Add warn(unreachable_pub) to rustc_macros.

compiler/rustc_macros/src/diagnostics/mod.rs

@@ -55,7 +55,7 @@ use synstructure::Structure;
 ///
 /// See rustc dev guide for more examples on using the `#[derive(Diagnostic)]`:
 /// <https://rustc-dev-guide.rust-lang.org/diagnostics/diagnostic-structs.html>
-pub fn diagnostic_derive(mut s: Structure<'_>) -> TokenStream {
+pub(super) fn diagnostic_derive(mut s: Structure<'_>) -> TokenStream {
     s.underscore_const(true);
     DiagnosticDerive::new(s).into_tokens()
 }
@@ -102,7 +102,7 @@ pub fn diagnostic_derive(mut s: Structure<'_>) -> TokenStream {
 ///
 /// See rustc dev guide for more examples on using the `#[derive(LintDiagnostic)]`:
 /// <https://rustc-dev-guide.rust-lang.org/diagnostics/diagnostic-structs.html#reference>
-pub fn lint_diagnostic_derive(mut s: Structure<'_>) -> TokenStream {
+pub(super) fn lint_diagnostic_derive(mut s: Structure<'_>) -> TokenStream {
     s.underscore_const(true);
     LintDiagnosticDerive::new(s).into_tokens()
 }
@@ -153,7 +153,7 @@ pub fn lint_diagnostic_derive(mut s: Structure<'_>) -> TokenStream {
 ///
 /// diag.subdiagnostic(RawIdentifierSuggestion { span, applicability, ident });
 /// ```
-pub fn subdiagnostic_derive(mut s: Structure<'_>) -> TokenStream {
+pub(super) fn subdiagnostic_derive(mut s: Structure<'_>) -> TokenStream {
     s.underscore_const(true);
     SubdiagnosticDerive::new().into_tokens(s)
 }

compiler/rustc_macros/src/lib.rs

@@ -6,6 +6,7 @@
 #![feature(proc_macro_diagnostic)]
 #![feature(proc_macro_span)]
 #![feature(proc_macro_tracked_env)]
+#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use proc_macro::TokenStream;

compiler/rustc_macros/src/lift.rs

@@ -1,7 +1,7 @@
 use quote::quote;
 use syn::parse_quote;
 
-pub fn lift_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
+pub(super) fn lift_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
     s.add_bounds(synstructure::AddBounds::Generics);
     s.bind_with(|_| synstructure::BindStyle::Move);
     s.underscore_const(true);

compiler/rustc_macros/src/query.rs

@@ -307,7 +307,7 @@ fn add_query_desc_cached_impl(
     });
 }
 
-pub fn rustc_queries(input: TokenStream) -> TokenStream {
+pub(super) fn rustc_queries(input: TokenStream) -> TokenStream {
     let queries = parse_macro_input!(input as List<Query>);
 
     let mut query_stream = quote! {};

compiler/rustc_macros/src/serialize.rs

@@ -3,7 +3,7 @@ use quote::{quote, quote_spanned};
 use syn::parse_quote;
 use syn::spanned::Spanned;
 
-pub 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 +20,7 @@ pub fn type_decodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2:
     decodable_body(s, decoder_ty)
 }
 
-pub 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 });
     }
@@ -32,7 +32,7 @@ pub fn meta_decodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2:
     decodable_body(s, decoder_ty)
 }
 
-pub fn decodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
+pub(super) fn decodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
     let decoder_ty = quote! { __D };
     s.add_impl_generic(parse_quote! { #decoder_ty: ::rustc_span::SpanDecoder });
     s.add_bounds(synstructure::AddBounds::Generics);
@@ -41,7 +41,7 @@ pub fn decodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::Toke
     decodable_body(s, decoder_ty)
 }
 
-pub 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 +123,7 @@ fn decode_field(field: &syn::Field) -> proc_macro2::TokenStream {
     quote_spanned! { field_span=> #decode_inner_method(#__decoder) }
 }
 
-pub 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 +140,7 @@ pub fn type_encodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2:
     encodable_body(s, encoder_ty, false)
 }
 
-pub 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 });
     }
@@ -152,7 +152,7 @@ pub fn meta_encodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2:
     encodable_body(s, encoder_ty, true)
 }
 
-pub fn encodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
+pub(super) fn encodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
     let encoder_ty = quote! { __E };
     s.add_impl_generic(parse_quote! { #encoder_ty: ::rustc_span::SpanEncoder });
     s.add_bounds(synstructure::AddBounds::Generics);
@@ -161,7 +161,7 @@ pub fn encodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::Toke
     encodable_body(s, encoder_ty, false)
 }
 
-pub 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/symbols.rs

@@ -131,7 +131,7 @@ impl Errors {
     }
 }
 
-pub fn symbols(input: TokenStream) -> TokenStream {
+pub(super) fn symbols(input: TokenStream) -> TokenStream {
     let (mut output, errors) = symbols_with_errors(input);
 
     // If we generated any errors, then report them as compiler_error!() macro calls.

compiler/rustc_macros/src/type_foldable.rs

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

compiler/rustc_macros/src/type_visitable.rs

@@ -1,7 +1,7 @@
 use quote::quote;
 use syn::parse_quote;
 
-pub 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")
     }