Auto merge of #130732 - matthiaskrgr:rollup-ke1j314, r=matthiaskrgr

Rollup of 10 pull requests

Successful merges:

 - #129550 (Add str.as_str() for easy Deref to string slices)
 - #130344 (Handle unsized consts with type `str`  in v0 symbol mangling)
 - #130659 (Support `char::encode_utf16` in const scenarios.)
 - #130705 (No longer mark RTN as incomplete)
 - #130712 (Don't call `ty::Const::normalize` in error reporting)
 - #130713 (Mark `u8::make_ascii_uppercase` and `u8::make_ascii_lowercase` as const.)
 - #130714 (Introduce `structurally_normalize_const`, use it in `rustc_hir_typeck`)
 - #130715 (Replace calls to `ty::Const::{try_}eval` in mir build/pattern analysis)
 - #130723 (Add test for `available_parallelism()`)
 - #130726 (tests: Remove spuriously failing vec-tryinto-array codegen test)

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

Author: bors

compiler/rustc_feature/src/unstable.rs

@@ -578,7 +578,7 @@ declare_features! (
     /// be used to describe E or vise-versa.
     (unstable, result_ffi_guarantees, "1.80.0", Some(110503)),
     /// Allows bounding the return type of AFIT/RPITIT.
-    (incomplete, return_type_notation, "1.70.0", Some(109417)),
+    (unstable, return_type_notation, "1.70.0", Some(109417)),
     /// Allows `extern "rust-cold"`.
     (unstable, rust_cold_cc, "1.63.0", Some(97544)),
     /// Allows use of x86 SHA512, SM3 and SM4 target-features and intrinsics

compiler/rustc_hir/src/hir.rs

@@ -1668,10 +1668,17 @@ pub enum ArrayLen<'hir> {
 }
 
 impl ArrayLen<'_> {
-    pub fn hir_id(&self) -> HirId {
+    pub fn span(self) -> Span {
+        match self {
+            ArrayLen::Infer(arg) => arg.span,
+            ArrayLen::Body(body) => body.span(),
+        }
+    }
+
+    pub fn hir_id(self) -> HirId {
         match self {
-            ArrayLen::Infer(InferArg { hir_id, .. }) | ArrayLen::Body(ConstArg { hir_id, .. }) => {
-                *hir_id
+            ArrayLen::Infer(InferArg { hir_id, .. }) | ArrayLen::Body(&ConstArg { hir_id, .. }) => {
+                hir_id
             }
         }
     }