Auto merge of #77798 - JohnTitor:rollup-82u711m, r=JohnTitor

Rollup of 10 pull requests

Successful merges:

 - #77195 (Link to documentation-specific guidelines.)
 - #77629 (Cleanup of `eat_while()` in lexer)
 - #77709 (Link Vec leak doc to Box)
 - #77738 (fix __rust_alloc_error_handler comment)
 - #77748 (Dead code cleanup in windows-gnu std)
 - #77754 (Add TraitDef::find_map_relevant_impl)
 - #77766 (Clarify the debug-related values should take boolean)
 - #77777 (doc: disambiguate stat in MetadataExt::as_raw_stat)
 - #77782 (Fix typo in error code description)
 - #77787 (Update `changelog-seen` in config.toml.example)

Failed merges:

r? `@ghost`

compiler/rustc_error_codes/src/error_codes/E0424.md

@@ -21,7 +21,7 @@ impl Foo {
 The `self` keyword can only be used inside methods, which are associated
 functions (functions defined inside of a `trait` or `impl` block) that have a
 `self` receiver as its first parameter, like `self`, `&self`, `&mut self` or
-`self: &mut Pin<Self>` (this last one is an example of an ["abitrary `self`
+`self: &mut Pin<Self>` (this last one is an example of an ["arbitrary `self`
 type"](https://github.com/rust-lang/rust/issues/44874)).
 
 Check if the associated function's parameter list should have contained a `self`

compiler/rustc_lexer/src/lib.rs

@@ -48,6 +48,7 @@ impl Token {
 }
 
 /// Enum representing common lexeme types.
+// perf note: Changing all `usize` to `u32` doesn't change performance. See #77629
 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
 pub enum TokenKind {
     // Multi-char tokens:
@@ -160,6 +161,7 @@ pub enum LiteralKind {
 /// - `r##~"abcde"##`: `InvalidStarter`
 /// - `r###"abcde"##`: `NoTerminator { expected: 3, found: 2, possible_terminator_offset: Some(11)`
 /// - Too many `#`s (>65535): `TooManyDelimiters`
+// perf note: It doesn't matter that this makes `Token` 36 bytes bigger. See #77629
 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
 pub enum RawStrError {
     /// Non `#` characters exist between `r` and `"` eg. `r#~"..`
@@ -689,7 +691,12 @@ impl Cursor<'_> {
         let mut max_hashes = 0;
 
         // Count opening '#' symbols.
-        let n_start_hashes = self.eat_while(|c| c == '#');
+        let mut eaten = 0;
+        while self.first() == '#' {
+            eaten += 1;
+            self.bump();
+        }
+        let n_start_hashes = eaten;
 
         // Check that string is started.
         match self.bump() {
@@ -724,16 +731,11 @@ impl Cursor<'_> {
             // Note that this will not consume extra trailing `#` characters:
             // `r###"abcde"####` is lexed as a `RawStr { n_hashes: 3 }`
             // followed by a `#` token.
-            let mut hashes_left = n_start_hashes;
+            let mut n_end_hashes = 0;
-            let is_closing_hash = |c| {
+            while self.first() == '#' && n_end_hashes < n_start_hashes {
-                if c == '#' && hashes_left != 0 {
+                n_end_hashes += 1;
-                    hashes_left -= 1;
+                self.bump();
-                    true
+            }
-                } else {
-                    false
-                }
-            };
-            let n_end_hashes = self.eat_while(is_closing_hash);
 
             if n_end_hashes == n_start_hashes {
                 return (n_start_hashes, None);
@@ -807,17 +809,9 @@ impl Cursor<'_> {
     }
 
     /// Eats symbols while predicate returns true or until the end of file is reached.
-    /// Returns amount of eaten symbols.
+    fn eat_while(&mut self, mut predicate: impl FnMut(char) -> bool) {
-    fn eat_while<F>(&mut self, mut predicate: F) -> usize
-    where
-        F: FnMut(char) -> bool,
-    {
-        let mut eaten: usize = 0;
         while predicate(self.first()) && !self.is_eof() {
-            eaten += 1;
             self.bump();
         }
-
-        eaten
     }
 }

compiler/rustc_middle/src/ty/trait_def.rs

@@ -123,10 +123,26 @@ impl<'tcx> TyCtxt<'tcx> {
         self_ty: Ty<'tcx>,
         mut f: F,
     ) {
+        let _: Option<()> = self.find_map_relevant_impl(def_id, self_ty, |did| {
+            f(did);
+            None
+        });
+    }
+
+    /// Applies function to every impl that could possibly match the self type `self_ty` and returns
+    /// the first non-none value.
+    pub fn find_map_relevant_impl<T, F: FnMut(DefId) -> Option<T>>(
+        self,
+        def_id: DefId,
+        self_ty: Ty<'tcx>,
+        mut f: F,
+    ) -> Option<T> {
         let impls = self.trait_impls_of(def_id);
 
         for &impl_def_id in impls.blanket_impls.iter() {
-            f(impl_def_id);
+            if let result @ Some(_) = f(impl_def_id) {
+                return result;
+            }
         }
 
         // simplify_type(.., false) basically replaces type parameters and
@@ -157,14 +173,20 @@ impl<'tcx> TyCtxt<'tcx> {
         if let Some(simp) = fast_reject::simplify_type(self, self_ty, true) {
             if let Some(impls) = impls.non_blanket_impls.get(&simp) {
                 for &impl_def_id in impls {
-                    f(impl_def_id);
+                    if let result @ Some(_) = f(impl_def_id) {
+                        return result;
+                    }
                 }
             }
         } else {
             for &impl_def_id in impls.non_blanket_impls.values().flatten() {
-                f(impl_def_id);
+                if let result @ Some(_) = f(impl_def_id) {
+                    return result;
+                }
             }
         }
+
+        None
     }
 
     /// Returns an iterator containing all impls

compiler/rustc_middle/src/ty/util.rs

@@ -346,14 +346,14 @@ impl<'tcx> TyCtxt<'tcx> {
         let drop_trait = self.lang_items().drop_trait()?;
         self.ensure().coherent_trait(drop_trait);
 
-        let mut dtor_did = None;
         let ty = self.type_of(adt_did);
-        self.for_each_relevant_impl(drop_trait, ty, |impl_did| {
+        let dtor_did = self.find_map_relevant_impl(drop_trait, ty, |impl_did| {
             if let Some(item) = self.associated_items(impl_did).in_definition_order().next() {
                 if validate(self, impl_did).is_ok() {
-                    dtor_did = Some(item.def_id);
+                    return Some(item.def_id);
                 }
             }
+            None
         });
 
         Some(ty::Destructor { did: dtor_did? })

compiler/rustc_mir/src/transform/check_const_item_mutation.rs

@@ -34,7 +34,6 @@ impl<'a, 'tcx> ConstMutationChecker<'a, 'tcx> {
 
     fn is_const_item_without_destructor(&self, local: Local) -> Option<DefId> {
         let def_id = self.is_const_item(local)?;
-        let mut any_dtor = |_tcx, _def_id| Ok(());
 
         // We avoid linting mutation of a const item if the const's type has a
         // Drop impl. The Drop logic observes the mutation which was performed.
@@ -54,7 +53,7 @@ impl<'a, 'tcx> ConstMutationChecker<'a, 'tcx> {
         //
         //     #[const_mutation_allowed]
         //     pub const LOG: Log = Log { msg: "" };
-        match self.tcx.calculate_dtor(def_id, &mut any_dtor) {
+        match self.tcx.calculate_dtor(def_id, &mut |_, _| Ok(())) {
             Some(_) => None,
             None => Some(def_id),
         }

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -1384,17 +1384,11 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> {
         trait_ref: &ty::PolyTraitRef<'tcx>,
     ) {
         let get_trait_impl = |trait_def_id| {
-            let mut trait_impl = None;
+            self.tcx.find_map_relevant_impl(
-            self.tcx.for_each_relevant_impl(
                 trait_def_id,
                 trait_ref.skip_binder().self_ty(),
-                |impl_def_id| {
+                |impl_def_id| Some(impl_def_id),
-                    if trait_impl.is_none() {
+            )
-                        trait_impl = Some(impl_def_id);
-                    }
-                },
-            );
-            trait_impl
         };
         let required_trait_path = self.tcx.def_path_str(trait_ref.def_id());
         let all_traits = self.tcx.all_traits(LOCAL_CRATE);

config.toml.example

@@ -13,7 +13,7 @@
 # If it does not match the version that is currently running,
 # `x.py` will prompt you to update it and read the changelog.
 # See `src/bootstrap/CHANGELOG.md` for more information.
-changelog-seen = 1
+changelog-seen = 2
 
 # =============================================================================
 # Global Settings
@@ -370,13 +370,13 @@ changelog-seen = 1
 # binary, otherwise they are omitted.
 #
 # Defaults to rust.debug value
-#debug-assertions = debug
+#debug-assertions = rust.debug (boolean)
 
 # Whether or not debug assertions are enabled for the standard library.
 # Overrides the `debug-assertions` option, if defined.
 #
 # Defaults to rust.debug-assertions value
-#debug-assertions-std = debug-assertions
+#debug-assertions-std = rust.debug-assertions (boolean)
 
 # Whether or not to leave debug! and trace! calls in the rust binary.
 # Overrides the `debug-assertions` option, if defined.
@@ -386,7 +386,7 @@ changelog-seen = 1
 # If you see a message from `tracing` saying
 # `max_level_info` is enabled and means logging won't be shown,
 # set this value to `true`.
-#debug-logging = debug-assertions
+#debug-logging = rust.debug-assertions (boolean)
 
 # Debuginfo level for most of Rust code, corresponds to the `-C debuginfo=N` option of `rustc`.
 # `0` - no debug info

library/alloc/src/alloc.rs

@@ -14,8 +14,9 @@ mod tests;
 
 extern "Rust" {
     // These are the magic symbols to call the global allocator.  rustc generates
-    // them from the `#[global_allocator]` attribute if there is one, or uses the
+    // them to call `__rg_alloc` etc if there is a `#[global_allocator]` attribute
-    // default implementations in libstd (`__rdl_alloc` etc in `src/libstd/alloc.rs`)
+    // (the code expanding that attribute macro generates those functions), or to call
+    // the default implementations in libstd (`__rdl_alloc` etc in `src/libstd/alloc.rs`)
     // otherwise.
     #[rustc_allocator]
     #[rustc_allocator_nounwind]
@@ -26,8 +27,6 @@ extern "Rust" {
     fn __rust_realloc(ptr: *mut u8, old_size: usize, align: usize, new_size: usize) -> *mut u8;
     #[rustc_allocator_nounwind]
     fn __rust_alloc_zeroed(size: usize, align: usize) -> *mut u8;
-    #[rustc_allocator_nounwind]
-    fn __rust_alloc_error_handler(size: usize, align: usize) -> !;
 }
 
 /// The global memory allocator.
@@ -323,6 +322,16 @@ pub(crate) unsafe fn box_free<T: ?Sized>(ptr: Unique<T>) {
     }
 }
 
+// # Allocation error handler
+
+extern "Rust" {
+    // This is the magic symbol to call the global alloc error handler.  rustc generates
+    // it to call `__rg_oom` if there is a `#[alloc_error_handler]`, or to call the
+    // default implementations below (`__rdl_oom`) otherwise.
+    #[rustc_allocator_nounwind]
+    fn __rust_alloc_error_handler(size: usize, align: usize) -> !;
+}
+
 /// Abort on memory allocation error or failure.
 ///
 /// Callers of memory allocation APIs wishing to abort computation
@@ -367,7 +376,7 @@ pub fn handle_alloc_error(layout: Layout) -> ! {
 #[doc(hidden)]
 #[allow(unused_attributes)]
 #[unstable(feature = "alloc_internals", issue = "none")]
-pub mod __default_lib_allocator {
+pub mod __alloc_error_handler {
     use crate::alloc::Layout;
 
     // called via generated `__rust_alloc_error_handler`

library/alloc/src/vec.rs

@@ -1476,7 +1476,8 @@ impl<T> Vec<T> {
     /// `'a`. If the type has only static references, or none at all, then this
     /// may be chosen to be `'static`.
     ///
-    /// This function is similar to the `leak` function on `Box`.
+    /// This function is similar to the [`leak`][Box::leak] function on [`Box`]
+    /// except that there is no way to recover the leaked memory.
     ///
     /// This function is mainly useful for data that lives for the remainder of
     /// the program's life. Dropping the returned reference will cause a memory

library/std/src/lib.rs

@@ -85,7 +85,7 @@
 //! # Contributing changes to the documentation
 //!
 //! Check out the rust contribution guidelines [here](
-//! https://rustc-dev-guide.rust-lang.org/getting-started.html).
+//! https://rustc-dev-guide.rust-lang.org/contributing.html#writing-documentation).
 //! The source for this documentation can be found on
 //! [GitHub](https://github.com/rust-lang/rust).
 //! To contribute changes, make sure you read the guidelines first, then submit

library/std/src/os/linux/fs.rs

@@ -20,7 +20,7 @@ pub trait MetadataExt {
     /// Unix platforms. The `os::unix::fs::MetadataExt` trait contains the
     /// cross-Unix abstractions contained within the raw stat.
     ///
-    /// [`stat`]: crate::os::linux::raw::stat
+    /// [`stat`]: struct@crate::os::linux::raw::stat
     ///
     /// # Examples
     ///

library/std/src/sys/windows/c.rs

@@ -47,7 +47,6 @@ pub type LPWCH = *mut WCHAR;
 pub type LPWIN32_FIND_DATAW = *mut WIN32_FIND_DATAW;
 pub type LPWSADATA = *mut WSADATA;
 pub type LPWSAPROTOCOL_INFO = *mut WSAPROTOCOL_INFO;
-pub type LPSTR = *mut CHAR;
 pub type LPWSTR = *mut WCHAR;
 pub type LPFILETIME = *mut FILETIME;
 pub type LPWSABUF = *mut WSABUF;
@@ -876,16 +875,6 @@ extern "system" {
     pub fn DeleteFileW(lpPathName: LPCWSTR) -> BOOL;
     pub fn GetCurrentDirectoryW(nBufferLength: DWORD, lpBuffer: LPWSTR) -> DWORD;
     pub fn SetCurrentDirectoryW(lpPathName: LPCWSTR) -> BOOL;
-    pub fn WideCharToMultiByte(
-        CodePage: UINT,
-        dwFlags: DWORD,
-        lpWideCharStr: LPCWSTR,
-        cchWideChar: c_int,
-        lpMultiByteStr: LPSTR,
-        cbMultiByte: c_int,
-        lpDefaultChar: LPCSTR,
-        lpUsedDefaultChar: LPBOOL,
-    ) -> c_int;
 
     pub fn closesocket(socket: SOCKET) -> c_int;
     pub fn recv(socket: SOCKET, buf: *mut c_void, len: c_int, flags: c_int) -> c_int;

library/std/src/sys/windows/mod.rs

@@ -4,7 +4,6 @@ use crate::ffi::{OsStr, OsString};
 use crate::io::ErrorKind;
 use crate::os::windows::ffi::{OsStrExt, OsStringExt};
 use crate::path::PathBuf;
-use crate::ptr;
 use crate::time::Duration;
 
 pub use self::rand::hashmap_random_keys;
@@ -206,58 +205,6 @@ fn os2path(s: &[u16]) -> PathBuf {
     PathBuf::from(OsString::from_wide(s))
 }
 
-#[allow(dead_code)] // Only used in backtrace::gnu::get_executable_filename()
-fn wide_char_to_multi_byte(
-    code_page: u32,
-    flags: u32,
-    s: &[u16],
-    no_default_char: bool,
-) -> crate::io::Result<Vec<i8>> {
-    unsafe {
-        let mut size = c::WideCharToMultiByte(
-            code_page,
-            flags,
-            s.as_ptr(),
-            s.len() as i32,
-            ptr::null_mut(),
-            0,
-            ptr::null(),
-            ptr::null_mut(),
-        );
-        if size == 0 {
-            return Err(crate::io::Error::last_os_error());
-        }
-
-        let mut buf = Vec::with_capacity(size as usize);
-        buf.set_len(size as usize);
-
-        let mut used_default_char = c::FALSE;
-        size = c::WideCharToMultiByte(
-            code_page,
-            flags,
-            s.as_ptr(),
-            s.len() as i32,
-            buf.as_mut_ptr(),
-            buf.len() as i32,
-            ptr::null(),
-            if no_default_char { &mut used_default_char } else { ptr::null_mut() },
-        );
-        if size == 0 {
-            return Err(crate::io::Error::last_os_error());
-        }
-        if no_default_char && used_default_char == c::TRUE {
-            return Err(crate::io::Error::new(
-                crate::io::ErrorKind::InvalidData,
-                "string cannot be converted to requested code page",
-            ));
-        }
-
-        buf.set_len(size as usize);
-
-        Ok(buf)
-    }
-}
-
 pub fn truncate_utf16_at_nul(v: &[u16]) -> &[u16] {
     match unrolled_find_u16s(0, v) {
         // don't include the 0

library/unwind/src/libunwind.rs

@@ -89,7 +89,7 @@ extern "C" {
 }
 
 cfg_if::cfg_if! {
-if #[cfg(all(any(target_os = "ios", target_os = "netbsd", not(target_arch = "arm"))))] {
+if #[cfg(any(target_os = "ios", target_os = "netbsd", not(target_arch = "arm")))] {
     // Not ARM EHABI
     #[repr(C)]
     #[derive(Copy, Clone, PartialEq)]

src/librustdoc/passes/collect_intra_doc_links.rs

@@ -650,14 +650,9 @@ fn traits_implemented_by(cx: &DocContext<'_>, type_: DefId, module: DefId) -> Fx
     let ty = cx.tcx.type_of(type_);
     let iter = in_scope_traits.iter().flat_map(|&trait_| {
         trace!("considering explicit impl for trait {:?}", trait_);
-        let mut saw_impl = false;
-        // Look at each trait implementation to see if it's an impl for `did`
-        cx.tcx.for_each_relevant_impl(trait_, ty, |impl_| {
-            // FIXME: this is inefficient, find a way to short-circuit for_each_* so this doesn't take as long
-            if saw_impl {
-                return;
-            }
 
+        // Look at each trait implementation to see if it's an impl for `did`
+        cx.tcx.find_map_relevant_impl(trait_, ty, |impl_| {
             let trait_ref = cx.tcx.impl_trait_ref(impl_).expect("this is not an inherent impl");
             // Check if these are the same type.
             let impl_type = trait_ref.self_ty();
@@ -668,7 +663,7 @@ fn traits_implemented_by(cx: &DocContext<'_>, type_: DefId, module: DefId) -> Fx
                 type_
             );
             // Fast path: if this is a primitive simple `==` will work
-            saw_impl = impl_type == ty
+            let saw_impl = impl_type == ty
                 || match impl_type.kind() {
                     // Check if these are the same def_id
                     ty::Adt(def, _) => {
@@ -678,8 +673,9 @@ fn traits_implemented_by(cx: &DocContext<'_>, type_: DefId, module: DefId) -> Fx
                     ty::Foreign(def_id) => *def_id == type_,
                     _ => false,
                 };
-        });
+
-        if saw_impl { Some(trait_) } else { None }
+            if saw_impl { Some(trait_) } else { None }
+        })
     });
     iter.collect()
 }