Auto merge of rust-lang#124895 - obeis:static-mut-hidden-ref, r=michaelwoerister

Disallow hidden references to mutable static

Closes rust-lang#123060

Tracking:
- rust-lang#123758

Author: bors

compiler/rustc_driver_impl/src/signal_handler.rs

@@ -34,6 +34,8 @@ macro raw_errln($tokens:tt) {
 }
 
 /// Signal handler installed for SIGSEGV
+// FIXME(obeis): Use `SyncUnsafeCell` instead of allowing `static_mut_refs` lint
+#[allow(static_mut_refs)]
 extern "C" fn print_stack_trace(_: libc::c_int) {
     const MAX_FRAMES: usize = 256;
     // Reserve data segment so we don't have to malloc in a signal handler, which might fail

compiler/rustc_hir_analysis/messages.ftl

@@ -463,24 +463,20 @@ hir_analysis_start_not_target_feature = `#[start]` function is not allowed to ha
 hir_analysis_start_not_track_caller = `#[start]` function is not allowed to be `#[track_caller]`
     .label = `#[start]` function is not allowed to be `#[track_caller]`
 
-hir_analysis_static_mut_ref = creating a {$shared} reference to a mutable static
-    .label = {$shared} reference to mutable static
-    .note = {$shared ->
-        [shared] this shared reference has lifetime `'static`, but if the static ever gets mutated, or a mutable reference is created, then any further use of this shared reference is Undefined Behavior
-        *[mutable] this mutable reference has lifetime `'static`, but if the static gets accessed (read or written) by any other means, or any other reference is created, then any further use of this mutable reference is Undefined Behavior
-    }
+hir_analysis_static_mut_ref = creating a {$shared_label}reference to a mutable static
+    .label = {$shared_label}reference to mutable static
+    .shared_note = shared references to mutable statics are dangerous since if there's any kind of mutation of, or mutable reference created for, that static while the reference lives, that's undefined behavior
+    .mut_note = mutable references to mutable statics are dangerous since if there's any other pointer used or reference created for that static while the reference lives, that's undefined behavior
     .suggestion = use `addr_of!` instead to create a raw pointer
     .suggestion_mut = use `addr_of_mut!` instead to create a raw pointer
 
-hir_analysis_static_mut_refs_lint = creating a {$shared} reference to mutable static is discouraged
-    .label = {$shared} reference to mutable static
+hir_analysis_static_mut_refs_lint = creating a {$shared_label}reference to mutable static is discouraged
+    .label = {$shared_label}reference to mutable static
     .suggestion = use `addr_of!` instead to create a raw pointer
     .suggestion_mut = use `addr_of_mut!` instead to create a raw pointer
     .note = this will be a hard error in the 2024 edition
-    .why_note = {$shared ->
-        [shared] this shared reference has lifetime `'static`, but if the static ever gets mutated, or a mutable reference is created, then any further use of this shared reference is Undefined Behavior
-        *[mutable] this mutable reference has lifetime `'static`, but if the static gets accessed (read or written) by any other means, or any other reference is created, then any further use of this mutable reference is Undefined Behavior
-    }
+    .shared_note = shared references to mutable statics are dangerous since if there's any kind of mutation of, or mutable reference created for, that static while the reference lives, that's undefined behavior
+    .mut_note = mutable references to mutable statics are dangerous since if there's any other pointer used or reference created for that static while the reference lives, that's undefined behavior
 
 hir_analysis_static_specialize = cannot specialize on `'static` lifetime