Auto merge of #54859 - pietroalbini:rollup, r=pietroalbini

Rollup of 11 pull requests

Successful merges:

 - #54078 (Expand the documentation for the `std::sync` module)
 - #54717 (Cleanup rustc/ty part 1)
 - #54781 (Add examples to `TyKind::FnDef` and `TyKind::FnPtr` docs)
 - #54787 (Only warn about unused `mut` in user-written code)
 - #54804 (add suggestion for inverted function parameters)
 - #54812 (Regression test for #32382.)
 - #54833 (make `Parser::parse_foreign_item()` return a foreign item or error)
 - #54834 (rustdoc: overflow:auto doesn't work nicely on small screens)
 - #54838 (Fix typo in src/libsyntax/parse/parser.rs)
 - #54851 (Fix a regression in 1.30 by reverting #53564)
 - #54853 (Remove unneccessary error from test, revealing NLL error.)

Failed merges:

r? @ghost

Author: bors

src/liballoc/collections/vec_deque.rs

@@ -19,7 +19,6 @@
 
 use core::cmp::Ordering;
 use core::fmt;
-use core::isize;
 use core::iter::{repeat, FromIterator, FusedIterator};
 use core::mem;
 use core::ops::Bound::{Excluded, Included, Unbounded};
@@ -203,33 +202,6 @@ impl<T> VecDeque<T> {
                                  len);
     }
 
-    /// Copies all values from `src` to the back of `self`, wrapping around if needed.
-    ///
-    /// # Safety
-    ///
-    /// The capacity must be sufficient to hold self.len() + src.len() elements.
-    /// If so, this function never panics.
-    #[inline]
-    unsafe fn copy_slice(&mut self, src: &[T]) {
-        /// This is guaranteed by `RawVec`.
-        debug_assert!(self.capacity() <= isize::MAX as usize);
-
-        let expected_new_len = self.len() + src.len();
-        debug_assert!(self.capacity() >= expected_new_len);
-
-        let dst_high_ptr = self.ptr().add(self.head);
-        let dst_high_len = self.cap() - self.head;
-
-        let split = cmp::min(src.len(), dst_high_len);
-        let (src_high, src_low) = src.split_at(split);
-
-        ptr::copy_nonoverlapping(src_high.as_ptr(), dst_high_ptr, src_high.len());
-        ptr::copy_nonoverlapping(src_low.as_ptr(), self.ptr(), src_low.len());
-
-        self.head = self.wrap_add(self.head, src.len());
-        debug_assert!(self.len() == expected_new_len);
-    }
-
     /// Copies a potentially wrapping block of memory len long from src to dest.
     /// (abs(dst - src) + len) must be no larger than cap() (There must be at
     /// most one continuous overlapping region between src and dest).
@@ -1052,7 +1024,7 @@ impl<T> VecDeque<T> {
             iter: Iter {
                 tail: drain_tail,
                 head: drain_head,
-                ring: unsafe { self.buffer_as_slice() },
+                ring: unsafe { self.buffer_as_mut_slice() },
             },
         }
     }
@@ -1862,22 +1834,8 @@ impl<T> VecDeque<T> {
     #[inline]
     #[stable(feature = "append", since = "1.4.0")]
     pub fn append(&mut self, other: &mut Self) {
-        unsafe {
-            // Guarantees there is space in `self` for `other`.
-            self.reserve(other.len());
-
-            {
-                let (src_high, src_low) = other.as_slices();
-
-                // This is only safe because copy_slice never panics when capacity is sufficient.
-                self.copy_slice(src_low);
-                self.copy_slice(src_high);
-            }
-
-            // Some values now exist in both `other` and `self` but are made inaccessible
-            // in`other`.
-            other.tail = other.head;
-        }
+        // naive impl
+        self.extend(other.drain(..));
     }
 
     /// Retains only the elements specified by the predicate.
@@ -2635,8 +2593,8 @@ impl<T> From<VecDeque<T>> for Vec<T> {
                         let mut right_offset = 0;
                         for i in left_edge..right_edge {
                             right_offset = (i - left_edge) % (cap - right_edge);
-                            let src = right_edge + right_offset;
-                            ptr::swap(buf.add(i), buf.add(src));
+                            let src: isize = (right_edge + right_offset) as isize;
+                            ptr::swap(buf.add(i), buf.offset(src));
                         }
                         let n_ops = right_edge - left_edge;
                         left_edge += n_ops;

src/librustc/hir/lowering.rs

@@ -4132,16 +4132,16 @@ impl<'a> LoweringContext<'a> {
                 // expand <head>
                 let head = self.lower_expr(head);
                 let head_sp = head.span;
+                let desugared_span = self.allow_internal_unstable(
+                    CompilerDesugaringKind::ForLoop,
+                    head_sp,
+                );
 
                 let iter = self.str_to_ident("iter");
 
                 let next_ident = self.str_to_ident("__next");
-                let next_sp = self.allow_internal_unstable(
-                    CompilerDesugaringKind::ForLoop,
-                    head_sp,
-                );
                 let next_pat = self.pat_ident_binding_mode(
-                    next_sp,
+                    desugared_span,
                     next_ident,
                     hir::BindingAnnotation::Mutable,
                 );
@@ -4170,8 +4170,11 @@ impl<'a> LoweringContext<'a> {
                 };
 
                 // `mut iter`
-                let iter_pat =
-                    self.pat_ident_binding_mode(head_sp, iter, hir::BindingAnnotation::Mutable);
+                let iter_pat = self.pat_ident_binding_mode(
+                    desugared_span,
+                    iter,
+                    hir::BindingAnnotation::Mutable
+                );
 
                 // `match ::std::iter::Iterator::next(&mut iter) { ... }`
                 let match_expr = {
@@ -4200,8 +4203,12 @@ impl<'a> LoweringContext<'a> {
                 let next_expr = P(self.expr_ident(head_sp, next_ident, next_pat.id));
 
                 // `let mut __next`
-                let next_let =
-                    self.stmt_let_pat(head_sp, None, next_pat, hir::LocalSource::ForLoopDesugar);
+                let next_let = self.stmt_let_pat(
+                    desugared_span,
+                    None,
+                    next_pat,
+                    hir::LocalSource::ForLoopDesugar,
+                );
 
                 // `let <pat> = __next`
                 let pat = self.lower_pat(pat);

src/librustc/traits/error_reporting.rs

@@ -46,7 +46,7 @@ use ty::subst::Subst;
 use ty::SubtypePredicate;
 use util::nodemap::{FxHashMap, FxHashSet};
 
-use syntax_pos::{DUMMY_SP, Span};
+use syntax_pos::{DUMMY_SP, Span, ExpnInfo, ExpnFormat};
 
 impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     pub fn report_fulfillment_errors(&self,
@@ -68,18 +68,30 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             }).collect();
 
         for (index, error) in errors.iter().enumerate() {
-            error_map.entry(error.obligation.cause.span).or_default().push(
+            // We want to ignore desugarings here: spans are equivalent even
+            // if one is the result of a desugaring and the other is not.
+            let mut span = error.obligation.cause.span;
+            if let Some(ExpnInfo {
+                format: ExpnFormat::CompilerDesugaring(_),
+                def_site: Some(def_span),
+                ..
+            }) = span.ctxt().outer().expn_info() {
+                span = def_span;
+            }
+
+            error_map.entry(span).or_default().push(
                 ErrorDescriptor {
                     predicate: error.obligation.predicate.clone(),
                     index: Some(index)
-                });
+                }
+            );
 
             self.reported_trait_errors.borrow_mut()
-                .entry(error.obligation.cause.span).or_default()
+                .entry(span).or_default()
                 .push(error.obligation.predicate.clone());
         }
 
-        // We do this in 2 passes because we want to display errors in order, tho
+        // We do this in 2 passes because we want to display errors in order, though
         // maybe it *is* better to sort errors by span or something.
         let mut is_suppressed = vec![false; errors.len()];
         for (_, error_set) in error_map.iter() {

src/librustc/ty/codec.rs

@@ -178,19 +178,19 @@ pub fn decode_predicates<'a, 'tcx, D>(decoder: &mut D)
     Ok(ty::GenericPredicates {
         parent: Decodable::decode(decoder)?,
         predicates: (0..decoder.read_usize()?).map(|_| {
-                // Handle shorthands first, if we have an usize > 0x80.
-                let predicate = if decoder.positioned_at_shorthand() {
-                    let pos = decoder.read_usize()?;
-                    assert!(pos >= SHORTHAND_OFFSET);
-                    let shorthand = pos - SHORTHAND_OFFSET;
-
-                    decoder.with_position(shorthand, ty::Predicate::decode)
-                } else {
-                    ty::Predicate::decode(decoder)
-                }?;
-                Ok((predicate, Decodable::decode(decoder)?))
-            })
-            .collect::<Result<Vec<_>, _>>()?,
+            // Handle shorthands first, if we have an usize > 0x80.
+            let predicate = if decoder.positioned_at_shorthand() {
+                let pos = decoder.read_usize()?;
+                assert!(pos >= SHORTHAND_OFFSET);
+                let shorthand = pos - SHORTHAND_OFFSET;
+
+                decoder.with_position(shorthand, ty::Predicate::decode)
+            } else {
+                ty::Predicate::decode(decoder)
+            }?;
+            Ok((predicate, Decodable::decode(decoder)?))
+        })
+        .collect::<Result<Vec<_>, _>>()?,
     })
 }
 
@@ -267,7 +267,7 @@ pub fn decode_const<'a, 'tcx, D>(decoder: &mut D)
 
 #[inline]
 pub fn decode_allocation<'a, 'tcx, D>(decoder: &mut D)
-                                 -> Result<&'tcx Allocation, D::Error>
+    -> Result<&'tcx Allocation, D::Error>
     where D: TyDecoder<'a, 'tcx>,
           'tcx: 'a,
 {

src/librustc/ty/context.rs

@@ -190,8 +190,8 @@ impl<'gcx: 'tcx, 'tcx> CtxtInterners<'tcx> {
             // types/regions in the global interner
             if local as *const _ as usize == global as *const _ as usize {
                 bug!("Attempted to intern `{:?}` which contains \
-                    inference types/regions in the global type context",
-                    &ty_struct);
+                      inference types/regions in the global type context",
+                     &ty_struct);
             }
 
             // Don't be &mut TyS.
@@ -272,9 +272,9 @@ fn validate_hir_id_for_typeck_tables(local_id_root: Option<DefId>,
 
                     bug!("node {} with HirId::owner {:?} cannot be placed in \
                           TypeckTables with local_id_root {:?}",
-                          tcx.hir.node_to_string(node_id),
-                          DefId::local(hir_id.owner),
-                          local_id_root)
+                         tcx.hir.node_to_string(node_id),
+                         DefId::local(hir_id.owner),
+                         local_id_root)
                 });
             }
         } else {
@@ -540,16 +540,13 @@ impl<'tcx> TypeckTables<'tcx> {
     }
 
     pub fn node_id_to_type(&self, id: hir::HirId) -> Ty<'tcx> {
-        match self.node_id_to_type_opt(id) {
-            Some(ty) => ty,
-            None => {
-                bug!("node_id_to_type: no type for node `{}`",
-                    tls::with(|tcx| {
-                        let id = tcx.hir.hir_to_node_id(id);
-                        tcx.hir.node_to_string(id)
-                    }))
-            }
-        }
+        self.node_id_to_type_opt(id).unwrap_or_else(||
+            bug!("node_id_to_type: no type for node `{}`",
+                 tls::with(|tcx| {
+                     let id = tcx.hir.hir_to_node_id(id);
+                     tcx.hir.node_to_string(id)
+                 }))
+        )
     }
 
     pub fn node_id_to_type_opt(&self, id: hir::HirId) -> Option<Ty<'tcx>> {
@@ -686,7 +683,7 @@ impl<'tcx> TypeckTables<'tcx> {
     }
 
     pub fn pat_adjustments_mut(&mut self)
-                           -> LocalTableInContextMut<'_, Vec<Ty<'tcx>>> {
+                               -> LocalTableInContextMut<'_, Vec<Ty<'tcx>>> {
         LocalTableInContextMut {
             local_id_root: self.local_id_root,
             data: &mut self.pat_adjustments,
@@ -1199,8 +1196,8 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             let hir_id = hir.node_to_hir_id(k);
             let map = trait_map.entry(hir_id.owner).or_default();
             Lrc::get_mut(map).unwrap()
-                            .insert(hir_id.local_id,
-                                    Lrc::new(StableVec::new(v)));
+                             .insert(hir_id.local_id,
+                                     Lrc::new(StableVec::new(v)));
         }
 
         let gcx = &GlobalCtxt {
@@ -2188,7 +2185,6 @@ macro_rules! sty_debug_print {
                 };
                 $(let mut $variant = total;)*
 
-
                 for &Interned(t) in tcx.interners.type_.borrow().iter() {
                     let variant = match t.sty {
                         ty::Bool | ty::Char | ty::Int(..) | ty::Uint(..) |
@@ -2207,7 +2203,7 @@ macro_rules! sty_debug_print {
                 }
                 println!("Ty interner             total           ty region  both");
                 $(println!("    {:18}: {uses:6} {usespc:4.1}%, \
-{ty:4.1}% {region:5.1}% {both:4.1}%",
+                            {ty:4.1}% {region:5.1}% {both:4.1}%",
                            stringify!($variant),
                            uses = $variant.total,
                            usespc = $variant.total as f64 * 100.0 / total.total as f64,
@@ -2216,7 +2212,7 @@ macro_rules! sty_debug_print {
                            both = $variant.both_infer as f64 * 100.0  / total.total as f64);
                   )*
                 println!("                  total {uses:6}        \
-{ty:4.1}% {region:5.1}% {both:4.1}%",
+                          {ty:4.1}% {region:5.1}% {both:4.1}%",
                          uses = total.total,
                          ty = total.ty_infer as f64 * 100.0  / total.total as f64,
                          region = total.region_infer as f64 * 100.0  / total.total as f64,
@@ -2653,7 +2649,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         }
 
     pub fn mk_closure(self, closure_id: DefId, closure_substs: ClosureSubsts<'tcx>)
-                                          -> Ty<'tcx> {
+                      -> Ty<'tcx> {
         self.mk_ty(Closure(closure_id, closure_substs))
     }
 
@@ -2686,8 +2682,8 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
     }
 
     pub fn mk_ty_param(self,
-                    index: u32,
-                    name: InternedString) -> Ty<'tcx> {
+                       index: u32,
+                       name: InternedString) -> Ty<'tcx> {
         self.mk_ty(Param(ParamTy { idx: index, name: name }))
     }