rust-lang · bors · Dec 20, 2025 · Nov 3, 2025 · Dec 20, 2025 · Dec 20, 2025
diff --git a/compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs b/compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs
@@ -690,6 +690,16 @@ impl<S: Stage> SingleAttributeParser<S> for SanitizeParser {
     }
 }
 
+pub(crate) struct ThreadLocalParser;
+
+impl<S: Stage> NoArgsAttributeParser<S> for ThreadLocalParser {
+    const PATH: &[Symbol] = &[sym::thread_local];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
+    const ALLOWED_TARGETS: AllowedTargets =
+        AllowedTargets::AllowList(&[Allow(Target::Static), Allow(Target::ForeignStatic)]);
+    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::ThreadLocal;
+}
+
 pub(crate) struct RustcPassIndirectlyInNonRusticAbisParser;
 
 impl<S: Stage> NoArgsAttributeParser<S> for RustcPassIndirectlyInNonRusticAbisParser {

diff --git a/compiler/rustc_attr_parsing/src/context.rs b/compiler/rustc_attr_parsing/src/context.rs
@@ -23,7 +23,7 @@ use crate::attributes::codegen_attrs::{
     ColdParser, CoverageParser, EiiExternItemParser, ExportNameParser, ForceTargetFeatureParser,
     NakedParser, NoMangleParser, ObjcClassParser, ObjcSelectorParser, OptimizeParser,
     RustcPassIndirectlyInNonRusticAbisParser, SanitizeParser, TargetFeatureParser,
-    TrackCallerParser, UsedParser,
+    ThreadLocalParser, TrackCallerParser, UsedParser,
 };
 use crate::attributes::confusables::ConfusablesParser;
 use crate::attributes::crate_level::{
@@ -269,6 +269,7 @@ attribute_parsers!(
         Single<WithoutArgs<RustcShouldNotBeCalledOnConstItems>>,
         Single<WithoutArgs<SpecializationTraitParser>>,
         Single<WithoutArgs<StdInternalSymbolParser>>,
+        Single<WithoutArgs<ThreadLocalParser>>,
         Single<WithoutArgs<TrackCallerParser>>,
         Single<WithoutArgs<TypeConstParser>>,
         Single<WithoutArgs<UnsafeSpecializationMarkerParser>>,

diff --git a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
@@ -350,6 +350,9 @@ fn process_builtin_attrs(
                         codegen_fn_attrs.flags |= CodegenFnAttrFlags::EXTERNALLY_IMPLEMENTABLE_ITEM;
                     }
                 }
+                AttributeKind::ThreadLocal => {
+                    codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL
+                }
                 _ => {}
             }
         }
@@ -366,7 +369,6 @@ fn process_builtin_attrs(
             sym::rustc_allocator_zeroed => {
                 codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR_ZEROED
             }
-            sym::thread_local => codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL,
             sym::instruction_set => {
                 codegen_fn_attrs.instruction_set = parse_instruction_set_attr(tcx, attr)
             }

diff --git a/compiler/rustc_hir/src/attrs/data_structures.rs b/compiler/rustc_hir/src/attrs/data_structures.rs
@@ -1010,6 +1010,9 @@ pub enum AttributeKind {
     /// `#[unsafe(force_target_feature(enable = "...")]`.
     TargetFeature { features: ThinVec<(Symbol, Span)>, attr_span: Span, was_forced: bool },
 
+    /// Represents `#[thread_local]`
+    ThreadLocal,
+
     /// Represents `#[track_caller]`
     TrackCaller(Span),
 

diff --git a/compiler/rustc_hir/src/attrs/encode_cross_crate.rs b/compiler/rustc_hir/src/attrs/encode_cross_crate.rs
@@ -114,6 +114,7 @@ impl AttributeKind {
             Stability { .. } => Yes,
             StdInternalSymbol(..) => No,
             TargetFeature { .. } => No,
+            ThreadLocal => No,
             TrackCaller(..) => Yes,
             TypeConst(..) => Yes,
             TypeLengthLimit { .. } => No,

diff --git a/compiler/rustc_metadata/src/errors.rs b/compiler/rustc_metadata/src/errors.rs
@@ -251,9 +251,7 @@ impl<'a> MissingNativeLibrary<'a> {
         // if it looks like the user has provided a complete filename rather just the bare lib name,
         // then provide a note that they might want to try trimming the name
         let suggested_name = if !verbatim {
-            if let Some(libname) = libname.strip_prefix("lib")
-                && let Some(libname) = libname.strip_suffix(".a")
-            {
+            if let Some(libname) = libname.strip_circumfix("lib", ".a") {
                 // this is a unix style filename so trim prefix & suffix
                 Some(libname)
             } else if let Some(libname) = libname.strip_suffix(".lib") {

diff --git a/compiler/rustc_metadata/src/lib.rs b/compiler/rustc_metadata/src/lib.rs
@@ -10,6 +10,7 @@
 #![feature(never_type)]
 #![feature(proc_macro_internals)]
 #![feature(result_option_map_or_default)]
+#![feature(strip_circumfix)]
 #![feature(trusted_len)]
 // tidy-alphabetical-end
 

diff --git a/compiler/rustc_passes/messages.ftl b/compiler/rustc_passes/messages.ftl
@@ -484,10 +484,6 @@ passes_sanitize_attribute_not_allowed =
     .no_body = function has no body
     .help = sanitize attribute can be applied to a function (with body), impl block, or module
 
-passes_should_be_applied_to_static =
-    attribute should be applied to a static
-    .label = not a static
-
 passes_should_be_applied_to_trait =
     attribute should be applied to a trait
     .label = not a trait

diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
@@ -297,6 +297,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     | AttributeKind::RustcPassIndirectlyInNonRusticAbis(..)
                     | AttributeKind::PinV2(..)
                     | AttributeKind::WindowsSubsystem(..)
+                    | AttributeKind::ThreadLocal
                 ) => { /* do nothing  */ }
                 Attribute::Unparsed(attr_item) => {
                     style = Some(attr_item.style);
@@ -310,7 +311,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                         [sym::diagnostic, sym::on_const, ..] => {
                             self.check_diagnostic_on_const(attr.span(), hir_id, target, item)
                         }
-                        [sym::thread_local, ..] => self.check_thread_local(attr, span, target),
                         [sym::rustc_clean, ..]
                         | [sym::rustc_dirty, ..]
                         | [sym::rustc_if_this_changed, ..]
@@ -768,19 +768,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         }
     }
 
-    /// Checks if the `#[thread_local]` attribute on `item` is valid.
-    fn check_thread_local(&self, attr: &Attribute, span: Span, target: Target) {
-        match target {
-            Target::ForeignStatic | Target::Static => {}
-            _ => {
-                self.dcx().emit_err(errors::AttrShouldBeAppliedToStatic {
-                    attr_span: attr.span(),
-                    defn_span: span,
-                });
-            }
-        }
-    }
-
     fn check_doc_alias_value(&self, span: Span, hir_id: HirId, target: Target, alias: Symbol) {
         if let Some(location) = match target {
             Target::AssocTy => {

diff --git a/compiler/rustc_passes/src/errors.rs b/compiler/rustc_passes/src/errors.rs
@@ -98,15 +98,6 @@ pub(crate) struct AttrShouldBeAppliedToTrait {
     pub defn_span: Span,
 }
 
-#[derive(Diagnostic)]
-#[diag(passes_should_be_applied_to_static)]
-pub(crate) struct AttrShouldBeAppliedToStatic {
-    #[primary_span]
-    pub attr_span: Span,
-    #[label]
-    pub defn_span: Span,
-}
-
 #[derive(Diagnostic)]
 #[diag(passes_doc_alias_bad_location)]
 pub(crate) struct DocAliasBadLocation<'a> {

diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs
@@ -1758,8 +1758,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 // specify a byte literal
                 (ty::Uint(ty::UintTy::U8), ty::Char) => {
                     if let Ok(code) = self.tcx.sess().source_map().span_to_snippet(span)
-                        && let Some(code) =
-                            code.strip_prefix('\'').and_then(|s| s.strip_suffix('\''))
+                        && let Some(code) = code.strip_circumfix('\'', '\'')
                         // forbid all Unicode escapes
                         && !code.starts_with("\\u")
                         // forbids literal Unicode characters beyond ASCII
@@ -1776,7 +1775,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 // specify a character literal (issue #92479)
                 (ty::Char, ty::Ref(_, r, _)) if r.is_str() => {
                     if let Ok(code) = self.tcx.sess().source_map().span_to_snippet(span)
-                        && let Some(code) = code.strip_prefix('"').and_then(|s| s.strip_suffix('"'))
+                        && let Some(code) = code.strip_circumfix('"', '"')
                         && code.chars().count() == 1
                     {
                         suggestions.push(TypeErrorAdditionalDiags::MeantCharLiteral {

diff --git a/compiler/rustc_trait_selection/src/lib.rs b/compiler/rustc_trait_selection/src/lib.rs
@@ -22,6 +22,7 @@
 #![feature(iter_intersperse)]
 #![feature(iterator_try_reduce)]
 #![feature(never_type)]
+#![feature(strip_circumfix)]
 #![feature(try_blocks)]
 #![feature(unwrap_infallible)]
 #![feature(yeet_expr)]

diff --git a/tests/ui/attributes/malformed-attrs.stderr b/tests/ui/attributes/malformed-attrs.stderr
@@ -141,12 +141,6 @@ LL | #[forbid(lint1, lint2, ...)]
 LL | #[forbid(lint1, lint2, lint3, reason = "...")]
    |         +++++++++++++++++++++++++++++++++++++
 
-error: malformed `thread_local` attribute input
-  --> $DIR/malformed-attrs.rs:210:1
-   |
-LL | #[thread_local()]
-   | ^^^^^^^^^^^^^^^^^ help: must be of the form: `#[thread_local]`
-
 error: the `#[proc_macro]` attribute is only usable with crates of the `proc-macro` crate type
   --> $DIR/malformed-attrs.rs:105:1
    |
@@ -618,6 +612,15 @@ LL | #[non_exhaustive = 1]
    | |                didn't expect any arguments here
    | help: must be of the form: `#[non_exhaustive]`
 
+error[E0565]: malformed `thread_local` attribute input
+  --> $DIR/malformed-attrs.rs:210:1
+   |
+LL | #[thread_local()]
+   | ^^^^^^^^^^^^^^--^
+   | |             |
+   | |             didn't expect any arguments here
+   | help: must be of the form: `#[thread_local]`
+
 error[E0565]: malformed `no_link` attribute input
   --> $DIR/malformed-attrs.rs:214:1
    |

diff --git a/tests/ui/thread-local/non-static.rs b/tests/ui/thread-local/non-static.rs
@@ -2,19 +2,19 @@
 #![feature(thread_local)]
 
 #[thread_local]
-//~^ ERROR attribute should be applied to a static
+//~^ ERROR `#[thread_local]` attribute cannot be used on constants
 const A: u32 = 0;
 
 #[thread_local]
-//~^ ERROR attribute should be applied to a static
+//~^ ERROR `#[thread_local]` attribute cannot be used on functions
 fn main() {
     #[thread_local] || {};
-    //~^ ERROR attribute should be applied to a static
+    //~^ ERROR `#[thread_local]` attribute cannot be used on closures
 }
 
 struct S {
     #[thread_local]
-    //~^ ERROR attribute should be applied to a static
+    //~^ ERROR `#[thread_local]` attribute cannot be used on struct fields
     a: String,
     b: String,
 }

diff --git a/tests/ui/thread-local/non-static.stderr b/tests/ui/thread-local/non-static.stderr
@@ -1,38 +1,34 @@
-error: attribute should be applied to a static
+error: `#[thread_local]` attribute cannot be used on constants
   --> $DIR/non-static.rs:4:1
    |
 LL | #[thread_local]
    | ^^^^^^^^^^^^^^^
-LL |
-LL | const A: u32 = 0;
-   | ----------------- not a static
+   |
+   = help: `#[thread_local]` can be applied to foreign statics and statics
 
-error: attribute should be applied to a static
+error: `#[thread_local]` attribute cannot be used on functions
   --> $DIR/non-static.rs:8:1
    |
-LL |   #[thread_local]
-   |   ^^^^^^^^^^^^^^^
-LL |
-LL | / fn main() {
-LL | |     #[thread_local] || {};
-LL | |
-LL | | }
-   | |_- not a static
+LL | #[thread_local]
+   | ^^^^^^^^^^^^^^^
+   |
+   = help: `#[thread_local]` can be applied to foreign statics and statics
 
-error: attribute should be applied to a static
+error: `#[thread_local]` attribute cannot be used on closures
   --> $DIR/non-static.rs:11:5
    |
 LL |     #[thread_local] || {};
-   |     ^^^^^^^^^^^^^^^ ----- not a static
+   |     ^^^^^^^^^^^^^^^
+   |
+   = help: `#[thread_local]` can be applied to foreign statics and statics
 
-error: attribute should be applied to a static
+error: `#[thread_local]` attribute cannot be used on struct fields
   --> $DIR/non-static.rs:16:5
    |
 LL |     #[thread_local]
    |     ^^^^^^^^^^^^^^^
-LL |
-LL |     a: String,
-   |     --------- not a static
+   |
+   = help: `#[thread_local]` can be applied to foreign statics and statics
 
 error: aborting due to 4 previous errors