Auto merge of #113422 - Urgau:cast_ref_to_mut-pre-beta, r=Nilstrieb

Rename and allow `cast_ref_to_mut` lint

This PR is a small subset of https://github.com/rust-lang/rust/pull/112431, that is the renaming of the lint (`cast_ref_to_mut` -> `invalid_reference_casting`).

BUT also temporarily change the default level of the lint from deny-by-default to allow-by-default until https://github.com/rust-lang/rust/pull/112431 is merged.

r? `@Nilstrieb`

3 files changed, 14 insertions, 13 deletions

diff --git a/compiler/rustc_lint/src/lib.rs b/compiler/rustc_lint/src/lib.rs
index beb38dbb94c..53089294fe2 100644
--- a/compiler/rustc_lint/src/lib.rs
+++ b/compiler/rustc_lint/src/lib.rs
@@ -50,7 +50,6 @@ extern crate tracing;
 
 mod array_into_iter;
 pub mod builtin;
-mod cast_ref_to_mut;
 mod context;
 mod deref_into_dyn_supertrait;
 mod drop_forget_useless;
@@ -78,6 +77,7 @@ mod opaque_hidden_inferred_bound;
 mod pass_by_value;
 mod passes;
 mod redundant_semicolon;
+mod reference_casting;
 mod traits;
 mod types;
 mod unused;
@@ -99,7 +99,6 @@ use rustc_span::Span;
 
 use array_into_iter::ArrayIntoIter;
 use builtin::*;
-use cast_ref_to_mut::*;
 use deref_into_dyn_supertrait::*;
 use drop_forget_useless::*;
 use enum_intrinsics_non_enums::EnumIntrinsicsNonEnums;
@@ -119,6 +118,7 @@ use noop_method_call::*;
 use opaque_hidden_inferred_bound::*;
 use pass_by_value::*;
 use redundant_semicolon::*;
+use reference_casting::*;
 use traits::*;
 use types::*;
 use unused::*;
@@ -218,7 +218,7 @@ late_lint_methods!(
             BoxPointers: BoxPointers,
             PathStatements: PathStatements,
             LetUnderscore: LetUnderscore,
-            CastRefToMut: CastRefToMut,
+            InvalidReferenceCasting: InvalidReferenceCasting,
             // Depends on referenced function signatures in expressions
             UnusedResults: UnusedResults,
             NonUpperCaseGlobals: NonUpperCaseGlobals,
diff --git a/compiler/rustc_lint/src/lints.rs b/compiler/rustc_lint/src/lints.rs
index 405ef62cd1f..968172693a9 100644
--- a/compiler/rustc_lint/src/lints.rs
+++ b/compiler/rustc_lint/src/lints.rs
@@ -743,10 +743,10 @@ pub enum InvalidFromUtf8Diag {
     },
 }
 
-// cast_ref_to_mut.rs
+// reference_casting.rs
 #[derive(LintDiagnostic)]
-#[diag(lint_cast_ref_to_mut)]
-pub struct CastRefToMutDiag;
+#[diag(lint_invalid_reference_casting)]
+pub struct InvalidReferenceCastingDiag;
 
 // hidden_unicode_codepoints.rs
 #[derive(LintDiagnostic)]
diff --git a/compiler/rustc_lint/src/cast_ref_to_mut.rs b/compiler/rustc_lint/src/reference_casting.rs
index 82bb70bc9e7..d343aaf35d5 100644
--- a/compiler/rustc_lint/src/cast_ref_to_mut.rs
+++ b/compiler/rustc_lint/src/reference_casting.rs
@@ -3,15 +3,16 @@ use rustc_hir::{Expr, ExprKind, MutTy, TyKind, UnOp};
 use rustc_middle::ty;
 use rustc_span::sym;
 
-use crate::{lints::CastRefToMutDiag, LateContext, LateLintPass, LintContext};
+use crate::{lints::InvalidReferenceCastingDiag, LateContext, LateLintPass, LintContext};
 
 declare_lint! {
-    /// The `cast_ref_to_mut` lint checks for casts of `&T` to `&mut T`
+    /// The `invalid_reference_casting` lint checks for casts of `&T` to `&mut T`
     /// without using interior mutability.
     ///
     /// ### Example
     ///
     /// ```rust,compile_fail
+    /// # #![deny(invalid_reference_casting)]
     /// fn x(r: &i32) {
     ///     unsafe {
     ///         *(r as *const i32 as *mut i32) += 1;
@@ -28,14 +29,14 @@ declare_lint! {
     ///
     /// `UnsafeCell` is the only way to obtain aliasable data that is considered
     /// mutable.
-    CAST_REF_TO_MUT,
-    Deny,
+    INVALID_REFERENCE_CASTING,
+    Allow,
     "casts of `&T` to `&mut T` without interior mutability"
 }
 
-declare_lint_pass!(CastRefToMut => [CAST_REF_TO_MUT]);
+declare_lint_pass!(InvalidReferenceCasting => [INVALID_REFERENCE_CASTING]);
 
-impl<'tcx> LateLintPass<'tcx> for CastRefToMut {
+impl<'tcx> LateLintPass<'tcx> for InvalidReferenceCasting {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
         let ExprKind::Unary(UnOp::Deref, e) = &expr.kind else {
             return;
@@ -68,7 +69,7 @@ impl<'tcx> LateLintPass<'tcx> for CastRefToMut {
 
         let e = e.peel_blocks();
         if let ty::Ref(..) = cx.typeck_results().node_type(e.hir_id).kind() {
-            cx.emit_spanned_lint(CAST_REF_TO_MUT, expr.span, CastRefToMutDiag);
+            cx.emit_spanned_lint(INVALID_REFERENCE_CASTING, expr.span, InvalidReferenceCastingDiag);
         }
     }
 }