[beta] backports

compiler/rustc_abi/src/lib.rs

@@ -1,4 +1,5 @@
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![cfg_attr(feature = "nightly", allow(internal_features))]
 #![cfg_attr(feature = "nightly", feature(rustc_attrs))]
 #![cfg_attr(feature = "nightly", feature(step_trait))]

compiler/rustc_borrowck/src/lib.rs

@@ -2,6 +2,7 @@
 
 // tidy-alphabetical-start
 #![allow(internal_features)]
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(box_patterns)]
 #![feature(default_field_values)]
 #![feature(file_buffered)]

compiler/rustc_builtin_macros/src/lib.rs

@@ -3,6 +3,7 @@
 
 // tidy-alphabetical-start
 #![allow(internal_features)]
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(box_patterns)]
 #![feature(decl_macro)]
 #![feature(iter_order_by)]

compiler/rustc_codegen_llvm/src/lib.rs

@@ -5,6 +5,7 @@
 //! This API is completely unstable and subject to change.
 
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(extern_types)]
 #![feature(file_buffered)]
 #![feature(impl_trait_in_assoc_type)]

compiler/rustc_codegen_ssa/src/lib.rs

@@ -1,4 +1,5 @@
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(box_patterns)]
 #![feature(file_buffered)]
 #![feature(negative_impls)]

compiler/rustc_const_eval/src/lib.rs

@@ -1,4 +1,5 @@
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(array_try_map)]
 #![feature(box_patterns)]
 #![feature(decl_macro)]

compiler/rustc_data_structures/src/lib.rs

@@ -10,6 +10,7 @@
 #![allow(internal_features)]
 #![allow(rustc::default_hash_types)]
 #![allow(rustc::potential_query_instability)]
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![cfg_attr(test, feature(test))]
 #![deny(unsafe_op_in_unsafe_fn)]
 #![feature(allocator_api)]

compiler/rustc_errors/src/lib.rs

@@ -5,6 +5,7 @@
 // tidy-alphabetical-start
 #![allow(internal_features)]
 #![allow(rustc::direct_use_of_rustc_type_ir)]
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(associated_type_defaults)]
 #![feature(default_field_values)]
 #![feature(macro_metavar_expr_concat)]

compiler/rustc_hir_analysis/src/lib.rs

@@ -56,6 +56,7 @@ This API is completely unstable and subject to change.
 */
 
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(default_field_values)]
 #![feature(gen_blocks)]
 #![feature(iter_intersperse)]

compiler/rustc_hir_typeck/src/lib.rs

@@ -1,4 +1,5 @@
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(box_patterns)]
 #![feature(iter_intersperse)]
 #![feature(iter_order_by)]

compiler/rustc_infer/src/lib.rs

@@ -14,6 +14,7 @@
 
 // tidy-alphabetical-start
 #![allow(rustc::direct_use_of_rustc_type_ir)]
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(extend_one)]
 #![recursion_limit = "512"] // For rustdoc
 // tidy-alphabetical-end

compiler/rustc_lint/src/lib.rs

@@ -21,6 +21,7 @@
 
 // tidy-alphabetical-start
 #![allow(internal_features)]
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(box_patterns)]
 #![feature(iter_order_by)]
 #![feature(rustc_attrs)]

compiler/rustc_middle/src/lib.rs

@@ -27,6 +27,7 @@
 // tidy-alphabetical-start
 #![allow(internal_features)]
 #![allow(rustc::direct_use_of_rustc_type_ir)]
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![cfg_attr(doc, feature(intra_doc_pointers))]
 #![feature(allocator_api)]
 #![feature(associated_type_defaults)]

compiler/rustc_mir_build/src/lib.rs

@@ -1,6 +1,7 @@
 //! Construction of MIR from HIR.
 
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(box_patterns)]
 #![feature(try_blocks)]
 // tidy-alphabetical-end

compiler/rustc_mir_dataflow/src/lib.rs

@@ -1,4 +1,5 @@
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(associated_type_defaults)]
 #![feature(box_patterns)]
 #![feature(exact_size_is_empty)]

compiler/rustc_mir_transform/src/lib.rs

@@ -1,4 +1,5 @@
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(box_patterns)]
 #![feature(const_type_name)]
 #![feature(cow_is_borrowed)]

compiler/rustc_parse/src/lib.rs

@@ -1,6 +1,7 @@
 //! The main parser interface.
 
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![cfg_attr(test, feature(iter_order_by))]
 #![feature(box_patterns)]
 #![feature(debug_closure_helpers)]

compiler/rustc_resolve/src/lib.rs

@@ -8,6 +8,7 @@
 
 // tidy-alphabetical-start
 #![allow(internal_features)]
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(arbitrary_self_types)]
 #![feature(box_patterns)]
 #![feature(const_default)]

compiler/rustc_symbol_mangling/src/lib.rs

@@ -87,6 +87,10 @@
 //! virtually impossible. Thus, symbol hash generation exclusively relies on
 //! DefPaths which are much more robust in the face of changes to the code base.
 
+// tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(assert_matches))]
+// tidy-alphabetical-end
+
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
 use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};

compiler/rustc_trait_selection/src/lib.rs

@@ -11,6 +11,7 @@
 //! This API is completely unstable and subject to change.
 
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(associated_type_defaults)]
 #![feature(box_patterns)]
 #![feature(default_field_values)]

compiler/rustc_ty_utils/src/lib.rs

@@ -5,6 +5,7 @@
 //! This API is completely unstable and subject to change.
 
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![feature(associated_type_defaults)]
 #![feature(box_patterns)]
 #![feature(iterator_try_collect)]

library/std/src/macros.rs

@@ -369,7 +369,8 @@ macro_rules! dbg {
 /// E.g. `dbg_internal!(() () (1, 2))` expands into
 /// ```rust, ignore
 /// match (1, 2) {
-///     (tmp_1, tmp_2) => {
+///     args => {
+///         let (tmp_1, tmp_2) = args;
 ///         eprint!("...", &tmp_1, &tmp_2, /* some other arguments */);
 ///         (tmp_1, tmp_2)
 ///     }
@@ -385,7 +386,9 @@ pub macro dbg_internal {
         // of temporaries - https://stackoverflow.com/a/48732525/1063961
         // Always put the arguments in a tuple to avoid an unused parens lint on the pattern.
         match ($($processed,)+) {
-            ($($bound,)+) => {
+            // Move the entire tuple so it doesn't stick around as a temporary (#154988).
+            args => {
+                let ($($bound,)+) = args;
                 $crate::eprint!(
                     $crate::concat!($($piece),+),
                     $(

library/std/src/macros/tests.rs

@@ -1,5 +1,7 @@
 // ignore-tidy-dbg
 
+use core::fmt::Debug;
+
 /// Test for <https://github.com/rust-lang/rust/issues/153850>:
 /// `dbg!` shouldn't drop arguments' temporaries.
 #[test]
@@ -11,3 +13,25 @@ fn no_dropping_temps() {
     *dbg!(0, &temp()).1;
     *dbg!(0, &temp(), 2).1;
 }
+
+/// Test for <https://github.com/rust-lang/rust/issues/154988>:
+/// `dbg!` shouldn't create a temporary that lives past its invocation.
+#[test]
+fn no_leaking_internal_temps_from_dbg() {
+    #[derive(Debug)]
+    struct Foo;
+
+    #[derive(Debug)]
+    struct Bar<'a>(#[allow(unused)] &'a Foo);
+    impl Drop for Bar<'_> {
+        fn drop(&mut self) {}
+    }
+
+    let foo = Foo;
+    let bar = Bar(&foo);
+    // If `dbg!` creates a `(Bar<'_>,)` temporary that lasts past its expansion, this will fail
+    // to compile, because it will be dropped after `foo`, which it borrows from. The tuple
+    // mimics the drop order of block tail expressions before Rust 2024: first the result of `dbg!`
+    // is dropped, then `foo`, then any temporaries left over from `dbg!` are dropped, if present.
+    (drop(dbg!(bar)), drop(foo));
+}

src/librustdoc/clean/cfg.rs

@@ -545,15 +545,15 @@ fn human_readable_target_arch(os: Symbol) -> Option<&'static str> {
     Some(match arch {
         // tidy-alphabetical-start
         AArch64 => "AArch64",
-        AmdGpu => "AMG GPU",
+        AmdGpu => "AMD GPU",
         Arm => "ARM",
         Arm64EC => "ARM64EC",
         Avr => "AVR",
         Bpf => "BPF",
         CSky => "C-SKY",
         Hexagon => "Hexagon",
-        LoongArch32 => "LoongArch64",
-        LoongArch64 => "LoongArch32",
+        LoongArch32 => "LoongArch32",
+        LoongArch64 => "LoongArch64",
         M68k => "Motorola 680x0",
         Mips => "MIPS",
         Mips32r6 => "MIPS release 6",

src/librustdoc/lib.rs

@@ -1,4 +1,5 @@
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(assert_matches))]
 #![doc(
     html_root_url = "https://doc.rust-lang.org/nightly/",
     html_playground_url = "https://play.rust-lang.org/"