Auto merge of rust-lang#121327 - Nilstrieb:rollup-zxcwwwy, r=Nilstrieb

Rollup of 10 pull requests

Successful merges:

 - rust-lang#120716 (Change leak check and suspicious auto trait lint warning messages)
 - rust-lang#121195 (unstable-book: Separate testing and production sanitizers)
 - rust-lang#121205 (Merge `CompilerError::CompilationFailed` and `CompilerError::ICE`.)
 - rust-lang#121233 (Move the extra directives for `Mode::CoverageRun` into `iter_header`)
 - rust-lang#121256 (Allow AST and HIR visitors to return `ControlFlow`)
 - rust-lang#121307 (Drive-by `DUMMY_SP` -> `Span` and fmt changes)
 - rust-lang#121308 (Add regression test for rust-lang#103369)
 - rust-lang#121310 (Remove an old hack for rustdoc)
 - rust-lang#121311 (Make `is_nonoverlapping` `#[inline]`)
 - rust-lang#121319 (return `ty::Error` when equating `ty::Error`)

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

Author: bors

compiler/rustc_ast/src/lib.rs

@@ -12,10 +12,12 @@
 #![allow(internal_features)]
 #![feature(rustdoc_internals)]
 #![feature(associated_type_bounds)]
+#![feature(associated_type_defaults)]
 #![feature(box_patterns)]
 #![feature(if_let_guard)]
 #![feature(let_chains)]
 #![cfg_attr(bootstrap, feature(min_specialization))]
+#![feature(never_type)]
 #![feature(negative_impls)]
 #![feature(stmt_expr_attributes)]