Add warn(unreachable_pub) to rustc_middle.

I am surprised the diff is so small for this enormous crate.

compiler/rustc_middle/src/dep_graph/dep_node.rs

@@ -61,8 +61,9 @@ use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LocalModDefId, ModDefId, LO
 use rustc_hir::definitions::DefPathHash;
 use rustc_hir::{HirId, ItemLocalId, OwnerId};
 pub use rustc_query_system::dep_graph::dep_node::DepKind;
+pub use rustc_query_system::dep_graph::DepNode;
 use rustc_query_system::dep_graph::FingerprintStyle;
-pub use rustc_query_system::dep_graph::{DepContext, DepNode, DepNodeParams};
+pub(crate) use rustc_query_system::dep_graph::{DepContext, DepNodeParams};
 use rustc_span::symbol::Symbol;
 
 use crate::mir::mono::MonoItem;
@@ -101,7 +102,7 @@ macro_rules! define_dep_nodes {
 
         // This checks that the discriminants of the variants have been assigned consecutively
         // from 0 so that they can be used as a dense index.
-        pub const DEP_KIND_VARIANTS: u16 = {
+        pub(crate) const DEP_KIND_VARIANTS: u16 = {
             let deps = &[$(dep_kinds::$variant,)*];
             let mut i = 0;
             while i < deps.len() {

compiler/rustc_middle/src/lib.rs

@@ -62,6 +62,7 @@
 #![feature(try_blocks)]
 #![feature(type_alias_impl_trait)]
 #![feature(yeet_expr)]
+#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 #[cfg(test)]

compiler/rustc_middle/src/mir/basic_blocks.rs

@@ -18,9 +18,9 @@ pub struct BasicBlocks<'tcx> {
 }
 
 // Typically 95%+ of basic blocks have 4 or fewer predecessors.
-pub type Predecessors = IndexVec<BasicBlock, SmallVec<[BasicBlock; 4]>>;
+type Predecessors = IndexVec<BasicBlock, SmallVec<[BasicBlock; 4]>>;
 
-pub type SwitchSources = FxHashMap<(BasicBlock, BasicBlock), SmallVec<[Option<u128>; 1]>>;
+type SwitchSources = FxHashMap<(BasicBlock, BasicBlock), SmallVec<[Option<u128>; 1]>>;
 
 #[derive(Clone, Default, Debug)]
 struct Cache {

compiler/rustc_middle/src/mir/generic_graph.rs

@@ -2,7 +2,7 @@ use gsgdt::{Edge, Graph, Node, NodeStyle};
 use rustc_middle::mir::*;
 
 /// Convert an MIR function into a gsgdt Graph
-pub fn mir_fn_to_generic_graph<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'_>) -> Graph {
+pub(crate) fn mir_fn_to_generic_graph<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'_>) -> Graph {
     let def_id = body.source.def_id();
     let def_name = graphviz_safe_def_name(def_id);
     let graph_name = format!("Mir_{def_name}");

compiler/rustc_middle/src/mir/interpret/allocation/init_mask.rs

@@ -243,7 +243,7 @@ impl hash::Hash for InitMaskMaterialized {
 }
 
 impl InitMaskMaterialized {
-    pub const BLOCK_SIZE: u64 = 64;
+    const BLOCK_SIZE: u64 = 64;
 
     fn new(size: Size, state: bool) -> Self {
         let mut m = InitMaskMaterialized { blocks: vec![] };

compiler/rustc_middle/src/mir/mono.rs

@@ -396,7 +396,7 @@ impl<'tcx> CodegenUnit<'tcx> {
         // The codegen tests rely on items being process in the same order as
         // they appear in the file, so for local items, we sort by node_id first
         #[derive(PartialEq, Eq, PartialOrd, Ord)]
-        pub struct ItemSortKey<'tcx>(Option<usize>, SymbolName<'tcx>);
+        struct ItemSortKey<'tcx>(Option<usize>, SymbolName<'tcx>);
 
         fn item_sort_key<'tcx>(tcx: TyCtxt<'tcx>, item: MonoItem<'tcx>) -> ItemSortKey<'tcx> {
             ItemSortKey(

compiler/rustc_middle/src/ty/context.rs

@@ -2190,7 +2190,7 @@ macro_rules! sty_debug_print {
                 all_infer: usize,
             }
 
-            pub fn go(fmt: &mut std::fmt::Formatter<'_>, tcx: TyCtxt<'_>) -> std::fmt::Result {
+            pub(crate) fn go(fmt: &mut std::fmt::Formatter<'_>, tcx: TyCtxt<'_>) -> std::fmt::Result {
                 let mut total = DebugStat {
                     total: 0,
                     lt_infer: 0,