Auto merge of #69507 - JohnTitor:rollup-jqf1gmw, r=JohnTitor

Rollup of 7 pull requests Successful merges: - #69324 (Backport only: avoid ICE on bad placeholder type) - #69439 (resolve: `lifetimes.rs` -> `late/lifetimes.rs`) - #69473 (update llvm to silence gcc 9 warnings) - #69479 (clarify operator precedence) - #69480 (Clean up E0373 explanation) - #69500 (Simplify the signature of par_for_each_in) - #69505 (Enable setting diagnostic labels) Failed merges: r? @ghost

Author: bors

src/libcore/hash/sip.rs

@@ -304,7 +304,7 @@ impl<S: Sip> super::Hasher for Hasher<S> {
 
  if self.ntail != 0 {
  needed = 8 - self.ntail;
- self.tail |= unsafe { u8to64_le(msg, 0, cmp::min(length, needed)) } << 8 * self.ntail;
+ self.tail |= unsafe { u8to64_le(msg, 0, cmp::min(length, needed)) } << (8 * self.ntail);
  if length < needed {
  self.ntail += length;
  return;

src/librustc/ty/query/on_disk_cache.rs

@@ -997,7 +997,7 @@ impl SpecializedEncoder<IntEncodedWithFixedSize> for opaque::Encoder {
  fn specialized_encode(&mut self, x: &IntEncodedWithFixedSize) -> Result<(), Self::Error> {
  let start_pos = self.position();
  for i in 0..IntEncodedWithFixedSize::ENCODED_SIZE {
- ((x.0 >> i * 8) as u8).encode(self)?;
+ ((x.0 >> (i * 8)) as u8).encode(self)?;
  }
  let end_pos = self.position();
  assert_eq!((end_pos - start_pos), IntEncodedWithFixedSize::ENCODED_SIZE);

src/librustc_data_structures/sip128.rs

@@ -274,7 +274,7 @@ impl Hasher for SipHasher128 {
 
  if self.ntail != 0 {
  needed = 8 - self.ntail;
- self.tail |= unsafe { u8to64_le(msg, 0, cmp::min(length, needed)) } << 8 * self.ntail;
+ self.tail |= unsafe { u8to64_le(msg, 0, cmp::min(length, needed)) } << (8 * self.ntail);
  if length < needed {
  self.ntail += length;
  return;

src/librustc_data_structures/sync.rs

@@ -203,11 +203,7 @@ cfg_if! {
  t.into_iter()
  }
 
- pub fn par_for_each_in<T: IntoIterator>(
- t: T,
- for_each:
- impl Fn(<<T as IntoIterator>::IntoIter as Iterator>::Item) + Sync + Send
- ) {
+ pub fn par_for_each_in<T: IntoIterator>(t: T, for_each: impl Fn(T::Item) + Sync + Send) {
  // We catch panics here ensuring that all the loop iterations execute.
  // This makes behavior consistent with the parallel compiler.
  let mut panic = None;
@@ -397,9 +393,7 @@ cfg_if! {
 
  pub fn par_for_each_in<T: IntoParallelIterator>(
  t: T,
- for_each: impl Fn(
- <<T as IntoParallelIterator>::Iter as ParallelIterator>::Item
- ) + Sync + Send
+ for_each: impl Fn(T::Item) + Sync + Send,
  ) {
  t.into_par_iter().for_each(for_each)
  }

src/librustc_error_codes/error_codes/E0373.md

@@ -1,6 +1,6 @@
-This error occurs when an attempt is made to use data captured by a closure,
-when that data may no longer exist. It's most commonly seen when attempting to
-return a closure:
+A captured variable in a closure may not live long enough.
+
+Erroneous code example:
 
 ```compile_fail,E0373
 fn foo() -> Box<Fn(u32) -> u32> {
@@ -9,6 +9,10 @@ fn foo() -> Box<Fn(u32) -> u32> {
 }
 ```
 
+This error occurs when an attempt is made to use data captured by a closure,
+when that data may no longer exist. It's most commonly seen when attempting to
+return a closure as shown in the previous code example.
+
 Notice that `x` is stack-allocated by `foo()`. By default, Rust captures
 closed-over data by reference. This means that once `foo()` returns, `x` no
 longer exists. An attempt to access `x` within the closure would thus be

src/librustc_resolve/diagnostics.rs

@@ -6,9 +6,8 @@ use rustc::session::Session;
 use rustc::ty::{self, DefIdTree};
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashSet;
-use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticBuilder};
+use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
 use rustc_feature::BUILTIN_ATTRIBUTES;
-use rustc_hir as hir;
 use rustc_hir::def::Namespace::{self, *};
 use rustc_hir::def::{self, CtorKind, CtorOf, DefKind, NonMacroAttrKind};
 use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
@@ -20,7 +19,6 @@ use syntax::ast::{self, Ident, Path};
 use syntax::util::lev_distance::find_best_match_for_name;
 
 use crate::imports::{ImportDirective, ImportDirectiveSubclass, ImportResolver};
-use crate::lifetimes::{ElisionFailureInfo, LifetimeContext};
 use crate::path_names_to_string;
 use crate::{AmbiguityError, AmbiguityErrorMisc, AmbiguityKind};
 use crate::{BindingError, CrateLint, HasGenericParams, LegacyScope, Module, ModuleOrUniformRoot};
@@ -49,40 +47,6 @@ crate struct ImportSuggestion {
  pub path: Path,
 }
 
-crate enum MissingLifetimeSpot<'tcx> {
- Generics(&'tcx hir::Generics<'tcx>),
- HigherRanked { span: Span, span_type: ForLifetimeSpanType },
-}
-
-crate enum ForLifetimeSpanType {
- BoundEmpty,
- BoundTail,
- TypeEmpty,
- TypeTail,
-}
-
-impl ForLifetimeSpanType {
- crate fn descr(&self) -> &'static str {
- match self {
- Self::BoundEmpty | Self::BoundTail => "bound",
- Self::TypeEmpty | Self::TypeTail => "type",
- }
- }
-
- crate fn suggestion(&self, sugg: &str) -> String {
- match self {
- Self::BoundEmpty | Self::TypeEmpty => format!("for<{}> ", sugg),
- Self::BoundTail | Self::TypeTail => format!(", {}", sugg),
- }
- }
-}
-
-impl<'tcx> Into<MissingLifetimeSpot<'tcx>> for &'tcx hir::Generics<'tcx> {
- fn into(self) -> MissingLifetimeSpot<'tcx> {
- MissingLifetimeSpot::Generics(self)
- }
-}
-
 /// Adjust the impl span so that just the `impl` keyword is taken by removing
 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`).
@@ -1491,208 +1455,3 @@ crate fn show_candidates(
  err.note(&msg);
  }
 }
-
-impl<'tcx> LifetimeContext<'_, 'tcx> {
- crate fn report_missing_lifetime_specifiers(
- &self,
- span: Span,
- count: usize,
- ) -> DiagnosticBuilder<'tcx> {
- struct_span_err!(
- self.tcx.sess,
- span,
- E0106,
- "missing lifetime specifier{}",
- pluralize!(count)
- )
- }
-
- crate fn emit_undeclared_lifetime_error(&self, lifetime_ref: &hir::Lifetime) {
- let mut err = struct_span_err!(
- self.tcx.sess,
- lifetime_ref.span,
- E0261,
- "use of undeclared lifetime name `{}`",
- lifetime_ref
- );
- err.span_label(lifetime_ref.span, "undeclared lifetime");
- for missing in &self.missing_named_lifetime_spots {
- match missing {
- MissingLifetimeSpot::Generics(generics) => {
- let (span, sugg) = if let Some(param) = generics
- .params
- .iter()
- .filter(|p| match p.kind {
- hir::GenericParamKind::Type {
- synthetic: Some(hir::SyntheticTyParamKind::ImplTrait),
- ..
- } => false,
- _ => true,
- })
- .next()
- {
- (param.span.shrink_to_lo(), format!("{}, ", lifetime_ref))
- } else {
- (generics.span, format!("<{}>", lifetime_ref))
- };
- err.span_suggestion(
- span,
- &format!("consider introducing lifetime `{}` here", lifetime_ref),
- sugg,
- Applicability::MaybeIncorrect,
- );
- }
- MissingLifetimeSpot::HigherRanked { span, span_type } => {
- err.span_suggestion(
- *span,
- &format!(
- "consider making the {} lifetime-generic with a new `{}` lifetime",
- span_type.descr(),
- lifetime_ref
- ),
- span_type.suggestion(&lifetime_ref.to_string()),
- Applicability::MaybeIncorrect,
- );
- err.note(
- "for more information on higher-ranked polymorphism, visit \
- https://doc.rust-lang.org/nomicon/hrtb.html",
- );
- }
- }
- }
- err.emit();
- }
-
- crate fn is_trait_ref_fn_scope(&mut self, trait_ref: &'tcx hir::PolyTraitRef<'tcx>) -> bool {
- if let def::Res::Def(_, did) = trait_ref.trait_ref.path.res {
- if [
- self.tcx.lang_items().fn_once_trait(),
- self.tcx.lang_items().fn_trait(),
- self.tcx.lang_items().fn_mut_trait(),
- ]
- .contains(&Some(did))
- {
- let (span, span_type) = match &trait_ref.bound_generic_params {
- [] => (trait_ref.span.shrink_to_lo(), ForLifetimeSpanType::BoundEmpty),
- [.., bound] => (bound.span.shrink_to_hi(), ForLifetimeSpanType::BoundTail),
- };
- self.missing_named_lifetime_spots
- .push(MissingLifetimeSpot::HigherRanked { span, span_type });
- return true;
- }
- };
- false
- }
-
- crate fn add_missing_lifetime_specifiers_label(
- &self,
- err: &mut DiagnosticBuilder<'_>,
- span: Span,
- count: usize,
- lifetime_names: &FxHashSet<ast::Ident>,
- params: &[ElisionFailureInfo],
- ) {
- if count > 1 {
- err.span_label(span, format!("expected {} lifetime parameters", count));
- } else {
- let snippet = self.tcx.sess.source_map().span_to_snippet(span).ok();
- let suggest_existing = |err: &mut DiagnosticBuilder<'_>, sugg| {
- err.span_suggestion(
- span,
- "consider using the named lifetime",
- sugg,
- Applicability::MaybeIncorrect,
- );
- };
- let suggest_new =
- |err: &mut DiagnosticBuilder<'_>, sugg: &str| {
- err.span_label(span, "expected named lifetime parameter");
-
- for missing in self.missing_named_lifetime_spots.iter().rev() {
- let mut introduce_suggestion = vec![];
- let msg;
- let should_break;
- introduce_suggestion.push(match missing {
- MissingLifetimeSpot::Generics(generics) => {
- msg = "consider introducing a named lifetime parameter".to_string();
- should_break = true;
- if let Some(param) = generics.params.iter().filter(|p| match p.kind {
- hir::GenericParamKind::Type {
- synthetic: Some(hir::SyntheticTyParamKind::ImplTrait),
- ..
- } => false,
- _ => true,
- }).next() {
- (param.span.shrink_to_lo(), "'a, ".to_string())
- } else {
- (generics.span, "<'a>".to_string())
- }
- }
- MissingLifetimeSpot::HigherRanked { span, span_type } => {
- msg = format!(
- "consider making the {} lifetime-generic with a new `'a` lifetime",
- span_type.descr(),
- );
- should_break = false;
- err.note(
- "for more information on higher-ranked polymorphism, visit \
- https://doc.rust-lang.org/nomicon/hrtb.html",
- );
- (*span, span_type.suggestion("'a"))
- }
- });
- for param in params {
- if let Ok(snippet) =
- self.tcx.sess.source_map().span_to_snippet(param.span)
- {
- if snippet.starts_with("&") && !snippet.starts_with("&'") {
- introduce_suggestion
- .push((param.span, format!("&'a {}", &snippet[1..])));
- } else if snippet.starts_with("&'_ ") {
- introduce_suggestion
- .push((param.span, format!("&'a {}", &snippet[4..])));
- }
- }
- }
- introduce_suggestion.push((span, sugg.to_string()));
- err.multipart_suggestion(
- &msg,
- introduce_suggestion,
- Applicability::MaybeIncorrect,
- );
- if should_break {
- break;
- }
- }
- };
-
- match (
- lifetime_names.len(),
- lifetime_names.iter().next(),
- snippet.as_ref().map(|s| s.as_str()),
- ) {
- (1, Some(name), Some("&")) => {
- suggest_existing(err, format!("&{} ", name));
- }
- (1, Some(name), Some("'_")) => {
- suggest_existing(err, name.to_string());
- }
- (1, Some(name), Some(snippet)) if !snippet.ends_with(">") => {
- suggest_existing(err, format!("{}<{}>", snippet, name));
- }
- (0, _, Some("&")) => {
- suggest_new(err, "&'a ");
- }
- (0, _, Some("'_")) => {
- suggest_new(err, "'a");
- }
- (0, _, Some(snippet)) if !snippet.ends_with(">") => {
- suggest_new(err, &format!("{}<'a>", snippet));
- }
- _ => {
- err.span_label(span, "expected lifetime parameter");
- }
- }
- }
- }
-}

src/librustc_resolve/late.rs

@@ -32,6 +32,7 @@ use std::collections::BTreeSet;
 use std::mem::replace;
 
 mod diagnostics;
+crate mod lifetimes;
 
 type Res = def::Res<NodeId>;