message: silence dead code warning
diff: use crate::parenthesized::Parenthesized;
  use proc_macro::TokenStream;
  use syn::parse::{Parse, ParseStream, Peek};
  -use syn::{Ident, Path, Token, Attribute, Visibility};
  +use syn::{Attribute, Ident, Path, Token, Visibility};
  /// Implementation for `salsa::database_storage!` macro.
  ///
  @@ -213,7 +213,7 @@ struct DatabaseStorage {
  }
  struct QueryGroup {
  - query_group: Path,
  + _query_group: Path,
  queries: Vec<Query>,
  }
  @@ -257,7 +257,7 @@ impl Parse for QueryGroup {
  syn::braced!(content in input);
  let queries: Vec<Query> = parse_while(Token![fn ], &content)?;
  Ok(QueryGroup {
  - query_group,
  + _query_group: query_group,
  queries,
  })
  }
  