Auto merge of #56051 - pietroalbini:rollup, r=pietroalbini

Rollup of 25 pull requests

Successful merges:

 - #55562 (Add powerpc- and powerpc64-unknown-linux-musl targets)
 - #55564 (test/linkage-visibility: Ignore on musl targets)
 - #55827 (A few tweaks to iterations/collecting)
 - #55834 (Forward the ABI of the non-zero sized fields of an union if they have the same ABI)
 - #55857 (remove unused dependency)
 - #55862 (in which the E0618 "expected function" diagnostic gets a makeover)
 - #55867 (do not panic just because cargo failed)
 - #55894 (miri enum discriminant handling: Fix treatment of pointers, better error when it is undef)
 - #55916 (Make miri value visitor useful for mutation)
 - #55919 (core/tests/num: Simplify `test_int_from_str_overflow()` test code)
 - #55923 (reword #[test] attribute error on fn items)
 - #55949 (ty: return impl Iterator from Predicate::walk_tys)
 - #55952 (Update to Clang 7 on CI.)
 - #55953 (#53488 Refactoring UpvarId)
 - #55962 (rustdoc: properly calculate spans for intra-doc link resolution errors)
 - #55963 (Stress test for MPSC)
 - #55968 (Clean up some non-mod-rs stuff.)
 - #55970 (Miri backtrace improvements)
 - #56007 (CTFE: dynamically make sure we do not call non-const-fn)
 - #56011 (Replace data.clone() by Arc::clone(&data) in mutex doc.)
 - #56012 (avoid shared ref in UnsafeCell::get)
 - #56016 (Add VecDeque::resize_with)
 - #56027 (docs: Add missing backtick in object_safety.rs docs)
 - #56043 (remove "approx env bounds" if we already know from trait)
 - #56059 (Increase `Duration` approximate equal threshold to 1us)

.travis.yml

@@ -227,9 +227,9 @@ install:
             chmod +x /usr/local/bin/sccache &&
           travis_retry curl -fo /usr/local/bin/stamp https://s3-us-west-1.amazonaws.com/rust-lang-ci2/rust-ci-mirror/2017-03-17-stamp-x86_64-apple-darwin &&
             chmod +x /usr/local/bin/stamp &&
-          travis_retry curl -f http://releases.llvm.org/6.0.0/clang+llvm-6.0.0-x86_64-apple-darwin.tar.xz | tar xJf - &&
-            export CC=`pwd`/clang+llvm-6.0.0-x86_64-apple-darwin/bin/clang &&
-            export CXX=`pwd`/clang+llvm-6.0.0-x86_64-apple-darwin/bin/clang++ &&
+          travis_retry curl -f http://releases.llvm.org/7.0.0/clang+llvm-7.0.0-x86_64-apple-darwin.tar.xz | tar xJf - &&
+            export CC=`pwd`/clang+llvm-7.0.0-x86_64-apple-darwin/bin/clang &&
+            export CXX=`pwd`/clang+llvm-7.0.0-x86_64-apple-darwin/bin/clang++ &&
             export AR=ar
           ;;
     esac

src/Cargo.lock

@@ -2191,7 +2191,6 @@ dependencies = [
  "graphviz 0.0.0",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "parking_lot_core 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-rayon 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-rayon-core 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",

src/bootstrap/compile.rs

@@ -22,7 +22,7 @@ use std::fs::{self, File};
 use std::io::BufReader;
 use std::io::prelude::*;
 use std::path::{Path, PathBuf};
-use std::process::{Command, Stdio};
+use std::process::{Command, Stdio, exit};
 use std::str;
 
 use build_helper::{output, mtime, up_to_date};
@@ -1098,7 +1098,7 @@ pub fn run_cargo(builder: &Builder,
     });
 
     if !ok {
-        panic!("cargo must succeed");
+        exit(1);
     }
 
     // Ok now we need to actually find all the files listed in `toplevel`. We've

src/ci/docker/dist-i686-linux/Dockerfile

@@ -67,7 +67,7 @@ RUN ./build-gcc.sh
 COPY dist-x86_64-linux/build-python.sh /tmp/
 RUN ./build-python.sh
 
-# Now build LLVM+Clang 6, afterwards configuring further compilations to use the
+# Now build LLVM+Clang 7, afterwards configuring further compilations to use the
 # clang/clang++ compilers.
 COPY dist-x86_64-linux/build-clang.sh /tmp/
 RUN ./build-clang.sh

src/ci/docker/dist-x86_64-linux/Dockerfile

@@ -67,7 +67,7 @@ RUN ./build-gcc.sh
 COPY dist-x86_64-linux/build-python.sh /tmp/
 RUN ./build-python.sh
 
-# Now build LLVM+Clang 6, afterwards configuring further compilations to use the
+# Now build LLVM+Clang 7, afterwards configuring further compilations to use the
 # clang/clang++ compilers.
 COPY dist-x86_64-linux/build-clang.sh /tmp/
 RUN ./build-clang.sh

src/ci/docker/dist-x86_64-linux/build-clang.sh

@@ -13,7 +13,7 @@ set -ex
 
 source shared.sh
 
-LLVM=6.0.0
+LLVM=7.0.0
 
 mkdir clang
 cd clang

src/ci/docker/scripts/musl.sh

@@ -51,7 +51,7 @@ hide_output make clean
 
 cd ..
 
-LLVM=60
+LLVM=70
 
 # may have been downloaded in a previous run
 if [ ! -d libunwind-release_$LLVM ]; then

src/liballoc/collections/vec_deque.rs

@@ -19,7 +19,7 @@
 
 use core::cmp::Ordering;
 use core::fmt;
-use core::iter::{repeat, FromIterator, FusedIterator};
+use core::iter::{repeat, repeat_with, FromIterator, FusedIterator};
 use core::mem;
 use core::ops::Bound::{Excluded, Included, Unbounded};
 use core::ops::{Index, IndexMut, RangeBounds};
@@ -1920,6 +1920,44 @@ impl<T: Clone> VecDeque<T> {
             self.truncate(new_len);
         }
     }
+
+    /// Modifies the `VecDeque` in-place so that `len()` is equal to `new_len`,
+    /// either by removing excess elements from the back or by appending
+    /// elements generated by calling `generator` to the back.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(vec_resize_with)]
+    ///
+    /// use std::collections::VecDeque;
+    ///
+    /// let mut buf = VecDeque::new();
+    /// buf.push_back(5);
+    /// buf.push_back(10);
+    /// buf.push_back(15);
+    /// assert_eq!(buf, [5, 10, 15]);
+    ///
+    /// buf.resize_with(5, Default::default);
+    /// assert_eq!(buf, [5, 10, 15, 0, 0]);
+    ///
+    /// buf.resize_with(2, || unreachable!());
+    /// assert_eq!(buf, [5, 10]);
+    ///
+    /// let mut state = 100;
+    /// buf.resize_with(5, || { state += 1; state });
+    /// assert_eq!(buf, [5, 10, 101, 102, 103]);
+    /// ```
+    #[unstable(feature = "vec_resize_with", issue = "41758")]
+    pub fn resize_with(&mut self, new_len: usize, generator: impl FnMut()->T) {
+        let len = self.len();
+
+        if new_len > len {
+            self.extend(repeat_with(generator).take(new_len - len))
+        } else {
+            self.truncate(new_len);
+        }
+    }
 }
 
 /// Returns the index in the underlying buffer for a given logical element index.

src/libcore/cell.rs

@@ -1509,7 +1509,9 @@ impl<T: ?Sized> UnsafeCell<T> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const fn get(&self) -> *mut T {
-        &self.value as *const T as *mut T
+        // We can just cast the pointer from `UnsafeCell<T>` to `T` because of
+        // #[repr(transparent)]
+        self as *const UnsafeCell<T> as *const T as *mut T
     }
 }
 

src/libcore/tests/num/mod.rs

@@ -82,36 +82,28 @@ fn from_str_issue7588() {
 
 #[test]
 fn test_int_from_str_overflow() {
-    let mut i8_val: i8 = 127;
-    assert_eq!("127".parse::<i8>().ok(), Some(i8_val));
+    assert_eq!("127".parse::<i8>().ok(), Some(127i8));
     assert_eq!("128".parse::<i8>().ok(), None);
 
-    i8_val = i8_val.wrapping_add(1);
-    assert_eq!("-128".parse::<i8>().ok(), Some(i8_val));
+    assert_eq!("-128".parse::<i8>().ok(), Some(-128i8));
     assert_eq!("-129".parse::<i8>().ok(), None);
 
-    let mut i16_val: i16 = 32_767;
-    assert_eq!("32767".parse::<i16>().ok(), Some(i16_val));
+    assert_eq!("32767".parse::<i16>().ok(), Some(32_767i16));
     assert_eq!("32768".parse::<i16>().ok(), None);
 
-    i16_val = i16_val.wrapping_add(1);
-    assert_eq!("-32768".parse::<i16>().ok(), Some(i16_val));
+    assert_eq!("-32768".parse::<i16>().ok(), Some(-32_768i16));
     assert_eq!("-32769".parse::<i16>().ok(), None);
 
-    let mut i32_val: i32 = 2_147_483_647;
-    assert_eq!("2147483647".parse::<i32>().ok(), Some(i32_val));
+    assert_eq!("2147483647".parse::<i32>().ok(), Some(2_147_483_647i32));
     assert_eq!("2147483648".parse::<i32>().ok(), None);
 
-    i32_val = i32_val.wrapping_add(1);
-    assert_eq!("-2147483648".parse::<i32>().ok(), Some(i32_val));
+    assert_eq!("-2147483648".parse::<i32>().ok(), Some(-2_147_483_648i32));
     assert_eq!("-2147483649".parse::<i32>().ok(), None);
 
-    let mut i64_val: i64 = 9_223_372_036_854_775_807;
-    assert_eq!("9223372036854775807".parse::<i64>().ok(), Some(i64_val));
+    assert_eq!("9223372036854775807".parse::<i64>().ok(), Some(9_223_372_036_854_775_807i64));
     assert_eq!("9223372036854775808".parse::<i64>().ok(), None);
 
-    i64_val = i64_val.wrapping_add(1);
-    assert_eq!("-9223372036854775808".parse::<i64>().ok(), Some(i64_val));
+    assert_eq!("-9223372036854775808".parse::<i64>().ok(), Some(-9_223_372_036_854_775_808i64));
     assert_eq!("-9223372036854775809".parse::<i64>().ok(), None);
 }
 

src/librustc/cfg/graphviz.rs

@@ -106,8 +106,7 @@ impl<'a> dot::GraphWalk<'a> for &'a cfg::CFG {
     type Node = Node<'a>;
     type Edge = Edge<'a>;
     fn nodes(&'a self) -> dot::Nodes<'a, Node<'a>> {
-        let mut v = Vec::new();
-        self.graph.each_node(|i, nd| { v.push((i, nd)); true });
+        let v: Vec<_> = self.graph.enumerated_nodes().collect();
         v.into()
     }
     fn edges(&'a self) -> dot::Edges<'a, Edge<'a>> {

src/librustc/hir/lowering.rs

@@ -1062,8 +1062,7 @@ impl<'a> LoweringContext<'a> {
         attrs
             .iter()
             .map(|a| self.lower_attr(a))
-            .collect::<Vec<_>>()
-            .into()
+            .collect()
     }
 
     fn lower_attr(&mut self, attr: &Attribute) -> Attribute {

src/librustc/ich/impls_ty.rs

@@ -216,7 +216,9 @@ impl<'gcx> HashStable<StableHashingContext<'gcx>> for ty::adjustment::AutoBorrow
     }
 }
 
-impl_stable_hash_for!(struct ty::UpvarId { var_id, closure_expr_id });
+impl_stable_hash_for!(struct ty::UpvarPath { hir_id });
+
+impl_stable_hash_for!(struct ty::UpvarId { var_path, closure_expr_id });
 
 impl_stable_hash_for!(enum ty::BorrowKind {
     ImmBorrow,
@@ -387,10 +389,10 @@ impl_stable_hash_for!(enum mir::interpret::ErrorHandled {
     TooGeneric
 });
 
-impl_stable_hash_for!(struct mir::interpret::FrameInfo {
-    span,
+impl_stable_hash_for!(struct mir::interpret::FrameInfo<'tcx> {
+    call_site,
     lint_root,
-    location
+    instance
 });
 
 impl_stable_hash_for!(struct ty::ClosureSubsts<'tcx> { substs });
@@ -451,7 +453,7 @@ impl_stable_hash_for!(
         FunctionRetMismatch(a, b),
         NoMirFor(s),
         UnterminatedCString(ptr),
-        PointerOutOfBounds { ptr, access, allocation_size },
+        PointerOutOfBounds { ptr, check, allocation_size },
         InvalidBoolOp(bop),
         Unimplemented(s),
         BoundsCheck { len, index },
@@ -471,6 +473,11 @@ impl_stable_hash_for!(
     }
 );
 
+impl_stable_hash_for!(enum mir::interpret::InboundsCheck {
+    Live,
+    MaybeDead
+});
+
 impl_stable_hash_for!(enum mir::interpret::Lock {
     NoLock,
     WriteLock(dl),

src/librustc/infer/error_reporting/mod.rs

@@ -1315,7 +1315,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                 format!(" for lifetime parameter `{}` in coherence check", name)
             }
             infer::UpvarRegion(ref upvar_id, _) => {
-                let var_node_id = self.tcx.hir.hir_to_node_id(upvar_id.var_id);
+                let var_node_id = self.tcx.hir.hir_to_node_id(upvar_id.var_path.hir_id);
                 let var_name = self.tcx.hir.name(var_node_id);
                 format!(" for capture of `{}` by closure", var_name)
             }

src/librustc/infer/error_reporting/note.rs

@@ -41,7 +41,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                               "...so that reference does not outlive borrowed content");
             }
             infer::ReborrowUpvar(span, ref upvar_id) => {
-                let var_node_id = self.tcx.hir.hir_to_node_id(upvar_id.var_id);
+                let var_node_id = self.tcx.hir.hir_to_node_id(upvar_id.var_path.hir_id);
                 let var_name = self.tcx.hir.name(var_node_id);
                 err.span_note(span,
                               &format!("...so that closure can access `{}`", var_name));
@@ -174,7 +174,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                 err
             }
             infer::ReborrowUpvar(span, ref upvar_id) => {
-                let var_node_id = self.tcx.hir.hir_to_node_id(upvar_id.var_id);
+                let var_node_id = self.tcx.hir.hir_to_node_id(upvar_id.var_path.hir_id);
                 let var_name = self.tcx.hir.name(var_node_id);
                 let mut err = struct_span_err!(self.tcx.sess,
                                                span,

src/librustc/infer/outlives/obligations.rs

@@ -389,22 +389,38 @@ where
         // rule might not apply (but another rule might). For now, we err
         // on the side of adding too few edges into the graph.
 
+        // Compute the bounds we can derive from the trait definition.
+        // These are guaranteed to apply, no matter the inference
+        // results.
+        let trait_bounds: Vec<_> = self.verify_bound
+            .projection_declared_bounds_from_trait(projection_ty)
+            .collect();
+
         // Compute the bounds we can derive from the environment. This
         // is an "approximate" match -- in some cases, these bounds
         // may not apply.
-        let approx_env_bounds = self.verify_bound
+        let mut approx_env_bounds = self.verify_bound
             .projection_approx_declared_bounds_from_env(projection_ty);
         debug!(
             "projection_must_outlive: approx_env_bounds={:?}",
             approx_env_bounds
         );
 
-        // Compute the bounds we can derive from the trait definition.
-        // These are guaranteed to apply, no matter the inference
-        // results.
-        let trait_bounds: Vec<_> = self.verify_bound
-            .projection_declared_bounds_from_trait(projection_ty)
-            .collect();
+        // Remove outlives bounds that we get from the environment but
+        // which are also deducable from the trait. This arises (cc
+        // #55756) in cases where you have e.g. `<T as Foo<'a>>::Item:
+        // 'a` in the environment but `trait Foo<'b> { type Item: 'b
+        // }` in the trait definition.
+        approx_env_bounds.retain(|bound| {
+            match bound.0.sty {
+                ty::Projection(projection_ty) => {
+                    self.verify_bound.projection_declared_bounds_from_trait(projection_ty)
+                        .all(|r| r != bound.1)
+                }
+
+                _ => panic!("expected only projection types from env, not {:?}", bound.0),
+            }
+        });
 
         // If declared bounds list is empty, the only applicable rule is
         // OutlivesProjectionComponent. If there are inference variables,

src/librustc/middle/expr_use_visitor.rs

@@ -938,7 +938,7 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
                 let var_hir_id = self.tcx().hir.node_to_hir_id(freevar.var_id());
                 let closure_def_id = self.tcx().hir.local_def_id(closure_expr.id);
                 let upvar_id = ty::UpvarId {
-                    var_id: var_hir_id,
+                    var_path: ty::UpvarPath { hir_id: var_hir_id },
                     closure_expr_id: closure_def_id.to_local(),
                 };
                 let upvar_capture = self.mc.tables.upvar_capture(upvar_id);

src/librustc/middle/mem_categorization.rs

@@ -818,7 +818,7 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
         let closure_expr_def_id = self.tcx.hir.local_def_id(fn_node_id);
         let var_hir_id = self.tcx.hir.node_to_hir_id(var_id);
         let upvar_id = ty::UpvarId {
-            var_id: var_hir_id,
+            var_path: ty::UpvarPath { hir_id: var_hir_id },
             closure_expr_id: closure_expr_def_id.to_local(),
         };
 

src/librustc/mir/interpret/allocation.rs

@@ -19,6 +19,14 @@ use mir;
 use std::ops::{Deref, DerefMut};
 use rustc_data_structures::sorted_map::SortedMap;
 
+/// Used by `check_bounds` to indicate whether the pointer needs to be just inbounds
+/// or also inbounds of a *live* allocation.
+#[derive(Debug, Copy, Clone, RustcEncodable, RustcDecodable)]
+pub enum InboundsCheck {
+    Live,
+    MaybeDead,
+}
+
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
 pub struct Allocation<Tag=(),Extra=()> {
     /// The actual bytes of the allocation.