diff --git a/compiler/rustc_incremental/src/lib.rs b/compiler/rustc_incremental/src/lib.rs
index bdae07a3946f5..dde138973b931 100644
--- a/compiler/rustc_incremental/src/lib.rs
+++ b/compiler/rustc_incremental/src/lib.rs
@@ -5,7 +5,6 @@
 #![cfg_attr(not(bootstrap), doc(rust_logo))]
 #![cfg_attr(not(bootstrap), feature(rustdoc_internals))]
 #![cfg_attr(not(bootstrap), allow(internal_features))]
-#![feature(never_type)]
 #![recursion_limit = "256"]
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
@@ -19,15 +18,11 @@ mod assert_dep_graph;
 mod errors;
 mod persist;
 
-use assert_dep_graph::assert_dep_graph;
 pub use persist::copy_cgu_workproduct_to_incr_comp_cache_dir;
-pub use persist::delete_workproduct_files;
 pub use persist::finalize_session_directory;
-pub use persist::garbage_collect_session_directories;
 pub use persist::in_incr_comp_dir;
 pub use persist::in_incr_comp_dir_sess;
 pub use persist::load_query_result_cache;
-pub use persist::prepare_session_directory;
 pub use persist::save_dep_graph;
 pub use persist::save_work_product_index;
 pub use persist::setup_dep_graph;
diff --git a/compiler/rustc_incremental/src/persist/fs.rs b/compiler/rustc_incremental/src/persist/fs.rs
index db8ea2bfe48aa..f56fb0d0534be 100644
--- a/compiler/rustc_incremental/src/persist/fs.rs
+++ b/compiler/rustc_incremental/src/persist/fs.rs
@@ -53,7 +53,7 @@
 //! ## Synchronization
 //!
 //! There is some synchronization needed in order for the compiler to be able to
-//! determine whether a given private session directory is not in used any more.
+//! determine whether a given private session directory is not in use any more.
 //! This is done by creating a lock file for each session directory and
 //! locking it while the directory is still being used. Since file locks have
 //! operating system support, we can rely on the lock being released if the
@@ -136,26 +136,29 @@ const QUERY_CACHE_FILENAME: &str = "query-cache.bin";
 const INT_ENCODE_BASE: usize = base_n::CASE_INSENSITIVE;
 
 /// Returns the path to a session's dependency graph.
-pub fn dep_graph_path(sess: &Session) -> PathBuf {
+pub(crate) fn dep_graph_path(sess: &Session) -> PathBuf {
     in_incr_comp_dir_sess(sess, DEP_GRAPH_FILENAME)
 }
+
 /// Returns the path to a session's staging dependency graph.
 ///
 /// On the difference between dep-graph and staging dep-graph,
 /// see `build_dep_graph`.
-pub fn staging_dep_graph_path(sess: &Session) -> PathBuf {
+pub(crate) fn staging_dep_graph_path(sess: &Session) -> PathBuf {
     in_incr_comp_dir_sess(sess, STAGING_DEP_GRAPH_FILENAME)
 }
-pub fn work_products_path(sess: &Session) -> PathBuf {
+
+pub(crate) fn work_products_path(sess: &Session) -> PathBuf {
     in_incr_comp_dir_sess(sess, WORK_PRODUCTS_FILENAME)
 }
+
 /// Returns the path to a session's query cache.
 pub fn query_cache_path(sess: &Session) -> PathBuf {
     in_incr_comp_dir_sess(sess, QUERY_CACHE_FILENAME)
 }
 
 /// Locks a given session directory.
-pub fn lock_file_path(session_dir: &Path) -> PathBuf {
+fn lock_file_path(session_dir: &Path) -> PathBuf {
     let crate_dir = session_dir.parent().unwrap();
 
     let directory_name = session_dir.file_name().unwrap().to_string_lossy();
@@ -202,7 +205,7 @@ pub fn in_incr_comp_dir(incr_comp_session_dir: &Path, file_name: &str) -> PathBu
 /// The garbage collection will take care of it.
 ///
 /// [`rustc_interface::queries::dep_graph`]: ../../rustc_interface/struct.Queries.html#structfield.dep_graph
-pub fn prepare_session_directory(
+pub(crate) fn prepare_session_directory(
     sess: &Session,
     crate_name: Symbol,
     stable_crate_id: StableCrateId,
@@ -373,7 +376,7 @@ pub fn finalize_session_directory(sess: &Session, svh: Option<Svh>) {
     let _ = garbage_collect_session_directories(sess);
 }
 
-pub fn delete_all_session_dir_contents(sess: &Session) -> io::Result<()> {
+pub(crate) fn delete_all_session_dir_contents(sess: &Session) -> io::Result<()> {
     let sess_dir_iterator = sess.incr_comp_session_dir().read_dir()?;
     for entry in sess_dir_iterator {
         let entry = entry?;
@@ -621,7 +624,7 @@ fn is_old_enough_to_be_collected(timestamp: SystemTime) -> bool {
 }
 
 /// Runs garbage collection for the current session.
-pub fn garbage_collect_session_directories(sess: &Session) -> io::Result<()> {
+pub(crate) fn garbage_collect_session_directories(sess: &Session) -> io::Result<()> {
     debug!("garbage_collect_session_directories() - begin");
 
     let session_directory = sess.incr_comp_session_dir();
diff --git a/compiler/rustc_incremental/src/persist/load.rs b/compiler/rustc_incremental/src/persist/load.rs
index 2310d0b12ef0c..cbd55fe420563 100644
--- a/compiler/rustc_incremental/src/persist/load.rs
+++ b/compiler/rustc_incremental/src/persist/load.rs
@@ -1,4 +1,4 @@
-//! Code to save/load the dep-graph from files.
+//! Code to load the dep-graph from files.
 
 use crate::errors;
 use rustc_data_structures::memmap::Mmap;
diff --git a/compiler/rustc_incremental/src/persist/mod.rs b/compiler/rustc_incremental/src/persist/mod.rs
index fdecaca5a2dc1..94c05f4a2c81e 100644
--- a/compiler/rustc_incremental/src/persist/mod.rs
+++ b/compiler/rustc_incremental/src/persist/mod.rs
@@ -11,14 +11,11 @@ mod save;
 mod work_product;
 
 pub use fs::finalize_session_directory;
-pub use fs::garbage_collect_session_directories;
 pub use fs::in_incr_comp_dir;
 pub use fs::in_incr_comp_dir_sess;
-pub use fs::prepare_session_directory;
 pub use load::load_query_result_cache;
 pub use load::setup_dep_graph;
 pub use load::LoadResult;
 pub use save::save_dep_graph;
 pub use save::save_work_product_index;
 pub use work_product::copy_cgu_workproduct_to_incr_comp_cache_dir;
-pub use work_product::delete_workproduct_files;
diff --git a/compiler/rustc_incremental/src/persist/save.rs b/compiler/rustc_incremental/src/persist/save.rs
index 210da751d95e4..fa21320be263e 100644
--- a/compiler/rustc_incremental/src/persist/save.rs
+++ b/compiler/rustc_incremental/src/persist/save.rs
@@ -1,3 +1,4 @@
+use crate::assert_dep_graph::assert_dep_graph;
 use crate::errors;
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::sync::join;
@@ -39,7 +40,7 @@ pub fn save_dep_graph(tcx: TyCtxt<'_>) {
         let dep_graph_path = dep_graph_path(sess);
         let staging_dep_graph_path = staging_dep_graph_path(sess);
 
-        sess.time("assert_dep_graph", || crate::assert_dep_graph(tcx));
+        sess.time("assert_dep_graph", || assert_dep_graph(tcx));
         sess.time("check_dirty_clean", || dirty_clean::check_dirty_clean_annotations(tcx));
 
         if sess.opts.unstable_opts.incremental_info {
diff --git a/compiler/rustc_incremental/src/persist/work_product.rs b/compiler/rustc_incremental/src/persist/work_product.rs
index bce5ca1e16bd1..fb96bed5a7180 100644
--- a/compiler/rustc_incremental/src/persist/work_product.rs
+++ b/compiler/rustc_incremental/src/persist/work_product.rs
@@ -11,7 +11,8 @@ use rustc_session::Session;
 use std::fs as std_fs;
 use std::path::Path;
 
-/// Copies a CGU work product to the incremental compilation directory, so next compilation can find and reuse it.
+/// Copies a CGU work product to the incremental compilation directory, so next compilation can
+/// find and reuse it.
 pub fn copy_cgu_workproduct_to_incr_comp_cache_dir(
     sess: &Session,
     cgu_name: &str,
@@ -45,7 +46,7 @@ pub fn copy_cgu_workproduct_to_incr_comp_cache_dir(
 }
 
 /// Removes files for a given work product.
-pub fn delete_workproduct_files(sess: &Session, work_product: &WorkProduct) {
+pub(crate) fn delete_workproduct_files(sess: &Session, work_product: &WorkProduct) {
     for (_, path) in work_product.saved_files.items().into_sorted_stable_ord() {
         let path = in_incr_comp_dir_sess(sess, path);
         if let Err(err) = std_fs::remove_file(&path) {