diff --git a/compiler/rustc_incremental/src/assert_dep_graph.rs b/compiler/rustc_incremental/src/assert_dep_graph.rs
index b29ba59c9f3..46f30526d2a 100644
--- a/compiler/rustc_incremental/src/assert_dep_graph.rs
+++ b/compiler/rustc_incremental/src/assert_dep_graph.rs
@@ -55,7 +55,7 @@ use {rustc_ast as ast, rustc_graphviz as dot, rustc_hir as hir};
 use crate::errors;
 
 #[allow(missing_docs)]
-pub fn assert_dep_graph(tcx: TyCtxt<'_>) {
+pub(crate) fn assert_dep_graph(tcx: TyCtxt<'_>) {
     tcx.dep_graph.with_ignore(|| {
         if tcx.sess.opts.unstable_opts.dump_dep_graph {
             tcx.dep_graph.with_query(dump_graph);
@@ -261,7 +261,7 @@ fn dump_graph(query: &DepGraphQuery) {
 }
 
 #[allow(missing_docs)]
-pub struct GraphvizDepGraph(FxIndexSet<DepKind>, Vec<(DepKind, DepKind)>);
+struct GraphvizDepGraph(FxIndexSet<DepKind>, Vec<(DepKind, DepKind)>);
 
 impl<'a> dot::GraphWalk<'a> for GraphvizDepGraph {
     type Node = DepKind;
diff --git a/compiler/rustc_incremental/src/errors.rs b/compiler/rustc_incremental/src/errors.rs
index c6f8b99bcd6..cb21f975878 100644
--- a/compiler/rustc_incremental/src/errors.rs
+++ b/compiler/rustc_incremental/src/errors.rs
@@ -6,7 +6,7 @@ use rustc_span::{Span, Symbol};
 
 #[derive(Diagnostic)]
 #[diag(incremental_unrecognized_depnode)]
-pub struct UnrecognizedDepNode {
+pub(crate) struct UnrecognizedDepNode {
     #[primary_span]
     pub span: Span,
     pub name: Symbol,
@@ -14,28 +14,28 @@ pub struct UnrecognizedDepNode {
 
 #[derive(Diagnostic)]
 #[diag(incremental_missing_depnode)]
-pub struct MissingDepNode {
+pub(crate) struct MissingDepNode {
     #[primary_span]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_missing_if_this_changed)]
-pub struct MissingIfThisChanged {
+pub(crate) struct MissingIfThisChanged {
     #[primary_span]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_ok)]
-pub struct Ok {
+pub(crate) struct Ok {
     #[primary_span]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_no_path)]
-pub struct NoPath {
+pub(crate) struct NoPath {
     #[primary_span]
     pub span: Span,
     pub target: Symbol,
@@ -44,7 +44,7 @@ pub struct NoPath {
 
 #[derive(Diagnostic)]
 #[diag(incremental_assertion_auto)]
-pub struct AssertionAuto<'a> {
+pub(crate) struct AssertionAuto<'a> {
     #[primary_span]
     pub span: Span,
     pub name: &'a str,
@@ -53,7 +53,7 @@ pub struct AssertionAuto<'a> {
 
 #[derive(Diagnostic)]
 #[diag(incremental_undefined_clean_dirty_assertions_item)]
-pub struct UndefinedCleanDirtyItem {
+pub(crate) struct UndefinedCleanDirtyItem {
     #[primary_span]
     pub span: Span,
     pub kind: String,
@@ -61,7 +61,7 @@ pub struct UndefinedCleanDirtyItem {
 
 #[derive(Diagnostic)]
 #[diag(incremental_undefined_clean_dirty_assertions)]
-pub struct UndefinedCleanDirty {
+pub(crate) struct UndefinedCleanDirty {
     #[primary_span]
     pub span: Span,
     pub kind: String,
@@ -69,7 +69,7 @@ pub struct UndefinedCleanDirty {
 
 #[derive(Diagnostic)]
 #[diag(incremental_repeated_depnode_label)]
-pub struct RepeatedDepNodeLabel<'a> {
+pub(crate) struct RepeatedDepNodeLabel<'a> {
     #[primary_span]
     pub span: Span,
     pub label: &'a str,
@@ -77,7 +77,7 @@ pub struct RepeatedDepNodeLabel<'a> {
 
 #[derive(Diagnostic)]
 #[diag(incremental_unrecognized_depnode_label)]
-pub struct UnrecognizedDepNodeLabel<'a> {
+pub(crate) struct UnrecognizedDepNodeLabel<'a> {
     #[primary_span]
     pub span: Span,
     pub label: &'a str,
@@ -85,7 +85,7 @@ pub struct UnrecognizedDepNodeLabel<'a> {
 
 #[derive(Diagnostic)]
 #[diag(incremental_not_dirty)]
-pub struct NotDirty<'a> {
+pub(crate) struct NotDirty<'a> {
     #[primary_span]
     pub span: Span,
     pub dep_node_str: &'a str,
@@ -93,7 +93,7 @@ pub struct NotDirty<'a> {
 
 #[derive(Diagnostic)]
 #[diag(incremental_not_clean)]
-pub struct NotClean<'a> {
+pub(crate) struct NotClean<'a> {
     #[primary_span]
     pub span: Span,
     pub dep_node_str: &'a str,
@@ -101,7 +101,7 @@ pub struct NotClean<'a> {
 
 #[derive(Diagnostic)]
 #[diag(incremental_not_loaded)]
-pub struct NotLoaded<'a> {
+pub(crate) struct NotLoaded<'a> {
     #[primary_span]
     pub span: Span,
     pub dep_node_str: &'a str,
@@ -109,7 +109,7 @@ pub struct NotLoaded<'a> {
 
 #[derive(Diagnostic)]
 #[diag(incremental_unknown_item)]
-pub struct UnknownItem {
+pub(crate) struct UnknownItem {
     #[primary_span]
     pub span: Span,
     pub name: Symbol,
@@ -117,14 +117,14 @@ pub struct UnknownItem {
 
 #[derive(Diagnostic)]
 #[diag(incremental_no_cfg)]
-pub struct NoCfg {
+pub(crate) struct NoCfg {
     #[primary_span]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_associated_value_expected_for)]
-pub struct AssociatedValueExpectedFor {
+pub(crate) struct AssociatedValueExpectedFor {
     #[primary_span]
     pub span: Span,
     pub ident: Ident,
@@ -132,21 +132,21 @@ pub struct AssociatedValueExpectedFor {
 
 #[derive(Diagnostic)]
 #[diag(incremental_associated_value_expected)]
-pub struct AssociatedValueExpected {
+pub(crate) struct AssociatedValueExpected {
     #[primary_span]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_unchecked_clean)]
-pub struct UncheckedClean {
+pub(crate) struct UncheckedClean {
     #[primary_span]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_delete_old)]
-pub struct DeleteOld<'a> {
+pub(crate) struct DeleteOld<'a> {
     pub name: &'a str,
     pub path: PathBuf,
     pub err: std::io::Error,
@@ -154,7 +154,7 @@ pub struct DeleteOld<'a> {
 
 #[derive(Diagnostic)]
 #[diag(incremental_create_new)]
-pub struct CreateNew<'a> {
+pub(crate) struct CreateNew<'a> {
     pub name: &'a str,
     pub path: PathBuf,
     pub err: std::io::Error,
@@ -162,7 +162,7 @@ pub struct CreateNew<'a> {
 
 #[derive(Diagnostic)]
 #[diag(incremental_write_new)]
-pub struct WriteNew<'a> {
+pub(crate) struct WriteNew<'a> {
     pub name: &'a str,
     pub path: PathBuf,
     pub err: std::io::Error,
@@ -170,14 +170,14 @@ pub struct WriteNew<'a> {
 
 #[derive(Diagnostic)]
 #[diag(incremental_canonicalize_path)]
-pub struct CanonicalizePath {
+pub(crate) struct CanonicalizePath {
     pub path: PathBuf,
     pub err: std::io::Error,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_create_incr_comp_dir)]
-pub struct CreateIncrCompDir<'a> {
+pub(crate) struct CreateIncrCompDir<'a> {
     pub tag: &'a str,
     pub path: &'a Path,
     pub err: std::io::Error,
@@ -185,7 +185,7 @@ pub struct CreateIncrCompDir<'a> {
 
 #[derive(Diagnostic)]
 #[diag(incremental_create_lock)]
-pub struct CreateLock<'a> {
+pub(crate) struct CreateLock<'a> {
     pub lock_err: std::io::Error,
     pub session_dir: &'a Path,
     #[note(incremental_lock_unsupported)]
@@ -197,84 +197,84 @@ pub struct CreateLock<'a> {
 
 #[derive(Diagnostic)]
 #[diag(incremental_delete_lock)]
-pub struct DeleteLock<'a> {
+pub(crate) struct DeleteLock<'a> {
     pub path: &'a Path,
     pub err: std::io::Error,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_hard_link_failed)]
-pub struct HardLinkFailed<'a> {
+pub(crate) struct HardLinkFailed<'a> {
     pub path: &'a Path,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_delete_partial)]
-pub struct DeletePartial<'a> {
+pub(crate) struct DeletePartial<'a> {
     pub path: &'a Path,
     pub err: std::io::Error,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_delete_full)]
-pub struct DeleteFull<'a> {
+pub(crate) struct DeleteFull<'a> {
     pub path: &'a Path,
     pub err: std::io::Error,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_finalize)]
-pub struct Finalize<'a> {
+pub(crate) struct Finalize<'a> {
     pub path: &'a Path,
     pub err: std::io::Error,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_invalid_gc_failed)]
-pub struct InvalidGcFailed<'a> {
+pub(crate) struct InvalidGcFailed<'a> {
     pub path: &'a Path,
     pub err: std::io::Error,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_finalized_gc_failed)]
-pub struct FinalizedGcFailed<'a> {
+pub(crate) struct FinalizedGcFailed<'a> {
     pub path: &'a Path,
     pub err: std::io::Error,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_session_gc_failed)]
-pub struct SessionGcFailed<'a> {
+pub(crate) struct SessionGcFailed<'a> {
     pub path: &'a Path,
     pub err: std::io::Error,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_assert_not_loaded)]
-pub struct AssertNotLoaded;
+pub(crate) struct AssertNotLoaded;
 
 #[derive(Diagnostic)]
 #[diag(incremental_assert_loaded)]
-pub struct AssertLoaded;
+pub(crate) struct AssertLoaded;
 
 #[derive(Diagnostic)]
 #[diag(incremental_delete_incompatible)]
-pub struct DeleteIncompatible {
+pub(crate) struct DeleteIncompatible {
     pub path: PathBuf,
     pub err: std::io::Error,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_load_dep_graph)]
-pub struct LoadDepGraph {
+pub(crate) struct LoadDepGraph {
     pub path: PathBuf,
     pub err: std::io::Error,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_move_dep_graph)]
-pub struct MoveDepGraph<'a> {
+pub(crate) struct MoveDepGraph<'a> {
     pub from: &'a Path,
     pub to: &'a Path,
     pub err: std::io::Error,
@@ -282,14 +282,14 @@ pub struct MoveDepGraph<'a> {
 
 #[derive(Diagnostic)]
 #[diag(incremental_create_dep_graph)]
-pub struct CreateDepGraph<'a> {
+pub(crate) struct CreateDepGraph<'a> {
     pub path: &'a Path,
     pub err: std::io::Error,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_copy_workproduct_to_cache)]
-pub struct CopyWorkProductToCache<'a> {
+pub(crate) struct CopyWorkProductToCache<'a> {
     pub from: &'a Path,
     pub to: &'a Path,
     pub err: std::io::Error,
@@ -297,13 +297,13 @@ pub struct CopyWorkProductToCache<'a> {
 
 #[derive(Diagnostic)]
 #[diag(incremental_delete_workproduct)]
-pub struct DeleteWorkProduct<'a> {
+pub(crate) struct DeleteWorkProduct<'a> {
     pub path: &'a Path,
     pub err: std::io::Error,
 }
 
 #[derive(Diagnostic)]
 #[diag(incremental_corrupt_file)]
-pub struct CorruptFile<'a> {
+pub(crate) struct CorruptFile<'a> {
     pub path: &'a Path,
 }
diff --git a/compiler/rustc_incremental/src/lib.rs b/compiler/rustc_incremental/src/lib.rs
index fcdcb08eed6..c79d108183c 100644
--- a/compiler/rustc_incremental/src/lib.rs
+++ b/compiler/rustc_incremental/src/lib.rs
@@ -6,6 +6,7 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]
 #![feature(rustdoc_internals)]
+#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 mod assert_dep_graph;
diff --git a/compiler/rustc_incremental/src/persist/data.rs b/compiler/rustc_incremental/src/persist/data.rs
index 81e5410978d..d962dc866f4 100644
--- a/compiler/rustc_incremental/src/persist/data.rs
+++ b/compiler/rustc_incremental/src/persist/data.rs
@@ -4,7 +4,7 @@ use rustc_macros::{Decodable, Encodable};
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
 
 #[derive(Debug, Encodable, Decodable)]
-pub struct SerializedWorkProduct {
+pub(crate) struct SerializedWorkProduct {
     /// node that produced the work-product
     pub id: WorkProductId,
 
diff --git a/compiler/rustc_incremental/src/persist/dirty_clean.rs b/compiler/rustc_incremental/src/persist/dirty_clean.rs
index 1e02324f404..88cb82f0f37 100644
--- a/compiler/rustc_incremental/src/persist/dirty_clean.rs
+++ b/compiler/rustc_incremental/src/persist/dirty_clean.rs
@@ -133,7 +133,7 @@ struct Assertion {
     loaded_from_disk: Labels,
 }
 
-pub fn check_dirty_clean_annotations(tcx: TyCtxt<'_>) {
+pub(crate) fn check_dirty_clean_annotations(tcx: TyCtxt<'_>) {
     if !tcx.sess.opts.unstable_opts.query_dep_graph {
         return;
     }
@@ -174,7 +174,7 @@ pub fn check_dirty_clean_annotations(tcx: TyCtxt<'_>) {
     })
 }
 
-pub struct DirtyCleanVisitor<'tcx> {
+struct DirtyCleanVisitor<'tcx> {
     tcx: TyCtxt<'tcx>,
     checked_attrs: FxHashSet<ast::AttrId>,
 }
@@ -429,7 +429,7 @@ fn expect_associated_value(tcx: TyCtxt<'_>, item: &NestedMetaItem) -> Symbol {
 /// A visitor that collects all `#[rustc_clean]` attributes from
 /// the HIR. It is used to verify that we really ran checks for all annotated
 /// nodes.
-pub struct FindAllAttrs<'tcx> {
+struct FindAllAttrs<'tcx> {
     tcx: TyCtxt<'tcx>,
     found_attrs: Vec<&'tcx Attribute>,
 }
diff --git a/compiler/rustc_incremental/src/persist/file_format.rs b/compiler/rustc_incremental/src/persist/file_format.rs
index 174414d0c85..f834c48cbf8 100644
--- a/compiler/rustc_incremental/src/persist/file_format.rs
+++ b/compiler/rustc_incremental/src/persist/file_format.rs
@@ -89,7 +89,7 @@ where
 ///   incompatible version of the compiler.
 /// - Returns `Err(..)` if some kind of IO error occurred while reading the
 ///   file.
-pub fn read_file(
+pub(crate) fn read_file(
     path: &Path,
     report_incremental_info: bool,
     is_nightly_build: bool,
diff --git a/compiler/rustc_incremental/src/persist/fs.rs b/compiler/rustc_incremental/src/persist/fs.rs
index 0e87bc1e692..feb25a9a89d 100644
--- a/compiler/rustc_incremental/src/persist/fs.rs
+++ b/compiler/rustc_incremental/src/persist/fs.rs
@@ -157,7 +157,7 @@ pub(crate) fn work_products_path(sess: &Session) -> PathBuf {
 }
 
 /// Returns the path to a session's query cache.
-pub fn query_cache_path(sess: &Session) -> PathBuf {
+pub(crate) fn query_cache_path(sess: &Session) -> PathBuf {
     in_incr_comp_dir_sess(sess, QUERY_CACHE_FILENAME)
 }