Auto merge of #64160 - Centril:rollup-vrfj1pt, r=Centril

Rollup of 15 pull requests

Successful merges:

 - #62860 (Stabilize checked_duration_since for 1.38.0)
 - #63549 (Rev::rposition counts from the wrong end)
 - #63985 (Stabilize pin_into_inner in 1.39.0)
 - #64005 (Add a `Place::is_indirect` method to determine whether a `Place` contains a `Deref` projection)
 - #64031 (Harden `param_attrs` test wrt. usage of a proc macro `#[attr]`)
 - #64038 (Check impl trait substs when checking for recursive types)
 - #64043 (Add some more tests for underscore imports)
 - #64092 (Update xLTO compatibility table in rustc book.)
 - #64110 (Refer to "`self` type" instead of "receiver type")
 - #64120 (Move path parsing earlier)
 - #64123 (Added warning around code with reference to uninit bytes)
 - #64128 (unused_parens: account for or-patterns and `&(mut x)`)
 - #64141 (Minimize uses of `LocalInternedString`)
 - #64142 (Fix doc links in `std::cmp` module)
 - #64148 (fix a few typos in comments)

Failed merges:

r? @ghost

src/doc/rustc/src/linker-plugin-lto.md

@@ -105,5 +105,6 @@ The following table shows known good combinations of toolchain versions.
 | Rust 1.34 |     ✗     |     ✓     |
 | Rust 1.35 |     ✗     |     ✓     |
 | Rust 1.36 |     ✗     |     ✓     |
+| Rust 1.37 |     ✗     |     ✓     |
 
 Note that the compatibility policy for this feature might change in the future.

src/libcore/cmp.rs

@@ -9,14 +9,22 @@
 //! * [`Ord`] and [`PartialOrd`] are traits that allow you to define total and
 //!   partial orderings between values, respectively. Implementing them overloads
 //!   the `<`, `<=`, `>`, and `>=` operators.
-//! * [`Ordering`][cmp::Ordering] is an enum returned by the
-//!   main functions of [`Ord`] and [`PartialOrd`], and describes an ordering.
-//! * [`Reverse`][cmp::Reverse] is a struct that allows you to easily reverse
-//!   an ordering.
-//! * [`max`][cmp::max] and [`min`][cmp::min] are functions that build off of
-//!   [`Ord`] and allow you to find the maximum or minimum of two values.
+//! * [`Ordering`] is an enum returned by the main functions of [`Ord`] and
+//!   [`PartialOrd`], and describes an ordering.
+//! * [`Reverse`] is a struct that allows you to easily reverse an ordering.
+//! * [`max`] and [`min`] are functions that build off of [`Ord`] and allow you
+//!   to find the maximum or minimum of two values.
 //!
 //! For more details, see the respective documentation of each item in the list.
+//!
+//! [`Eq`]: trait.Eq.html
+//! [`PartialEq`]: trait.PartialEq.html
+//! [`Ord`]: trait.Ord.html
+//! [`PartialOrd`]: trait.PartialOrd.html
+//! [`Ordering`]: enum.Ordering.html
+//! [`Reverse`]: struct.Reverse.html
+//! [`max`]: fn.max.html
+//! [`min`]: fn.min.html
 
 #![stable(feature = "rust1", since = "1.0.0")]
 

src/libcore/iter/adapters/mod.rs

@@ -66,13 +66,6 @@ impl<I> Iterator for Rev<I> where I: DoubleEndedIterator {
     {
         self.iter.rfind(predicate)
     }
-
-    #[inline]
-    fn rposition<P>(&mut self, predicate: P) -> Option<usize> where
-        P: FnMut(Self::Item) -> bool
-    {
-        self.iter.position(predicate)
-    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]

src/libcore/pin.rs

@@ -462,7 +462,7 @@ impl<P: Deref<Target: Unpin>> Pin<P> {
     /// can ignore the pinning invariants when unwrapping it.
     ///
     /// [`Unpin`]: ../../std/marker/trait.Unpin.html
-    #[unstable(feature = "pin_into_inner", issue = "60245")]
+    #[stable(feature = "pin_into_inner", since = "1.39.0")]
     #[inline(always)]
     pub fn into_inner(pin: Pin<P>) -> P {
         pin.pointer
@@ -569,7 +569,7 @@ impl<P: Deref> Pin<P> {
     ///
     /// [`Unpin`]: ../../std/marker/trait.Unpin.html
     /// [`Pin::into_inner`]: #method.into_inner
-    #[unstable(feature = "pin_into_inner", issue = "60245")]
+    #[stable(feature = "pin_into_inner", since = "1.39.0")]
     #[inline(always)]
     pub unsafe fn into_inner_unchecked(pin: Pin<P>) -> P {
         pin.pointer

src/libcore/tests/iter.rs

@@ -1688,6 +1688,12 @@ fn test_rposition() {
     assert!(v.iter().rposition(g).is_none());
 }
 
+#[test]
+fn test_rev_rposition() {
+    let v = [0, 0, 1, 1];
+    assert_eq!(v.iter().rev().rposition(|&x| x == 1), Some(1));
+}
+
 #[test]
 #[should_panic]
 fn test_rposition_panic() {

src/librustc/error_codes.rs

@@ -39,7 +39,7 @@ Generally, `Self: Sized` is used to indicate that the trait should not be used
 as a trait object. If the trait comes from your own crate, consider removing
 this restriction.
 
-### Method references the `Self` type in its arguments or return type
+### Method references the `Self` type in its parameters or return type
 
 This happens when a trait has a method like the following:
 

src/librustc/hir/map/collector.rs

@@ -186,7 +186,7 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
             });
 
         let mut upstream_crates: Vec<_> = cstore.crates_untracked().iter().map(|&cnum| {
-            let name = cstore.crate_name_untracked(cnum).as_str();
+            let name = cstore.crate_name_untracked(cnum).as_interned_str();
             let disambiguator = cstore.crate_disambiguator_untracked(cnum).to_fingerprint();
             let hash = cstore.crate_hash_untracked(cnum);
             (name, disambiguator, hash)

src/librustc/ich/impls_syntax.rs

@@ -9,7 +9,7 @@ use std::mem;
 use syntax::ast;
 use syntax::feature_gate;
 use syntax::parse::token;
-use syntax::symbol::{InternedString, LocalInternedString};
+use syntax::symbol::InternedString;
 use syntax::tokenstream;
 use syntax_pos::SourceFile;
 
@@ -39,27 +39,6 @@ impl<'a> ToStableHashKey<StableHashingContext<'a>> for InternedString {
     }
 }
 
-impl<'a> HashStable<StableHashingContext<'a>> for LocalInternedString {
-    #[inline]
-    fn hash_stable<W: StableHasherResult>(&self,
-                                          hcx: &mut StableHashingContext<'a>,
-                                          hasher: &mut StableHasher<W>) {
-        let s: &str = &**self;
-        s.hash_stable(hcx, hasher);
-    }
-}
-
-impl<'a> ToStableHashKey<StableHashingContext<'a>> for LocalInternedString {
-    type KeyType = LocalInternedString;
-
-    #[inline]
-    fn to_stable_hash_key(&self,
-                          _: &StableHashingContext<'a>)
-                          -> LocalInternedString {
-        self.clone()
-    }
-}
-
 impl<'a> HashStable<StableHashingContext<'a>> for ast::Name {
     #[inline]
     fn hash_stable<W: StableHasherResult>(&self,

src/librustc/infer/error_reporting/mod.rs

@@ -1627,7 +1627,7 @@ impl<'tcx> ObligationCause<'tcx> {
             MainFunctionType => Error0580("main function has wrong type"),
             StartFunctionType => Error0308("start function has wrong type"),
             IntrinsicType => Error0308("intrinsic has wrong type"),
-            MethodReceiver => Error0308("mismatched method receiver"),
+            MethodReceiver => Error0308("mismatched `self` parameter type"),
 
             // In the case where we have no more specific thing to
             // say, also take a look at the error code, maybe we can

src/librustc/lint/context.rs

@@ -33,7 +33,7 @@ use crate::util::common::time;
 use std::default::Default as StdDefault;
 use syntax::ast;
 use syntax::edition;
-use syntax_pos::{MultiSpan, Span, symbol::{LocalInternedString, Symbol}};
+use syntax_pos::{MultiSpan, Span, symbol::Symbol};
 use errors::DiagnosticBuilder;
 use crate::hir;
 use crate::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
@@ -405,7 +405,7 @@ impl LintStore {
     pub fn check_lint_name(
         &self,
         lint_name: &str,
-        tool_name: Option<LocalInternedString>,
+        tool_name: Option<Symbol>,
     ) -> CheckLintNameResult<'_> {
         let complete_name = if let Some(tool_name) = tool_name {
             format!("{}::{}", tool_name, lint_name)

src/librustc/lint/levels.rs

@@ -291,7 +291,7 @@ impl<'a> LintLevelsBuilder<'a> {
                         continue;
                     }
 
-                    Some(tool_ident.as_str())
+                    Some(tool_ident.name)
                 } else {
                     None
                 };

src/librustc/mir/mod.rs

@@ -1808,6 +1808,23 @@ pub enum ProjectionElem<V, T> {
     Downcast(Option<Symbol>, VariantIdx),
 }
 
+impl<V, T> ProjectionElem<V, T> {
+    /// Returns `true` if the target of this projection may refer to a different region of memory
+    /// than the base.
+    fn is_indirect(&self) -> bool {
+        match self {
+            Self::Deref => true,
+
+            | Self::Field(_, _)
+            | Self::Index(_)
+            | Self::ConstantIndex { .. }
+            | Self::Subslice { .. }
+            | Self::Downcast(_, _)
+            => false
+        }
+    }
+}
+
 /// Alias for projections as they appear in places, where the base is a place
 /// and the index is a local.
 pub type PlaceElem<'tcx> = ProjectionElem<Local, Ty<'tcx>>;
@@ -1869,6 +1886,14 @@ impl<'tcx> Place<'tcx> {
         }
     }
 
+    /// Returns `true` if this `Place` contains a `Deref` projection.
+    ///
+    /// If `Place::is_indirect` returns false, the caller knows that the `Place` refers to the
+    /// same region of memory as its base.
+    pub fn is_indirect(&self) -> bool {
+        self.iterate(|_, mut projections| projections.any(|proj| proj.elem.is_indirect()))
+    }
+
     /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
     /// a single deref of a local.
     //

src/librustc/traits/error_reporting.rs

@@ -1384,7 +1384,10 @@ impl<'tcx> TyCtxt<'tcx> {
         let mut reported_violations = FxHashSet::default();
         for violation in violations {
             if reported_violations.insert(violation.clone()) {
-                err.note(&violation.error_msg());
+                match violation.span() {
+                    Some(span) => err.span_label(span, violation.error_msg()),
+                    None => err.note(&violation.error_msg()),
+                };
             }
         }
         Some(err)

src/librustc/traits/object_safety.rs

@@ -20,7 +20,7 @@ use std::borrow::Cow;
 use std::iter::{self};
 use syntax::ast::{self};
 use syntax::symbol::InternedString;
-use syntax_pos::Span;
+use syntax_pos::{Span, DUMMY_SP};
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
 pub enum ObjectSafetyViolation {
@@ -32,10 +32,10 @@ pub enum ObjectSafetyViolation {
     SupertraitSelf,
 
     /// Method has something illegal.
-    Method(ast::Name, MethodViolationCode),
+    Method(ast::Name, MethodViolationCode, Span),
 
     /// Associated const.
-    AssocConst(ast::Name),
+    AssocConst(ast::Name, Span),
 }
 
 impl ObjectSafetyViolation {
@@ -46,22 +46,35 @@ impl ObjectSafetyViolation {
             ObjectSafetyViolation::SupertraitSelf =>
                 "the trait cannot use `Self` as a type parameter \
                  in the supertraits or where-clauses".into(),
-            ObjectSafetyViolation::Method(name, MethodViolationCode::StaticMethod) =>
-                format!("method `{}` has no receiver", name).into(),
-            ObjectSafetyViolation::Method(name, MethodViolationCode::ReferencesSelf) =>
-                format!("method `{}` references the `Self` type \
-                         in its arguments or return type", name).into(),
-            ObjectSafetyViolation::Method(name,
-                                            MethodViolationCode::WhereClauseReferencesSelf(_)) =>
-                format!("method `{}` references the `Self` type in where clauses", name).into(),
-            ObjectSafetyViolation::Method(name, MethodViolationCode::Generic) =>
+            ObjectSafetyViolation::Method(name, MethodViolationCode::StaticMethod, _) =>
+                format!("associated function `{}` has no `self` parameter", name).into(),
+            ObjectSafetyViolation::Method(name, MethodViolationCode::ReferencesSelf, _) => format!(
+                "method `{}` references the `Self` type in its parameters or return type",
+                name,
+            ).into(),
+            ObjectSafetyViolation::Method(
+                name,
+                MethodViolationCode::WhereClauseReferencesSelf,
+                _,
+            ) => format!("method `{}` references the `Self` type in where clauses", name).into(),
+            ObjectSafetyViolation::Method(name, MethodViolationCode::Generic, _) =>
                 format!("method `{}` has generic type parameters", name).into(),
-            ObjectSafetyViolation::Method(name, MethodViolationCode::UndispatchableReceiver) =>
-                format!("method `{}`'s receiver cannot be dispatched on", name).into(),
-            ObjectSafetyViolation::AssocConst(name) =>
+            ObjectSafetyViolation::Method(name, MethodViolationCode::UndispatchableReceiver, _) =>
+                format!("method `{}`'s `self` parameter cannot be dispatched on", name).into(),
+            ObjectSafetyViolation::AssocConst(name, _) =>
                 format!("the trait cannot contain associated consts like `{}`", name).into(),
         }
     }
+
+    pub fn span(&self) -> Option<Span> {
+        // When `span` comes from a separate crate, it'll be `DUMMY_SP`. Treat it as `None` so
+        // diagnostics use a `note` instead of a `span_label`.
+        match *self {
+            ObjectSafetyViolation::AssocConst(_, span) |
+            ObjectSafetyViolation::Method(_, _, span) if span != DUMMY_SP => Some(span),
+            _ => None,
+        }
+    }
 }
 
 /// Reasons a method might not be object-safe.
@@ -74,7 +87,7 @@ pub enum MethodViolationCode {
     ReferencesSelf,
 
     /// e.g., `fn foo(&self) where Self: Clone`
-    WhereClauseReferencesSelf(Span),
+    WhereClauseReferencesSelf,
 
     /// e.g., `fn foo<A>()`
     Generic,
@@ -88,9 +101,10 @@ impl<'tcx> TyCtxt<'tcx> {
     /// astconv -- currently, `Self` in supertraits. This is needed
     /// because `object_safety_violations` can't be used during
     /// type collection.
-    pub fn astconv_object_safety_violations(self, trait_def_id: DefId)
-                                            -> Vec<ObjectSafetyViolation>
-    {
+    pub fn astconv_object_safety_violations(
+        self,
+        trait_def_id: DefId,
+    ) -> Vec<ObjectSafetyViolation> {
         debug_assert!(self.generics_of(trait_def_id).has_self);
         let violations = traits::supertrait_def_ids(self, trait_def_id)
             .filter(|&def_id| self.predicates_reference_self(def_id, true))
@@ -128,7 +142,7 @@ impl<'tcx> TyCtxt<'tcx> {
         }
 
         match self.virtual_call_violation_for_method(trait_def_id, method) {
-            None | Some(MethodViolationCode::WhereClauseReferencesSelf(_)) => true,
+            None | Some(MethodViolationCode::WhereClauseReferencesSelf) => true,
             Some(_) => false,
         }
     }
@@ -138,12 +152,15 @@ impl<'tcx> TyCtxt<'tcx> {
         let mut violations: Vec<_> = self.associated_items(trait_def_id)
             .filter(|item| item.kind == ty::AssocKind::Method)
             .filter_map(|item|
-                self.object_safety_violation_for_method(trait_def_id, &item)
-                    .map(|code| ObjectSafetyViolation::Method(item.ident.name, code))
+                self.object_safety_violation_for_method(trait_def_id, &item).map(|code| {
+                    ObjectSafetyViolation::Method(item.ident.name, code, item.ident.span)
+                })
             ).filter(|violation| {
-                if let ObjectSafetyViolation::Method(_,
-                    MethodViolationCode::WhereClauseReferencesSelf(span)) = violation
-                {
+                if let ObjectSafetyViolation::Method(
+                    _,
+                    MethodViolationCode::WhereClauseReferencesSelf,
+                    span,
+                ) = violation {
                     // Using `CRATE_NODE_ID` is wrong, but it's hard to get a more precise id.
                     // It's also hard to get a use site span, so we use the method definition span.
                     self.lint_node_note(
@@ -169,7 +186,7 @@ impl<'tcx> TyCtxt<'tcx> {
 
         violations.extend(self.associated_items(trait_def_id)
             .filter(|item| item.kind == ty::AssocKind::Const)
-            .map(|item| ObjectSafetyViolation::AssocConst(item.ident.name)));
+            .map(|item| ObjectSafetyViolation::AssocConst(item.ident.name, item.ident.span)));
 
         debug!("object_safety_violations_for_trait(trait_def_id={:?}) = {:?}",
                trait_def_id,
@@ -325,8 +342,7 @@ impl<'tcx> TyCtxt<'tcx> {
                 .visit_tys_shallow(|t| {
                     self.contains_illegal_self_type_reference(trait_def_id, t)
                 }) {
-            let span = self.def_span(method.def_id);
-            return Some(MethodViolationCode::WhereClauseReferencesSelf(span));
+            return Some(MethodViolationCode::WhereClauseReferencesSelf);
         }
 
         let receiver_ty = self.liberate_late_bound_regions(