Auto merge of #120620 - matthiaskrgr:rollup-sscmbsm, r=matthiaskrgr

Rollup of 10 pull requests

Successful merges:

 - #119543 (add avx512fp16 to x86 target features)
 - #120004 (Release notes for 1.76)
 - #120562 (Revert unsound libcore changes)
 - #120566 (coverage: Use normal `edition:` headers in coverage tests)
 - #120570 (Suggest changing type to const parameters if we encounter a type in the trait bound position)
 - #120571 (Miscellaneous diagnostics cleanups)
 - #120573 (Remove `BorrowckErrors::tainted_by_errors`)
 - #120592 (Remove unnecessary `.to_string()`/`.as_str()`s)
 - #120610 (hir: Remove the generic type parameter from `MaybeOwned`)
 - #120616 (Fix ICE on field access on a tainted type after const-eval failure)

Failed merges:

 - #120569 (coverage: Improve handling of function/closure spans)

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

1 files changed, 3 insertions, 4 deletions

diff --git a/compiler/rustc_middle/src/error.rs b/compiler/rustc_middle/src/error.rs
index 211da800202..3ebbcd65030 100644
--- a/compiler/rustc_middle/src/error.rs
+++ b/compiler/rustc_middle/src/error.rs
@@ -1,7 +1,6 @@
-use std::borrow::Cow;
 use std::fmt;
 
-use rustc_errors::{codes::*, DiagnosticArgValue, DiagnosticMessage};
+use rustc_errors::{codes::*, DiagnosticArgName, DiagnosticArgValue, DiagnosticMessage};
 use rustc_macros::Diagnostic;
 use rustc_span::{Span, Symbol};
 
@@ -95,14 +94,14 @@ pub(super) struct ConstNotUsedTraitAlias {
 
 pub struct CustomSubdiagnostic<'a> {
     pub msg: fn() -> DiagnosticMessage,
-    pub add_args: Box<dyn FnOnce(&mut dyn FnMut(Cow<'static, str>, DiagnosticArgValue)) + 'a>,
+    pub add_args: Box<dyn FnOnce(&mut dyn FnMut(DiagnosticArgName, DiagnosticArgValue)) + 'a>,
 }
 
 impl<'a> CustomSubdiagnostic<'a> {
     pub fn label(x: fn() -> DiagnosticMessage) -> Self {
         Self::label_and_then(x, |_| {})
     }
-    pub fn label_and_then<F: FnOnce(&mut dyn FnMut(Cow<'static, str>, DiagnosticArgValue)) + 'a>(
+    pub fn label_and_then<F: FnOnce(&mut dyn FnMut(DiagnosticArgName, DiagnosticArgValue)) + 'a>(
         msg: fn() -> DiagnosticMessage,
         f: F,
     ) -> Self {