From 981f625ba7c8e8ddcf6e470eb54d822eaf9fb300 Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Thu, 12 Dec 2024 11:45:10 +0000
Subject: [PATCH] Remove registered_lints field from Session

It only exists to pass some information from one part of the driver to
another part. We can directly pass this information to the function that
needs it to reduce the amount of mutation of the Session.
---
 compiler/rustc_driver_impl/src/lib.rs     | 8 +++++---
 compiler/rustc_interface/src/interface.rs | 1 -
 compiler/rustc_session/src/session.rs     | 4 ----
 src/librustdoc/lib.rs                     | 4 +++-
 4 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/compiler/rustc_driver_impl/src/lib.rs b/compiler/rustc_driver_impl/src/lib.rs
index 2e01c385a667..b8d5281087ef 100644
--- a/compiler/rustc_driver_impl/src/lib.rs
+++ b/compiler/rustc_driver_impl/src/lib.rs
@@ -350,6 +350,8 @@ fn run_compiler(
 
     callbacks.config(&mut config);
 
+    let registered_lints = config.register_lints.is_some();
+
     interface::run_compiler(config, |compiler| {
         let sess = &compiler.sess;
         let codegen_backend = &*compiler.codegen_backend;
@@ -365,7 +367,7 @@ fn run_compiler(
         // `--help`/`-Zhelp`/`-Chelp`. This is the earliest it can run, because
         // it must happen after lints are registered, during session creation.
         if sess.opts.describe_lints {
-            describe_lints(sess);
+            describe_lints(sess, registered_lints);
             return early_exit();
         }
 
@@ -982,7 +984,7 @@ fn print_wall_help() {
 }
 
 /// Write to stdout lint command options, together with a list of all available lints
-pub fn describe_lints(sess: &Session) {
+pub fn describe_lints(sess: &Session, registered_lints: bool) {
     safe_println!(
         "
 Available lint options:
@@ -1086,7 +1088,7 @@ fn sort_lint_groups(
 
     print_lint_groups(builtin_groups, true);
 
-    match (sess.registered_lints, loaded.len(), loaded_groups.len()) {
+    match (registered_lints, loaded.len(), loaded_groups.len()) {
         (false, 0, _) | (false, _, 0) => {
             safe_println!("Lint tools like Clippy can load additional lints and lint groups.");
         }
diff --git a/compiler/rustc_interface/src/interface.rs b/compiler/rustc_interface/src/interface.rs
index 07ae24ee6d32..7ad893f61ab5 100644
--- a/compiler/rustc_interface/src/interface.rs
+++ b/compiler/rustc_interface/src/interface.rs
@@ -479,7 +479,6 @@ pub fn run_compiler<R: Send>(config: Config, f: impl FnOnce(&Compiler) -> R + Se
             let mut lint_store = rustc_lint::new_lint_store(sess.enable_internal_lints());
             if let Some(register_lints) = config.register_lints.as_deref() {
                 register_lints(&sess, &mut lint_store);
-                sess.registered_lints = true;
             }
             sess.lint_store = Some(Lrc::new(lint_store));
 
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index 160525cead03..9f6106f9cfb7 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -156,9 +156,6 @@ pub struct Session {
     /// This only ever stores a `LintStore` but we don't want a dependency on that type here.
     pub lint_store: Option<Lrc<dyn LintStoreMarker>>,
 
-    /// Should be set if any lints are registered in `lint_store`.
-    pub registered_lints: bool,
-
     /// Cap lint level specified by a driver specifically.
     pub driver_lint_caps: FxHashMap<lint::LintId, lint::Level>,
 
@@ -1068,7 +1065,6 @@ pub fn build_session(
         prof,
         code_stats: Default::default(),
         lint_store: None,
-        registered_lints: false,
         driver_lint_caps,
         ctfe_backtrace,
         miri_unleashed_features: Lock::new(Default::default()),
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index a384c286039d..5d82b8e309a6 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -846,11 +846,13 @@ fn main_args(
 
     let config = core::create_config(input, options, &render_options, using_internal_features);
 
+    let registered_lints = config.register_lints.is_some();
+
     interface::run_compiler(config, |compiler| {
         let sess = &compiler.sess;
 
         if sess.opts.describe_lints {
-            rustc_driver::describe_lints(sess);
+            rustc_driver::describe_lints(sess, registered_lints);
             return;
         }