src/lints.rs b/compiler/rustc_lint/src/lints.rs index 8ab64fbd127..487184b836a 100644 --- a/compiler/rustc_lint/src/lints.rs +++ b/compiler/rustc_lint/src/lints.rs @@ -55,6 +55,26 @@ pub(crate) enum ShadowedIntoIterDiagSub { }, } +// autorefs.rs +#[derive(LintDiagnostic)] +#[diag(lint_implicit_unsafe_autorefs)] +#[note] +pub(crate) struct ImplicitUnsafeAutorefsDiag { + #[subdiagnostic] + pub suggestion: ImplicitUnsafeAutorefsSuggestion, +} + +#[derive(Subdiagnostic)] +#[multipart_suggestion(lint_suggestion, applicability = "maybe-incorrect")] +pub(crate) struct ImplicitUnsafeAutorefsSuggestion { + pub mutbl: &'static str, + pub deref: &'static str, + #[suggestion_part(code = "({mutbl}{deref}")] + pub start_span: Span, + #[suggestion_part(code = ")")] + pub end_span: Span, +} + // builtin.rs #[derive(LintDiagnostic)] #[diag(lint_builtin_while_true)] diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs index 68e4add30e5..65a83cb98ba 100644 --- a/library/alloc/src/vec/mod.rs +++ b/library/alloc/src/vec/mod.rs @@ -2588,7 +2588,7 @@ impl<T, A: Allocator> Vec<T, A> { #[inline] #[track_caller] unsafe fn append_elements(&mut self, other: *const [T]) { - let count = unsafe { (*other).len() }; + let count = other.len(); self.reserve(count); let len = self.len(); unsafe { ptr::copy_nonoverlapping(other as *const T, self.as_mut_ptr().add(len), count) }; diff --git a/tests/ui/lint/implicit_autorefs.fixed b/tests/ui/lint/implicit_autorefs.fixed new file mode 100644 index 00000000000..96a617b20c9 --- /dev/null +++ b/tests/ui/lint/implicit_autorefs.fixed @@ -0,0 +1,99 @@ +//@ check-pass +//@ run-rustfix + +#![allow(dead_code)] // For the rustfix-ed code. + +use std::mem::ManuallyDrop; +use std::ops::Deref; + +unsafe fn test_const(ptr: *const [u8]) { + let _ = (&(*ptr))[..16]; + //~^ WARN implicit autoref +} + +struct Test { + field: [u8], +} + +unsafe fn test_field(ptr: *const Test) -> *const [u8] { + let l = (&(*ptr).field).len(); + //~^ WARN implicit autoref + + &raw const (&(*ptr).field)[..l - 1] + //~^ WARN implicit autoref +} + +unsafe fn test_builtin_index(a: *mut [String]) { + _ = (&(*a)[0]).len(); + //~^ WARN implicit autoref + + _ = (&(&(*a))[..1][0]).len(); + //~^ WARN implicit autoref + //~^^ WARN implicit autoref +} + +unsafe fn test_overloaded_deref_const(ptr: *const ManuallyDrop<Test>) { + let _ = (&(*ptr)).field; + //~^ WARN implicit autoref + let _ = &raw const (&(*ptr)).field; + //~^ WARN implicit autoref +} + +unsafe fn test_overloaded_deref_mut(ptr: *mut ManuallyDrop<Test>) { + let _ = (&(*ptr)).field; + //~^ WARN implicit autoref +} + +unsafe fn test_double_overloaded_deref_const(ptr: *const ManuallyDrop<ManuallyDrop<Test>>) { + let _ = (&(*ptr)).field; + //~^ WARN implicit autoref +} + +unsafe fn test_manually_overloaded_deref() { + struct W<T>(T); + + impl<T> Deref for W<T> { + type Target = T; + fn deref(&self) -> &T { &self.0 } + } + + let w: W<i32> = W(5); + let w = &raw const w; + let _p: *const i32 = &raw const *(&**w); + //~^ WARN implicit autoref +} + +struct Test2 { + // Derefs to `[u8]`. + field: &'static [u8] +} + +fn test_more_manual_deref(ptr: *const Test2) -> usize { + unsafe { (&(*ptr).field).len() } + //~^ WARN implicit autoref +} + +unsafe fn test_no_attr(ptr: *mut ManuallyDrop<u8>) { + ptr.write(ManuallyDrop::new(1)); // Should not warn, as `ManuallyDrop::write` is not + // annotated with `#[rustc_no_implicit_auto_ref]` +} + +unsafe fn test_vec_get(ptr: *mut Vec<u8>) { + let _ = (&(*ptr)).get(0); + //~^ WARN implicit autoref + let _ = (&(*ptr)).get_unchecked(0); + //~^ WARN implicit autoref + let _ = (&mut (*ptr)).get_mut(0); + //~^ WARN implicit autoref + let _ = (&mut (*ptr)).get_unchecked_mut(0); + //~^ WARN implicit autoref +} + +unsafe fn test_string(ptr: *mut String) { + let _ = (&(*ptr)).len(); + //~^ WARN implicit autoref + let _ = (&(*ptr)).is_empty(); + //~^ WARN implicit autoref +} + +fn main() {} diff --git a/tests/ui/lint/implicit_autorefs.rs b/tests/ui/lint/implicit_autorefs.rs new file mode 100644 index 00000000000..61dd0ac50ce --- /dev/null +++ b/tests/ui/lint/implicit_autorefs.rs @@ -0,0 +1,99 @@ +//@ check-pass +//@ run-rustfix + +#![allow(dead_code)] // For the rustfix-ed code. + +use std::mem::ManuallyDrop; +use std::ops::Deref; + +unsafe fn test_const(ptr: *const [u8]) { + let _ = (*ptr)[..16]; + //~^ WARN implicit autoref +} + +struct Test { + field: [u8], +} + +unsafe fn test_field(ptr: *const Test) -> *const [u8] { + let l = (*ptr).field.len(); + //~^ WARN implicit autoref + + &raw const (*ptr).field[..l - 1] + //~^ WARN implicit autoref +} + +unsafe fn test_builtin_index(a: *mut [String]) { + _ = (*a)[0].len(); + //~^ WARN implicit autoref + + _ = (*a)[..1][0].len(); + //~^ WARN implicit autoref + //~^^ WARN implicit autoref +} + +unsafe fn test_overloaded_deref_const(ptr: *const ManuallyDrop<Test>) { + let _ = (*ptr).field; + //~^ WARN implicit autoref + let _ = &raw const (*ptr).field; + //~^ WARN implicit autoref +} + +unsafe fn test_overloaded_deref_mut(ptr: *mut ManuallyDrop<Test>) { + let _ = (*ptr).field; + //~^ WARN implicit autoref +} + +unsafe fn test_double_overloaded_deref_const(ptr: *const ManuallyDrop<ManuallyDrop<Test>>) { + let _ = (*ptr).field; + //~^ WARN implicit autoref +} + +unsafe fn test_manually_overloaded_deref() { + struct W<T>(T); + + impl<T> Deref for W<T> { + type Target = T; + fn deref(&self) -> &T { &self.0 } + } + + let w: W<i32> = W(5); + let w = &raw const w; + let _p: *const i32 = &raw const **w; + //~^ WARN implicit autoref +} + +struct Test2 { + // Derefs to `[u8]`. + field: &'static [u8] +} + +fn test_more_manual_deref(ptr: *const Test2) -> usize { + unsafe { (*ptr).field.len() } + //~^ WARN implicit autoref +} + +unsafe fn test_no_attr(ptr: *mut ManuallyDrop<u8>) { + ptr.write(ManuallyDrop::new(1)); // Should not warn, as `ManuallyDrop::write` is not + // annotated with `#[rustc_no_implicit_auto_ref]` +} + +unsafe fn test_vec_get(ptr: *mut Vec<u8>) { + let _ = (*ptr).get(0); + //~^ WARN implicit autoref + let _ = (*ptr).get_unchecked(0); + //~^ WARN implicit autoref + let _ = (*ptr).get_mut(0); + //~^ WARN implicit autoref + let _ = (*ptr).get_unchecked_mut(0); + //~^ WARN implicit autoref +} + +unsafe fn test_string(ptr: *mut String) { + let _ = (*ptr).len(); + //~^ WARN implicit autoref + let _ = (*ptr).is_empty(); + //~^ WARN implicit autoref +} + +fn main() {} diff --git a/tests/ui/lint/implicit_autorefs.stderr b/tests/ui/lint/implicit_autorefs.stderr new file mode 100644 index 00000000000..6dd1ac65ada --- /dev/null +++ b/tests/ui/lint/implicit_autorefs.stderr @@ -0,0 +1,219 @@ +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:10:13 + | +LL | let _ = (*ptr)[..16]; + | ^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements + = note: `#[warn(dangerous_implicit_autorefs)]` on by default +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | let _ = (&(*ptr))[..16]; + | ++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:19:13 + | +LL | let l = (*ptr).field.len(); + | ^^^^^^^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | let l = (&(*ptr).field).len(); + | ++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:22:16 + | +LL | &raw const (*ptr).field[..l - 1] + | ^^^^^^^^^^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | &raw const (&(*ptr).field)[..l - 1] + | ++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:27:9 + | +LL | _ = (*a)[0].len(); + | ^^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | _ = (&(*a)[0]).len(); + | ++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:30:9 + | +LL | _ = (*a)[..1][0].len(); + | ^^^^^^^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | _ = (&(*a)[..1][0]).len(); + | ++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:30:9 + | +LL | _ = (*a)[..1][0].len(); + | ^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | _ = (&(*a))[..1][0].len(); + | ++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:36:13 + | +LL | let _ = (*ptr).field; + | ^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | let _ = (&(*ptr)).field; + | ++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:38:24 + | +LL | let _ = &raw const (*ptr).field; + | ^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | let _ = &raw const (&(*ptr)).field; + | ++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:43:13 + | +LL | let _ = (*ptr).field; + | ^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | let _ = (&(*ptr)).field; + | ++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:48:13 + | +LL | let _ = (*ptr).field; + | ^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | let _ = (&(*ptr)).field; + | ++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:62:26 + | +LL | let _p: *const i32 = &raw const **w; + | ^^^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | let _p: *const i32 = &raw const *(&**w); + | +++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:72:14 + | +LL | unsafe { (*ptr).field.len() } + | ^^^^^^^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | unsafe { (&(*ptr).field).len() } + | ++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:82:13 + | +LL | let _ = (*ptr).get(0); + | ^^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | let _ = (&(*ptr)).get(0); + | ++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:84:13 + | +LL | let _ = (*ptr).get_unchecked(0); + | ^^^^^^^^^^^^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | let _ = (&(*ptr)).get_unchecked(0); + | ++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:86:13 + | +LL | let _ = (*ptr).get_mut(0); + | ^^^^^^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | let _ = (&mut (*ptr)).get_mut(0); + | +++++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:88:13 + | +LL | let _ = (*ptr).get_unchecked_mut(0); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | let _ = (&mut (*ptr)).get_unchecked_mut(0); + | +++++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:93:13 + | +LL | let _ = (*ptr).len(); + | ^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | let _ = (&(*ptr)).len(); + | ++ + + +warning: implicit autoref creates a reference to the dereference of a raw pointer + --> $DIR/implicit_autorefs.rs:95:13 + | +LL | let _ = (*ptr).is_empty(); + | ^^^^^^^^^^^^^^^^^ + | + = note: creating a reference requires the pointer target to be valid and imposes aliasing requirements +help: try using a raw pointer method instead; or if this reference is intentional, make it explicit + | +LL | let _ = (&(*ptr)).is_empty(); + | ++ + + +warning: 18 warnings emitted + |