Auto merge of #96692 - ehuss:beta-backports, r=ehuss

[beta] Beta backports

* Revert diagnostic duplication and accidental stabilization #96516
* Revert "Re-export core::ffi types from std::ffi" #96492
* Make [e]println macros eagerly drop temporaries (for backport) #96490
* Revert "impl From<&[T; N]> and From<&mut [T; N]> for Vec<T>" #96489
* Cargo:
    * move workspace inheritance unstable docs to the correct place (rust-lang/cargo#10616)

Author: bors

compiler/rustc_typeck/src/check/check.rs

@@ -102,6 +102,12 @@ pub(super) fn check_fn<'a, 'tcx>(
             DUMMY_SP,
             param_env,
         ));
+    // HACK(oli-obk): we rewrite the declared return type, too, so that we don't end up inferring all
+    // unconstrained RPIT to have `()` as their hidden type. This would happen because further down we
+    // compare the ret_coercion with declared_ret_ty, and anything uninferred would be inferred to the
+    // opaque type itself. That again would cause writeback to assume we have a recursive call site
+    // and do the sadly stabilized fallback to `()`.
+    let declared_ret_ty = ret_ty;
     fcx.ret_coercion = Some(RefCell::new(CoerceMany::new(ret_ty)));
     fcx.ret_type_span = Some(decl.output.span());
 

library/alloc/src/vec/mod.rs

@@ -2931,48 +2931,6 @@ impl<T, const N: usize> From<[T; N]> for Vec<T> {
     }
 }
 
-#[cfg(not(no_global_oom_handling))]
-#[stable(feature = "vec_from_array_ref", since = "1.61.0")]
-impl<T: Clone, const N: usize> From<&[T; N]> for Vec<T> {
-    /// Allocate a `Vec<T>` and fill it by cloning `s`'s items.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// assert_eq!(Vec::from(b"raw"), vec![b'r', b'a', b'w']);
-    /// ```
-    #[cfg(not(test))]
-    fn from(s: &[T; N]) -> Vec<T> {
-        s.to_vec()
-    }
-
-    #[cfg(test)]
-    fn from(s: &[T; N]) -> Vec<T> {
-        crate::slice::to_vec(s, Global)
-    }
-}
-
-#[cfg(not(no_global_oom_handling))]
-#[stable(feature = "vec_from_array_ref", since = "1.61.0")]
-impl<T: Clone, const N: usize> From<&mut [T; N]> for Vec<T> {
-    /// Allocate a `Vec<T>` and fill it by cloning `s`'s items.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// assert_eq!(Vec::from(&mut [1, 2, 3]), vec![1, 2, 3]);
-    /// ```
-    #[cfg(not(test))]
-    fn from(s: &mut [T; N]) -> Vec<T> {
-        s.to_vec()
-    }
-
-    #[cfg(test)]
-    fn from(s: &mut [T; N]) -> Vec<T> {
-        crate::slice::to_vec(s, Global)
-    }
-}
-
 #[stable(feature = "vec_from_cow_slice", since = "1.14.0")]
 impl<'a, T> From<Cow<'a, [T]>> for Vec<T>
 where

library/std/src/ffi/mod.rs

@@ -159,15 +159,6 @@ pub use self::os_str::{OsStr, OsString};
 #[stable(feature = "core_c_void", since = "1.30.0")]
 pub use core::ffi::c_void;
 
-#[unstable(feature = "core_ffi_c", issue = "94501")]
-pub use core::ffi::{
-    c_char, c_double, c_float, c_int, c_long, c_longlong, c_schar, c_short, c_uchar, c_uint,
-    c_ulong, c_ulonglong, c_ushort,
-};
-
-#[unstable(feature = "c_size_t", issue = "88345")]
-pub use core::ffi::{c_ptrdiff_t, c_size_t, c_ssize_t};
-
 #[unstable(
     feature = "c_variadic",
     reason = "the `c_variadic` feature has not been properly tested on \

library/std/src/lib.rs

@@ -303,7 +303,6 @@
 // Only for re-exporting:
 #![feature(assert_matches)]
 #![feature(async_iterator)]
-#![feature(c_size_t)]
 #![feature(c_variadic)]
 #![feature(cfg_accessible)]
 #![feature(cfg_eval)]

library/std/src/macros.rs

@@ -99,9 +99,9 @@ macro_rules! println {
     () => {
         $crate::print!("\n")
     };
-    ($($arg:tt)*) => {
-        $crate::io::_print($crate::format_args_nl!($($arg)*))
-    };
+    ($($arg:tt)*) => {{
+        $crate::io::_print($crate::format_args_nl!($($arg)*));
+    }};
 }
 
 /// Prints to the standard error.
@@ -164,9 +164,9 @@ macro_rules! eprintln {
     () => {
         $crate::eprint!("\n")
     };
-    ($($arg:tt)*) => {
-        $crate::io::_eprint($crate::format_args_nl!($($arg)*))
-    };
+    ($($arg:tt)*) => {{
+        $crate::io::_eprint($crate::format_args_nl!($($arg)*));
+    }};
 }
 
 /// Prints and returns the value of a given expression for quick and dirty

src/test/pretty/dollar-crate.pp

@@ -9,5 +9,5 @@
 // pp-exact:dollar-crate.pp
 
 fn main() {
-    ::std::io::_print(::core::fmt::Arguments::new_v1(&["rust\n"], &[]));
+    { ::std::io::_print(::core::fmt::Arguments::new_v1(&["rust\n"], &[])); };
 }

src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.closure.txt

@@ -116,8 +116,8 @@
   116|      1|
   117|      1|    let
   118|      1|        _unused_closure
-  119|      1|    =
-  120|      1|        |
+  119|       |    =
+  120|       |        |
   121|       |            mut countdown
   122|       |        |
   123|      0|    {
@@ -173,7 +173,7 @@
   169|       |    ;
   170|       |
   171|      1|    let short_used_not_covered_closure_line_break_no_block_embedded_branch =
-  172|      1|        | _unused_arg: u8 |
+  172|       |        | _unused_arg: u8 |
   173|      0|            println!(
   174|      0|                "not called: {}",
   175|      0|                if is_true { "check" } else { "me" }
@@ -191,7 +191,7 @@
   187|       |    ;
   188|       |
   189|      1|    let short_used_covered_closure_line_break_no_block_embedded_branch =
-  190|       |        | _unused_arg: u8 |
+  190|      1|        | _unused_arg: u8 |
   191|      1|            println!(
   192|      1|                "not called: {}",
   193|      1|                if is_true { "check" } else { "me" }

src/test/ui/associated-types/impl-trait-return-missing-constraint.rs

@@ -24,7 +24,6 @@ fn bar() -> impl Bar {
 
 fn baz() -> impl Bar<Item = i32> {
     //~^ ERROR type mismatch resolving `<impl Bar as Foo>::Item == i32`
-    //~| ERROR type mismatch resolving `<impl Bar as Foo>::Item == i32`
     bar()
 }
 

src/test/ui/associated-types/impl-trait-return-missing-constraint.stderr

@@ -16,29 +16,6 @@ help: consider constraining the associated type `<impl Bar as Foo>::Item` to `i3
 LL | fn bar() -> impl Bar<Item = i32> {
    |                     ++++++++++++
 
-error[E0271]: type mismatch resolving `<impl Bar as Foo>::Item == i32`
-  --> $DIR/impl-trait-return-missing-constraint.rs:25:34
-   |
-LL |   fn bar() -> impl Bar {
-   |               -------- the expected opaque type
-...
-LL |   fn baz() -> impl Bar<Item = i32> {
-   |  __________________________________^
-LL | |
-LL | |
-LL | |     bar()
-LL | | }
-   | |_^ expected associated type, found `i32`
-   |
-   = note: expected associated type `<impl Bar as Foo>::Item`
-                         found type `i32`
-   = help: consider constraining the associated type `<impl Bar as Foo>::Item` to `i32` or calling a method that returns `<impl Bar as Foo>::Item`
-   = note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html
-help: consider constraining the associated type `<impl Bar as Foo>::Item` to `i32`
-   |
-LL | fn bar() -> impl Bar<Item = i32> {
-   |                     ++++++++++++
-
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 
 For more information about this error, try `rustc --explain E0271`.

src/test/ui/conservative_impl_trait.rs

@@ -2,7 +2,6 @@
 
 fn will_ice(something: &u32) -> impl Iterator<Item = &u32> {
     //~^ ERROR `()` is not an iterator
-    //~| ERROR `()` is not an iterator
 }
 
 fn main() {}