Rollup of 5 pull requests

src/libcore/future/future.rs

@@ -21,7 +21,7 @@ use crate::task::{Context, Poll};
 /// task.
 ///
 /// When using a future, you generally won't call `poll` directly, but instead
-/// `await!` the value.
+/// `.await` the value.
 #[doc(spotlight)]
 #[must_use = "futures do nothing unless you `.await` or poll them"]
 #[stable(feature = "futures_api", since = "1.36.0")]

src/libcore/macros.rs

@@ -445,9 +445,10 @@ macro_rules! writeln {
 /// * Iterators that dynamically terminate.
 ///
 /// 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 compiler to
-/// optimize the code out of the release version entirely.
+/// program immediately terminates with a [`panic!`].
+///
+/// The unsafe counterpart of this macro is the [`unreachable_unchecked`] function, which
+/// will cause undefined behavior if the code is reached.
 ///
 /// [`panic!`]:  ../std/macro.panic.html
 /// [`unreachable_unchecked`]: ../std/hint/fn.unreachable_unchecked.html

src/librustc/lint/context.rs

@@ -759,35 +759,35 @@ impl<'a, 'tcx> LateContext<'a, 'tcx> {
     /// # Examples
     ///
     /// ```rust,ignore (no context or def id available)
-    /// if cx.match_def_path(def_id, &["core", "option", "Option"]) {
+    /// if cx.match_def_path(def_id, &[sym::core, sym::option, sym::Option]) {
     ///     // The given `def_id` is that of an `Option` type
     /// }
     /// ```
-    pub fn match_def_path(&self, def_id: DefId, path: &[&str]) -> bool {
+    pub fn match_def_path(&self, def_id: DefId, path: &[Symbol]) -> bool {
         let names = self.get_def_path(def_id);
 
-        names.len() == path.len() && names.into_iter().zip(path.iter()).all(|(a, &b)| *a == *b)
+        names.len() == path.len() && names.into_iter().zip(path.iter()).all(|(a, &b)| a == b)
     }
 
-    /// Gets the absolute path of `def_id` as a vector of `&str`.
+    /// Gets the absolute path of `def_id` as a vector of `Symbol`.
     ///
     /// # Examples
     ///
     /// ```rust,ignore (no context or def id available)
     /// let def_path = cx.get_def_path(def_id);
-    /// if let &["core", "option", "Option"] = &def_path[..] {
+    /// if let &[sym::core, sym::option, sym::Option] = &def_path[..] {
     ///     // The given `def_id` is that of an `Option` type
     /// }
     /// ```
-    pub fn get_def_path(&self, def_id: DefId) -> Vec<LocalInternedString> {
+    pub fn get_def_path(&self, def_id: DefId) -> Vec<Symbol> {
         pub struct AbsolutePathPrinter<'a, 'tcx> {
             pub tcx: TyCtxt<'a, 'tcx, 'tcx>,
         }
 
         impl<'tcx> Printer<'tcx, 'tcx> for AbsolutePathPrinter<'_, 'tcx> {
             type Error = !;
 
-            type Path = Vec<LocalInternedString>;
+            type Path = Vec<Symbol>;
             type Region = ();
             type Type = ();
             type DynExistential = ();
@@ -820,14 +820,14 @@ impl<'a, 'tcx> LateContext<'a, 'tcx> {
             }
 
             fn path_crate(self, cnum: CrateNum) -> Result<Self::Path, Self::Error> {
-                Ok(vec![self.tcx.original_crate_name(cnum).as_str()])
+                Ok(vec![self.tcx.original_crate_name(cnum)])
             }
 
             fn path_qualified(
                 self,
                 self_ty: Ty<'tcx>,
                 trait_ref: Option<ty::TraitRef<'tcx>>,
-                ) -> Result<Self::Path, Self::Error> {
+            ) -> Result<Self::Path, Self::Error> {
                 if trait_ref.is_none() {
                     if let ty::Adt(def, substs) = self_ty.sty {
                         return self.print_def_path(def.did, substs);
@@ -836,8 +836,8 @@ impl<'a, 'tcx> LateContext<'a, 'tcx> {
 
                 // This shouldn't ever be needed, but just in case:
                 Ok(vec![match trait_ref {
-                    Some(trait_ref) => LocalInternedString::intern(&format!("{:?}", trait_ref)),
-                    None => LocalInternedString::intern(&format!("<{}>", self_ty)),
+                    Some(trait_ref) => Symbol::intern(&format!("{:?}", trait_ref)),
+                    None => Symbol::intern(&format!("<{}>", self_ty)),
                 }])
             }
 
@@ -847,16 +847,16 @@ impl<'a, 'tcx> LateContext<'a, 'tcx> {
                 _disambiguated_data: &DisambiguatedDefPathData,
                 self_ty: Ty<'tcx>,
                 trait_ref: Option<ty::TraitRef<'tcx>>,
-                ) -> Result<Self::Path, Self::Error> {
+            ) -> Result<Self::Path, Self::Error> {
                 let mut path = print_prefix(self)?;
 
                 // This shouldn't ever be needed, but just in case:
                 path.push(match trait_ref {
                     Some(trait_ref) => {
-                        LocalInternedString::intern(&format!("<impl {} for {}>", trait_ref,
+                        Symbol::intern(&format!("<impl {} for {}>", trait_ref,
                                                     self_ty))
                     },
-                    None => LocalInternedString::intern(&format!("<impl {}>", self_ty)),
+                    None => Symbol::intern(&format!("<impl {}>", self_ty)),
                 });
 
                 Ok(path)
@@ -866,7 +866,7 @@ impl<'a, 'tcx> LateContext<'a, 'tcx> {
                 self,
                 print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
                 disambiguated_data: &DisambiguatedDefPathData,
-                ) -> Result<Self::Path, Self::Error> {
+            ) -> Result<Self::Path, Self::Error> {
                 let mut path = print_prefix(self)?;
 
                 // Skip `::{{constructor}}` on tuple/unit structs.
@@ -875,15 +875,15 @@ impl<'a, 'tcx> LateContext<'a, 'tcx> {
                     _ => {}
                 }
 
-                path.push(disambiguated_data.data.as_interned_str().as_str());
+                path.push(disambiguated_data.data.as_interned_str().as_symbol());
                 Ok(path)
             }
 
             fn path_generic_args(
                 self,
                 print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
                 _args: &[Kind<'tcx>],
-                ) -> Result<Self::Path, Self::Error> {
+            ) -> Result<Self::Path, Self::Error> {
                 print_prefix(self)
             }
         }

src/librustc/lint/internal.rs

@@ -8,6 +8,7 @@ use crate::lint::{
 use errors::Applicability;
 use rustc_data_structures::fx::FxHashMap;
 use syntax::ast::Ident;
+use syntax::symbol::{sym, Symbol};
 
 declare_lint! {
     pub DEFAULT_HASH_TYPES,
@@ -16,14 +17,16 @@ declare_lint! {
 }
 
 pub struct DefaultHashTypes {
-    map: FxHashMap<String, String>,
+    map: FxHashMap<Symbol, Symbol>,
 }
 
 impl DefaultHashTypes {
+    // we are allowed to use `HashMap` and `HashSet` as identifiers for implementing the lint itself
+    #[allow(internal)]
     pub fn new() -> Self {
         let mut map = FxHashMap::default();
-        map.insert("HashMap".to_string(), "FxHashMap".to_string());
-        map.insert("HashSet".to_string(), "FxHashSet".to_string());
+        map.insert(sym::HashMap, sym::FxHashMap);
+        map.insert(sym::HashSet, sym::FxHashSet);
         Self { map }
     }
 }
@@ -32,11 +35,10 @@ impl_lint_pass!(DefaultHashTypes => [DEFAULT_HASH_TYPES]);
 
 impl EarlyLintPass for DefaultHashTypes {
     fn check_ident(&mut self, cx: &EarlyContext<'_>, ident: Ident) {
-        let ident_string = ident.to_string();
-        if let Some(replace) = self.map.get(&ident_string) {
+        if let Some(replace) = self.map.get(&ident.name) {
             let msg = format!(
                 "Prefer {} over {}, it has better performance",
-                replace, ident_string
+                replace, ident
             );
             let mut db = cx.struct_span_lint(DEFAULT_HASH_TYPES, ident.span, &msg);
             db.span_suggestion(
@@ -169,25 +171,29 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TyTyKind {
 }
 
 fn lint_ty_kind_usage(cx: &LateContext<'_, '_>, segment: &PathSegment) -> bool {
-    if segment.ident.as_str() == "TyKind" {
+    if segment.ident.name == sym::TyKind {
         if let Some(res) = segment.res {
             if let Some(did) = res.opt_def_id() {
-                return cx.match_def_path(did, &["rustc", "ty", "sty", "TyKind"]);
+                return cx.match_def_path(did, TYKIND_PATH);
             }
         }
     }
 
     false
 }
 
+const TYKIND_PATH: &[Symbol] = &[sym::rustc, sym::ty, sym::sty, sym::TyKind];
+const TY_PATH: &[Symbol] = &[sym::rustc, sym::ty, sym::Ty];
+const TYCTXT_PATH: &[Symbol] = &[sym::rustc, sym::ty, sym::context, sym::TyCtxt];
+
 fn is_ty_or_ty_ctxt(cx: &LateContext<'_, '_>, ty: &Ty) -> Option<String> {
     match &ty.node {
         TyKind::Path(qpath) => {
             if let QPath::Resolved(_, path) = qpath {
                 let did = path.res.opt_def_id()?;
-                if cx.match_def_path(did, &["rustc", "ty", "Ty"]) {
+                if cx.match_def_path(did, TY_PATH) {
                     return Some(format!("Ty{}", gen_args(path.segments.last().unwrap())));
-                } else if cx.match_def_path(did, &["rustc", "ty", "context", "TyCtxt"]) {
+                } else if cx.match_def_path(did, TYCTXT_PATH) {
                     return Some(format!("TyCtxt{}", gen_args(path.segments.last().unwrap())));
                 }
             }

src/librustc/lint/levels.rs

@@ -191,7 +191,7 @@ impl<'a> LintLevelsBuilder<'a> {
         let store = self.sess.lint_store.borrow();
         let sess = self.sess;
         let bad_attr = |span| {
-            struct_span_err!(sess, span, E0452, "malformed lint attribute")
+            struct_span_err!(sess, span, E0452, "malformed lint attribute input")
         };
         for attr in attrs {
             let level = match Level::from_symbol(attr.name_or_empty()) {
@@ -238,18 +238,20 @@ impl<'a> LintLevelsBuilder<'a> {
                                 }
                                 reason = Some(rationale);
                             } else {
-                                let mut err = bad_attr(name_value.span);
-                                err.help("reason must be a string literal");
-                                err.emit();
+                                bad_attr(name_value.span)
+                                    .span_label(name_value.span, "reason must be a string literal")
+                                    .emit();
                             }
                         } else {
-                            let mut err = bad_attr(item.span);
-                            err.emit();
+                            bad_attr(item.span)
+                                .span_label(item.span, "bad attribute argument")
+                                .emit();
                         }
                     },
                     ast::MetaItemKind::List(_) => {
-                        let mut err = bad_attr(item.span);
-                        err.emit();
+                        bad_attr(item.span)
+                            .span_label(item.span, "bad attribute argument")
+                            .emit();
                     }
                 }
             }
@@ -258,14 +260,20 @@ impl<'a> LintLevelsBuilder<'a> {
                 let meta_item = match li.meta_item() {
                     Some(meta_item) if meta_item.is_word() => meta_item,
                     _ => {
-                        let mut err = bad_attr(li.span());
+                        let sp = li.span();
+                        let mut err = bad_attr(sp);
+                        let mut add_label = true;
                         if let Some(item) = li.meta_item() {
                             if let ast::MetaItemKind::NameValue(_) = item.node {
                                 if item.path == sym::reason {
-                                    err.help("reason in lint attribute must come last");
+                                    err.span_label(sp, "reason in lint attribute must come last");
+                                    add_label = false;
                                 }
                             }
                         }
+                        if add_label {
+                            err.span_label(sp, "bad attribute argument");
+                        }
                         err.emit();
                         continue;
                     }
@@ -318,15 +326,14 @@ impl<'a> LintLevelsBuilder<'a> {
                                      Also `cfg_attr(cargo-clippy)` won't be necessary anymore",
                                     name
                                 );
-                                let mut err = lint::struct_lint_level(
+                                lint::struct_lint_level(
                                     self.sess,
                                     lint,
                                     lvl,
                                     src,
                                     Some(li.span().into()),
                                     &msg,
-                                );
-                                err.span_suggestion(
+                                ).span_suggestion(
                                     li.span(),
                                     "change it to",
                                     new_lint_name.to_string(),

src/librustc/mir/interpret/allocation.rs

@@ -7,7 +7,7 @@ use super::{
 
 use crate::ty::layout::{Size, Align};
 use syntax::ast::Mutability;
-use std::iter;
+use std::{iter, fmt::{self, Display}};
 use crate::mir;
 use std::ops::{Deref, DerefMut};
 use rustc_data_structures::sorted_map::SortedMap;
@@ -22,6 +22,28 @@ pub enum InboundsCheck {
     MaybeDead,
 }
 
+/// Used by `check_in_alloc` to indicate context of check
+#[derive(Debug, Copy, Clone, RustcEncodable, RustcDecodable, HashStable)]
+pub enum CheckInAllocMsg {
+    MemoryAccessTest,
+    NullPointerTest,
+    PointerArithmeticTest,
+    InboundsTest,
+}
+
+impl Display for CheckInAllocMsg {
+    /// When this is printed as an error the context looks like this
+    /// "{test name} failed: pointer must be in-bounds at offset..."
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", match *self {
+            CheckInAllocMsg::MemoryAccessTest => "Memory access",
+            CheckInAllocMsg::NullPointerTest => "Null pointer test",
+            CheckInAllocMsg::PointerArithmeticTest => "Pointer arithmetic",
+            CheckInAllocMsg::InboundsTest => "Inbounds test",
+        })
+    }
+}
+
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
 pub struct Allocation<Tag=(),Extra=()> {
     /// The actual bytes of the allocation.
@@ -131,9 +153,10 @@ impl<'tcx, Tag, Extra> Allocation<Tag, Extra> {
     fn check_bounds_ptr(
         &self,
         ptr: Pointer<Tag>,
+        msg: CheckInAllocMsg,
     ) -> EvalResult<'tcx> {
         let allocation_size = self.bytes.len() as u64;
-        ptr.check_in_alloc(Size::from_bytes(allocation_size), InboundsCheck::Live)
+        ptr.check_in_alloc(Size::from_bytes(allocation_size), msg)
     }
 
     /// Checks if the memory range beginning at `ptr` and of size `Size` is "in-bounds".
@@ -143,9 +166,10 @@ impl<'tcx, Tag, Extra> Allocation<Tag, Extra> {
         cx: &impl HasDataLayout,
         ptr: Pointer<Tag>,
         size: Size,
+        msg: CheckInAllocMsg,
     ) -> EvalResult<'tcx> {
         // if ptr.offset is in bounds, then so is ptr (because offset checks for overflow)
-        self.check_bounds_ptr(ptr.offset(size, cx)?)
+        self.check_bounds_ptr(ptr.offset(size, cx)?, msg)
     }
 }
 
@@ -164,9 +188,10 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
         ptr: Pointer<Tag>,
         size: Size,
         check_defined_and_ptr: bool,
+        msg: CheckInAllocMsg,
     ) -> EvalResult<'tcx, &[u8]>
     {
-        self.check_bounds(cx, ptr, size)?;
+        self.check_bounds(cx, ptr, size, msg)?;
 
         if check_defined_and_ptr {
             self.check_defined(ptr, size)?;
@@ -192,7 +217,7 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
         size: Size,
     ) -> EvalResult<'tcx, &[u8]>
     {
-        self.get_bytes_internal(cx, ptr, size, true)
+        self.get_bytes_internal(cx, ptr, size, true, CheckInAllocMsg::MemoryAccessTest)
     }
 
     /// It is the caller's responsibility to handle undefined and pointer bytes.
@@ -205,7 +230,7 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
         size: Size,
     ) -> EvalResult<'tcx, &[u8]>
     {
-        self.get_bytes_internal(cx, ptr, size, false)
+        self.get_bytes_internal(cx, ptr, size, false, CheckInAllocMsg::MemoryAccessTest)
     }
 
     /// Just calling this already marks everything as defined and removes relocations,
@@ -218,7 +243,7 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
     ) -> EvalResult<'tcx, &mut [u8]>
     {
         assert_ne!(size.bytes(), 0, "0-sized accesses should never even get a `Pointer`");
-        self.check_bounds(cx, ptr, size)?;
+        self.check_bounds(cx, ptr, size, CheckInAllocMsg::MemoryAccessTest)?;
 
         self.mark_definedness(ptr, size, true)?;
         self.clear_relocations(cx, ptr, size)?;