Merge from rustc

Author: RalfJung

tests/fail/uninit/padding-enum.rs

@@ -17,10 +17,11 @@ fn main() {
         assert!(matches!(*p.as_ptr(), E::None));
 
         // Turns out the discriminant is (currently) stored
-        // in the 2nd pointer, so the first half is padding.
+        // in the 1st pointer, so the second half is padding.
         let c = &p as *const _ as *const u8;
+        let padding_offset = mem::size_of::<&'static ()>();
         // Read a padding byte.
-        let _val = *c.add(0);
+        let _val = *c.add(padding_offset);
         //~^ERROR: uninitialized
     }
 }

tests/fail/uninit/padding-enum.stderr

@@ -1,8 +1,8 @@
 error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
   --> tests/fail/uninit/padding-enum.rs:LL:CC
    |
-LL |         let _val = *c.add(0);
-   |                    ^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+LL |         let _val = *c.add(padding_offset);
+   |                    ^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

tests/pass-dep/concurrency/linux-futex.rs

@@ -1,6 +1,9 @@
 //@only-target: linux
 //@compile-flags: -Zmiri-disable-isolation
 
+// FIXME(static_mut_refs): Do not allow `static_mut_refs` lint
+#![allow(static_mut_refs)]
+
 use std::mem::MaybeUninit;
 use std::ptr::{self, addr_of};
 use std::sync::atomic::AtomicI32;

tests/pass-dep/concurrency/tls_pthread_drop_order.rs

@@ -5,6 +5,9 @@
 //! the fallback path in `guard::key::enable`, which uses a *single* pthread_key
 //! to manage a thread-local list of dtors to call.
 
+// FIXME(static_mut_refs): Do not allow `static_mut_refs` lint
+#![allow(static_mut_refs)]
+
 use std::mem;
 use std::ptr;
 

tests/pass-dep/libc/libc-eventfd.rs

@@ -2,6 +2,9 @@
 // test_race depends on a deterministic schedule.
 //@compile-flags: -Zmiri-preemption-rate=0
 
+// FIXME(static_mut_refs): Do not allow `static_mut_refs` lint
+#![allow(static_mut_refs)]
+
 use std::thread;
 
 fn main() {

tests/pass-dep/libc/libc-pipe.rs

@@ -72,6 +72,8 @@ fn test_pipe_threaded() {
     thread2.join().unwrap();
 }
 
+// FIXME(static_mut_refs): Do not allow `static_mut_refs` lint
+#[allow(static_mut_refs)]
 fn test_race() {
     static mut VAL: u8 = 0;
     let mut fds = [-1, -1];

tests/pass-dep/libc/libc-socketpair.rs

@@ -1,6 +1,10 @@
 //@ignore-target: windows # No libc socketpair on Windows
 // test_race depends on a deterministic schedule.
 //@compile-flags: -Zmiri-preemption-rate=0
+
+// FIXME(static_mut_refs): Do not allow `static_mut_refs` lint
+#![allow(static_mut_refs)]
+
 use std::thread;
 fn main() {
     test_socketpair();

tests/pass/atomic.rs

@@ -1,7 +1,11 @@
 //@revisions: stack tree
 //@[tree]compile-flags: -Zmiri-tree-borrows
 //@compile-flags: -Zmiri-strict-provenance
+
 #![feature(strict_provenance, strict_provenance_atomic_ptr)]
+// FIXME(static_mut_refs): Do not allow `static_mut_refs` lint
+#![allow(static_mut_refs)]
+
 use std::sync::atomic::{
     compiler_fence, fence, AtomicBool, AtomicIsize, AtomicPtr, AtomicU64, Ordering::*,
 };

tests/pass/drop_on_array_elements.rs

@@ -1,3 +1,5 @@
+#![allow(static_mut_refs)]
+
 struct Bar(u16); // ZSTs are tested separately
 
 static mut DROP_COUNT: usize = 0;

tests/pass/drop_on_fat_ptr_array_elements.rs

@@ -1,3 +1,5 @@
+#![allow(static_mut_refs)]
+
 trait Foo {}
 
 struct Bar;