Auto merge of #78562 - JohnTitor:rollup-otg906u, r=JohnTitor

Rollup of 8 pull requests

Successful merges:

 - #77334 (Reorder benches const variable)
 - #77888 (Simplify a nested bool match)
 - #77921 (f64: Refactor collapsible_if)
 - #78523 (Revert invalid `fn` return type parsing change)
 - #78524 (Avoid BorrowMutError with RUSTC_LOG=debug)
 - #78545 (Make anonymous binders start at 0)
 - #78554 (Improve wording of `core::ptr::drop_in_place` docs)
 - #78556 (Link to pass docs from NRVO module docs)

Failed merges:

 - #78424 (Fix some more clippy warnings)

r? `@ghost`

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -156,24 +156,13 @@ fn tt_prepend_space(tt: &TokenTree, prev: &TokenTree) -> bool {
         }
     }
     match tt {
-        TokenTree::Token(token) => match token.kind {
-            token::Comma => false,
-            _ => true,
-        },
-        TokenTree::Delimited(_, DelimToken::Paren, _) => match prev {
-            TokenTree::Token(token) => match token.kind {
-                token::Ident(_, _) => false,
-                _ => true,
-            },
-            _ => true,
-        },
-        TokenTree::Delimited(_, DelimToken::Bracket, _) => match prev {
-            TokenTree::Token(token) => match token.kind {
-                token::Pound => false,
-                _ => true,
-            },
-            _ => true,
-        },
+        TokenTree::Token(token) => token.kind != token::Comma,
+        TokenTree::Delimited(_, DelimToken::Paren, _) => {
+            !matches!(prev, TokenTree::Token(Token { kind: token::Ident(..), .. }))
+        }
+        TokenTree::Delimited(_, DelimToken::Bracket, _) => {
+            !matches!(prev, TokenTree::Token(Token { kind: token::Pound, .. }))
+        }
         TokenTree::Delimited(..) => true,
     }
 }

compiler/rustc_data_structures/src/sync.rs

@@ -512,7 +512,7 @@ impl<T: Clone> Clone for Lock<T> {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, Default)]
 pub struct RwLock<T>(InnerRwLock<T>);
 
 impl<T> RwLock<T> {

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -2042,6 +2042,10 @@ fn encode_metadata_impl(tcx: TyCtxt<'_>) -> EncodedMetadata {
     encoder.emit_raw_bytes(&[0, 0, 0, 0]);
 
     let source_map_files = tcx.sess.source_map().files();
+    let source_file_cache = (source_map_files[0].clone(), 0);
+    let required_source_files = Some(GrowableBitSet::with_capacity(source_map_files.len()));
+    drop(source_map_files);
+
     let hygiene_ctxt = HygieneEncodeContext::default();
 
     let mut ecx = EncodeContext {
@@ -2052,13 +2056,12 @@ fn encode_metadata_impl(tcx: TyCtxt<'_>) -> EncodedMetadata {
         lazy_state: LazyState::NoNode,
         type_shorthands: Default::default(),
         predicate_shorthands: Default::default(),
-        source_file_cache: (source_map_files[0].clone(), 0),
+        source_file_cache,
         interpret_allocs: Default::default(),
-        required_source_files: Some(GrowableBitSet::with_capacity(source_map_files.len())),
+        required_source_files,
         is_proc_macro: tcx.sess.crate_types().contains(&CrateType::ProcMacro),
         hygiene_ctxt: &hygiene_ctxt,
     };
-    drop(source_map_files);
 
     // Encode the rustc version string in a predictable location.
     rustc_version().encode(&mut ecx).unwrap();

compiler/rustc_middle/src/ty/fold.rs

@@ -684,7 +684,7 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     /// Rewrite any late-bound regions so that they are anonymous. Region numbers are
-    /// assigned starting at 1 and increasing monotonically in the order traversed
+    /// assigned starting at 0 and increasing monotonically in the order traversed
     /// by the fold operation.
     ///
     /// The chief purpose of this function is to canonicalize regions so that two
@@ -698,8 +698,9 @@ impl<'tcx> TyCtxt<'tcx> {
         let mut counter = 0;
         Binder::bind(
             self.replace_late_bound_regions(sig, |_| {
+                let r = self.mk_region(ty::ReLateBound(ty::INNERMOST, ty::BrAnon(counter)));
                 counter += 1;
-                self.mk_region(ty::ReLateBound(ty::INNERMOST, ty::BrAnon(counter)))
+                r
             })
             .0,
         )

compiler/rustc_mir/src/transform/nrvo.rs

@@ -1,3 +1,5 @@
+//! See the docs for [`RenameReturnPlace`].
+
 use rustc_hir::Mutability;
 use rustc_index::bit_set::HybridBitSet;
 use rustc_middle::mir::visit::{MutVisitor, NonUseContext, PlaceContext, Visitor};

compiler/rustc_parse/src/parser/item.rs

@@ -1666,19 +1666,10 @@ impl<'a> Parser<'a> {
         req_name: ReqName,
         ret_allow_plus: AllowPlus,
     ) -> PResult<'a, P<FnDecl>> {
-        let inputs = self.parse_fn_params(req_name)?;
-        let output = self.parse_ret_ty(ret_allow_plus, RecoverQPath::Yes)?;
-
-        if let ast::FnRetTy::Ty(ty) = &output {
-            if let TyKind::Path(_, Path { segments, .. }) = &ty.kind {
-                if let [.., last] = &segments[..] {
-                    // Detect and recover `fn foo() -> Vec<i32>> {}`
-                    self.check_trailing_angle_brackets(last, &[&token::OpenDelim(token::Brace)]);
-                }
-            }
-        }
-
-        Ok(P(FnDecl { inputs, output }))
+        Ok(P(FnDecl {
+            inputs: self.parse_fn_params(req_name)?,
+            output: self.parse_ret_ty(ret_allow_plus, RecoverQPath::Yes)?,
+        }))
     }
 
     /// Parses the parameter list of a function, including the `(` and `)` delimiters.

compiler/rustc_span/src/source_map.rs

@@ -12,7 +12,7 @@ pub use crate::*;
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::StableHasher;
-use rustc_data_structures::sync::{AtomicU32, Lock, LockGuard, Lrc, MappedLockGuard};
+use rustc_data_structures::sync::{AtomicU32, Lrc, MappedReadGuard, ReadGuard, RwLock};
 use std::cmp;
 use std::convert::TryFrom;
 use std::hash::Hash;
@@ -168,7 +168,7 @@ pub struct SourceMap {
     /// The address space below this value is currently used by the files in the source map.
     used_address_space: AtomicU32,
 
-    files: Lock<SourceMapFiles>,
+    files: RwLock<SourceMapFiles>,
     file_loader: Box<dyn FileLoader + Sync + Send>,
     // This is used to apply the file path remapping as specified via
     // `--remap-path-prefix` to all `SourceFile`s allocated within this `SourceMap`.
@@ -236,8 +236,8 @@ impl SourceMap {
 
     // By returning a `MonotonicVec`, we ensure that consumers cannot invalidate
     // any existing indices pointing into `files`.
-    pub fn files(&self) -> MappedLockGuard<'_, monotonic::MonotonicVec<Lrc<SourceFile>>> {
-        LockGuard::map(self.files.borrow(), |files| &mut files.source_files)
+    pub fn files(&self) -> MappedReadGuard<'_, monotonic::MonotonicVec<Lrc<SourceFile>>> {
+        ReadGuard::map(self.files.borrow(), |files| &files.source_files)
     }
 
     pub fn source_file_by_stable_id(

compiler/rustc_symbol_mangling/src/v0.rs

@@ -200,15 +200,9 @@ impl SymbolMangler<'tcx> {
 
         let lifetimes = regions
             .into_iter()
-            .map(|br| {
-                match br {
-                    ty::BrAnon(i) => {
-                        // FIXME(eddyb) for some reason, `anonymize_late_bound_regions` starts at `1`.
-                        assert_ne!(i, 0);
-                        i - 1
-                    }
-                    _ => bug!("symbol_names: non-anonymized region `{:?}` in `{:?}`", br, value),
-                }
+            .map(|br| match br {
+                ty::BrAnon(i) => i,
+                _ => bug!("symbol_names: non-anonymized region `{:?}` in `{:?}`", br, value),
             })
             .max()
             .map_or(0, |max| max + 1);
@@ -327,10 +321,6 @@ impl Printer<'tcx> for SymbolMangler<'tcx> {
             // Late-bound lifetimes use indices starting at 1,
             // see `BinderLevel` for more details.
             ty::ReLateBound(debruijn, ty::BrAnon(i)) => {
-                // FIXME(eddyb) for some reason, `anonymize_late_bound_regions` starts at `1`.
-                assert_ne!(i, 0);
-                let i = i - 1;
-
                 let binder = &self.binders[self.binders.len() - 1 - debruijn.index()];
                 let depth = binder.lifetime_depths.start + i;
 

compiler/rustc_typeck/src/check/generator_interior.rs

@@ -186,8 +186,9 @@ pub fn resolve_interior<'a, 'tcx>(
                 // which means that none of the regions inside relate to any other, even if
                 // typeck had previously found constraints that would cause them to be related.
                 let folded = fcx.tcx.fold_regions(&erased, &mut false, |_, current_depth| {
+                    let r = fcx.tcx.mk_region(ty::ReLateBound(current_depth, ty::BrAnon(counter)));
                     counter += 1;
-                    fcx.tcx.mk_region(ty::ReLateBound(current_depth, ty::BrAnon(counter)))
+                    r
                 });
 
                 cause.ty = folded;

library/alloc/benches/vec.rs

@@ -570,6 +570,8 @@ fn bench_in_place_collect_droppable(b: &mut Bencher) {
     })
 }
 
+const LEN: usize = 16384;
+
 #[bench]
 fn bench_chain_collect(b: &mut Bencher) {
     let data = black_box([0; LEN]);
@@ -613,8 +615,6 @@ pub fn map_fast(l: &[(u32, u32)]) -> Vec<u32> {
     result
 }
 
-const LEN: usize = 16384;
-
 #[bench]
 fn bench_range_map_collect(b: &mut Bencher) {
     b.iter(|| (0..LEN).map(|_| u32::default()).collect::<Vec<_>>());

library/core/src/ptr/mod.rs

@@ -99,9 +99,9 @@ mod mut_ptr;
 ///   dropped normally.
 ///
 /// * It is friendlier to the optimizer to do this over [`ptr::read`] when
-///   dropping manually allocated memory (e.g., when writing Box/Rc/Vec),
-///   as the compiler doesn't need to prove that it's sound to elide the
-///   copy.
+///   dropping manually allocated memory (e.g., in the implementations of
+///   `Box`/`Rc`/`Vec`), as the compiler doesn't need to prove that it's
+///   sound to elide the copy.
 ///
 /// * It can be used to drop [pinned] data when `T` is not `repr(packed)`
 ///   (pinned data must not be moved before it is dropped).

library/std/src/f32.rs

@@ -1,7 +1,7 @@
 //! This module provides constants which are specific to the implementation
 //! of the `f32` floating point data type.
 //!
-//! *[See also the `f32` primitive type](../../std/primitive.f32.html).*
+//! *[See also the `f32` primitive type](primitive@f32).*
 //!
 //! Mathematically significant numbers are provided in the `consts` sub-module.
 //!

library/std/src/f64.rs

@@ -1,7 +1,7 @@
 //! This module provides constants which are specific to the implementation
 //! of the `f64` floating point data type.
 //!
-//! *[See also the `f64` primitive type](../../std/primitive.f64.html).*
+//! *[See also the `f64` primitive type](primitive@f64).*
 //!
 //! Mathematically significant numbers are provided in the `consts` sub-module.
 //!
@@ -920,22 +920,20 @@ impl f64 {
     fn log_wrapper<F: Fn(f64) -> f64>(self, log_fn: F) -> f64 {
         if !cfg!(any(target_os = "solaris", target_os = "illumos")) {
             log_fn(self)
-        } else {
-            if self.is_finite() {
-                if self > 0.0 {
-                    log_fn(self)
-                } else if self == 0.0 {
-                    Self::NEG_INFINITY // log(0) = -Inf
-                } else {
-                    Self::NAN // log(-n) = NaN
-                }
-            } else if self.is_nan() {
-                self // log(NaN) = NaN
-            } else if self > 0.0 {
-                self // log(Inf) = Inf
+        } else if self.is_finite() {
+            if self > 0.0 {
+                log_fn(self)
+            } else if self == 0.0 {
+                Self::NEG_INFINITY // log(0) = -Inf
             } else {
-                Self::NAN // log(-Inf) = NaN
+                Self::NAN // log(-n) = NaN
             }
+        } else if self.is_nan() {
+            self // log(NaN) = NaN
+        } else if self > 0.0 {
+            self // log(Inf) = Inf
+        } else {
+            Self::NAN // log(-Inf) = NaN
         }
     }
 }

src/test/ui/auxiliary/rustc-rust-log-aux.rs

@@ -0,0 +1 @@
+// rustc-env:RUSTC_LOG=debug

src/test/ui/closure-expected-type/expect-fn-supply-fn.stderr

@@ -6,7 +6,7 @@ LL |     with_closure_expecting_fn_with_free_region(|x: fn(&'x u32), y| {});
    |
    = note: expected fn pointer `fn(&u32)`
               found fn pointer `fn(&'x u32)`
-note: the anonymous lifetime #2 defined on the body at 16:48...
+note: the anonymous lifetime #1 defined on the body at 16:48...
   --> $DIR/expect-fn-supply-fn.rs:16:48
    |
 LL |     with_closure_expecting_fn_with_free_region(|x: fn(&'x u32), y| {});
@@ -30,7 +30,7 @@ note: the lifetime `'x` as defined on the function body at 13:36...
    |
 LL | fn expect_free_supply_free_from_fn<'x>(x: &'x u32) {
    |                                    ^^
-note: ...does not necessarily outlive the anonymous lifetime #2 defined on the body at 16:48
+note: ...does not necessarily outlive the anonymous lifetime #1 defined on the body at 16:48
   --> $DIR/expect-fn-supply-fn.rs:16:48
    |
 LL |     with_closure_expecting_fn_with_free_region(|x: fn(&'x u32), y| {});

src/test/ui/closures/closure-expected-type/expect-region-supply-region-2.stderr

@@ -6,7 +6,7 @@ LL |     closure_expecting_bound(|x: &'x u32| {
    |
    = note: expected reference `&u32`
               found reference `&'x u32`
-note: the anonymous lifetime #2 defined on the body at 14:29...
+note: the anonymous lifetime #1 defined on the body at 14:29...
   --> $DIR/expect-region-supply-region-2.rs:14:29
    |
 LL |       closure_expecting_bound(|x: &'x u32| {
@@ -37,7 +37,7 @@ note: the lifetime `'x` as defined on the function body at 9:30...
    |
 LL | fn expect_bound_supply_named<'x>() {
    |                              ^^
-note: ...does not necessarily outlive the anonymous lifetime #2 defined on the body at 14:29
+note: ...does not necessarily outlive the anonymous lifetime #1 defined on the body at 14:29
   --> $DIR/expect-region-supply-region-2.rs:14:29
    |
 LL |       closure_expecting_bound(|x: &'x u32| {

src/test/ui/issues/issue-10291.stderr

@@ -4,7 +4,7 @@ error[E0312]: lifetime of reference outlives lifetime of borrowed content...
 LL |         x
    |         ^
    |
-note: ...the reference is valid for the anonymous lifetime #2 defined on the body at 2:69...
+note: ...the reference is valid for the anonymous lifetime #1 defined on the body at 2:69...
   --> $DIR/issue-10291.rs:2:69
    |
 LL |       drop::<Box<dyn for<'z> FnMut(&'z isize) -> &'z isize>>(Box::new(|z| {

src/test/ui/issues/issue-52533-1.stderr

@@ -6,12 +6,12 @@ LL |     gimme(|x, y| y)
    |
    = note: expected reference `&Foo<'_, '_, u32>`
               found reference `&Foo<'_, '_, u32>`
-note: the anonymous lifetime #4 defined on the body at 9:11...
+note: the anonymous lifetime #3 defined on the body at 9:11...
   --> $DIR/issue-52533-1.rs:9:11
    |
 LL |     gimme(|x, y| y)
    |           ^^^^^^^^
-note: ...does not necessarily outlive the anonymous lifetime #3 defined on the body at 9:11
+note: ...does not necessarily outlive the anonymous lifetime #2 defined on the body at 9:11
   --> $DIR/issue-52533-1.rs:9:11
    |
 LL |     gimme(|x, y| y)

src/test/ui/issues/issue-52533.stderr

@@ -4,12 +4,12 @@ error[E0312]: lifetime of reference outlives lifetime of borrowed content...
 LL |     foo(|a, b| b)
    |                ^
    |
-note: ...the reference is valid for the anonymous lifetime #2 defined on the body at 5:9...
+note: ...the reference is valid for the anonymous lifetime #1 defined on the body at 5:9...
   --> $DIR/issue-52533.rs:5:9
    |
 LL |     foo(|a, b| b)
    |         ^^^^^^^^
-note: ...but the borrowed content is only valid for the anonymous lifetime #3 defined on the body at 5:9
+note: ...but the borrowed content is only valid for the anonymous lifetime #2 defined on the body at 5:9
   --> $DIR/issue-52533.rs:5:9
    |
 LL |     foo(|a, b| b)

src/test/ui/parser/fn-returns-fn-pointer.rs

@@ -0,0 +1,6 @@
+// check-pass
+// Regression test for #78507.
+fn foo() -> Option<fn() -> Option<bool>> {
+    Some(|| Some(true))
+}
+fn main() {}

src/test/ui/parser/issue-24780.rs

@@ -1,8 +1,8 @@
 // Verify that '>' is not both expected and found at the same time, as it used
 // to happen in #24780. For example, following should be an error:
-// expected one of ..., `>`, ... found `>`. No longer exactly this, but keeping for posterity.
+// expected one of ..., `>`, ... found `>`.
 
-fn foo() -> Vec<usize>> { //~ ERROR unmatched angle bracket
+fn foo() -> Vec<usize>> { //~ ERROR expected one of `!`, `+`, `::`, `;`, `where`, or `{`, found `>`
     Vec::new()
 }
 

src/test/ui/parser/issue-24780.stderr

@@ -1,8 +1,8 @@
-error: unmatched angle bracket
+error: expected one of `!`, `+`, `::`, `;`, `where`, or `{`, found `>`
   --> $DIR/issue-24780.rs:5:23
    |
 LL | fn foo() -> Vec<usize>> {
-   |                       ^^ help: remove extra angle bracket
+   |                       ^ expected one of `!`, `+`, `::`, `;`, `where`, or `{`
 
 error: aborting due to previous error