Auto merge of #59684 - Centril:rollup-n7pnare, r=Centril

Rollup of 6 pull requests

Successful merges:

 - #59316 (Internal lints take 2)
 - #59663 (Be more direct about borrow contract)
 - #59664 (Updated the documentation of spin_loop and spin_loop_hint)
 - #59666 (Updated the environment description in rustc.)
 - #59669 (Reduce repetition in librustc(_lint) wrt. impl LintPass by using macros)
 - #59677 (rustfix coverage: Skip UI tests with non-json error-format)

Failed merges:

r? @ghost

3 files changed, 4 insertions, 2 deletions

diff --git a/src/librustc_interface/interface.rs b/src/librustc_interface/interface.rs
index 245a2bf92d5..74085123f89 100644
--- a/src/librustc_interface/interface.rs
+++ b/src/librustc_interface/interface.rs
@@ -12,7 +12,6 @@ use rustc_data_structures::OnDrop;
 use rustc_data_structures::sync::Lrc;
 use rustc_data_structures::fx::{FxHashSet, FxHashMap};
 use rustc_metadata::cstore::CStore;
-use std::collections::HashSet;
 use std::io::Write;
 use std::path::PathBuf;
 use std::result;
diff --git a/src/librustc_interface/lib.rs b/src/librustc_interface/lib.rs
index 3314681b698..353ff6a57a5 100644
--- a/src/librustc_interface/lib.rs
+++ b/src/librustc_interface/lib.rs
@@ -7,6 +7,7 @@
 #![cfg_attr(unix, feature(libc))]
 
 #![deny(rust_2018_idioms)]
+#![cfg_attr(not(stage0), deny(internal))]
 
 #![allow(unused_imports)]
 
diff --git a/src/librustc_interface/util.rs b/src/librustc_interface/util.rs
index 6e4f2bf24e3..17523aedffb 100644
--- a/src/librustc_interface/util.rs
+++ b/src/librustc_interface/util.rs
@@ -21,7 +21,6 @@ use rustc_plugin;
 use rustc_privacy;
 use rustc_resolve;
 use rustc_typeck;
-use std::collections::HashSet;
 use std::env;
 use std::env::consts::{DLL_PREFIX, DLL_SUFFIX};
 use std::io::{self, Write};
@@ -109,6 +108,9 @@ pub fn create_session(
     let codegen_backend = get_codegen_backend(&sess);
 
     rustc_lint::register_builtins(&mut sess.lint_store.borrow_mut(), Some(&sess));
+    if sess.unstable_options() {
+        rustc_lint::register_internals(&mut sess.lint_store.borrow_mut(), Some(&sess));
+    }
 
     let mut cfg = config::build_configuration(&sess, config::to_crate_config(cfg));
     add_configuration(&mut cfg, &sess, &*codegen_backend);