Auto merge of rust-lang#90347 - matthiaskrgr:rollup-rp2ms7j, r=matthiaskrgr

Rollup of 5 pull requests

Successful merges:

 - rust-lang#90239 (Consistent big O notation in map.rs)
 - rust-lang#90267 (fix: inner attribute followed by outer attribute causing ICE)
 - rust-lang#90288 (Add hint for people missing `TryFrom`, `TryInto`, `FromIterator` import pre-2021)
 - rust-lang#90304 (Add regression test for rust-lang#75961)
 - rust-lang#90344 (Add tracking issue number to const_cstr_unchecked)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

alloc/src/collections/btree/map.rs

@@ -55,7 +55,7 @@ pub(super) const MIN_LEN: usize = node::MIN_LEN_AFTER_SPLIT;
 /// performance on *small* nodes of elements which are cheap to compare. However in the future we
 /// would like to further explore choosing the optimal search strategy based on the choice of B,
 /// and possibly other factors. Using linear search, searching for a random element is expected
-/// to take O(B * log(n)) comparisons, which is generally worse than a BST. In practice,
+/// to take B * log(n) comparisons, which is generally worse than a BST. In practice,
 /// however, performance is excellent.
 ///
 /// It is a logic error for a key to be modified in such a way that the key's ordering relative to

std/src/ffi/c_str.rs

@@ -1257,7 +1257,7 @@ impl CStr {
     #[inline]
     #[must_use]
     #[stable(feature = "cstr_from_bytes", since = "1.10.0")]
-    #[rustc_const_unstable(feature = "const_cstr_unchecked", issue = "none")]
+    #[rustc_const_unstable(feature = "const_cstr_unchecked", issue = "90343")]
     pub const unsafe fn from_bytes_with_nul_unchecked(bytes: &[u8]) -> &CStr {
         // SAFETY: Casting to CStr is safe because its internal representation
         // is a [u8] too (safe only inside std).