Mark #[automatically_derived] for generated impls

Author: oxalica

impl/src/expand.rs

@@ -36,6 +36,7 @@ fn fallback(input: &DeriveInput, error: syn::Error) -> TokenStream {
  #error
 
  #[allow(unused_qualifications)]
+ #[automatically_derived]
  impl #impl_generics std::error::Error for #ty #ty_generics #where_clause
  where
  // Work around trivial bounds being unstable.
@@ -44,6 +45,7 @@ fn fallback(input: &DeriveInput, error: syn::Error) -> TokenStream {
  {}
 
  #[allow(unused_qualifications)]
+ #[automatically_derived]
  impl #impl_generics ::core::fmt::Display for #ty #ty_generics #where_clause {
  fn fmt(&self, __formatter: &mut ::core::fmt::Formatter) -> ::core::fmt::Result {
  ::core::unreachable!()
@@ -178,6 +180,7 @@ fn impl_struct(input: Struct) -> TokenStream {
  let display_where_clause = display_inferred_bounds.augment_where_clause(input.generics);
  quote! {
  #[allow(unused_qualifications)]
+ #[automatically_derived]
  impl #impl_generics ::core::fmt::Display for #ty #ty_generics #display_where_clause {
  #[allow(clippy::used_underscore_binding)]
  fn fmt(&self, __formatter: &mut ::core::fmt::Formatter) -> ::core::fmt::Result {
@@ -193,6 +196,7 @@ fn impl_struct(input: Struct) -> TokenStream {
  let body = from_initializer(from_field, backtrace_field);
  quote! {
  #[allow(unused_qualifications)]
+ #[automatically_derived]
  impl #impl_generics ::core::convert::From<#from> for #ty #ty_generics #where_clause {
  #[allow(deprecated)]
  fn from(source: #from) -> Self {
@@ -211,6 +215,7 @@ fn impl_struct(input: Struct) -> TokenStream {
 
  quote! {
  #[allow(unused_qualifications)]
+ #[automatically_derived]
  impl #impl_generics std::error::Error for #ty #ty_generics #error_where_clause {
  #source_method
  #provide_method
@@ -427,6 +432,7 @@ fn impl_enum(input: Enum) -> TokenStream {
  let display_where_clause = display_inferred_bounds.augment_where_clause(input.generics);
  Some(quote! {
  #[allow(unused_qualifications)]
+ #[automatically_derived]
  impl #impl_generics ::core::fmt::Display for #ty #ty_generics #display_where_clause {
  fn fmt(&self, __formatter: &mut ::core::fmt::Formatter) -> ::core::fmt::Result {
  #use_as_display
@@ -449,6 +455,7 @@ fn impl_enum(input: Enum) -> TokenStream {
  let body = from_initializer(from_field, backtrace_field);
  Some(quote! {
  #[allow(unused_qualifications)]
+ #[automatically_derived]
  impl #impl_generics ::core::convert::From<#from> for #ty #ty_generics #where_clause {
  #[allow(deprecated)]
  fn from(source: #from) -> Self {
@@ -467,6 +474,7 @@ fn impl_enum(input: Enum) -> TokenStream {
 
  quote! {
  #[allow(unused_qualifications)]
+ #[automatically_derived]
  impl #impl_generics std::error::Error for #ty #ty_generics #error_where_clause {
  #source_method
  #provide_method