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

compiler/rustc_macros/src/serialize.rs

@@ -3,7 +3,9 @@ use quote::{quote, quote_spanned};
 use syn::parse_quote;
 use syn::spanned::Spanned;
 
-pub(super) fn type_decodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
+pub(super) fn type_decodable_derive(
+    mut s: synstructure::Structure<'_>,
+) -> proc_macro2::TokenStream {
     let decoder_ty = quote! { __D };
     let bound = if s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") {
         quote! { <I = ::rustc_middle::ty::TyCtxt<'tcx>> }
@@ -20,7 +22,9 @@ pub(super) fn type_decodable_derive(mut s: synstructure::Structure<'_>) -> proc_
     decodable_body(s, decoder_ty)
 }
 
-pub(super) fn meta_decodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
+pub(super) fn meta_decodable_derive(
+    mut s: synstructure::Structure<'_>,
+) -> proc_macro2::TokenStream {
     if !s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") {
         s.add_impl_generic(parse_quote! { 'tcx });
     }
@@ -41,7 +45,9 @@ pub(super) fn decodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro
     decodable_body(s, decoder_ty)
 }
 
-pub(super) fn decodable_generic_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
+pub(super) fn decodable_generic_derive(
+    mut s: synstructure::Structure<'_>,
+) -> proc_macro2::TokenStream {
     let decoder_ty = quote! { __D };
     s.add_impl_generic(parse_quote! { #decoder_ty: ::rustc_serialize::Decoder });
     s.add_bounds(synstructure::AddBounds::Generics);
@@ -123,7 +129,9 @@ fn decode_field(field: &syn::Field) -> proc_macro2::TokenStream {
     quote_spanned! { field_span=> #decode_inner_method(#__decoder) }
 }
 
-pub(super) fn type_encodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
+pub(super) fn type_encodable_derive(
+    mut s: synstructure::Structure<'_>,
+) -> proc_macro2::TokenStream {
     let bound = if s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") {
         quote! { <I = ::rustc_middle::ty::TyCtxt<'tcx>> }
     } else if s.ast().generics.type_params().any(|ty| ty.ident == "I") {
@@ -140,7 +148,9 @@ pub(super) fn type_encodable_derive(mut s: synstructure::Structure<'_>) -> proc_
     encodable_body(s, encoder_ty, false)
 }
 
-pub(super) fn meta_encodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
+pub(super) fn meta_encodable_derive(
+    mut s: synstructure::Structure<'_>,
+) -> proc_macro2::TokenStream {
     if !s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") {
         s.add_impl_generic(parse_quote! { 'tcx });
     }
@@ -161,7 +171,9 @@ pub(super) fn encodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro
     encodable_body(s, encoder_ty, false)
 }
 
-pub(super) fn encodable_generic_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
+pub(super) fn encodable_generic_derive(
+    mut s: synstructure::Structure<'_>,
+) -> proc_macro2::TokenStream {
     let encoder_ty = quote! { __E };
     s.add_impl_generic(parse_quote! { #encoder_ty: ::rustc_serialize::Encoder });
     s.add_bounds(synstructure::AddBounds::Generics);

compiler/rustc_macros/src/type_visitable.rs

@@ -1,7 +1,9 @@
 use quote::quote;
 use syn::parse_quote;
 
-pub(super) fn type_visitable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
+pub(super) fn type_visitable_derive(
+    mut s: synstructure::Structure<'_>,
+) -> proc_macro2::TokenStream {
     if let syn::Data::Union(_) = s.ast().data {
         panic!("cannot derive on union")
     }

compiler/rustc_metadata/src/lib.rs

@@ -16,6 +16,7 @@
 #![feature(proc_macro_internals)]
 #![feature(rustdoc_internals)]
 #![feature(trusted_len)]
+#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 extern crate proc_macro;

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -56,13 +56,13 @@ impl std::ops::Deref for MetadataBlob {
 
 impl MetadataBlob {
     /// Runs the [`MemDecoder`] validation and if it passes, constructs a new [`MetadataBlob`].
-    pub fn new(slice: OwnedSlice) -> Result<Self, ()> {
+    pub(crate) fn new(slice: OwnedSlice) -> Result<Self, ()> {
         if MemDecoder::new(&slice, 0).is_ok() { Ok(Self(slice)) } else { Err(()) }
     }
 
     /// Since this has passed the validation of [`MetadataBlob::new`], this returns bytes which are
     /// known to pass the [`MemDecoder`] validation.
-    pub fn bytes(&self) -> &OwnedSlice {
+    pub(crate) fn bytes(&self) -> &OwnedSlice {
         &self.0
     }
 }
@@ -332,12 +332,12 @@ impl<'a, 'tcx> DecodeContext<'a, 'tcx> {
     }
 
     #[inline]
-    pub fn blob(&self) -> &'a MetadataBlob {
+    pub(crate) fn blob(&self) -> &'a MetadataBlob {
         self.blob
     }
 
     #[inline]
-    pub fn cdata(&self) -> CrateMetadataRef<'a> {
+    fn cdata(&self) -> CrateMetadataRef<'a> {
         debug_assert!(self.cdata.is_some(), "missing CrateMetadata in DecodeContext");
         self.cdata.unwrap()
     }
@@ -377,7 +377,7 @@ impl<'a, 'tcx> DecodeContext<'a, 'tcx> {
     }
 
     #[inline]
-    pub fn read_raw_bytes(&mut self, len: usize) -> &[u8] {
+    fn read_raw_bytes(&mut self, len: usize) -> &[u8] {
         self.opaque.read_raw_bytes(len)
     }
 }

compiler/rustc_metadata/src/rmeta/def_path_hash_map.rs

@@ -17,7 +17,7 @@ parameterized_over_tcx! {
 
 impl DefPathHashMapRef<'_> {
     #[inline]
-    pub fn def_path_hash_to_def_index(&self, def_path_hash: &DefPathHash) -> DefIndex {
+    pub(crate) fn def_path_hash_to_def_index(&self, def_path_hash: &DefPathHash) -> DefIndex {
         match *self {
             DefPathHashMapRef::OwnedFromMetadata(ref map) => {
                 map.get(&def_path_hash.local_hash()).unwrap()

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -2309,7 +2309,7 @@ fn encode_root_position(mut file: &File, pos: usize) -> Result<(), std::io::Erro
     Ok(())
 }
 
-pub fn provide(providers: &mut Providers) {
+pub(crate) fn provide(providers: &mut Providers) {
     *providers = Providers {
         doc_link_resolutions: |tcx, def_id| {
             tcx.resolutions(())