Auto merge of #77606 - JohnTitor:rollup-7rgahdt, r=JohnTitor

Rollup of 13 pull requests

Successful merges:

 - #76388 (Add a note about the panic behavior of math operations on time objects)
 - #76855 (Revamp rustdoc docs about documentation using `cfg`)
 - #76995 (Reduce boilerplate with the matches! macro)
 - #77228 (Add missing examples for MaybeUninit)
 - #77528 (Avoid unchecked casts in net parser)
 - #77534 (Disallow overriding forbid in same scope)
 - #77555 (Allow anyone to set regression labels)
 - #77558 (Rename bootstrap/defaults/{config.toml.PROFILE => config.PROFILE.toml})
 - #77559 (Fix rustdoc warnings about invalid Rust syntax)
 - #77560 (Fix LitKind's byte buffer to use refcounted slice)
 - #77573 (Hint doc use convert::identity relative link)
 - #77587 (Fix span for unicode escape suggestion.)
 - #77591 (Record `expansion_that_defined` into crate metadata)

Failed merges:

r? `@ghost`

Author: bors

compiler/rustc_ast/src/ast.rs

@@ -1606,7 +1606,7 @@ pub enum LitKind {
     /// A string literal (`"foo"`).
     Str(Symbol, StrStyle),
     /// A byte string (`b"foo"`).
-    ByteStr(Lrc<Vec<u8>>),
+    ByteStr(Lrc<[u8]>),
     /// A byte char (`b'f'`).
     Byte(u8),
     /// A character literal (`'a'`).

compiler/rustc_ast/src/util/literal.rs

@@ -4,7 +4,6 @@ use crate::ast::{self, Lit, LitKind};
 use crate::token::{self, Token};
 use crate::tokenstream::TokenTree;
 
-use rustc_data_structures::sync::Lrc;
 use rustc_lexer::unescape::{unescape_byte, unescape_char};
 use rustc_lexer::unescape::{unescape_byte_literal, unescape_literal, Mode};
 use rustc_span::symbol::{kw, sym, Symbol};
@@ -108,7 +107,7 @@ impl LitKind {
                 });
                 error?;
                 buf.shrink_to_fit();
-                LitKind::ByteStr(Lrc::new(buf))
+                LitKind::ByteStr(buf.into())
             }
             token::ByteStrRaw(_) => {
                 let s = symbol.as_str();
@@ -128,7 +127,7 @@ impl LitKind {
                     symbol.to_string().into_bytes()
                 };
 
-                LitKind::ByteStr(Lrc::new(bytes))
+                LitKind::ByteStr(bytes.into())
             }
             token::Err => LitKind::Err(symbol),
         })

compiler/rustc_builtin_macros/src/source_util.rs

@@ -13,8 +13,6 @@ use rustc_span::{self, Pos, Span};
 use smallvec::SmallVec;
 use std::rc::Rc;
 
-use rustc_data_structures::sync::Lrc;
-
 // These macros all relate to the file system; they either return
 // the column/row/filename of the expression, or they include
 // a given file into the current one.
@@ -216,7 +214,7 @@ pub fn expand_include_bytes(
         }
     };
     match cx.source_map().load_binary_file(&file) {
-        Ok(bytes) => base::MacEager::expr(cx.expr_lit(sp, ast::LitKind::ByteStr(Lrc::new(bytes)))),
+        Ok(bytes) => base::MacEager::expr(cx.expr_lit(sp, ast::LitKind::ByteStr(bytes.into()))),
         Err(e) => {
             cx.span_err(sp, &format!("couldn't read {}: {}", file.display(), e));
             DummyResult::any(sp)

compiler/rustc_lint/src/levels.rs

@@ -10,6 +10,7 @@ use rustc_hir as hir;
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
 use rustc_hir::{intravisit, HirId};
 use rustc_middle::hir::map::Map;
+use rustc_middle::lint::LevelSource;
 use rustc_middle::lint::LintDiagnosticBuilder;
 use rustc_middle::lint::{struct_lint_level, LintLevelMap, LintLevelSets, LintSet, LintSource};
 use rustc_middle::ty::query::Providers;
@@ -95,6 +96,44 @@ impl<'s> LintLevelsBuilder<'s> {
         self.sets.list.push(LintSet::CommandLine { specs });
     }
 
+    /// Attempts to insert the `id` to `level_src` map entry. If unsuccessful
+    /// (e.g. if a forbid was already inserted on the same scope), then emits a
+    /// diagnostic with no change to `specs`.
+    fn insert_spec(
+        &mut self,
+        specs: &mut FxHashMap<LintId, LevelSource>,
+        id: LintId,
+        (level, src): LevelSource,
+    ) {
+        if let Some((old_level, old_src)) = specs.get(&id) {
+            if old_level == &Level::Forbid && level != Level::Forbid {
+                let mut diag_builder = struct_span_err!(
+                    self.sess,
+                    src.span(),
+                    E0453,
+                    "{}({}) incompatible with previous forbid in same scope",
+                    level.as_str(),
+                    src.name(),
+                );
+                match *old_src {
+                    LintSource::Default => {}
+                    LintSource::Node(_, forbid_source_span, reason) => {
+                        diag_builder.span_label(forbid_source_span, "`forbid` level set here");
+                        if let Some(rationale) = reason {
+                            diag_builder.note(&rationale.as_str());
+                        }
+                    }
+                    LintSource::CommandLine(_) => {
+                        diag_builder.note("`forbid` lint level was set on command line");
+                    }
+                }
+                diag_builder.emit();
+                return;
+            }
+        }
+        specs.insert(id, (level, src));
+    }
+
     /// Pushes a list of AST lint attributes onto this context.
     ///
     /// This function will return a `BuilderPush` object which should be passed
@@ -109,7 +148,7 @@ impl<'s> LintLevelsBuilder<'s> {
     ///   `#[allow]`
     ///
     /// Don't forget to call `pop`!
-    pub fn push(
+    pub(crate) fn push(
         &mut self,
         attrs: &[ast::Attribute],
         store: &LintStore,
@@ -221,7 +260,7 @@ impl<'s> LintLevelsBuilder<'s> {
                         let src = LintSource::Node(name, li.span(), reason);
                         for &id in ids {
                             self.check_gated_lint(id, attr.span);
-                            specs.insert(id, (level, src));
+                            self.insert_spec(&mut specs, id, (level, src));
                         }
                     }
 
@@ -235,7 +274,7 @@ impl<'s> LintLevelsBuilder<'s> {
                                     reason,
                                 );
                                 for id in ids {
-                                    specs.insert(*id, (level, src));
+                                    self.insert_spec(&mut specs, *id, (level, src));
                                 }
                             }
                             Err((Some(ids), new_lint_name)) => {
@@ -272,7 +311,7 @@ impl<'s> LintLevelsBuilder<'s> {
                                     reason,
                                 );
                                 for id in ids {
-                                    specs.insert(*id, (level, src));
+                                    self.insert_spec(&mut specs, *id, (level, src));
                                 }
                             }
                             Err((None, _)) => {

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -1011,6 +1011,10 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
         self.root.tables.impl_trait_ref.get(self, id).map(|tr| tr.decode((self, tcx)))
     }
 
+    fn get_expn_that_defined(&self, id: DefIndex, sess: &Session) -> ExpnId {
+        self.root.tables.expn_that_defined.get(self, id).unwrap().decode((self, sess))
+    }
+
     /// Iterates over all the stability attributes in the given crate.
     fn get_lib_features(&self, tcx: TyCtxt<'tcx>) -> &'tcx [(Symbol, Option<Symbol>)] {
         // FIXME: For a proc macro crate, not sure whether we should return the "host"

compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs

@@ -238,6 +238,7 @@ provide! { <'tcx> tcx, def_id, other, cdata,
     }
 
     crate_extern_paths => { cdata.source().paths().cloned().collect() }
+    expn_that_defined => { cdata.get_expn_that_defined(def_id.index, tcx.sess) }
 }
 
 pub fn provide(providers: &mut Providers) {

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -747,6 +747,7 @@ impl EncodeContext<'a, 'tcx> {
             ty::Visibility::from_hir(enum_vis, enum_id, self.tcx));
         record!(self.tables.span[def_id] <- self.tcx.def_span(def_id));
         record!(self.tables.attributes[def_id] <- &self.tcx.get_attrs(def_id)[..]);
+        record!(self.tables.expn_that_defined[def_id] <- self.tcx.expansion_that_defined(def_id));
         record!(self.tables.children[def_id] <- variant.fields.iter().map(|f| {
             assert!(f.did.is_local());
             f.did.index
@@ -883,6 +884,7 @@ impl EncodeContext<'a, 'tcx> {
         record!(self.tables.visibility[def_id] <- field.vis);
         record!(self.tables.span[def_id] <- self.tcx.def_span(def_id));
         record!(self.tables.attributes[def_id] <- variant_data.fields()[field_index].attrs);
+        record!(self.tables.expn_that_defined[def_id] <- self.tcx.expansion_that_defined(def_id));
         self.encode_ident_span(def_id, field.ident);
         self.encode_stability(def_id);
         self.encode_deprecation(def_id);
@@ -924,6 +926,7 @@ impl EncodeContext<'a, 'tcx> {
         record!(self.tables.kind[def_id] <- EntryKind::Struct(self.lazy(data), adt_def.repr));
         record!(self.tables.visibility[def_id] <- ctor_vis);
         record!(self.tables.span[def_id] <- self.tcx.def_span(def_id));
+        record!(self.tables.expn_that_defined[def_id] <- self.tcx.expansion_that_defined(def_id));
         self.encode_stability(def_id);
         self.encode_deprecation(def_id);
         self.encode_item_type(def_id);
@@ -1339,6 +1342,7 @@ impl EncodeContext<'a, 'tcx> {
             ty::Visibility::from_hir(&item.vis, item.hir_id, tcx));
         record!(self.tables.span[def_id] <- self.tcx.def_span(def_id));
         record!(self.tables.attributes[def_id] <- item.attrs);
+        record!(self.tables.expn_that_defined[def_id] <- self.tcx.expansion_that_defined(def_id));
         // FIXME(eddyb) there should be a nicer way to do this.
         match item.kind {
             hir::ItemKind::ForeignMod(ref fm) => record!(self.tables.children[def_id] <-

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -294,6 +294,7 @@ define_tables! {
     variances: Table<DefIndex, Lazy<[ty::Variance]>>,
     generics: Table<DefIndex, Lazy<ty::Generics>>,
     explicit_predicates: Table<DefIndex, Lazy!(ty::GenericPredicates<'tcx>)>,
+    expn_that_defined: Table<DefIndex, Lazy<ExpnId>>,
     // FIXME(eddyb) this would ideally be `Lazy<[...]>` but `ty::Predicate`
     // doesn't handle shorthands in its own (de)serialization impls,
     // as it's an `enum` for which we want to derive (de)serialization,

compiler/rustc_middle/src/hir/map/mod.rs

@@ -535,15 +535,15 @@ impl<'hir> Map<'hir> {
             Some(Node::Binding(_)) => (),
             _ => return false,
         }
-        match self.find(self.get_parent_node(id)) {
+        matches!(
+            self.find(self.get_parent_node(id)),
             Some(
                 Node::Item(_)
                 | Node::TraitItem(_)
                 | Node::ImplItem(_)
                 | Node::Expr(Expr { kind: ExprKind::Closure(..), .. }),
-            ) => true,
-            _ => false,
-        }
+            )
+        )
     }
 
     /// Whether the expression pointed at by `hir_id` belongs to a `const` evaluation context.
@@ -554,10 +554,10 @@ impl<'hir> Map<'hir> {
 
     /// Whether `hir_id` corresponds to a `mod` or a crate.
     pub fn is_hir_id_module(&self, hir_id: HirId) -> bool {
-        match self.get_entry(hir_id).node {
-            Node::Item(Item { kind: ItemKind::Mod(_), .. }) | Node::Crate(..) => true,
-            _ => false,
-        }
+        matches!(
+            self.get_entry(hir_id).node,
+            Node::Item(Item { kind: ItemKind::Mod(_), .. }) | Node::Crate(..)
+        )
     }
 
     /// Retrieves the `HirId` for `id`'s enclosing method, unless there's a

compiler/rustc_middle/src/lint.rs

@@ -9,7 +9,7 @@ use rustc_session::lint::{builtin, Level, Lint, LintId};
 use rustc_session::{DiagnosticMessageId, Session};
 use rustc_span::hygiene::MacroKind;
 use rustc_span::source_map::{DesugaringKind, ExpnKind, MultiSpan};
-use rustc_span::{Span, Symbol};
+use rustc_span::{symbol, Span, Symbol, DUMMY_SP};
 
 /// How a lint level was set.
 #[derive(Clone, Copy, PartialEq, Eq, HashStable)]
@@ -25,6 +25,24 @@ pub enum LintSource {
     CommandLine(Symbol),
 }
 
+impl LintSource {
+    pub fn name(&self) -> Symbol {
+        match *self {
+            LintSource::Default => symbol::kw::Default,
+            LintSource::Node(name, _, _) => name,
+            LintSource::CommandLine(name) => name,
+        }
+    }
+
+    pub fn span(&self) -> Span {
+        match *self {
+            LintSource::Default => DUMMY_SP,
+            LintSource::Node(_, span, _) => span,
+            LintSource::CommandLine(_) => DUMMY_SP,
+        }
+    }
+}
+
 pub type LevelSource = (Level, LintSource);
 
 pub struct LintLevelSets {

compiler/rustc_middle/src/mir/interpret/mod.rs

@@ -486,10 +486,10 @@ impl<'tcx> TyCtxt<'tcx> {
         // `main as fn() == main as fn()` is false, while `let x = main as fn(); x == x` is true.
         // However, formatting code relies on function identity (see #58320), so we only do
         // this for generic functions.  Lifetime parameters are ignored.
-        let is_generic = instance.substs.into_iter().any(|kind| match kind.unpack() {
-            GenericArgKind::Lifetime(_) => false,
-            _ => true,
-        });
+        let is_generic = instance
+            .substs
+            .into_iter()
+            .any(|kind| !matches!(kind.unpack(), GenericArgKind::Lifetime(_)));
         if is_generic {
             // Get a fresh ID.
             let mut alloc_map = self.alloc_map.lock();

compiler/rustc_middle/src/mir/interpret/value.rs

@@ -445,19 +445,13 @@ impl<'tcx, Tag> Scalar<Tag> {
     /// Do not call this method!  Dispatch based on the type instead.
     #[inline]
     pub fn is_bits(self) -> bool {
-        match self {
-            Scalar::Raw { .. } => true,
-            _ => false,
-        }
+        matches!(self, Scalar::Raw { .. })
     }
 
     /// Do not call this method!  Dispatch based on the type instead.
     #[inline]
     pub fn is_ptr(self) -> bool {
-        match self {
-            Scalar::Ptr(_) => true,
-            _ => false,
-        }
+        matches!(self, Scalar::Ptr(_))
     }
 
     pub fn to_bool(self) -> InterpResult<'tcx, bool> {