Rollup merge of #138331 - nnethercote:use-RUSTC_LINT_FLAGS-more, r=onur-ozkan,jieyouxu

Use `RUSTC_LINT_FLAGS` more

An alternative to the failed #138084.

Fixes #138106.

r? ````@jieyouxu````

71 files changed, 39 insertions, 95 deletions

diff --git a/compiler/rustc_abi/src/lib.rs b/compiler/rustc_abi/src/lib.rs
index 1b737582009..078b676e40e 100644
--- a/compiler/rustc_abi/src/lib.rs
+++ b/compiler/rustc_abi/src/lib.rs
@@ -5,7 +5,6 @@
 #![cfg_attr(feature = "nightly", feature(rustc_attrs))]
 #![cfg_attr(feature = "nightly", feature(rustdoc_internals))]
 #![cfg_attr(feature = "nightly", feature(step_trait))]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 /*! ABI handling for rustc
diff --git a/compiler/rustc_arena/src/lib.rs b/compiler/rustc_arena/src/lib.rs
index 3b44e996358..6aaac072e4b 100644
--- a/compiler/rustc_arena/src/lib.rs
+++ b/compiler/rustc_arena/src/lib.rs
@@ -23,7 +23,6 @@
 #![feature(maybe_uninit_slice)]
 #![feature(rustc_attrs)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use std::alloc::Layout;
diff --git a/compiler/rustc_ast/src/lib.rs b/compiler/rustc_ast/src/lib.rs
index 6372c66050e..294c6c9ba7a 100644
--- a/compiler/rustc_ast/src/lib.rs
+++ b/compiler/rustc_ast/src/lib.rs
@@ -19,7 +19,6 @@
 #![feature(never_type)]
 #![feature(rustdoc_internals)]
 #![feature(stmt_expr_attributes)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 pub mod util {
diff --git a/compiler/rustc_ast_ir/src/lib.rs b/compiler/rustc_ast_ir/src/lib.rs
index 9884e191ea7..6d05cd18cec 100644
--- a/compiler/rustc_ast_ir/src/lib.rs
+++ b/compiler/rustc_ast_ir/src/lib.rs
@@ -9,7 +9,6 @@
 #![cfg_attr(feature = "nightly", allow(internal_features))]
 #![cfg_attr(feature = "nightly", feature(never_type))]
 #![cfg_attr(feature = "nightly", feature(rustc_attrs))]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 #[cfg(feature = "nightly")]
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index 1bf85bbf26c..e5569458dbd 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -39,7 +39,6 @@
 #![feature(if_let_guard)]
 #![feature(let_chains)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use std::sync::Arc;
diff --git a/compiler/rustc_ast_passes/src/lib.rs b/compiler/rustc_ast_passes/src/lib.rs
index b4ed70d83e5..093199cf342 100644
--- a/compiler/rustc_ast_passes/src/lib.rs
+++ b/compiler/rustc_ast_passes/src/lib.rs
@@ -10,7 +10,6 @@
 #![feature(iter_is_partitioned)]
 #![feature(let_chains)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 pub mod ast_validation;
diff --git a/compiler/rustc_ast_pretty/src/lib.rs b/compiler/rustc_ast_pretty/src/lib.rs
index 602ab69ee5b..84d9ce278a2 100644
--- a/compiler/rustc_ast_pretty/src/lib.rs
+++ b/compiler/rustc_ast_pretty/src/lib.rs
@@ -3,7 +3,6 @@
 #![doc(rust_logo)]
 #![feature(box_patterns)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 mod helpers;
diff --git a/compiler/rustc_attr_data_structures/src/lib.rs b/compiler/rustc_attr_data_structures/src/lib.rs
index 389d8c2413b..bbd3308809c 100644
--- a/compiler/rustc_attr_data_structures/src/lib.rs
+++ b/compiler/rustc_attr_data_structures/src/lib.rs
@@ -3,7 +3,6 @@
 #![doc(rust_logo)]
 #![feature(let_chains)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 mod attributes;
diff --git a/compiler/rustc_attr_parsing/src/lib.rs b/compiler/rustc_attr_parsing/src/lib.rs
index 386f2c98447..249e71ef70d 100644
--- a/compiler/rustc_attr_parsing/src/lib.rs
+++ b/compiler/rustc_attr_parsing/src/lib.rs
@@ -80,7 +80,6 @@
 #![doc(rust_logo)]
 #![feature(let_chains)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 #[macro_use]
diff --git a/compiler/rustc_baked_icu_data/src/lib.rs b/compiler/rustc_baked_icu_data/src/lib.rs
index f86a9db61c6..f3f6522f575 100644
--- a/compiler/rustc_baked_icu_data/src/lib.rs
+++ b/compiler/rustc_baked_icu_data/src/lib.rs
@@ -23,6 +23,7 @@
 // tidy-alphabetical-start
 #![allow(elided_lifetimes_in_paths)]
 #![allow(internal_features)]
+#![allow(unreachable_pub)] // because this crate is mostly generated code
 #![doc(rust_logo)]
 #![feature(rustdoc_internals)]
 // #![warn(unreachable_pub)] // don't use because this crate is mostly generated code
diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs
index 64a533e05ff..4d3774682ce 100644
--- a/compiler/rustc_borrowck/src/lib.rs
+++ b/compiler/rustc_borrowck/src/lib.rs
@@ -13,7 +13,6 @@
 #![feature(rustdoc_internals)]
 #![feature(stmt_expr_attributes)]
 #![feature(try_blocks)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use std::borrow::Cow;
diff --git a/compiler/rustc_builtin_macros/src/lib.rs b/compiler/rustc_builtin_macros/src/lib.rs
index c5d2a84fba4..1defd3867a0 100644
--- a/compiler/rustc_builtin_macros/src/lib.rs
+++ b/compiler/rustc_builtin_macros/src/lib.rs
@@ -18,7 +18,6 @@
 #![feature(rustdoc_internals)]
 #![feature(string_from_utf8_lossy_owned)]
 #![feature(try_blocks)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 extern crate proc_macro;
diff --git a/compiler/rustc_codegen_llvm/src/lib.rs b/compiler/rustc_codegen_llvm/src/lib.rs
index dec93bbccc3..f622646a5d9 100644
--- a/compiler/rustc_codegen_llvm/src/lib.rs
+++ b/compiler/rustc_codegen_llvm/src/lib.rs
@@ -19,7 +19,6 @@
 #![feature(rustdoc_internals)]
 #![feature(slice_as_array)]
 #![feature(try_blocks)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use std::any::Any;
diff --git a/compiler/rustc_codegen_ssa/src/lib.rs b/compiler/rustc_codegen_ssa/src/lib.rs
index 4e758bfdec3..8ad04032414 100644
--- a/compiler/rustc_codegen_ssa/src/lib.rs
+++ b/compiler/rustc_codegen_ssa/src/lib.rs
@@ -14,7 +14,6 @@
 #![feature(rustdoc_internals)]
 #![feature(trait_alias)]
 #![feature(try_blocks)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 //! This crate contains codegen code that is used by all codegen backends (LLVM and others).
diff --git a/compiler/rustc_const_eval/src/lib.rs b/compiler/rustc_const_eval/src/lib.rs
index ed5489652fb..da52d60ae59 100644
--- a/compiler/rustc_const_eval/src/lib.rs
+++ b/compiler/rustc_const_eval/src/lib.rs
@@ -16,7 +16,6 @@
 #![feature(unqualified_local_imports)]
 #![feature(yeet_expr)]
 #![warn(unqualified_local_imports)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 pub mod check_consts;
diff --git a/compiler/rustc_data_structures/src/graph/tests.rs b/compiler/rustc_data_structures/src/graph/tests.rs
index b69b9dbc4a8..e48b9686c26 100644
--- a/compiler/rustc_data_structures/src/graph/tests.rs
+++ b/compiler/rustc_data_structures/src/graph/tests.rs
@@ -3,7 +3,7 @@ use std::cmp::max;
 use super::*;
 use crate::fx::FxHashMap;
 
-pub struct TestGraph {
+pub(super) struct TestGraph {
     num_nodes: usize,
     start_node: usize,
     successors: FxHashMap<usize, Vec<usize>>,
@@ -11,7 +11,7 @@ pub struct TestGraph {
 }
 
 impl TestGraph {
-    pub fn new(start_node: usize, edges: &[(usize, usize)]) -> Self {
+    pub(super) fn new(start_node: usize, edges: &[(usize, usize)]) -> Self {
         let mut graph = TestGraph {
             num_nodes: start_node + 1,
             start_node,
diff --git a/compiler/rustc_data_structures/src/obligation_forest/mod.rs b/compiler/rustc_data_structures/src/obligation_forest/mod.rs
index ea3ac467340..f63b201742d 100644
--- a/compiler/rustc_data_structures/src/obligation_forest/mod.rs
+++ b/compiler/rustc_data_structures/src/obligation_forest/mod.rs
@@ -313,7 +313,7 @@ pub struct Error<O, E> {
 
 mod helper {
     use super::*;
-    pub type ObligationTreeIdGenerator = impl Iterator<Item = ObligationTreeId>;
+    pub(super) type ObligationTreeIdGenerator = impl Iterator<Item = ObligationTreeId>;
     impl<O: ForestObligation> ObligationForest<O> {
         #[cfg_attr(not(bootstrap), define_opaque(ObligationTreeIdGenerator))]
         pub fn new() -> ObligationForest<O> {
diff --git a/compiler/rustc_data_structures/src/sync.rs b/compiler/rustc_data_structures/src/sync.rs
index a1cc75c4985..616a18a72ab 100644
--- a/compiler/rustc_data_structures/src/sync.rs
+++ b/compiler/rustc_data_structures/src/sync.rs
@@ -88,7 +88,7 @@ mod mode {
 
     // Whether thread safety might be enabled.
     #[inline]
-    pub fn might_be_dyn_thread_safe() -> bool {
+    pub(super) fn might_be_dyn_thread_safe() -> bool {
         DYN_THREAD_SAFE_MODE.load(Ordering::Relaxed) != DYN_NOT_THREAD_SAFE
     }
 
diff --git a/compiler/rustc_data_structures/src/sync/parallel.rs b/compiler/rustc_data_structures/src/sync/parallel.rs
index 1ba631b8623..8ef8a3f3585 100644
--- a/compiler/rustc_data_structures/src/sync/parallel.rs
+++ b/compiler/rustc_data_structures/src/sync/parallel.rs
@@ -46,7 +46,7 @@ pub fn parallel_guard<R>(f: impl FnOnce(&ParallelGuard) -> R) -> R {
     ret
 }
 
-pub fn serial_join<A, B, RA, RB>(oper_a: A, oper_b: B) -> (RA, RB)
+fn serial_join<A, B, RA, RB>(oper_a: A, oper_b: B) -> (RA, RB)
 where
     A: FnOnce() -> RA,
     B: FnOnce() -> RB,
diff --git a/compiler/rustc_data_structures/src/tagged_ptr/tests.rs b/compiler/rustc_data_structures/src/tagged_ptr/tests.rs
index 9c1e4cefa69..85b21a7c8ec 100644
--- a/compiler/rustc_data_structures/src/tagged_ptr/tests.rs
+++ b/compiler/rustc_data_structures/src/tagged_ptr/tests.rs
@@ -7,7 +7,7 @@ use crate::stable_hasher::{HashStable, StableHasher};
 
 /// A tag type used in [`TaggedRef`] tests.
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
-pub enum Tag2 {
+enum Tag2 {
     B00 = 0b00,
     B01 = 0b01,
     B10 = 0b10,
diff --git a/compiler/rustc_driver_impl/src/lib.rs b/compiler/rustc_driver_impl/src/lib.rs
index a2ddff7183e..6e4020c6eca 100644
--- a/compiler/rustc_driver_impl/src/lib.rs
+++ b/compiler/rustc_driver_impl/src/lib.rs
@@ -16,7 +16,6 @@
 #![feature(result_flattening)]
 #![feature(rustdoc_internals)]
 #![feature(try_blocks)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use std::cmp::max;
diff --git a/compiler/rustc_error_codes/src/lib.rs b/compiler/rustc_error_codes/src/lib.rs
index d53d5678832..dfeef5a957d 100644
--- a/compiler/rustc_error_codes/src/lib.rs
+++ b/compiler/rustc_error_codes/src/lib.rs
@@ -6,7 +6,6 @@
 #![deny(rustdoc::invalid_codeblock_attributes)]
 #![doc(rust_logo)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 // This higher-order macro defines the error codes that are in use. It is used
diff --git a/compiler/rustc_error_messages/src/lib.rs b/compiler/rustc_error_messages/src/lib.rs
index 6d02d6370fc..066546ecf74 100644
--- a/compiler/rustc_error_messages/src/lib.rs
+++ b/compiler/rustc_error_messages/src/lib.rs
@@ -4,7 +4,6 @@
 #![feature(rustc_attrs)]
 #![feature(rustdoc_internals)]
 #![feature(type_alias_impl_trait)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use std::borrow::Cow;
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index 86959b28e53..80e43ede445 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -25,7 +25,6 @@
 #![feature(trait_alias)]
 #![feature(try_blocks)]
 #![feature(yeet_expr)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 extern crate self as rustc_errors;
diff --git a/compiler/rustc_expand/src/lib.rs b/compiler/rustc_expand/src/lib.rs
index 777044e3f33..4222c9fe906 100644
--- a/compiler/rustc_expand/src/lib.rs
+++ b/compiler/rustc_expand/src/lib.rs
@@ -13,7 +13,6 @@
 #![feature(rustdoc_internals)]
 #![feature(try_blocks)]
 #![feature(yeet_expr)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 extern crate proc_macro as pm;
diff --git a/compiler/rustc_feature/src/lib.rs b/compiler/rustc_feature/src/lib.rs
index 0b034a2ae10..25764755a8f 100644
--- a/compiler/rustc_feature/src/lib.rs
+++ b/compiler/rustc_feature/src/lib.rs
@@ -15,7 +15,6 @@
 #![allow(internal_features)]
 #![doc(rust_logo)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 mod accepted;
diff --git a/compiler/rustc_fluent_macro/src/lib.rs b/compiler/rustc_fluent_macro/src/lib.rs
index 3ad51fa1e64..c6e0484b921 100644
--- a/compiler/rustc_fluent_macro/src/lib.rs
+++ b/compiler/rustc_fluent_macro/src/lib.rs
@@ -7,7 +7,6 @@
 #![feature(proc_macro_span)]
 #![feature(rustdoc_internals)]
 #![feature(track_path)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use proc_macro::TokenStream;
diff --git a/compiler/rustc_graphviz/src/lib.rs b/compiler/rustc_graphviz/src/lib.rs
index b5774f64b66..c8f8fd5be02 100644
--- a/compiler/rustc_graphviz/src/lib.rs
+++ b/compiler/rustc_graphviz/src/lib.rs
@@ -277,7 +277,6 @@
 )]
 #![doc(rust_logo)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use std::borrow::Cow;
diff --git a/compiler/rustc_hir/src/lib.rs b/compiler/rustc_hir/src/lib.rs
index 270d4fbec30..84d369f1edd 100644
--- a/compiler/rustc_hir/src/lib.rs
+++ b/compiler/rustc_hir/src/lib.rs
@@ -13,7 +13,6 @@
 #![feature(never_type)]
 #![feature(rustc_attrs)]
 #![feature(variant_count)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 extern crate self as rustc_hir;
diff --git a/compiler/rustc_hir_analysis/src/lib.rs b/compiler/rustc_hir_analysis/src/lib.rs
index 50b0e32b95e..26a20690a95 100644
--- a/compiler/rustc_hir_analysis/src/lib.rs
+++ b/compiler/rustc_hir_analysis/src/lib.rs
@@ -73,7 +73,6 @@ This API is completely unstable and subject to change.
 #![feature(slice_partition_dedup)]
 #![feature(try_blocks)]
 #![feature(unwrap_infallible)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 // These are used by Clippy.
diff --git a/compiler/rustc_hir_pretty/src/lib.rs b/compiler/rustc_hir_pretty/src/lib.rs
index ae624fc253f..3067766fb4d 100644
--- a/compiler/rustc_hir_pretty/src/lib.rs
+++ b/compiler/rustc_hir_pretty/src/lib.rs
@@ -3,7 +3,6 @@
 
 // tidy-alphabetical-start
 #![recursion_limit = "256"]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use std::cell::Cell;
diff --git a/compiler/rustc_hir_typeck/src/lib.rs b/compiler/rustc_hir_typeck/src/lib.rs
index 8b9c2b4a6ca..263fb84206e 100644
--- a/compiler/rustc_hir_typeck/src/lib.rs
+++ b/compiler/rustc_hir_typeck/src/lib.rs
@@ -8,7 +8,6 @@
 #![feature(let_chains)]
 #![feature(never_type)]
 #![feature(try_blocks)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 mod _match;
diff --git a/compiler/rustc_incremental/src/lib.rs b/compiler/rustc_incremental/src/lib.rs
index 563ed7614c6..299ee487638 100644
--- a/compiler/rustc_incremental/src/lib.rs
+++ b/compiler/rustc_incremental/src/lib.rs
@@ -7,7 +7,6 @@
 #![doc(rust_logo)]
 #![feature(file_buffered)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 mod assert_dep_graph;
diff --git a/compiler/rustc_index/src/lib.rs b/compiler/rustc_index/src/lib.rs
index 3441a5f65c7..cc680838e7e 100644
--- a/compiler/rustc_index/src/lib.rs
+++ b/compiler/rustc_index/src/lib.rs
@@ -4,7 +4,6 @@
 #![cfg_attr(feature = "nightly", feature(extend_one, step_trait, test))]
 #![cfg_attr(feature = "nightly", feature(new_range_api))]
 #![cfg_attr(feature = "nightly", feature(new_zeroed_alloc))]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 pub mod bit_set;
diff --git a/compiler/rustc_index_macros/src/newtype.rs b/compiler/rustc_index_macros/src/newtype.rs
index 67ec7761133..f0b58eabbff 100644
--- a/compiler/rustc_index_macros/src/newtype.rs
+++ b/compiler/rustc_index_macros/src/newtype.rs
@@ -305,7 +305,7 @@ impl Parse for Newtype {
     }
 }
 
-pub fn newtype(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+pub(crate) fn newtype(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
     let input = parse_macro_input!(input as Newtype);
     input.0.into()
 }
diff --git a/compiler/rustc_infer/src/lib.rs b/compiler/rustc_infer/src/lib.rs
index a04b2bb2b08..ece18f4ea64 100644
--- a/compiler/rustc_infer/src/lib.rs
+++ b/compiler/rustc_infer/src/lib.rs
@@ -24,7 +24,6 @@
 #![feature(let_chains)]
 #![feature(rustdoc_internals)]
 #![recursion_limit = "512"] // For rustdoc
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 mod errors;
diff --git a/compiler/rustc_interface/src/lib.rs b/compiler/rustc_interface/src/lib.rs
index 54cd341698f..67e0be93523 100644
--- a/compiler/rustc_interface/src/lib.rs
+++ b/compiler/rustc_interface/src/lib.rs
@@ -4,7 +4,6 @@
 #![feature(iter_intersperse)]
 #![feature(let_chains)]
 #![feature(try_blocks)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 mod callbacks;
diff --git a/compiler/rustc_lexer/src/lib.rs b/compiler/rustc_lexer/src/lib.rs
index bf18845a083..61638e45253 100644
--- a/compiler/rustc_lexer/src/lib.rs
+++ b/compiler/rustc_lexer/src/lib.rs
@@ -23,7 +23,6 @@
 // We want to be able to build this crate with a stable compiler,
 // so no `#![feature]` attributes should be added.
 #![deny(unstable_features)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 mod cursor;
diff --git a/compiler/rustc_lint/src/lib.rs b/compiler/rustc_lint/src/lib.rs
index 7018774e5c6..35867d8c9ef 100644
--- a/compiler/rustc_lint/src/lib.rs
+++ b/compiler/rustc_lint/src/lib.rs
@@ -32,7 +32,6 @@
 #![feature(rustc_attrs)]
 #![feature(rustdoc_internals)]
 #![feature(try_blocks)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 mod async_closures;
diff --git a/compiler/rustc_lint_defs/src/lib.rs b/compiler/rustc_lint_defs/src/lib.rs
index e564235c41a..46b4b1d4383 100644
--- a/compiler/rustc_lint_defs/src/lib.rs
+++ b/compiler/rustc_lint_defs/src/lib.rs
@@ -1,7 +1,3 @@
-// tidy-alphabetical-start
-#![warn(unreachable_pub)]
-// tidy-alphabetical-end
-
 use rustc_abi::ExternAbi;
 use rustc_ast::AttrId;
 use rustc_ast::attr::AttributeExt;
diff --git a/compiler/rustc_llvm/src/lib.rs b/compiler/rustc_llvm/src/lib.rs
index eda9b2b1fc0..68058250a26 100644
--- a/compiler/rustc_llvm/src/lib.rs
+++ b/compiler/rustc_llvm/src/lib.rs
@@ -4,7 +4,6 @@
 #![doc(rust_logo)]
 #![feature(extern_types)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use std::cell::RefCell;
diff --git a/compiler/rustc_macros/src/lib.rs b/compiler/rustc_macros/src/lib.rs
index 34fc0f00320..44ba064dd82 100644
--- a/compiler/rustc_macros/src/lib.rs
+++ b/compiler/rustc_macros/src/lib.rs
@@ -6,7 +6,6 @@
 #![feature(proc_macro_diagnostic)]
 #![feature(proc_macro_span)]
 #![feature(proc_macro_tracked_env)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use proc_macro::TokenStream;
diff --git a/compiler/rustc_metadata/src/lib.rs b/compiler/rustc_metadata/src/lib.rs
index ebcc0efd5a6..8898c5824fa 100644
--- a/compiler/rustc_metadata/src/lib.rs
+++ b/compiler/rustc_metadata/src/lib.rs
@@ -15,7 +15,6 @@
 #![feature(proc_macro_internals)]
 #![feature(rustdoc_internals)]
 #![feature(trusted_len)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 extern crate proc_macro;
diff --git a/compiler/rustc_middle/src/lib.rs b/compiler/rustc_middle/src/lib.rs
index 48ea7df5c23..8fe2cc7101b 100644
--- a/compiler/rustc_middle/src/lib.rs
+++ b/compiler/rustc_middle/src/lib.rs
@@ -61,7 +61,6 @@
 #![feature(try_trait_v2_yeet)]
 #![feature(type_alias_impl_trait)]
 #![feature(yeet_expr)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 #[cfg(test)]
diff --git a/compiler/rustc_mir_build/src/lib.rs b/compiler/rustc_mir_build/src/lib.rs
index fa5db32d913..8e96d46dac2 100644
--- a/compiler/rustc_mir_build/src/lib.rs
+++ b/compiler/rustc_mir_build/src/lib.rs
@@ -8,7 +8,6 @@
 #![feature(if_let_guard)]
 #![feature(let_chains)]
 #![feature(try_blocks)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 // The `builder` module used to be named `build`, but that was causing GitHub's
diff --git a/compiler/rustc_mir_dataflow/src/lib.rs b/compiler/rustc_mir_dataflow/src/lib.rs
index a8a56baa1ff..a0efc623b8e 100644
--- a/compiler/rustc_mir_dataflow/src/lib.rs
+++ b/compiler/rustc_mir_dataflow/src/lib.rs
@@ -7,7 +7,6 @@
 #![feature(let_chains)]
 #![feature(never_type)]
 #![feature(try_blocks)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use rustc_middle::ty;
diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs
index 8aa14d15644..739cee5d7f4 100644
--- a/compiler/rustc_mir_transform/src/lib.rs
+++ b/compiler/rustc_mir_transform/src/lib.rs
@@ -12,7 +12,6 @@
 #![feature(never_type)]
 #![feature(try_blocks)]
 #![feature(yeet_expr)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use hir::ConstContext;
diff --git a/compiler/rustc_monomorphize/src/lib.rs b/compiler/rustc_monomorphize/src/lib.rs
index 714b64b3a23..8f6914f3d72 100644
--- a/compiler/rustc_monomorphize/src/lib.rs
+++ b/compiler/rustc_monomorphize/src/lib.rs
@@ -4,7 +4,6 @@
 #![feature(if_let_guard)]
 #![feature(impl_trait_in_assoc_type)]
 #![feature(let_chains)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use rustc_hir::lang_items::LangItem;
diff --git a/compiler/rustc_next_trait_solver/src/lib.rs b/compiler/rustc_next_trait_solver/src/lib.rs
index d67ae2550d9..f6963a79067 100644
--- a/compiler/rustc_next_trait_solver/src/lib.rs
+++ b/compiler/rustc_next_trait_solver/src/lib.rs
@@ -6,7 +6,6 @@
 
 // tidy-alphabetical-start
 #![allow(rustc::usage_of_type_ir_inherent)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 pub mod canonicalizer;
diff --git a/compiler/rustc_parse/src/lib.rs b/compiler/rustc_parse/src/lib.rs
index 1a104ff5e33..2edc8c83017 100644
--- a/compiler/rustc_parse/src/lib.rs
+++ b/compiler/rustc_parse/src/lib.rs
@@ -12,7 +12,6 @@
 #![feature(iter_intersperse)]
 #![feature(let_chains)]
 #![feature(string_from_utf8_lossy_owned)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use std::path::{Path, PathBuf};
diff --git a/compiler/rustc_parse_format/src/lib.rs b/compiler/rustc_parse_format/src/lib.rs
index e05cc6d29d8..5b8a2fe52d3 100644
--- a/compiler/rustc_parse_format/src/lib.rs
+++ b/compiler/rustc_parse_format/src/lib.rs
@@ -13,7 +13,6 @@
     html_playground_url = "https://play.rust-lang.org/",
     test(attr(deny(warnings)))
 )]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 pub use Alignment::*;
diff --git a/compiler/rustc_passes/src/lib.rs b/compiler/rustc_passes/src/lib.rs
index 1aa077ad2bb..93ff0f66d69 100644
--- a/compiler/rustc_passes/src/lib.rs
+++ b/compiler/rustc_passes/src/lib.rs
@@ -12,7 +12,6 @@
 #![feature(map_try_insert)]
 #![feature(rustdoc_internals)]
 #![feature(try_blocks)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use rustc_middle::query::Providers;
diff --git a/compiler/rustc_pattern_analysis/src/lib.rs b/compiler/rustc_pattern_analysis/src/lib.rs
index a3400ebb799..eeea724a29b 100644
--- a/compiler/rustc_pattern_analysis/src/lib.rs
+++ b/compiler/rustc_pattern_analysis/src/lib.rs
@@ -6,7 +6,6 @@
 #![allow(rustc::diagnostic_outside_of_impl)]
 #![allow(rustc::untranslatable_diagnostic)]
 #![cfg_attr(feature = "rustc", feature(let_chains))]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 pub mod constructor;
diff --git a/compiler/rustc_pattern_analysis/tests/common/mod.rs b/compiler/rustc_pattern_analysis/tests/common/mod.rs
index 365bc2d863f..8980b644f59 100644
--- a/compiler/rustc_pattern_analysis/tests/common/mod.rs
+++ b/compiler/rustc_pattern_analysis/tests/common/mod.rs
@@ -5,7 +5,7 @@ use rustc_pattern_analysis::usefulness::{PlaceValidity, UsefulnessReport};
 use rustc_pattern_analysis::{MatchArm, PatCx, PrivateUninhabitedField};
 
 /// Sets up `tracing` for easier debugging. Tries to look like the `rustc` setup.
-pub fn init_tracing() {
+fn init_tracing() {
     use tracing_subscriber::Layer;
     use tracing_subscriber::layer::SubscriberExt;
     use tracing_subscriber::util::SubscriberInitExt;
@@ -24,7 +24,7 @@ pub fn init_tracing() {
 /// A simple set of types.
 #[allow(dead_code)]
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
-pub enum Ty {
+pub(super) enum Ty {
     /// Booleans
     Bool,
     /// 8-bit unsigned integers
@@ -41,7 +41,7 @@ pub enum Ty {
 
 /// The important logic.
 impl Ty {
-    pub fn sub_tys(&self, ctor: &Constructor<Cx>) -> Vec<Self> {
+    pub(super) fn sub_tys(&self, ctor: &Constructor<Cx>) -> Vec<Self> {
         use Constructor::*;
         match (ctor, *self) {
             (Struct, Ty::Tuple(tys)) => tys.iter().copied().collect(),
@@ -63,7 +63,7 @@ impl Ty {
         }
     }
 
-    pub fn ctor_set(&self) -> ConstructorSet<Cx> {
+    fn ctor_set(&self) -> ConstructorSet<Cx> {
         match *self {
             Ty::Bool => ConstructorSet::Bool,
             Ty::U8 => ConstructorSet::Integers {
@@ -104,7 +104,7 @@ impl Ty {
         }
     }
 
-    pub fn write_variant_name(
+    fn write_variant_name(
         &self,
         f: &mut std::fmt::Formatter<'_>,
         ctor: &Constructor<Cx>,
@@ -120,7 +120,7 @@ impl Ty {
 }
 
 /// Compute usefulness in our simple context (and set up tracing for easier debugging).
-pub fn compute_match_usefulness<'p>(
+pub(super) fn compute_match_usefulness<'p>(
     arms: &[MatchArm<'p, Cx>],
     ty: Ty,
     scrut_validity: PlaceValidity,
@@ -137,7 +137,7 @@ pub fn compute_match_usefulness<'p>(
 }
 
 #[derive(Debug)]
-pub struct Cx;
+pub(super) struct Cx;
 
 /// The context for pattern analysis. Forwards anything interesting to `Ty` methods.
 impl PatCx for Cx {
diff --git a/compiler/rustc_privacy/src/lib.rs b/compiler/rustc_privacy/src/lib.rs
index ff203b2938e..6b4acc1e7a8 100644
--- a/compiler/rustc_privacy/src/lib.rs
+++ b/compiler/rustc_privacy/src/lib.rs
@@ -6,7 +6,6 @@
 #![feature(let_chains)]
 #![feature(rustdoc_internals)]
 #![feature(try_blocks)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 mod errors;
diff --git a/compiler/rustc_query_impl/src/lib.rs b/compiler/rustc_query_impl/src/lib.rs
index 73c205fdb17..40da46a027d 100644
--- a/compiler/rustc_query_impl/src/lib.rs
+++ b/compiler/rustc_query_impl/src/lib.rs
@@ -8,7 +8,6 @@
 #![feature(min_specialization)]
 #![feature(rustc_attrs)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use rustc_data_structures::stable_hasher::HashStable;
diff --git a/compiler/rustc_query_system/src/lib.rs b/compiler/rustc_query_system/src/lib.rs
index 41ebf2d5ac7..2aedd365adc 100644
--- a/compiler/rustc_query_system/src/lib.rs
+++ b/compiler/rustc_query_system/src/lib.rs
@@ -5,7 +5,6 @@
 #![feature(dropck_eyepatch)]
 #![feature(let_chains)]
 #![feature(min_specialization)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 pub mod cache;
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index ccdca855232..f724ecf76b3 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -20,7 +20,6 @@
 #![feature(let_chains)]
 #![feature(rustc_attrs)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use std::cell::{Cell, RefCell};
diff --git a/compiler/rustc_sanitizers/src/lib.rs b/compiler/rustc_sanitizers/src/lib.rs
index 55be931bcd6..e4792563e71 100644
--- a/compiler/rustc_sanitizers/src/lib.rs
+++ b/compiler/rustc_sanitizers/src/lib.rs
@@ -5,7 +5,6 @@
 
 // tidy-alphabetical-start
 #![feature(let_chains)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 pub mod cfi;
diff --git a/compiler/rustc_serialize/src/lib.rs b/compiler/rustc_serialize/src/lib.rs
index 9e9b78cfdd5..13c1a273eb8 100644
--- a/compiler/rustc_serialize/src/lib.rs
+++ b/compiler/rustc_serialize/src/lib.rs
@@ -14,7 +14,6 @@
 #![feature(min_specialization)]
 #![feature(never_type)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 pub use self::serialize::{Decodable, Decoder, Encodable, Encoder};
diff --git a/compiler/rustc_session/src/lib.rs b/compiler/rustc_session/src/lib.rs
index d432e84fdb2..0e19b982a13 100644
--- a/compiler/rustc_session/src/lib.rs
+++ b/compiler/rustc_session/src/lib.rs
@@ -7,7 +7,6 @@
 // To generate CodegenOptionsTargetModifiers and UnstableOptionsTargetModifiers enums
 // with macro_rules, it is necessary to use recursive mechanic ("Incremental TT Munchers").
 #![recursion_limit = "256"]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 pub mod errors;
diff --git a/compiler/rustc_smir/src/lib.rs b/compiler/rustc_smir/src/lib.rs
index 2215e2f01ad..9f888875306 100644
--- a/compiler/rustc_smir/src/lib.rs
+++ b/compiler/rustc_smir/src/lib.rs
@@ -15,7 +15,6 @@
 )]
 #![doc(rust_logo)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 pub mod rustc_internal;
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index 798e186a94b..f19d4d9f362 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -32,7 +32,6 @@
 #![feature(rustc_attrs)]
 #![feature(rustdoc_internals)]
 #![feature(slice_as_chunks)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 // The code produced by the `Encodable`/`Decodable` derive macros refer to
diff --git a/compiler/rustc_symbol_mangling/src/lib.rs b/compiler/rustc_symbol_mangling/src/lib.rs
index 4312c82815c..269401ef3a2 100644
--- a/compiler/rustc_symbol_mangling/src/lib.rs
+++ b/compiler/rustc_symbol_mangling/src/lib.rs
@@ -93,7 +93,6 @@
 #![doc(rust_logo)]
 #![feature(let_chains)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use rustc_hir::def::DefKind;
diff --git a/compiler/rustc_target/src/lib.rs b/compiler/rustc_target/src/lib.rs
index 7ebe96960ed..a8d7da5692d 100644
--- a/compiler/rustc_target/src/lib.rs
+++ b/compiler/rustc_target/src/lib.rs
@@ -16,7 +16,6 @@
 #![feature(let_chains)]
 #![feature(rustc_attrs)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use std::path::{Path, PathBuf};
diff --git a/compiler/rustc_trait_selection/src/lib.rs b/compiler/rustc_trait_selection/src/lib.rs
index b235d0da83c..b18fb0fb8fd 100644
--- a/compiler/rustc_trait_selection/src/lib.rs
+++ b/compiler/rustc_trait_selection/src/lib.rs
@@ -31,7 +31,6 @@
 #![feature(unwrap_infallible)]
 #![feature(yeet_expr)]
 #![recursion_limit = "512"] // For rustdoc
-#![warn(unreachable_pub)] // For rustdoc
 // tidy-alphabetical-end
 
 pub mod error_reporting;
diff --git a/compiler/rustc_traits/src/lib.rs b/compiler/rustc_traits/src/lib.rs
index d2f979bd6d9..697c8391803 100644
--- a/compiler/rustc_traits/src/lib.rs
+++ b/compiler/rustc_traits/src/lib.rs
@@ -2,7 +2,6 @@
 
 // tidy-alphabetical-start
 #![recursion_limit = "256"]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 mod codegen;
diff --git a/compiler/rustc_transmute/src/lib.rs b/compiler/rustc_transmute/src/lib.rs
index 81a11f7cfb2..00928137d29 100644
--- a/compiler/rustc_transmute/src/lib.rs
+++ b/compiler/rustc_transmute/src/lib.rs
@@ -1,6 +1,5 @@
 // tidy-alphabetical-start
 #![feature(never_type)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 pub(crate) use rustc_data_structures::fx::{FxIndexMap as Map, FxIndexSet as Set};
diff --git a/compiler/rustc_ty_utils/src/lib.rs b/compiler/rustc_ty_utils/src/lib.rs
index 8be1611bb9a..35cc6f39856 100644
--- a/compiler/rustc_ty_utils/src/lib.rs
+++ b/compiler/rustc_ty_utils/src/lib.rs
@@ -16,7 +16,6 @@
 #![feature(let_chains)]
 #![feature(never_type)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use rustc_middle::query::Providers;
diff --git a/compiler/rustc_type_ir/src/lib.rs b/compiler/rustc_type_ir/src/lib.rs
index 15ef4e7d6c1..e2dfd9173fa 100644
--- a/compiler/rustc_type_ir/src/lib.rs
+++ b/compiler/rustc_type_ir/src/lib.rs
@@ -6,7 +6,6 @@
     feature(associated_type_defaults, never_type, rustc_attrs, negative_impls)
 )]
 #![cfg_attr(feature = "nightly", allow(internal_features))]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 extern crate self as rustc_type_ir;
diff --git a/src/bootstrap/src/core/builder/cargo.rs b/src/bootstrap/src/core/builder/cargo.rs
index 12dd40d14e9..62d23c4ae6b 100644
--- a/src/bootstrap/src/core/builder/cargo.rs
+++ b/src/bootstrap/src/core/builder/cargo.rs
@@ -1045,8 +1045,11 @@ impl Builder<'_> {
         // so this line allows the use of custom libcs.
         cargo.env("LIBC_CHECK_CFG", "1");
 
+        let mut lint_flags = Vec::new();
+
+        // Lints for all in-tree code: compiler, rustdoc, cranelift, gcc,
+        // clippy, rustfmt, rust-analyzer, etc.
         if source_type == SourceType::InTree {
-            let mut lint_flags = Vec::new();
             // When extending this list, add the new lints to the RUSTFLAGS of the
             // build_bootstrap function of src/bootstrap/bootstrap.py as well as
             // some code doesn't go through this `rustc` wrapper.
@@ -1058,27 +1061,32 @@ impl Builder<'_> {
                 rustdocflags.arg("-Dwarnings");
             }
 
-            // This does not use RUSTFLAGS due to caching issues with Cargo.
-            // Clippy is treated as an "in tree" tool, but shares the same
-            // cache as other "submodule" tools. With these options set in
-            // RUSTFLAGS, that causes *every* shared dependency to be rebuilt.
-            // By injecting this into the rustc wrapper, this circumvents
-            // Cargo's fingerprint detection. This is fine because lint flags
-            // are always ignored in dependencies. Eventually this should be
-            // fixed via better support from Cargo.
-            cargo.env("RUSTC_LINT_FLAGS", lint_flags.join(" "));
-
             rustdocflags.arg("-Wrustdoc::invalid_codeblock_attributes");
         }
 
+        // Lints just for `compiler/` crates.
         if mode == Mode::Rustc {
-            rustflags.arg("-Wrustc::internal");
-            rustflags.arg("-Drustc::symbol_intern_string_literal");
+            lint_flags.push("-Wrustc::internal");
+            lint_flags.push("-Drustc::symbol_intern_string_literal");
             // FIXME(edition_2024): Change this to `-Wrust_2024_idioms` when all
             // of the individual lints are satisfied.
-            rustflags.arg("-Wkeyword_idents_2024");
-            rustflags.arg("-Wunsafe_op_in_unsafe_fn");
-        }
+            lint_flags.push("-Wkeyword_idents_2024");
+            lint_flags.push("-Wunreachable_pub");
+            lint_flags.push("-Wunsafe_op_in_unsafe_fn");
+        }
+
+        // This does not use RUSTFLAGS for two reasons.
+        // - Due to caching issues with Cargo. Clippy is treated as an "in
+        //   tree" tool, but shares the same cache as other "submodule" tools.
+        //   With these options set in RUSTFLAGS, that causes *every* shared
+        //   dependency to be rebuilt. By injecting this into the rustc
+        //   wrapper, this circumvents Cargo's fingerprint detection. This is
+        //   fine because lint flags are always ignored in dependencies.
+        //   Eventually this should be fixed via better support from Cargo.
+        // - RUSTFLAGS is ignored for proc macro crates that are being built on
+        //   the host (because `--target` is given). But we want the lint flags
+        //   to be applied to proc macro crates.
+        cargo.env("RUSTC_LINT_FLAGS", lint_flags.join(" "));
 
         if self.config.rust_frame_pointers {
             rustflags.arg("-Cforce-frame-pointers=true");