Auto merge of #55859 - pietroalbini:rollup, r=kennytm

Rollup of 17 pull requests

Successful merges:

 - #55630 (resolve: Filter away macro prelude in modules with `#[no_implicit_prelude]` on 2018 edition)
 - #55687 (Take supertraits into account when calculating associated types)
 - #55745 (Convert `outlives_components`' return value to a `SmallVec` outparam.)
 - #55764 (Fix Rc/Arc allocation layout)
 - #55792 (Prevent ICE in const-prop array oob check)
 - #55799 (Removed unneeded instance of `// revisions` from a lint test)
 - #55800 (Fix ICE in `return_type_impl_trait`)
 - #55801 (NLL: Update box insensitivity test)
 - #55802 (Don't inline virtual calls (take 2))
 - #55816 (Use `SmallVec` to avoid allocations in `from_decimal_string`.)
 - #55819 (Typecheck patterns of all match arms first, so we get types for bindings)
 - #55822 (ICE with #![feature(nll)] and elided lifetimes)
 - #55828 (Add missing `rustc_promotable` attribute to unsigned `min_value` and `max_value`)
 - #55839 (Fix docstring spelling mistakes)
 - #55844 (Fix documentation typos.)
 - #55845 (Set BINARYEN_TRAP_MODE=clamp)
 - #55856 (rustdoc: refactor: move all static-file include!s into a single module)

src/Cargo.lock

@@ -2096,6 +2096,7 @@ version = "0.0.0"
 dependencies = [
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_cratesio_shim 0.0.0",
+ "smallvec 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]

src/liballoc/rc.rs

@@ -672,14 +672,16 @@ impl<T: ?Sized> Rc<T> {
         // Previously, layout was calculated on the expression
         // `&*(ptr as *const RcBox<T>)`, but this created a misaligned
         // reference (see #54908).
-        let (layout, _) = Layout::new::<RcBox<()>>()
-            .extend(Layout::for_value(&*ptr)).unwrap();
+        let layout = Layout::new::<RcBox<()>>()
+            .extend(Layout::for_value(&*ptr)).unwrap().0
+            .pad_to_align().unwrap();
 
         let mem = Global.alloc(layout)
             .unwrap_or_else(|_| handle_alloc_error(layout));
 
         // Initialize the RcBox
         let inner = set_data_ptr(ptr as *mut T, mem.as_ptr() as *mut u8) as *mut RcBox<T>;
+        debug_assert_eq!(Layout::for_value(&*inner), layout);
 
         ptr::write(&mut (*inner).strong, Cell::new(1));
         ptr::write(&mut (*inner).weak, Cell::new(1));

src/liballoc/sync.rs

@@ -575,14 +575,16 @@ impl<T: ?Sized> Arc<T> {
         // Previously, layout was calculated on the expression
         // `&*(ptr as *const ArcInner<T>)`, but this created a misaligned
         // reference (see #54908).
-        let (layout, _) = Layout::new::<ArcInner<()>>()
-            .extend(Layout::for_value(&*ptr)).unwrap();
+        let layout = Layout::new::<ArcInner<()>>()
+            .extend(Layout::for_value(&*ptr)).unwrap().0
+            .pad_to_align().unwrap();
 
         let mem = Global.alloc(layout)
             .unwrap_or_else(|_| handle_alloc_error(layout));
 
         // Initialize the ArcInner
         let inner = set_data_ptr(ptr as *mut T, mem.as_ptr() as *mut u8) as *mut ArcInner<T>;
+        debug_assert_eq!(Layout::for_value(&*inner), layout);
 
         ptr::write(&mut (*inner).strong, atomic::AtomicUsize::new(1));
         ptr::write(&mut (*inner).weak, atomic::AtomicUsize::new(1));

src/libcore/alloc.rs

@@ -218,6 +218,23 @@ impl Layout {
         len_rounded_up.wrapping_sub(len)
     }
 
+    /// Creates a layout by rounding the size of this layout up to a multiple
+    /// of the layout's alignment.
+    ///
+    /// Returns `Err` if the padded size would overflow.
+    ///
+    /// This is equivalent to adding the result of `padding_needed_for`
+    /// to the layout's current size.
+    #[unstable(feature = "alloc_layout_extra", issue = "55724")]
+    #[inline]
+    pub fn pad_to_align(&self) -> Result<Layout, LayoutErr> {
+        let pad = self.padding_needed_for(self.align());
+        let new_size = self.size().checked_add(pad)
+            .ok_or(LayoutErr { private: () })?;
+
+        Layout::from_size_align(new_size, self.align())
+    }
+
     /// Creates a layout describing the record for `n` instances of
     /// `self`, with a suitable amount of padding between each to
     /// ensure that each instance is given its requested size and
@@ -506,7 +523,7 @@ pub unsafe trait GlobalAlloc {
         ptr
     }
 
-    /// Shink or grow a block of memory to the given `new_size`.
+    /// Shrink or grow a block of memory to the given `new_size`.
     /// The block is described by the given `ptr` pointer and `layout`.
     ///
     /// If this returns a non-null pointer, then ownership of the memory block
@@ -757,7 +774,7 @@ pub unsafe trait Alloc {
     // realloc. alloc_excess, realloc_excess
 
     /// Returns a pointer suitable for holding data described by
-    /// a new layout with `layout`’s alginment and a size given
+    /// a new layout with `layout`’s alignment and a size given
     /// by `new_size`. To
     /// accomplish this, this may extend or shrink the allocation
     /// referenced by `ptr` to fit the new layout.

src/libcore/future/future.rs

@@ -17,7 +17,7 @@ use ops;
 use pin::Pin;
 use task::{Poll, LocalWaker};
 
-/// A future represents an asychronous computation.
+/// A future represents an asynchronous computation.
 ///
 /// A future is a value that may not have finished computing yet. This kind of
 /// "asynchronous value" makes it possible for a thread to continue doing useful

src/libcore/lib.rs

@@ -228,7 +228,7 @@ mod nonzero;
 mod tuple;
 mod unit;
 
-// Pull in the the `coresimd` crate directly into libcore. This is where all the
+// Pull in the `coresimd` crate directly into libcore. This is where all the
 // architecture-specific (and vendor-specific) intrinsics are defined. AKA
 // things like SIMD and such. Note that the actual source for all this lies in a
 // different repository, rust-lang-nursery/stdsimd. That's why the setup here is

src/libcore/macros.rs

@@ -350,9 +350,8 @@ macro_rules! try {
 /// assert_eq!(v, b"s = \"abc 123\"");
 /// ```
 ///
-/// Note: This macro can be used in `no_std` setups as well
-/// In a `no_std` setup you are responsible for the
-/// implementation details of the components.
+/// Note: This macro can be used in `no_std` setups as well.
+/// In a `no_std` setup you are responsible for the implementation details of the components.
 ///
 /// ```no_run
 /// # extern crate core;
@@ -440,7 +439,7 @@ macro_rules! writeln {
 ///
 /// If the determination that the code is unreachable proves incorrect, the
 /// program immediately terminates with a [`panic!`].  The function [`unreachable_unchecked`],
-/// which belongs to the [`std::hint`] module, informs the compilier to
+/// which belongs to the [`std::hint`] module, informs the compiler to
 /// optimize the code out of the release version entirely.
 ///
 /// [`panic!`]:  ../std/macro.panic.html

src/libcore/mem.rs

@@ -202,7 +202,7 @@ pub fn forget<T>(t: T) {
 ///
 /// ## Size of Enums
 ///
-/// Enums that carry no data other than the descriminant have the same size as C enums
+/// Enums that carry no data other than the discriminant have the same size as C enums
 /// on the platform they are compiled for.
 ///
 /// ## Size of Unions
@@ -1081,7 +1081,7 @@ impl<T> MaybeUninit<T> {
     ///
     /// # Unsafety
     ///
-    /// It is up to the caller to guarantee that the the `MaybeUninit` really is in an initialized
+    /// It is up to the caller to guarantee that the `MaybeUninit` really is in an initialized
     /// state, otherwise this will immediately cause undefined behavior.
     #[unstable(feature = "maybe_uninit", issue = "53491")]
     pub unsafe fn into_inner(self) -> T {
@@ -1092,7 +1092,7 @@ impl<T> MaybeUninit<T> {
     ///
     /// # Unsafety
     ///
-    /// It is up to the caller to guarantee that the the `MaybeUninit` really is in an initialized
+    /// It is up to the caller to guarantee that the `MaybeUninit` really is in an initialized
     /// state, otherwise this will immediately cause undefined behavior.
     #[unstable(feature = "maybe_uninit", issue = "53491")]
     pub unsafe fn get_ref(&self) -> &T {
@@ -1103,7 +1103,7 @@ impl<T> MaybeUninit<T> {
     ///
     /// # Unsafety
     ///
-    /// It is up to the caller to guarantee that the the `MaybeUninit` really is in an initialized
+    /// It is up to the caller to guarantee that the `MaybeUninit` really is in an initialized
     /// state, otherwise this will immediately cause undefined behavior.
     #[unstable(feature = "maybe_uninit", issue = "53491")]
     pub unsafe fn get_mut(&mut self) -> &mut T {

src/libcore/num/mod.rs

@@ -2152,6 +2152,7 @@ Basic usage:
 ", $Feature, "assert_eq!(", stringify!($SelfT), "::min_value(), 0);", $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
+            #[rustc_promotable]
             #[inline]
             pub const fn min_value() -> Self { 0 }
         }
@@ -2168,6 +2169,7 @@ Basic usage:
 stringify!($MaxV), ");", $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
+            #[rustc_promotable]
             #[inline]
             pub const fn max_value() -> Self { !0 }
         }

src/libcore/pin.rs

@@ -3,7 +3,7 @@
 //! It is sometimes useful to have objects that are guaranteed to not move,
 //! in the sense that their placement in memory does not change, and can thus be relied upon.
 //!
-//! A prime example of such a scenario would be building self-referencial structs,
+//! A prime example of such a scenario would be building self-referential structs,
 //! since moving an object with pointers to itself will invalidate them,
 //! which could cause undefined behavior.
 //!
@@ -39,7 +39,7 @@
 //! use std::marker::Pinned;
 //! use std::ptr::NonNull;
 //!
-//! // This is a self referencial struct since the slice field points to the data field.
+//! // This is a self-referential struct since the slice field points to the data field.
 //! // We cannot inform the compiler about that with a normal reference,
 //! // since this pattern cannot be described with the usual borrowing rules.
 //! // Instead we use a raw pointer, though one which is known to not be null,

src/libcore/ptr.rs

@@ -120,7 +120,7 @@ pub use intrinsics::write_bytes;
 ///
 /// Additionally, if `T` is not [`Copy`], using the pointed-to value after
 /// calling `drop_in_place` can cause undefined behavior. Note that `*to_drop =
-/// foo` counts as a use because it will cause the the value to be dropped
+/// foo` counts as a use because it will cause the value to be dropped
 /// again. [`write`] can be used to overwrite data without causing it to be
 /// dropped.
 ///
@@ -371,7 +371,7 @@ pub(crate) unsafe fn swap_nonoverlapping_one<T>(x: *mut T, y: *mut T) {
 #[inline]
 unsafe fn swap_nonoverlapping_bytes(x: *mut u8, y: *mut u8, len: usize) {
     // The approach here is to utilize simd to swap x & y efficiently. Testing reveals
-    // that swapping either 32 bytes or 64 bytes at a time is most efficient for intel
+    // that swapping either 32 bytes or 64 bytes at a time is most efficient for Intel
     // Haswell E processors. LLVM is more able to optimize if we give a struct a
     // #[repr(simd)], even if we don't actually use this struct directly.
     //
@@ -1005,7 +1005,7 @@ impl<T: ?Sized> *const T {
     /// # Null-unchecked version
     ///
     /// If you are sure the pointer can never be null and are looking for some kind of
-    /// `as_ref_unchecked` that returns the `&T` instead of `Option<&T>, know that you can
+    /// `as_ref_unchecked` that returns the `&T` instead of `Option<&T>`, know that you can
     /// dereference the pointer directly.
     ///
     /// ```
@@ -1625,7 +1625,7 @@ impl<T: ?Sized> *mut T {
     /// # Null-unchecked version
     ///
     /// If you are sure the pointer can never be null and are looking for some kind of
-    /// `as_ref_unchecked` that returns the `&T` instead of `Option<&T>, know that you can
+    /// `as_ref_unchecked` that returns the `&T` instead of `Option<&T>`, know that you can
     /// dereference the pointer directly.
     ///
     /// ```

src/librustc/diagnostics.rs

@@ -2134,7 +2134,7 @@ static X: u32 = 42;
 
 
 register_diagnostics! {
-//  E0006 // merged with E0005
+//  E0006, // merged with E0005
 //  E0101, // replaced with E0282
 //  E0102, // replaced with E0282
 //  E0134,
@@ -2183,9 +2183,7 @@ register_diagnostics! {
     E0657, // `impl Trait` can only capture lifetimes bound at the fn level
     E0687, // in-band lifetimes cannot be used in `fn`/`Fn` syntax
     E0688, // in-band lifetimes cannot be mixed with explicit lifetime binders
-
     E0697, // closures cannot be static
-
     E0707, // multiple elided lifetimes used in arguments of `async fn`
     E0708, // `async` non-`move` closures with arguments are not currently supported
     E0709, // multiple different lifetimes used in arguments of `async fn`

src/librustc/hir/mod.rs

@@ -506,9 +506,9 @@ pub enum TraitBoundModifier {
 }
 
 /// The AST represents all type param bounds as types.
-/// typeck::collect::compute_bounds matches these against
-/// the "special" built-in traits (see middle::lang_items) and
-/// detects Copy, Send and Sync.
+/// `typeck::collect::compute_bounds` matches these against
+/// the "special" built-in traits (see `middle::lang_items`) and
+/// detects `Copy`, `Send` and `Sync`.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum GenericBound {
     Trait(PolyTraitRef, TraitBoundModifier),

src/librustc/infer/opaque_types/mod.rs

@@ -366,7 +366,8 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         let mut types = vec![concrete_ty];
         let bound_region = |r| self.sub_regions(infer::CallReturn(span), least_region, r);
         while let Some(ty) = types.pop() {
-            let mut components = self.tcx.outlives_components(ty);
+            let mut components = smallvec![];
+            self.tcx.push_outlives_components(ty, &mut components);
             while let Some(component) = components.pop() {
                 match component {
                     Component::Region(r) => {

src/librustc/infer/outlives/obligations.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 //! Code that handles "type-outlives" constraints like `T: 'a`. This
-//! is based on the `outlives_components` function defined on the tcx,
+//! is based on the `push_outlives_components` function defined on the tcx,
 //! but it adds a bit of heuristics on top, in particular to deal with
 //! associated types and projections.
 //!
@@ -307,31 +307,32 @@ where
 
         assert!(!ty.has_escaping_bound_vars());
 
-        let components = self.tcx.outlives_components(ty);
-        self.components_must_outlive(origin, components, region);
+        let mut components = smallvec![];
+        self.tcx.push_outlives_components(ty, &mut components);
+        self.components_must_outlive(origin, &components, region);
     }
 
     fn components_must_outlive(
         &mut self,
         origin: infer::SubregionOrigin<'tcx>,
-        components: Vec<Component<'tcx>>,
+        components: &[Component<'tcx>],
         region: ty::Region<'tcx>,
     ) {
-        for component in components {
+        for component in components.iter() {
             let origin = origin.clone();
             match component {
                 Component::Region(region1) => {
                     self.delegate
                         .push_sub_region_constraint(origin, region, region1);
                 }
                 Component::Param(param_ty) => {
-                    self.param_ty_must_outlive(origin, region, param_ty);
+                    self.param_ty_must_outlive(origin, region, *param_ty);
                 }
                 Component::Projection(projection_ty) => {
-                    self.projection_must_outlive(origin, region, projection_ty);
+                    self.projection_must_outlive(origin, region, *projection_ty);
                 }
                 Component::EscapingProjection(subcomponents) => {
-                    self.components_must_outlive(origin, subcomponents, region);
+                    self.components_must_outlive(origin, &subcomponents, region);
                 }
                 Component::UnresolvedInferenceVariable(v) => {
                     // ignore this, we presume it will yield an error

src/librustc/infer/outlives/verify.rs

@@ -155,7 +155,8 @@ impl<'cx, 'gcx, 'tcx> VerifyBoundCx<'cx, 'gcx, 'tcx> {
             .map(|subty| self.type_bound(subty))
             .collect::<Vec<_>>();
 
-        let mut regions = ty.regions();
+        let mut regions = smallvec![];
+        ty.push_regions(&mut regions);
         regions.retain(|r| !r.is_late_bound()); // ignore late-bound regions
         bounds.push(VerifyBound::AllBounds(
             regions

src/librustc/lint/builtin.rs

@@ -300,12 +300,6 @@ declare_lint! {
     "detects labels that are never used"
 }
 
-declare_lint! {
-    pub DUPLICATE_ASSOCIATED_TYPE_BINDINGS,
-    Warn,
-    "warns about duplicate associated type bindings in generics"
-}
-
 declare_lint! {
     pub DUPLICATE_MACRO_EXPORTS,
     Deny,
@@ -418,7 +412,6 @@ impl LintPass for HardwiredLints {
             ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
             UNSTABLE_NAME_COLLISIONS,
             IRREFUTABLE_LET_PATTERNS,
-            DUPLICATE_ASSOCIATED_TYPE_BINDINGS,
             DUPLICATE_MACRO_EXPORTS,
             INTRA_DOC_LINK_RESOLUTION_FAILURE,
             MISSING_DOC_CODE_EXAMPLES,

src/librustc/session/mod.rs

@@ -963,6 +963,10 @@ impl Session {
         self.opts.debugging_opts.teach && self.diagnostic().must_teach(code)
     }
 
+    pub fn rust_2015(&self) -> bool {
+        self.opts.edition == Edition::Edition2015
+    }
+
     /// Are we allowed to use features from the Rust 2018 edition?
     pub fn rust_2018(&self) -> bool {
         self.opts.edition >= Edition::Edition2018

src/librustc/traits/mod.rs

@@ -50,11 +50,8 @@ pub use self::select::{EvaluationResult, IntercrateAmbiguityCause, OverflowError
 pub use self::specialize::{OverlapError, specialization_graph, translate_substs};
 pub use self::specialize::find_associated_item;
 pub use self::engine::{TraitEngine, TraitEngineExt};
-pub use self::util::elaborate_predicates;
-pub use self::util::supertraits;
-pub use self::util::Supertraits;
-pub use self::util::supertrait_def_ids;
-pub use self::util::SupertraitDefIds;
+pub use self::util::{elaborate_predicates, elaborate_trait_ref, elaborate_trait_refs};
+pub use self::util::{supertraits, supertrait_def_ids, Supertraits, SupertraitDefIds};
 pub use self::util::transitive_bounds;
 
 #[allow(dead_code)]