Rollup of 11 pull requests

src/librustc/error_codes.rs

@@ -335,7 +335,7 @@ This works because `Box` is a pointer, so its size is well-known.
 "##,
 
 E0080: r##"
-This error indicates that the compiler was unable to sensibly evaluate an
+This error indicates that the compiler was unable to sensibly evaluate a
 constant expression that had to be evaluated. Attempting to divide by 0
 or causing integer overflow are two ways to induce this error. For example:
 

src/librustc/hir/lowering.rs

@@ -65,7 +65,6 @@ use syntax::ast;
 use syntax::ptr::P as AstP;
 use syntax::ast::*;
 use syntax::errors;
-use syntax::expand::SpecialDerives;
 use syntax::print::pprust;
 use syntax::parse::token::{self, Nonterminal, Token};
 use syntax::tokenstream::{TokenStream, TokenTree};
@@ -184,8 +183,6 @@ pub trait Resolver {
         ns: Namespace,
     ) -> (ast::Path, Res<NodeId>);
 
-    fn has_derives(&self, node_id: NodeId, derives: SpecialDerives) -> bool;
-
     fn lint_buffer(&mut self) -> &mut lint::LintBuffer;
 }
 

src/librustc/hir/lowering/item.rs

@@ -18,7 +18,6 @@ use smallvec::SmallVec;
 use syntax::attr;
 use syntax::ast::*;
 use syntax::visit::{self, Visitor};
-use syntax::expand::SpecialDerives;
 use syntax::source_map::{respan, DesugaringKind, Spanned};
 use syntax::symbol::{kw, sym};
 use syntax_pos::Span;
@@ -227,13 +226,7 @@ impl LoweringContext<'_> {
     pub fn lower_item(&mut self, i: &Item) -> Option<hir::Item> {
         let mut ident = i.ident;
         let mut vis = self.lower_visibility(&i.vis, None);
-        let mut attrs = self.lower_attrs_extendable(&i.attrs);
-        if self.resolver.has_derives(i.id, SpecialDerives::PARTIAL_EQ | SpecialDerives::EQ) {
-            // Add `#[structural_match]` if the item derived both `PartialEq` and `Eq`.
-            let ident = Ident::new(sym::structural_match, i.span);
-            attrs.push(attr::mk_attr_outer(attr::mk_word_item(ident)));
-        }
-        let attrs = attrs.into();
+        let attrs = self.lower_attrs(&i.attrs);
 
         if let ItemKind::MacroDef(ref def) = i.kind {
             if !def.legacy || attr::contains_name(&i.attrs, sym::macro_export) {

src/librustc/hir/map/definitions.rs

@@ -19,7 +19,7 @@ use std::hash::Hash;
 use syntax::ast;
 use syntax_pos::symbol::{Symbol, sym};
 use syntax_pos::hygiene::ExpnId;
-use syntax_pos::{Span, DUMMY_SP};
+use syntax_pos::Span;
 
 /// The `DefPathTable` maps `DefIndex`es to `DefKey`s and vice versa.
 /// Internally the `DefPathTable` holds a tree of `DefKey`s, where each `DefKey`
@@ -310,10 +310,6 @@ pub enum DefPathData {
     AnonConst,
     /// An `impl Trait` type node.
     ImplTrait,
-    /// Identifies a piece of crate metadata that is global to a whole crate
-    /// (as opposed to just one item). `GlobalMetaData` components are only
-    /// supposed to show up right below the crate root.
-    GlobalMetaData(Symbol),
 }
 
 #[derive(Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Debug,
@@ -444,9 +440,6 @@ impl Definitions {
         self.node_to_def_index.insert(ast::CRATE_NODE_ID, root_index);
         self.set_invocation_parent(ExpnId::root(), root_index);
 
-        // Allocate some other `DefIndex`es that always must exist.
-        GlobalMetaDataKind::allocate_def_indices(self);
-
         root_index
     }
 
@@ -553,8 +546,7 @@ impl DefPathData {
             TypeNs(name) |
             ValueNs(name) |
             MacroNs(name) |
-            LifetimeNs(name) |
-            GlobalMetaData(name) => Some(name),
+            LifetimeNs(name) => Some(name),
 
             Impl |
             CrateRoot |
@@ -572,8 +564,7 @@ impl DefPathData {
             TypeNs(name) |
             ValueNs(name) |
             MacroNs(name) |
-            LifetimeNs(name) |
-            GlobalMetaData(name) => {
+            LifetimeNs(name) => {
                 name
             }
             // Note that this does not show up in user print-outs.
@@ -591,78 +582,3 @@ impl DefPathData {
         self.as_symbol().to_string()
     }
 }
-
-// We define the `GlobalMetaDataKind` enum with this macro because we want to
-// make sure that we exhaustively iterate over all variants when registering
-// the corresponding `DefIndex`es in the `DefTable`.
-macro_rules! define_global_metadata_kind {
-    (pub enum GlobalMetaDataKind {
-        $($variant:ident),*
-    }) => (
-        pub enum GlobalMetaDataKind {
-            $($variant),*
-        }
-
-        impl GlobalMetaDataKind {
-            fn allocate_def_indices(definitions: &mut Definitions) {
-                $({
-                    let instance = GlobalMetaDataKind::$variant;
-                    definitions.create_def_with_parent(
-                        CRATE_DEF_INDEX,
-                        ast::DUMMY_NODE_ID,
-                        DefPathData::GlobalMetaData(instance.name()),
-                        ExpnId::root(),
-                        DUMMY_SP
-                    );
-
-                    // Make sure calling `def_index` does not crash.
-                    instance.def_index(&definitions.table);
-                })*
-            }
-
-            pub fn def_index(&self, def_path_table: &DefPathTable) -> DefIndex {
-                let def_key = DefKey {
-                    parent: Some(CRATE_DEF_INDEX),
-                    disambiguated_data: DisambiguatedDefPathData {
-                        data: DefPathData::GlobalMetaData(self.name()),
-                        disambiguator: 0,
-                    }
-                };
-
-                // These `DefKey`s are all right after the root,
-                // so a linear search is fine.
-                let index = def_path_table.index_to_key
-                                          .iter()
-                                          .position(|k| *k == def_key)
-                                          .unwrap();
-
-                DefIndex::from(index)
-            }
-
-            fn name(&self) -> Symbol {
-
-                let string = match *self {
-                    $(
-                        GlobalMetaDataKind::$variant => {
-                            concat!("{{GlobalMetaData::", stringify!($variant), "}}")
-                        }
-                    )*
-                };
-
-                Symbol::intern(string)
-            }
-        }
-    )
-}
-
-define_global_metadata_kind!(pub enum GlobalMetaDataKind {
-    Krate,
-    CrateDeps,
-    DylibDependencyFormats,
-    LangItems,
-    LangItemsMissing,
-    NativeLibraries,
-    SourceMap,
-    Impls,
-    ExportedSymbols
-});

src/librustc/infer/error_reporting/mod.rs

@@ -1234,8 +1234,16 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             }
         }
 
+        // In some (most?) cases cause.body_id points to actual body, but in some cases
+        // it's a actual definition. According to the comments (e.g. in
+        // librustc_typeck/check/compare_method.rs:compare_predicate_entailment) the latter
+        // is relied upon by some other code. This might (or might not) need cleanup.
+        let body_owner_def_id = self.tcx.hir().opt_local_def_id(cause.body_id)
+            .unwrap_or_else(|| {
+                self.tcx.hir().body_owner_def_id(hir::BodyId { hir_id: cause.body_id })
+            });
         self.check_and_note_conflicting_crates(diag, terr, span);
-        self.tcx.note_and_explain_type_err(diag, terr, span);
+        self.tcx.note_and_explain_type_err(diag, terr, span, body_owner_def_id);
 
         // It reads better to have the error origin as the final
         // thing.

src/librustc/session/mod.rs

@@ -148,9 +148,6 @@ pub struct Session {
     /// Metadata about the allocators for the current crate being compiled.
     pub has_global_allocator: Once<bool>,
 
-    /// Metadata about the panic handlers for the current crate being compiled.
-    pub has_panic_handler: Once<bool>,
-
     /// Cap lint level specified by a driver specifically.
     pub driver_lint_caps: FxHashMap<lint::LintId, lint::Level>,
 
@@ -1211,7 +1208,6 @@ fn build_session_(
         print_fuel,
         jobserver: jobserver::client(),
         has_global_allocator: Once::new(),
-        has_panic_handler: Once::new(),
         driver_lint_caps,
         trait_methods_not_found: Lock::new(Default::default()),
         confused_type_with_std_module: Lock::new(Default::default()),

src/librustc/traits/error_reporting.rs

@@ -1231,7 +1231,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     fn suggest_fn_call(
         &self,
         obligation: &PredicateObligation<'tcx>,
-        err: &mut DiagnosticBuilder<'tcx>,
+        err: &mut DiagnosticBuilder<'_>,
         trait_ref: &ty::Binder<ty::TraitRef<'tcx>>,
         points_at_arg: bool,
     ) {

src/librustc/ty/context.rs

@@ -3045,4 +3045,9 @@ pub fn provide(providers: &mut ty::query::Providers<'_>) {
         assert_eq!(cnum, LOCAL_CRATE);
         attr::contains_name(tcx.hir().krate_attrs(), sym::compiler_builtins)
     };
+    providers.has_panic_handler = |tcx, cnum| {
+        assert_eq!(cnum, LOCAL_CRATE);
+        // We want to check if the panic handler was defined in this crate
+        tcx.lang_items().panic_impl().map_or(false, |did| did.is_local())
+    };
 }

src/librustc/ty/error.rs

@@ -241,7 +241,7 @@ impl<'tcx> ty::TyS<'tcx> {
             ty::Infer(ty::FreshFloatTy(_)) => "fresh floating-point type".into(),
             ty::Projection(_) => "associated type".into(),
             ty::UnnormalizedProjection(_) => "non-normalized associated type".into(),
-            ty::Param(_) => "type parameter".into(),
+            ty::Param(p) => format!("type parameter `{}`", p).into(),
             ty::Opaque(..) => "opaque type".into(),
             ty::Error => "type error".into(),
         }
@@ -254,6 +254,7 @@ impl<'tcx> TyCtxt<'tcx> {
         db: &mut DiagnosticBuilder<'_>,
         err: &TypeError<'tcx>,
         sp: Span,
+        body_owner_def_id: DefId,
     ) {
         use self::TypeError::*;
 
@@ -288,7 +289,16 @@ impl<'tcx> TyCtxt<'tcx> {
                             );
                         }
                     },
-                    (ty::Param(_), ty::Param(_)) => {
+                    (ty::Param(expected), ty::Param(found)) => {
+                        let generics = self.generics_of(body_owner_def_id);
+                        let e_span = self.def_span(generics.type_param(expected, self).def_id);
+                        if !sp.contains(e_span) {
+                            db.span_label(e_span, "expected type parameter");
+                        }
+                        let f_span = self.def_span(generics.type_param(found, self).def_id);
+                        if !sp.contains(f_span) {
+                            db.span_label(f_span, "found type parameter");
+                        }
                         db.note("a type parameter was expected, but a different one was found; \
                                  you might be missing a type parameter or trait bound");
                         db.note("for more information, visit \
@@ -301,7 +311,12 @@ impl<'tcx> TyCtxt<'tcx> {
                     (ty::Param(_), ty::Projection(_)) | (ty::Projection(_), ty::Param(_)) => {
                         db.note("you might be missing a type parameter or trait bound");
                     }
-                    (ty::Param(_), _) | (_, ty::Param(_)) => {
+                    (ty::Param(p), _) | (_, ty::Param(p)) => {
+                        let generics = self.generics_of(body_owner_def_id);
+                        let p_span = self.def_span(generics.type_param(p, self).def_id);
+                        if !sp.contains(p_span) {
+                            db.span_label(p_span, "this type parameter");
+                        }
                         db.help("type parameters must be constrained to match other types");
                         if self.sess.teach(&db.get_code().unwrap()) {
                             db.help("given a type parameter `T` and a method `foo`:

src/librustc_codegen_utils/symbol_names/v0.rs

@@ -601,8 +601,7 @@ impl Printer<'tcx> for SymbolMangler<'tcx> {
             | DefPathData::Misc
             | DefPathData::Impl
             | DefPathData::MacroNs(_)
-            | DefPathData::LifetimeNs(_)
-            | DefPathData::GlobalMetaData(_) => {
+            | DefPathData::LifetimeNs(_) => {
                 bug!("symbol_names: unexpected DefPathData: {:?}", disambiguated_data.data)
             }
         };

src/librustc_errors/emitter.rs

@@ -424,6 +424,14 @@ impl Emitter for EmitterWriter {
     }
 }
 
+/// An emitter that does nothing when emitting a diagnostic.
+pub struct SilentEmitter;
+
+impl Emitter for SilentEmitter {
+    fn source_map(&self) -> Option<&Lrc<SourceMapperDyn>> { None }
+    fn emit_diagnostic(&mut self, _: &Diagnostic) {}
+}
+
 /// maximum number of lines we will print for each error; arbitrary.
 pub const MAX_HIGHLIGHT_LINES: usize = 6;
 /// maximum number of suggestions to be shown

src/librustc_interface/interface.rs

@@ -17,10 +17,9 @@ use std::sync::{Arc, Mutex};
 use syntax::{self, parse};
 use syntax::ast::{self, MetaItemKind};
 use syntax::parse::token;
-use syntax::source_map::{FileName, FilePathMapping, FileLoader, SourceMap};
+use syntax::source_map::{FileName, FileLoader, SourceMap};
 use syntax::sess::ParseSess;
 use syntax_pos::edition;
-use rustc_errors::{Diagnostic, emitter::Emitter, Handler, SourceMapperDyn};
 
 pub type Result<T> = result::Result<T, ErrorReported>;
 
@@ -63,18 +62,9 @@ impl Compiler {
 
 /// Converts strings provided as `--cfg [cfgspec]` into a `crate_cfg`.
 pub fn parse_cfgspecs(cfgspecs: Vec<String>) -> FxHashSet<(String, Option<String>)> {
-    struct NullEmitter;
-    impl Emitter for NullEmitter {
-        fn emit_diagnostic(&mut self, _: &Diagnostic) {}
-        fn source_map(&self) -> Option<&Lrc<SourceMapperDyn>> { None }
-    }
-
     syntax::with_default_globals(move || {
         let cfg = cfgspecs.into_iter().map(|s| {
-
-            let cm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
-            let handler = Handler::with_emitter(false, None, Box::new(NullEmitter));
-            let sess = ParseSess::with_span_handler(handler, cm);
+            let sess = ParseSess::with_silent_emitter();
             let filename = FileName::cfg_spec_source_code(&s);
             let mut parser = parse::new_parser_from_source_str(&sess, filename, s.to_string());
 

src/librustc_metadata/encoder.rs

@@ -542,7 +542,6 @@ impl<'tcx> EncodeContext<'tcx> {
         let attrs = tcx.hir().krate_attrs();
         let has_default_lib_allocator = attr::contains_name(&attrs, sym::default_lib_allocator);
         let has_global_allocator = *tcx.sess.has_global_allocator.get();
-        let has_panic_handler = *tcx.sess.has_panic_handler.try_get().unwrap_or(&false);
 
         let root = self.lazy(CrateRoot {
             name: tcx.crate_name(LOCAL_CRATE),
@@ -553,7 +552,7 @@ impl<'tcx> EncodeContext<'tcx> {
             panic_strategy: tcx.sess.panic_strategy(),
             edition: tcx.sess.edition(),
             has_global_allocator: has_global_allocator,
-            has_panic_handler: has_panic_handler,
+            has_panic_handler: tcx.has_panic_handler(LOCAL_CRATE),
             has_default_lib_allocator: has_default_lib_allocator,
             plugin_registrar_fn: tcx.plugin_registrar_fn(LOCAL_CRATE).map(|id| id.index),
             proc_macro_decls_static: if is_proc_macro {

src/librustc_mir/interpret/memory.rs

@@ -314,16 +314,18 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
         align: Align,
     ) -> InterpResult<'tcx, Option<Pointer<M::PointerTag>>> {
         let align = if M::CHECK_ALIGN { Some(align) } else { None };
-        self.check_ptr_access_align(sptr, size, align)
+        self.check_ptr_access_align(sptr, size, align, CheckInAllocMsg::MemoryAccessTest)
     }
 
     /// Like `check_ptr_access`, but *definitely* checks alignment when `align`
-    /// is `Some` (overriding `M::CHECK_ALIGN`).
-    pub(super) fn check_ptr_access_align(
+    /// is `Some` (overriding `M::CHECK_ALIGN`). Also lets the caller control
+    /// the error message for the out-of-bounds case.
+    pub fn check_ptr_access_align(
         &self,
         sptr: Scalar<M::PointerTag>,
         size: Size,
         align: Option<Align>,
+        msg: CheckInAllocMsg,
     ) -> InterpResult<'tcx, Option<Pointer<M::PointerTag>>> {
         fn check_offset_align(offset: u64, align: Align) -> InterpResult<'static> {
             if offset % align.bytes() == 0 {
@@ -368,7 +370,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
                 // It is sufficient to check this for the end pointer. The addition
                 // checks for overflow.
                 let end_ptr = ptr.offset(size, self)?;
-                end_ptr.check_inbounds_alloc(allocation_size, CheckInAllocMsg::MemoryAccessTest)?;
+                end_ptr.check_inbounds_alloc(allocation_size, msg)?;
                 // Test align. Check this last; if both bounds and alignment are violated
                 // we want the error to be about the bounds.
                 if let Some(align) = align {