Rollup merge of #119449 - Nilstrieb:library-clippy, r=cuviper

Fix `clippy::correctness` in the library

needs https://github.com/rust-lang/backtrace-rs/pull/579 to be complete

for https://github.com/rust-lang/compiler-team/issues/709

library/core/src/ffi/c_str.rs

@@ -88,6 +88,7 @@ use crate::str;
 // want `repr(transparent)` but we don't want it to show up in rustdoc, so we hide it under
 // `cfg(doc)`. This is an ad-hoc implementation of attribute privacy.
 #[cfg_attr(not(doc), repr(transparent))]
+#[allow(clippy::derived_hash_with_manual_eq)]
 pub struct CStr {
     // FIXME: this should not be represented with a DST slice but rather with
     //        just a raw `c_char` along with some form of marker to make

library/core/src/num/f32.rs

@@ -462,6 +462,7 @@ impl f32 {
     /// and target platforms isn't guaranteed.
     #[stable(feature = "assoc_int_consts", since = "1.43.0")]
     #[rustc_diagnostic_item = "f32_nan"]
+    #[allow(clippy::eq_op)]
     pub const NAN: f32 = 0.0_f32 / 0.0_f32;
     /// Infinity (∞).
     #[stable(feature = "assoc_int_consts", since = "1.43.0")]
@@ -483,6 +484,7 @@ impl f32 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")]
     #[inline]
+    #[allow(clippy::eq_op)] // > if you intended to check if the operand is NaN, use `.is_nan()` instead :)
     pub const fn is_nan(self) -> bool {
         self != self
     }

library/core/src/num/f64.rs

@@ -461,6 +461,7 @@ impl f64 {
     /// and target platforms isn't guaranteed.
     #[rustc_diagnostic_item = "f64_nan"]
     #[stable(feature = "assoc_int_consts", since = "1.43.0")]
+    #[allow(clippy::eq_op)]
     pub const NAN: f64 = 0.0_f64 / 0.0_f64;
     /// Infinity (∞).
     #[stable(feature = "assoc_int_consts", since = "1.43.0")]
@@ -482,6 +483,7 @@ impl f64 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")]
     #[inline]
+    #[allow(clippy::eq_op)] // > if you intended to check if the operand is NaN, use `.is_nan()` instead :)
     pub const fn is_nan(self) -> bool {
         self != self
     }

library/core/src/option.rs

@@ -567,6 +567,7 @@ use crate::{
 #[rustc_diagnostic_item = "Option"]
 #[lang = "Option"]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[allow(clippy::derived_hash_with_manual_eq)] // PartialEq is specialized
 pub enum Option<T> {
     /// No value.
     #[lang = "None"]

library/core/src/ptr/mod.rs

@@ -376,6 +376,8 @@
 //! [Stacked Borrows]: https://plv.mpi-sws.org/rustbelt/stacked-borrows/
 
 #![stable(feature = "rust1", since = "1.0.0")]
+// There are many unsafe functions taking pointers that don't dereference them.
+#![allow(clippy::not_unsafe_ptr_arg_deref)]
 
 use crate::cmp::Ordering;
 use crate::fmt;

library/core/src/sync/atomic.rs

@@ -216,6 +216,10 @@
 #![cfg_attr(not(target_has_atomic_load_store = "8"), allow(dead_code))]
 #![cfg_attr(not(target_has_atomic_load_store = "8"), allow(unused_imports))]
 #![rustc_diagnostic_item = "atomic_mod"]
+// Clippy complains about the pattern of "safe function calling unsafe function taking pointers".
+// This happens with AtomicPtr intrinsics but is fine, as the pointers clippy is concerned about
+// are just normal values that get loaded/stored, but not dereferenced.
+#![allow(clippy::not_unsafe_ptr_arg_deref)]
 
 use self::Ordering::*;
 

library/proc_macro/src/bridge/arena.rs

@@ -102,6 +102,7 @@ impl Arena {
         }
     }
 
+    #[allow(clippy::mut_from_ref)] // arena allocator
     pub(crate) fn alloc_str<'a>(&'a self, string: &str) -> &'a mut str {
         let alloc = self.alloc_raw(string.len());
         let bytes = MaybeUninit::write_slice(alloc, string.as_bytes());

library/proc_macro/src/lib.rs

@@ -201,6 +201,7 @@ impl ToString for TokenStream {
 /// `TokenTree::Punct`, or `TokenTree::Literal`.
 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
 impl fmt::Display for TokenStream {
+    #[allow(clippy::recursive_format_impl)] // clippy doesn't see the specialization
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(&self.to_string())
     }
@@ -776,6 +777,7 @@ impl ToString for TokenTree {
 /// `TokenTree::Punct`, or `TokenTree::Literal`.
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 impl fmt::Display for TokenTree {
+    #[allow(clippy::recursive_format_impl)] // clippy doesn't see the specialization
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(&self.to_string())
     }
@@ -906,6 +908,7 @@ impl ToString for Group {
 /// with `Delimiter::None` delimiters.
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 impl fmt::Display for Group {
+    #[allow(clippy::recursive_format_impl)] // clippy doesn't see the specialization
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(&self.to_string())
     }