Add `warn(unreachable_pub)` to `rustc_transmute`.

compiler/rustc_transmute/src/layout/tree.rs

@@ -204,7 +204,7 @@ pub(crate) mod rustc {
     }
 
     impl<'tcx> Tree<Def<'tcx>, Ref<'tcx>> {
-        pub fn from_ty(ty: Ty<'tcx>, cx: LayoutCx<'tcx, TyCtxt<'tcx>>) -> Result<Self, Err> {
+        pub(crate) fn from_ty(ty: Ty<'tcx>, cx: LayoutCx<'tcx, TyCtxt<'tcx>>) -> Result<Self, Err> {
             use rustc_target::abi::HasDataLayout;
             let layout = layout_of(cx, ty)?;
 

compiler/rustc_transmute/src/layout/tree/tests.rs

@@ -1,7 +1,7 @@
 use super::Tree;
 
 #[derive(Debug, Hash, Eq, PartialEq, Clone, Copy)]
-pub enum Def {
+enum Def {
     NoSafetyInvariants,
     HasSafetyInvariants,
 }

compiler/rustc_transmute/src/lib.rs

@@ -2,6 +2,7 @@
 #![allow(unused_variables)]
 #![feature(alloc_layout_extra)]
 #![feature(never_type)]
+#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 pub(crate) use rustc_data_structures::fx::{FxIndexMap as Map, FxIndexSet as Set};

compiler/rustc_transmute/src/maybe_transmutable/mod.rs

@@ -366,13 +366,13 @@ where
     }
 }
 
-pub enum Quantifier {
+enum Quantifier {
     ThereExists,
     ForAll,
 }
 
 impl Quantifier {
-    pub fn apply<R, I>(&self, iter: I) -> Answer<R>
+    fn apply<R, I>(&self, iter: I) -> Answer<R>
     where
         R: layout::Ref,
         I: IntoIterator<Item = Answer<R>>,