Auto merge of #78270 - JohnTitor:rollup-bldrjh5, r=JohnTitor

Rollup of 17 pull requests

Successful merges:

 - #77268 (Link to "Contributing to Rust" rather than "Getting Started".)
 - #77339 (Implement TryFrom between NonZero types.)
 - #77488 (Mark `repr128` as `incomplete_features`)
 - #77890 (Fixing escaping to ensure generation of welformed json.)
 - #77918 (Cleanup network tests)
 - #77920 (Avoid extraneous space between visibility kw and ident for statics)
 - #77969 (Doc formating consistency between slice sort and sort_unstable, and big O notation consistency)
 - #78098 (Clean up and improve some docs)
 - #78116 (Make inline const work in range patterns)
 - #78153 (Sync LLVM submodule if it has been initialized)
 - #78163 (Clean up lib docs)
 - #78169 (Update cargo)
 - #78231 (Make closures inherit the parent function's target features)
 - #78235 (Explain where the closure return type was inferred)
 - #78255 (Reduce diagram mess in 'match arms have incompatible types' error)
 - #78263 (Add regression test of issue-77668)
 - #78265 (Add some inference-related regression tests about incorrect diagnostics)

Failed merges:

r? `@ghost`

CONTRIBUTING.md

@@ -2,14 +2,14 @@
 
 Thank you for your interest in contributing to Rust!
 
-To get started, read the [Getting Started] guide in the [rustc-dev-guide].
+To get started, read the [Contributing to Rust] chapter of the [rustc-dev-guide].
 
 ## Bug reports
 
 Did a compiler error message tell you to come here? If you want to create an ICE report,
 refer to [this section][contributing-bug-reports] and [open an issue][issue template].
 
-[Getting Started]: https://rustc-dev-guide.rust-lang.org/getting-started.html
+[Contributing to Rust]: https://rustc-dev-guide.rust-lang.org/contributing.html#contributing-to-rust
 [rustc-dev-guide]: https://rustc-dev-guide.rust-lang.org/
 [contributing-bug-reports]: https://rustc-dev-guide.rust-lang.org/contributing.html#bug-reports
 [issue template]: https://github.com/rust-lang/rust/issues/new/choose

Cargo.lock

@@ -310,7 +310,7 @@ dependencies = [
  "crypto-hash",
  "curl",
  "curl-sys",
- "env_logger 0.7.1",
+ "env_logger 0.8.1",
  "filetime",
  "flate2",
  "fwdansi",
@@ -1035,6 +1035,19 @@ dependencies = [
  "termcolor",
 ]
 
+[[package]]
+name = "env_logger"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "54532e3223c5af90a6a757c90b5c5521564b07e5e7a958681bcd2afad421cdcd"
+dependencies = [
+ "atty",
+ "humantime 2.0.1",
+ "log",
+ "regex",
+ "termcolor",
+]
+
 [[package]]
 name = "error_index_generator"
 version = "0.0.0"

compiler/rustc_feature/src/active.rs

@@ -622,6 +622,7 @@ pub const INCOMPLETE_FEATURES: &[Symbol] = &[
     sym::lazy_normalization_consts,
     sym::specialization,
     sym::inline_const,
+    sym::repr128,
 ];
 
 /// Some features are not allowed to be used together at the same time, if

compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -619,6 +619,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 scrut_hir_id,
                 opt_suggest_box_span,
                 arm_span,
+                scrut_span,
                 ..
             }) => match source {
                 hir::MatchSource::IfLetDesugar { .. } => {
@@ -664,18 +665,29 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                         Some(ty::error::ExpectedFound { expected, .. }) => expected,
                         _ => last_ty,
                     });
-                    let msg = "`match` arms have incompatible types";
-                    err.span_label(cause.span, msg);
+                    let source_map = self.tcx.sess.source_map();
+                    let mut any_multiline_arm = source_map.is_multiline(arm_span);
                     if prior_arms.len() <= 4 {
                         for sp in prior_arms {
+                            any_multiline_arm |= source_map.is_multiline(*sp);
                             err.span_label(*sp, format!("this is found to be of type `{}`", t));
                         }
                     } else if let Some(sp) = prior_arms.last() {
+                        any_multiline_arm |= source_map.is_multiline(*sp);
                         err.span_label(
                             *sp,
                             format!("this and all prior arms are found to be of type `{}`", t),
                         );
                     }
+                    let outer_error_span = if any_multiline_arm {
+                        // Cover just `match` and the scrutinee expression, not
+                        // the entire match body, to reduce diagram noise.
+                        cause.span.shrink_to_lo().to(scrut_span)
+                    } else {
+                        cause.span
+                    };
+                    let msg = "`match` arms have incompatible types";
+                    err.span_label(outer_error_span, msg);
                     if let Some(sp) = semi_span {
                         err.span_suggestion_short(
                             sp,

compiler/rustc_middle/src/middle/region.rs

@@ -292,20 +292,20 @@ pub struct ScopeTree {
     ///
     /// Then:
     ///
-    ///     1. From the ordering guarantee of HIR visitors (see
-    ///     `rustc_hir::intravisit`), `D` does not dominate `U`.
+    ///   1. From the ordering guarantee of HIR visitors (see
+    ///   `rustc_hir::intravisit`), `D` does not dominate `U`.
     ///
-    ///     2. Therefore, `D` is *potentially* storage-dead at `U` (because
-    ///     we might visit `U` without ever getting to `D`).
+    ///   2. Therefore, `D` is *potentially* storage-dead at `U` (because
+    ///   we might visit `U` without ever getting to `D`).
     ///
-    ///     3. However, we guarantee that at each HIR point, each
-    ///     binding/temporary is always either always storage-live
-    ///     or always storage-dead. This is what is being guaranteed
-    ///     by `terminating_scopes` including all blocks where the
-    ///     count of executions is not guaranteed.
+    ///   3. However, we guarantee that at each HIR point, each
+    ///   binding/temporary is always either always storage-live
+    ///   or always storage-dead. This is what is being guaranteed
+    ///   by `terminating_scopes` including all blocks where the
+    ///   count of executions is not guaranteed.
     ///
-    ///     4. By `2.` and `3.`, `D` is *statically* storage-dead at `U`,
-    ///     QED.
+    ///   4. By `2.` and `3.`, `D` is *statically* storage-dead at `U`,
+    ///   QED.
     ///
     /// This property ought to not on (3) in an essential way -- it
     /// is probably still correct even if we have "unrestricted" terminating

compiler/rustc_middle/src/traits/mod.rs

@@ -343,6 +343,7 @@ static_assert_size!(ObligationCauseCode<'_>, 32);
 #[derive(Clone, Debug, PartialEq, Eq, Hash, Lift)]
 pub struct MatchExpressionArmCause<'tcx> {
     pub arm_span: Span,
+    pub scrut_span: Span,
     pub semi_span: Option<Span>,
     pub source: hir::MatchSource,
     pub prior_arms: Vec<Span>,

compiler/rustc_mir_build/src/thir/pattern/_match.rs

@@ -78,20 +78,26 @@
 //! new pattern `p`.
 //!
 //! For example, say we have the following:
+//!
 //! ```
-//!     // x: (Option<bool>, Result<()>)
-//!     match x {
-//!         (Some(true), _) => {}
-//!         (None, Err(())) => {}
-//!         (None, Err(_)) => {}
-//!     }
+//! // x: (Option<bool>, Result<()>)
+//! match x {
+//!     (Some(true), _) => {}
+//!     (None, Err(())) => {}
+//!     (None, Err(_)) => {}
+//! }
 //! ```
+//!
 //! Here, the matrix `P` starts as:
+//!
+//! ```
 //! [
 //!     [(Some(true), _)],
 //!     [(None, Err(()))],
 //!     [(None, Err(_))],
 //! ]
+//! ```
+//!
 //! We can tell it's not exhaustive, because `U(P, _)` is true (we're not covering
 //! `[(Some(false), _)]`, for instance). In addition, row 3 is not useful, because
 //! all the values it covers are already covered by row 2.
@@ -178,10 +184,14 @@
 //! This special case is handled in `is_useful_specialized`.
 //!
 //! For example, if `P` is:
+//!
+//! ```
 //! [
-//! [Some(true), _],
-//! [None, 0],
+//!     [Some(true), _],
+//!     [None, 0],
 //! ]
+//! ```
+//!
 //! and `p` is [Some(false), 0], then we don't care about row 2 since we know `p` only
 //! matches values that row 2 doesn't. For row 1 however, we need to dig into the
 //! arguments of `Some` to know whether some new value is covered. So we compute
@@ -198,10 +208,14 @@
 //! `U(P, p) := U(D(P), D(p))`
 //!
 //! For example, if `P` is:
+//!
+//! ```
 //! [
 //!     [_, true, _],
 //!     [None, false, 1],
 //! ]
+//! ```
+//!
 //! and `p` is [_, false, _], the `Some` constructor doesn't appear in `P`. So if we
 //! only had row 2, we'd know that `p` is useful. However row 1 starts with a
 //! wildcard, so we need to check whether `U([[true, _]], [false, 1])`.
@@ -215,10 +229,14 @@
 //! `U(P, p) := ∃(k ϵ constructors) U(S(k, P), S(k, p))`
 //!
 //! For example, if `P` is:
+//!
+//! ```
 //! [
 //!     [Some(true), _],
 //!     [None, false],
 //! ]
+//! ```
+//!
 //! and `p` is [_, false], both `None` and `Some` constructors appear in the first
 //! components of `P`. We will therefore try popping both constructors in turn: we
 //! compute `U([[true, _]], [_, false])` for the `Some` constructor, and `U([[false]],
@@ -1496,6 +1514,7 @@ struct PatCtxt<'tcx> {
 /// multiple patterns.
 ///
 /// For example, if we are constructing a witness for the match against
+///
 /// ```
 /// struct Pair(Option<(u32, u32)>, bool);
 ///
@@ -1619,12 +1638,14 @@ fn all_constructors<'a, 'tcx>(
             // actually match against them all themselves. So we always return only the fictitious
             // constructor.
             // E.g., in an example like:
+            //
             // ```
             //     let err: io::ErrorKind = ...;
             //     match err {
             //         io::ErrorKind::NotFound => {},
             //     }
             // ```
+            //
             // we don't want to show every possible IO error, but instead have only `_` as the
             // witness.
             let is_declared_nonexhaustive = cx.is_foreign_non_exhaustive_enum(pcx.ty);
@@ -2017,6 +2038,7 @@ crate fn is_useful<'p, 'tcx>(
         let mut unreachable_branches = Vec::new();
         // Subpatterns that are unreachable from all branches. E.g. in the following case, the last
         // `true` is unreachable only from one branch, so it is overall reachable.
+        //
         // ```
         // match (true, true) {
         //     (true, true) => {}
@@ -2161,10 +2183,12 @@ crate fn is_useful<'p, 'tcx>(
             // to do this and instead report a single `_` witness:
             // if the user didn't actually specify a constructor
             // in this arm, e.g., in
+            //
             // ```
             //     let x: (Direction, Direction, bool) = ...;
             //     let (_, _, false) = x;
             // ```
+            //
             // we don't want to show all 16 possible witnesses
             // `(<direction-1>, <direction-2>, true)` - we are
             // satisfied with `(_, _, true)`. In this case,

compiler/rustc_parse/src/parser/expr.rs

@@ -1062,8 +1062,8 @@ impl<'a> Parser<'a> {
             })
         } else if self.eat_keyword(kw::Unsafe) {
             self.parse_block_expr(None, lo, BlockCheckMode::Unsafe(ast::UserProvided), attrs)
-        } else if self.check_inline_const() {
-            self.parse_const_expr(lo.to(self.token.span))
+        } else if self.check_inline_const(0) {
+            self.parse_const_block(lo.to(self.token.span))
         } else if self.is_do_catch_block() {
             self.recover_do_catch(attrs)
         } else if self.is_try_block() {

compiler/rustc_parse/src/parser/mod.rs

@@ -522,9 +522,9 @@ impl<'a> Parser<'a> {
         self.check_or_expected(self.token.can_begin_const_arg(), TokenType::Const)
     }
 
-    fn check_inline_const(&mut self) -> bool {
-        self.check_keyword(kw::Const)
-            && self.look_ahead(1, |t| match t.kind {
+    fn check_inline_const(&self, dist: usize) -> bool {
+        self.is_keyword_ahead(dist, &[kw::Const])
+            && self.look_ahead(dist + 1, |t| match t.kind {
                 token::Interpolated(ref nt) => matches!(**nt, token::NtBlock(..)),
                 token::OpenDelim(DelimToken::Brace) => true,
                 _ => false,
@@ -864,7 +864,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses inline const expressions.
-    fn parse_const_expr(&mut self, span: Span) -> PResult<'a, P<Expr>> {
+    fn parse_const_block(&mut self, span: Span) -> PResult<'a, P<Expr>> {
         self.sess.gated_spans.gate(sym::inline_const, span);
         self.eat_keyword(kw::Const);
         let blk = self.parse_block()?;

compiler/rustc_parse/src/parser/pat.rs

@@ -313,9 +313,15 @@ impl<'a> Parser<'a> {
             let pat = self.parse_pat_with_range_pat(false, None)?;
             self.sess.gated_spans.gate(sym::box_patterns, lo.to(self.prev_token.span));
             PatKind::Box(pat)
-        } else if self.check_inline_const() {
+        } else if self.check_inline_const(0) {
             // Parse `const pat`
-            PatKind::Lit(self.parse_const_expr(lo.to(self.token.span))?)
+            let const_expr = self.parse_const_block(lo.to(self.token.span))?;
+
+            if let Some(re) = self.parse_range_end() {
+                self.parse_pat_range_begin_with(const_expr, re)?
+            } else {
+                PatKind::Lit(const_expr)
+            }
         } else if self.can_be_ident_pat() {
             // Parse `ident @ pat`
             // This can give false positives and parse nullary enums,
@@ -717,16 +723,19 @@ impl<'a> Parser<'a> {
 
     /// Is the token `dist` away from the current suitable as the start of a range patterns end?
     fn is_pat_range_end_start(&self, dist: usize) -> bool {
-        self.look_ahead(dist, |t| {
-            t.is_path_start() // e.g. `MY_CONST`;
+        self.check_inline_const(dist)
+            || self.look_ahead(dist, |t| {
+                t.is_path_start() // e.g. `MY_CONST`;
                 || t.kind == token::Dot // e.g. `.5` for recovery;
                 || t.can_begin_literal_maybe_minus() // e.g. `42`.
                 || t.is_whole_expr()
-        })
+            })
     }
 
     fn parse_pat_range_end(&mut self) -> PResult<'a, P<Expr>> {
-        if self.check_path() {
+        if self.check_inline_const(0) {
+            self.parse_const_block(self.token.span)
+        } else if self.check_path() {
             let lo = self.token.span;
             let (qself, path) = if self.eat_lt() {
                 // Parse a qualified path

compiler/rustc_typeck/src/check/_match.rs

@@ -201,6 +201,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         expr.span,
                         ObligationCauseCode::MatchExpressionArm(box MatchExpressionArmCause {
                             arm_span,
+                            scrut_span: scrut.span,
                             semi_span,
                             source: match_src,
                             prior_arms: other_arms.clone(),

compiler/rustc_typeck/src/check/coercion.rs

@@ -1475,6 +1475,28 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
         if let (Some(sp), Some(fn_output)) = (fcx.ret_coercion_span.borrow().as_ref(), fn_output) {
             self.add_impl_trait_explanation(&mut err, cause, fcx, expected, *sp, fn_output);
         }
+
+        if let Some(sp) = fcx.ret_coercion_span.borrow().as_ref() {
+            // If the closure has an explicit return type annotation,
+            // then a type error may occur at the first return expression we
+            // see in the closure (if it conflicts with the declared
+            // return type). Skip adding a note in this case, since it
+            // would be incorrect.
+            if !err.span.primary_spans().iter().any(|span| span == sp) {
+                let hir = fcx.tcx.hir();
+                let body_owner = hir.body_owned_by(hir.enclosing_body_owner(fcx.body_id));
+                if fcx.tcx.is_closure(hir.body_owner_def_id(body_owner).to_def_id()) {
+                    err.span_note(
+                        *sp,
+                        &format!(
+                            "return type inferred to be `{}` here",
+                            fcx.resolve_vars_if_possible(&expected)
+                        ),
+                    );
+                }
+            }
+        }
+
         err
     }
 

compiler/rustc_typeck/src/collect.rs

@@ -40,7 +40,7 @@ use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::subst::InternalSubsts;
 use rustc_middle::ty::util::Discr;
 use rustc_middle::ty::util::IntTypeExt;
-use rustc_middle::ty::{self, AdtKind, Const, ToPolyTraitRef, Ty, TyCtxt};
+use rustc_middle::ty::{self, AdtKind, Const, DefIdTree, ToPolyTraitRef, Ty, TyCtxt};
 use rustc_middle::ty::{ReprOptions, ToPredicate, WithConstness};
 use rustc_session::config::SanitizerSet;
 use rustc_session::lint;
@@ -2786,6 +2786,14 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, id: DefId) -> CodegenFnAttrs {
         }
     });
 
+    // #73631: closures inherit `#[target_feature]` annotations
+    if tcx.features().target_feature_11 && tcx.is_closure(id) {
+        let owner_id = tcx.parent(id).expect("closure should have a parent");
+        codegen_fn_attrs
+            .target_features
+            .extend(tcx.codegen_fn_attrs(owner_id).target_features.iter().copied())
+    }
+
     // If a function uses #[target_feature] it can't be inlined into general
     // purpose functions as they wouldn't have the right target features
     // enabled. For that reason we also forbid #[inline(always)] as it can't be