Auto merge of #97548 - Dylan-DPC:rollup-9x0va1d, r=Dylan-DPC

Rollup of 6 pull requests

Successful merges:

 - #97494 (Use Box::new() instead of box syntax in library tests)
 - #97499 (Remove "sys isn't exported yet" phrase)
 - #97504 (Ensure source file present when calculating max line number)
 - #97519 (Re-add help_on_error for download-ci-llvm)
 - #97531 (Note pattern mismatch coming from `for` loop desugaring)
 - #97545 (Reword safety comments in core/hash/sip.rs)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_errors/src/emitter.rs

@@ -1261,16 +1261,23 @@ impl EmitterWriter {
             return 0;
         };
 
+        let will_be_emitted = |span: Span| {
+            !span.is_dummy() && {
+                let file = sm.lookup_source_file(span.hi());
+                sm.ensure_source_file_source_present(file)
+            }
+        };
+
         let mut max = 0;
         for primary_span in msp.primary_spans() {
-            if !primary_span.is_dummy() {
+            if will_be_emitted(*primary_span) {
                 let hi = sm.lookup_char_pos(primary_span.hi());
                 max = (hi.line).max(max);
             }
         }
         if !self.short_message {
             for span_label in msp.span_labels() {
-                if !span_label.span.is_dummy() {
+                if will_be_emitted(span_label.span) {
                     let hi = sm.lookup_char_pos(span_label.span.hi());
                     max = (hi.line).max(max);
                 }

compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -609,7 +609,14 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 if !matches!(ty.kind(), ty::Infer(ty::InferTy::TyVar(_) | ty::InferTy::FreshTy(_)))
                 {
                     // don't show type `_`
-                    err.span_label(span, format!("this expression has type `{}`", ty));
+                    if span.desugaring_kind() == Some(DesugaringKind::ForLoop)
+                    && let ty::Adt(def, substs) = ty.kind()
+                    && Some(def.did()) == self.tcx.get_diagnostic_item(sym::Option)
+                    {
+                        err.span_label(span, format!("this is an iterator with items of type `{}`", substs.type_at(0)));
+                    } else {
+                        err.span_label(span, format!("this expression has type `{}`", ty));
+                    }
                 }
                 if let Some(ty::error::ExpectedFound { found, .. }) = exp_found
                     && ty.is_box() && ty.boxed_ty() == found

library/alloc/src/alloc/tests.rs

@@ -25,6 +25,6 @@ fn allocate_zeroed() {
 #[cfg_attr(miri, ignore)] // isolated Miri does not support benchmarks
 fn alloc_owned_small(b: &mut Bencher) {
     b.iter(|| {
-        let _: Box<_> = box 10;
+        let _: Box<_> = Box::new(10);
     })
 }

library/alloc/src/collections/binary_heap/tests.rs

@@ -183,22 +183,22 @@ fn test_push() {
 
 #[test]
 fn test_push_unique() {
-    let mut heap = BinaryHeap::<Box<_>>::from(vec![box 2, box 4, box 9]);
+    let mut heap = BinaryHeap::<Box<_>>::from(vec![Box::new(2), Box::new(4), Box::new(9)]);
     assert_eq!(heap.len(), 3);
     assert!(**heap.peek().unwrap() == 9);
-    heap.push(box 11);
+    heap.push(Box::new(11));
     assert_eq!(heap.len(), 4);
     assert!(**heap.peek().unwrap() == 11);
-    heap.push(box 5);
+    heap.push(Box::new(5));
     assert_eq!(heap.len(), 5);
     assert!(**heap.peek().unwrap() == 11);
-    heap.push(box 27);
+    heap.push(Box::new(27));
     assert_eq!(heap.len(), 6);
     assert!(**heap.peek().unwrap() == 27);
-    heap.push(box 3);
+    heap.push(Box::new(3));
     assert_eq!(heap.len(), 7);
     assert!(**heap.peek().unwrap() == 27);
-    heap.push(box 103);
+    heap.push(Box::new(103));
     assert_eq!(heap.len(), 8);
     assert!(**heap.peek().unwrap() == 103);
 }

library/alloc/src/collections/linked_list.rs

@@ -791,7 +791,7 @@ impl<T> LinkedList<T> {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn push_front(&mut self, elt: T) {
-        self.push_front_node(box Node::new(elt));
+        self.push_front_node(Box::new(Node::new(elt)));
     }
 
     /// Removes the first element and returns it, or `None` if the list is
@@ -834,7 +834,7 @@ impl<T> LinkedList<T> {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn push_back(&mut self, elt: T) {
-        self.push_back_node(box Node::new(elt));
+        self.push_back_node(Box::new(Node::new(elt)));
     }
 
     /// Removes the last element from a list and returns it, or `None` if

library/alloc/src/collections/linked_list/tests.rs

@@ -12,20 +12,20 @@ fn test_basic() {
     assert_eq!(m.pop_front(), None);
     assert_eq!(m.pop_back(), None);
     assert_eq!(m.pop_front(), None);
-    m.push_front(box 1);
-    assert_eq!(m.pop_front(), Some(box 1));
-    m.push_back(box 2);
-    m.push_back(box 3);
+    m.push_front(Box::new(1));
+    assert_eq!(m.pop_front(), Some(Box::new(1)));
+    m.push_back(Box::new(2));
+    m.push_back(Box::new(3));
     assert_eq!(m.len(), 2);
-    assert_eq!(m.pop_front(), Some(box 2));
-    assert_eq!(m.pop_front(), Some(box 3));
+    assert_eq!(m.pop_front(), Some(Box::new(2)));
+    assert_eq!(m.pop_front(), Some(Box::new(3)));
     assert_eq!(m.len(), 0);
     assert_eq!(m.pop_front(), None);
-    m.push_back(box 1);
-    m.push_back(box 3);
-    m.push_back(box 5);
-    m.push_back(box 7);
-    assert_eq!(m.pop_front(), Some(box 1));
+    m.push_back(Box::new(1));
+    m.push_back(Box::new(3));
+    m.push_back(Box::new(5));
+    m.push_back(Box::new(7));
+    assert_eq!(m.pop_front(), Some(Box::new(1)));
 
     let mut n = LinkedList::new();
     n.push_front(2);

library/alloc/src/rc.rs

@@ -369,7 +369,8 @@ impl<T> Rc<T> {
         // if the weak pointer is stored inside the strong one.
         unsafe {
             Self::from_inner(
-                Box::leak(box RcBox { strong: Cell::new(1), weak: Cell::new(1), value }).into(),
+                Box::leak(Box::new(RcBox { strong: Cell::new(1), weak: Cell::new(1), value }))
+                    .into(),
             )
         }
     }
@@ -433,11 +434,11 @@ impl<T> Rc<T> {
     {
         // Construct the inner in the "uninitialized" state with a single
         // weak reference.
-        let uninit_ptr: NonNull<_> = Box::leak(box RcBox {
+        let uninit_ptr: NonNull<_> = Box::leak(Box::new(RcBox {
             strong: Cell::new(0),
             weak: Cell::new(1),
             value: mem::MaybeUninit::<T>::uninit(),
-        })
+        }))
         .into();
 
         let init_ptr: NonNull<RcBox<T>> = uninit_ptr.cast();

library/alloc/src/rc/tests.rs

@@ -32,7 +32,7 @@ fn test_simple_clone() {
 
 #[test]
 fn test_destructor() {
-    let x: Rc<Box<_>> = Rc::new(box 5);
+    let x: Rc<Box<_>> = Rc::new(Box::new(5));
     assert_eq!(**x, 5);
 }
 
@@ -153,7 +153,7 @@ fn try_unwrap() {
 
 #[test]
 fn into_from_raw() {
-    let x = Rc::new(box "hello");
+    let x = Rc::new(Box::new("hello"));
     let y = x.clone();
 
     let x_ptr = Rc::into_raw(x);
@@ -192,7 +192,7 @@ fn test_into_from_raw_unsized() {
 
 #[test]
 fn into_from_weak_raw() {
-    let x = Rc::new(box "hello");
+    let x = Rc::new(Box::new("hello"));
     let y = Rc::downgrade(&x);
 
     let y_ptr = Weak::into_raw(y);
@@ -409,7 +409,7 @@ fn test_clone_from_slice_panic() {
 
 #[test]
 fn test_from_box() {
-    let b: Box<u32> = box 123;
+    let b: Box<u32> = Box::new(123);
     let r: Rc<u32> = Rc::from(b);
 
     assert_eq!(*r, 123);
@@ -438,7 +438,7 @@ fn test_from_box_trait() {
     use std::fmt::Display;
     use std::string::ToString;
 
-    let b: Box<dyn Display> = box 123;
+    let b: Box<dyn Display> = Box::new(123);
     let r: Rc<dyn Display> = Rc::from(b);
 
     assert_eq!(r.to_string(), "123");
@@ -448,7 +448,7 @@ fn test_from_box_trait() {
 fn test_from_box_trait_zero_sized() {
     use std::fmt::Debug;
 
-    let b: Box<dyn Debug> = box ();
+    let b: Box<dyn Debug> = Box::new(());
     let r: Rc<dyn Debug> = Rc::from(b);
 
     assert_eq!(format!("{r:?}"), "()");

library/alloc/src/sync.rs

@@ -343,11 +343,11 @@ impl<T> Arc<T> {
     pub fn new(data: T) -> Arc<T> {
         // Start the weak pointer count as 1 which is the weak pointer that's
         // held by all the strong pointers (kinda), see std/rc.rs for more info
-        let x: Box<_> = box ArcInner {
+        let x: Box<_> = Box::new(ArcInner {
             strong: atomic::AtomicUsize::new(1),
             weak: atomic::AtomicUsize::new(1),
             data,
-        };
+        });
         unsafe { Self::from_inner(Box::leak(x).into()) }
     }
 
@@ -411,11 +411,11 @@ impl<T> Arc<T> {
     {
         // Construct the inner in the "uninitialized" state with a single
         // weak reference.
-        let uninit_ptr: NonNull<_> = Box::leak(box ArcInner {
+        let uninit_ptr: NonNull<_> = Box::leak(Box::new(ArcInner {
             strong: atomic::AtomicUsize::new(0),
             weak: atomic::AtomicUsize::new(1),
             data: mem::MaybeUninit::<T>::uninit(),
-        })
+        }))
         .into();
         let init_ptr: NonNull<ArcInner<T>> = uninit_ptr.cast();
 

library/alloc/src/sync/tests.rs

@@ -103,7 +103,7 @@ fn try_unwrap() {
 
 #[test]
 fn into_from_raw() {
-    let x = Arc::new(box "hello");
+    let x = Arc::new(Box::new("hello"));
     let y = x.clone();
 
     let x_ptr = Arc::into_raw(x);
@@ -142,7 +142,7 @@ fn test_into_from_raw_unsized() {
 
 #[test]
 fn into_from_weak_raw() {
-    let x = Arc::new(box "hello");
+    let x = Arc::new(Box::new("hello"));
     let y = Arc::downgrade(&x);
 
     let y_ptr = Weak::into_raw(y);
@@ -467,7 +467,7 @@ fn test_clone_from_slice_panic() {
 
 #[test]
 fn test_from_box() {
-    let b: Box<u32> = box 123;
+    let b: Box<u32> = Box::new(123);
     let r: Arc<u32> = Arc::from(b);
 
     assert_eq!(*r, 123);
@@ -496,7 +496,7 @@ fn test_from_box_trait() {
     use std::fmt::Display;
     use std::string::ToString;
 
-    let b: Box<dyn Display> = box 123;
+    let b: Box<dyn Display> = Box::new(123);
     let r: Arc<dyn Display> = Arc::from(b);
 
     assert_eq!(r.to_string(), "123");
@@ -506,7 +506,7 @@ fn test_from_box_trait() {
 fn test_from_box_trait_zero_sized() {
     use std::fmt::Debug;
 
-    let b: Box<dyn Debug> = box ();
+    let b: Box<dyn Debug> = Box::new(());
     let r: Arc<dyn Debug> = Arc::from(b);
 
     assert_eq!(format!("{r:?}"), "()");

library/alloc/tests/slice.rs

@@ -268,9 +268,9 @@ fn test_swap_remove_fail() {
 fn test_swap_remove_noncopyable() {
     // Tests that we don't accidentally run destructors twice.
     let mut v: Vec<Box<_>> = Vec::new();
-    v.push(box 0);
-    v.push(box 0);
-    v.push(box 0);
+    v.push(Box::new(0));
+    v.push(Box::new(0));
+    v.push(Box::new(0));
     let mut _e = v.swap_remove(0);
     assert_eq!(v.len(), 2);
     _e = v.swap_remove(1);
@@ -296,7 +296,7 @@ fn test_push() {
 
 #[test]
 fn test_truncate() {
-    let mut v: Vec<Box<_>> = vec![box 6, box 5, box 4];
+    let mut v: Vec<Box<_>> = vec![Box::new(6), Box::new(5), Box::new(4)];
     v.truncate(1);
     let v = v;
     assert_eq!(v.len(), 1);
@@ -306,7 +306,7 @@ fn test_truncate() {
 
 #[test]
 fn test_clear() {
-    let mut v: Vec<Box<_>> = vec![box 6, box 5, box 4];
+    let mut v: Vec<Box<_>> = vec![Box::new(6), Box::new(5), Box::new(4)];
     v.clear();
     assert_eq!(v.len(), 0);
     // If the unsafe block didn't drop things properly, we blow up here.
@@ -1516,14 +1516,14 @@ fn test_mut_last() {
 
 #[test]
 fn test_to_vec() {
-    let xs: Box<_> = box [1, 2, 3];
+    let xs: Box<_> = Box::new([1, 2, 3]);
     let ys = xs.to_vec();
     assert_eq!(ys, [1, 2, 3]);
 }
 
 #[test]
 fn test_in_place_iterator_specialization() {
-    let src: Box<[usize]> = box [1, 2, 3];
+    let src: Box<[usize]> = Box::new([1, 2, 3]);
     let src_ptr = src.as_ptr();
     let sink: Box<_> = src.into_vec().into_iter().map(std::convert::identity).collect();
     let sink_ptr = sink.as_ptr();

library/alloc/tests/vec.rs

@@ -266,8 +266,8 @@ fn test_clone() {
 #[test]
 fn test_clone_from() {
     let mut v = vec![];
-    let three: Vec<Box<_>> = vec![box 1, box 2, box 3];
-    let two: Vec<Box<_>> = vec![box 4, box 5];
+    let three: Vec<Box<_>> = vec![Box::new(1), Box::new(2), Box::new(3)];
+    let two: Vec<Box<_>> = vec![Box::new(4), Box::new(5)];
     // zero, long
     v.clone_from(&three);
     assert_eq!(v, three);
@@ -407,11 +407,11 @@ fn test_dedup_by() {
 
 #[test]
 fn test_dedup_unique() {
-    let mut v0: Vec<Box<_>> = vec![box 1, box 1, box 2, box 3];
+    let mut v0: Vec<Box<_>> = vec![Box::new(1), Box::new(1), Box::new(2), Box::new(3)];
     v0.dedup();
-    let mut v1: Vec<Box<_>> = vec![box 1, box 2, box 2, box 3];
+    let mut v1: Vec<Box<_>> = vec![Box::new(1), Box::new(2), Box::new(2), Box::new(3)];
     v1.dedup();
-    let mut v2: Vec<Box<_>> = vec![box 1, box 2, box 3, box 3];
+    let mut v2: Vec<Box<_>> = vec![Box::new(1), Box::new(2), Box::new(3), Box::new(3)];
     v2.dedup();
     // If the boxed pointers were leaked or otherwise misused, valgrind
     // and/or rt should raise errors.

library/core/src/hash/sip.rs

@@ -96,7 +96,8 @@ macro_rules! compress {
 /// `copy_nonoverlapping` to let the compiler generate the most efficient way
 /// to load it from a possibly unaligned address.
 ///
-/// Unsafe because: unchecked indexing at i..i+size_of(int_ty)
+/// Safety: this performs unchecked indexing of `$buf` at
+/// `$i..$i+size_of::<$int_ty>()`, so that must be in-bounds.
 macro_rules! load_int_le {
     ($buf:expr, $i:expr, $int_ty:ident) => {{
         debug_assert!($i + mem::size_of::<$int_ty>() <= $buf.len());
@@ -114,7 +115,8 @@ macro_rules! load_int_le {
 /// `copy_nonoverlapping` calls that occur (via `load_int_le!`) all have fixed
 /// sizes and avoid calling `memcpy`, which is good for speed.
 ///
-/// Unsafe because: unchecked indexing at start..start+len
+/// Safety: this performs unchecked indexing of `buf` at `start..start+len`, so
+/// that must be in-bounds.
 #[inline]
 unsafe fn u8to64_le(buf: &[u8], start: usize, len: usize) -> u64 {
     debug_assert!(len < 8);

library/core/tests/any.rs

@@ -24,8 +24,11 @@ fn any_referenced() {
 
 #[test]
 fn any_owning() {
-    let (a, b, c) =
-        (box 5_usize as Box<dyn Any>, box TEST as Box<dyn Any>, box Test as Box<dyn Any>);
+    let (a, b, c) = (
+        Box::new(5_usize) as Box<dyn Any>,
+        Box::new(TEST) as Box<dyn Any>,
+        Box::new(Test) as Box<dyn Any>,
+    );
 
     assert!(a.is::<usize>());
     assert!(!b.is::<usize>());
@@ -58,7 +61,7 @@ fn any_downcast_ref() {
 #[test]
 fn any_downcast_mut() {
     let mut a = 5_usize;
-    let mut b: Box<_> = box 7_usize;
+    let mut b: Box<_> = Box::new(7_usize);
 
     let a_r = &mut a as &mut dyn Any;
     let tmp: &mut usize = &mut *b;