Rollup of 7 pull requests

src/liballoc/vec.rs

@@ -154,8 +154,8 @@ use crate::raw_vec::RawVec;
 /// println!("{}", v[6]); // it will panic!
 /// ```
 ///
-/// In conclusion: always check if the index you want to get really exists
-/// before doing it.
+/// Use [`get`] and [`get_mut`] if you want to check whether the index is in
+/// the `Vec`.
 ///
 /// # Slicing
 ///
@@ -277,6 +277,8 @@ use crate::raw_vec::RawVec;
 /// The order has changed in the past and may change again.
 ///
 /// [`vec!`]: ../../std/macro.vec.html
+/// [`get`]: ../../std/vec/struct.Vec.html#method.get
+/// [`get_mut`]: ../../std/vec/struct.Vec.html#method.get_mut
 /// [`Index`]: ../../std/ops/trait.Index.html
 /// [`String`]: ../../std/string/struct.String.html
 /// [`&str`]: ../../std/primitive.str.html

src/librustc/hir/map/collector.rs

@@ -149,7 +149,7 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
         let mut collector = NodeCollector {
             krate,
             source_map: sess.source_map(),
-            map: vec![None; definitions.def_index_count()],
+            map: IndexVec::from_elem_n(IndexVec::new(), definitions.def_index_count()),
             parent_node: hir::CRATE_HIR_ID,
             current_signature_dep_index: root_mod_sig_dep_index,
             current_full_dep_index: root_mod_full_dep_index,
@@ -227,12 +227,8 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
 
     fn insert_entry(&mut self, id: HirId, entry: Entry<'hir>) {
         debug!("hir_map: {:?} => {:?}", id, entry);
-        let local_map = &mut self.map[id.owner.index()];
+        let local_map = &mut self.map[id.owner];
         let i = id.local_id.as_u32() as usize;
-        if local_map.is_none() {
-            *local_map = Some(IndexVec::with_capacity(i + 1));
-        }
-        let local_map = local_map.as_mut().unwrap();
         let len = local_map.len();
         if i >= len {
             local_map.extend(repeat(None).take(i - len + 1));

src/librustc/hir/map/definitions.rs

@@ -27,8 +27,8 @@ use syntax_pos::{Span, DUMMY_SP};
 /// There is one `DefPathTable` for each crate.
 #[derive(Clone, Default, RustcDecodable, RustcEncodable)]
 pub struct DefPathTable {
-    index_to_key: Vec<DefKey>,
-    def_path_hashes: Vec<DefPathHash>,
+    index_to_key: IndexVec<DefIndex, DefKey>,
+    def_path_hashes: IndexVec<DefIndex, DefPathHash>,
 }
 
 impl DefPathTable {
@@ -53,14 +53,14 @@ impl DefPathTable {
 
     #[inline(always)]
     pub fn def_key(&self, index: DefIndex) -> DefKey {
-        self.index_to_key[index.index()]
+        self.index_to_key[index]
     }
 
     #[inline(always)]
     pub fn def_path_hash(&self, index: DefIndex) -> DefPathHash {
-        let ret = self.def_path_hashes[index.index()];
-        debug!("def_path_hash({:?}) = {:?}", index, ret);
-        return ret
+        let hash = self.def_path_hashes[index];
+        debug!("def_path_hash({:?}) = {:?}", index, hash);
+        hash
     }
 
     pub fn add_def_path_hashes_to(&self,
@@ -92,7 +92,7 @@ impl DefPathTable {
 pub struct Definitions {
     table: DefPathTable,
     node_to_def_index: NodeMap<DefIndex>,
-    def_index_to_node: Vec<ast::NodeId>,
+    def_index_to_node: IndexVec<DefIndex, ast::NodeId>,
     pub(super) node_to_hir_id: IndexVec<ast::NodeId, hir::HirId>,
     /// If `ExpnId` is an ID of some macro expansion,
     /// then `DefId` is the normal module (`mod`) in which the expanded macro was defined.
@@ -375,7 +375,7 @@ impl Definitions {
     #[inline]
     pub fn as_local_node_id(&self, def_id: DefId) -> Option<ast::NodeId> {
         if def_id.krate == LOCAL_CRATE {
-            let node_id = self.def_index_to_node[def_id.index.index()];
+            let node_id = self.def_index_to_node[def_id.index];
             if node_id != ast::DUMMY_NODE_ID {
                 return Some(node_id);
             }
@@ -404,7 +404,7 @@ impl Definitions {
 
     #[inline]
     pub fn def_index_to_hir_id(&self, def_index: DefIndex) -> hir::HirId {
-        let node_id = self.def_index_to_node[def_index.index()];
+        let node_id = self.def_index_to_node[def_index];
         self.node_to_hir_id[node_id]
     }
 

src/librustc/hir/map/mod.rs

@@ -156,9 +156,9 @@ impl Forest {
 
 /// This type is effectively a `HashMap<HirId, Entry<'hir>>`,
 /// but it is implemented as 2 layers of arrays.
-/// - first we have `A = Vec<Option<B>>` mapping a `DefIndex`'s index to an inner value
+/// - first we have `A = IndexVec<DefIndex, B>` mapping `DefIndex`s to an inner value
 /// - which is `B = IndexVec<ItemLocalId, Option<Entry<'hir>>` which gives you the `Entry`.
-pub(super) type HirEntryMap<'hir> = Vec<Option<IndexVec<ItemLocalId, Option<Entry<'hir>>>>>;
+pub(super) type HirEntryMap<'hir> = IndexVec<DefIndex, IndexVec<ItemLocalId, Option<Entry<'hir>>>>;
 
 /// Represents a mapping from `NodeId`s to AST elements and their parent `NodeId`s.
 #[derive(Clone)]
@@ -222,8 +222,8 @@ impl<'map> Iterator for ParentHirIterator<'map> {
 impl<'hir> Map<'hir> {
     #[inline]
     fn lookup(&self, id: HirId) -> Option<&Entry<'hir>> {
-        let local_map = self.map.get(id.owner.index())?;
-        local_map.as_ref()?.get(id.local_id)?.as_ref()
+        let local_map = self.map.get(id.owner)?;
+        local_map.get(id.local_id)?.as_ref()
     }
 
     /// Registers a read in the dependency graph of the AST node with
@@ -1031,14 +1031,12 @@ impl<'hir> Map<'hir> {
         // see the comment on `HirEntryMap`.
         // Iterate over all the indices and return a reference to
         // local maps and their index given that they exist.
-        self.map.iter().enumerate().filter_map(|(i, local_map)| {
-            local_map.as_ref().map(|m| (i, m))
-        }).flat_map(move |(array_index, local_map)| {
+        self.map.iter_enumerated().flat_map(move |(owner, local_map)| {
             // Iterate over each valid entry in the local map.
             local_map.iter_enumerated().filter_map(move |(i, entry)| entry.map(move |_| {
                 // Reconstruct the `HirId` based on the 3 indices we used to find it.
                 HirId {
-                    owner: DefIndex::from(array_index),
+                    owner,
                     local_id: i,
                 }
             }))

src/librustc/hir/print.rs

@@ -1523,9 +1523,17 @@ impl<'a> State<'a> {
                                         colons_before_params)
             }
             hir::QPath::TypeRelative(ref qself, ref item_segment) => {
-                self.s.word("<");
-                self.print_type(qself);
-                self.s.word(">");
+                // If we've got a compound-qualified-path, let's push an additional pair of angle
+                // brackets, so that we pretty-print `<<A::B>::C>` as `<A::B>::C`, instead of just
+                // `A::B::C` (since the latter could be ambiguous to the user)
+                if let hir::TyKind::Path(hir::QPath::Resolved(None, _)) = &qself.kind {
+                    self.print_type(qself);
+                } else {
+                    self.s.word("<");
+                    self.print_type(qself);
+                    self.s.word(">");
+                }
+
                 self.s.word("::");
                 self.print_ident(item_segment.ident);
                 self.print_generic_args(item_segment.generic_args(),

src/librustc/infer/error_reporting/nice_region_error/mod.rs

@@ -12,6 +12,7 @@ mod named_anon_conflict;
 mod placeholder_error;
 mod outlives_closure;
 mod static_impl_trait;
+mod trait_impl_difference;
 mod util;
 
 impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
@@ -73,6 +74,7 @@ impl<'cx, 'tcx> NiceRegionError<'cx, 'tcx> {
             .or_else(|| self.try_report_anon_anon_conflict())
             .or_else(|| self.try_report_outlives_closure())
             .or_else(|| self.try_report_static_impl_trait())
+            .or_else(|| self.try_report_impl_not_conforming_to_trait())
     }
 
     pub fn get_regions(&self) -> (Span, ty::Region<'tcx>, ty::Region<'tcx>) {

src/librustc/infer/error_reporting/nice_region_error/trait_impl_difference.rs

@@ -0,0 +1,59 @@
+//! Error Reporting for `impl` items that do not match the obligations from their `trait`.
+
+use syntax_pos::Span;
+use crate::ty::Ty;
+use crate::infer::{ValuePairs, Subtype};
+use crate::infer::error_reporting::nice_region_error::NiceRegionError;
+use crate::infer::lexical_region_resolve::RegionResolutionError;
+use crate::util::common::ErrorReported;
+use crate::traits::ObligationCauseCode::CompareImplMethodObligation;
+
+impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
+    /// Print the error message for lifetime errors when the `impl` doesn't conform to the `trait`.
+    pub(super) fn try_report_impl_not_conforming_to_trait(&self) -> Option<ErrorReported> {
+        if let Some(ref error) = self.error {
+            debug!("try_report_impl_not_conforming_to_trait {:?}", error);
+            if let RegionResolutionError::SubSupConflict(
+                _,
+                var_origin,
+                sub_origin,
+                _sub,
+                sup_origin,
+                _sup,
+            ) = error.clone() {
+                match (&sup_origin, &sub_origin) {
+                    (&Subtype(ref sup_trace), &Subtype(ref sub_trace)) => {
+                        if let (
+                            ValuePairs::Types(sub_expected_found),
+                            ValuePairs::Types(sup_expected_found),
+                            CompareImplMethodObligation { trait_item_def_id, .. },
+                        ) = (&sub_trace.values, &sup_trace.values, &sub_trace.cause.code) {
+                            if sup_expected_found == sub_expected_found {
+                                self.emit_err(
+                                    var_origin.span(),
+                                    sub_expected_found.expected,
+                                    sub_expected_found.found,
+                                    self.tcx().def_span(*trait_item_def_id),
+                                );
+                                return Some(ErrorReported);
+                            }
+                        }
+                    }
+                    _ => {}
+                }
+            }
+        }
+        None
+    }
+
+    fn emit_err(&self, sp: Span, expected: Ty<'tcx>, found: Ty<'tcx>, impl_sp: Span) {
+        let mut err = self.tcx().sess.struct_span_err(
+            sp,
+            "`impl` item signature doesn't match `trait` item signature",
+        );
+        err.note(&format!("expected `{:?}`\n   found `{:?}`", expected, found));
+        err.span_label(sp, &format!("found {:?}", found));
+        err.span_label(impl_sp, &format!("expected {:?}", expected));
+        err.emit();
+    }
+}

src/librustc/ty/context.rs

@@ -1408,6 +1408,7 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     pub fn encode_metadata(self)-> EncodedMetadata {
+        let _prof_timer = self.prof.generic_activity("generate_crate_metadata");
         self.cstore.encode_metadata(self)
     }
 

src/librustc/ty/flags.rs

@@ -114,6 +114,7 @@ impl FlagComputation {
             }
 
             &ty::Placeholder(..) => {
+                self.add_flags(TypeFlags::HAS_FREE_LOCAL_NAMES);
                 self.add_flags(TypeFlags::HAS_TY_PLACEHOLDER);
             }
 
@@ -123,8 +124,7 @@ impl FlagComputation {
                 match infer {
                     ty::FreshTy(_) |
                     ty::FreshIntTy(_) |
-                    ty::FreshFloatTy(_) => {
-                    }
+                    ty::FreshFloatTy(_) => {}
 
                     ty::TyVar(_) |
                     ty::IntVar(_) |
@@ -245,14 +245,16 @@ impl FlagComputation {
             }
             ConstValue::Bound(debruijn, _) => self.add_binder(debruijn),
             ConstValue::Param(_) => {
-                self.add_flags(TypeFlags::HAS_FREE_LOCAL_NAMES | TypeFlags::HAS_PARAMS);
+                self.add_flags(TypeFlags::HAS_FREE_LOCAL_NAMES);
+                self.add_flags(TypeFlags::HAS_PARAMS);
             }
             ConstValue::Placeholder(_) => {
-                self.add_flags(TypeFlags::HAS_FREE_REGIONS | TypeFlags::HAS_CT_PLACEHOLDER);
+                self.add_flags(TypeFlags::HAS_FREE_LOCAL_NAMES);
+                self.add_flags(TypeFlags::HAS_CT_PLACEHOLDER);
             }
-            ConstValue::Scalar(_) => { }
-            ConstValue::Slice { data: _, start: _, end: _ } => { }
-            ConstValue::ByRef { alloc: _, offset: _ } => { }
+            ConstValue::Scalar(_) => {}
+            ConstValue::Slice { .. } => {}
+            ConstValue::ByRef { .. } => {}
         }
     }
 

src/librustc_codegen_ssa/base.rs

@@ -574,8 +574,6 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
 
     if need_metadata_module {
         // Codegen the encoded metadata.
-        let _prof_timer = tcx.prof.generic_activity("codegen_crate_metadata");
-
         let metadata_cgu_name = cgu_name_builder.build_cgu_name(LOCAL_CRATE,
                                                                 &["crate"],
                                                                 Some("metadata")).as_str()

src/librustc_typeck/check/demand.rs

@@ -172,10 +172,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 }).peekable();
 
             if compatible_variants.peek().is_some() {
-                let expr_text = print::to_string(print::NO_ANN, |s| s.print_expr(expr));
+                let expr_text = self.tcx.sess
+                    .source_map()
+                    .span_to_snippet(expr.span)
+                    .unwrap_or_else(|_| {
+                        print::to_string(print::NO_ANN, |s| s.print_expr(expr))
+                    });
                 let suggestions = compatible_variants
                     .map(|v| format!("{}({})", v, expr_text));
-                let msg = "try using a variant of the expected type";
+                let msg = "try using a variant of the expected enum";
                 err.span_suggestions(expr.span, msg, suggestions, Applicability::MaybeIncorrect);
             }
         }

src/librustc_typeck/error_codes.rs

@@ -3891,6 +3891,25 @@ details.
 [issue #33685]: https://github.com/rust-lang/rust/issues/33685
 "##,
 
+E0587: r##"
+A type has both `packed` and `align` representation hints.
+
+Erroneous code example:
+
+```compile_fail,E0587
+#[repr(packed, align(8))] // error!
+struct Umbrella(i32);
+```
+
+You cannot use `packed` and `align` hints on a same type. If you want to pack a
+type to a given size, you should provide a size to packed:
+
+```
+#[repr(packed)] // ok!
+struct Umbrella(i32);
+```
+"##,
+
 E0588: r##"
 A type with `packed` representation hint has a field with `align`
 representation hint.
@@ -5097,7 +5116,6 @@ struct B<const X: A>; // ok!
 //  E0563, // cannot determine a type for this `impl Trait` removed in 6383de15
 //  E0564, // only named lifetimes are allowed in `impl Trait`,
            // but `{}` was found in the type `{}`
-    E0587, // type has conflicting packed and align representation hints
 //  E0611, // merged into E0616
 //  E0612, // merged into E0609
 //  E0613, // Removed (merged with E0609)

src/test/pretty/issue-4264.pp

@@ -30,7 +30,7 @@
 
 
                   ((::alloc::fmt::format as
-                       for<'r> fn(std::fmt::Arguments<'r>) -> std::string::String {std::fmt::format})(((<::core::fmt::Arguments>::new_v1
+                       for<'r> fn(std::fmt::Arguments<'r>) -> std::string::String {std::fmt::format})(((::core::fmt::Arguments::new_v1
                                                                                                            as
                                                                                                            fn(&[&str], &[std::fmt::ArgumentV1<'_>]) -> std::fmt::Arguments<'_> {std::fmt::Arguments::<'_>::new_v1})((&([("test"
                                                                                                                                                                                                                             as

src/test/ui/conflicting-repr-hints.stderr

@@ -66,4 +66,5 @@ LL | | }
 
 error: aborting due to 8 previous errors
 
-For more information about this error, try `rustc --explain E0566`.
+Some errors have detailed explanations: E0566, E0587.
+For more information about an error, try `rustc --explain E0566`.

src/test/ui/did_you_mean/issue-42764.rs

@@ -10,7 +10,7 @@ fn main() {
     let n: usize = 42;
     this_function_expects_a_double_option(n);
     //~^ ERROR mismatched types
-    //~| HELP try using a variant of the expected type
+    //~| HELP try using a variant of the expected enum
 }
 
 

src/test/ui/did_you_mean/issue-42764.stderr

@@ -6,7 +6,7 @@ LL |     this_function_expects_a_double_option(n);
    |
    = note: expected type `DoubleOption<_>`
               found type `usize`
-help: try using a variant of the expected type
+help: try using a variant of the expected enum
    |
 LL |     this_function_expects_a_double_option(DoubleOption::FirstSome(n));
    |                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^

src/test/ui/error-codes/E0164.stderr

@@ -1,4 +1,4 @@
-error[E0164]: expected tuple struct/variant, found associated constant `<Foo>::B`
+error[E0164]: expected tuple struct/variant, found associated constant `Foo::B`
   --> $DIR/E0164.rs:9:9
    |
 LL |         Foo::B(i) => i,

src/test/ui/fn-in-pat.stderr

@@ -1,4 +1,4 @@
-error[E0164]: expected tuple struct/variant, found method `<A>::new`
+error[E0164]: expected tuple struct/variant, found method `A::new`
   --> $DIR/fn-in-pat.rs:11:9
    |
 LL |         A::new() => (),