Revert "Rollup merge of #154994 - dianne:no-dbg-temp, r=Mark-Simulacrum"

This reverts commit 59b36a5283, reversing
changes made to 197eb8c6c0.

(cherry picked from commit 73931c4422)

library/std/src/macros.rs

@@ -369,8 +369,7 @@ macro_rules! dbg {
 /// E.g. `dbg_internal!(() () (1, 2))` expands into
 /// ```rust, ignore
 /// match (1, 2) {
-///     args => {
-///         let (tmp_1, tmp_2) = args;
+///     (tmp_1, tmp_2) => {
 ///         eprint!("...", &tmp_1, &tmp_2, /* some other arguments */);
 ///         (tmp_1, tmp_2)
 ///     }
@@ -386,9 +385,7 @@ macro_rules! dbg {
         // 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,)+) {
-            // Move the entire tuple so it doesn't stick around as a temporary (#154988).
-            args => {
-                let ($($bound,)+) = args;
+            ($($bound,)+) => {
                 $crate::eprint!(
                     $crate::concat!($($piece),+),
                     $(

library/std/src/macros/tests.rs

@@ -1,7 +1,5 @@
 // ignore-tidy-dbg
 
-use core::fmt::Debug;
-
 /// Test for <https://github.com/rust-lang/rust/issues/153850>:
 /// `dbg!` shouldn't drop arguments' temporaries.
 #[test]
@@ -13,25 +11,3 @@ fn temp() {}
     *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));
-}