gccrs: expand: Make to_derive argument const

This string will never change and can be constified.

gcc/rust/ChangeLog:

	* expand/rust-expand-visitor.cc (derive_item): Add const
	attribute to the trait name argument.
	* expand/rust-macro-expand.h (struct MacroExpander): Likewise.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

diff --git a/gcc/rust/expand/rust-expand-visitor.cc b/gcc/rust/expand/rust-expand-visitor.cc
index c7a5f573d7edfa89389a78cdd407d5cdb6d7b54c..3601287be9963423c0eeef0e939487be09d6cead 100644 (file)
--- a/gcc/rust/expand/rust-expand-visitor.cc
+++ b/gcc/rust/expand/rust-expand-visitor.cc
@@ -104,7 +104,7 @@ builtin_derive_item (std::unique_ptr<AST::Item> &item,
 }
 
 static std::vector<std::unique_ptr<AST::Item>>
-derive_item (std::unique_ptr<AST::Item> &item, std::string &to_derive,
+derive_item (std::unique_ptr<AST::Item> &item, const std::string &to_derive,
             MacroExpander &expander)
 {
   std::vector<std::unique_ptr<AST::Item>> result;

diff --git a/gcc/rust/expand/rust-macro-expand.h b/gcc/rust/expand/rust-macro-expand.h
index 0e53913438a79a933594d3115595b285b1c94d9c..8ac84d513b2bd05d8310704d0183ce61ad794470 100644 (file)
--- a/gcc/rust/expand/rust-macro-expand.h
+++ b/gcc/rust/expand/rust-macro-expand.h
@@ -340,7 +340,8 @@ struct MacroExpander
   void import_proc_macros (std::string extern_crate);
 
   template <typename T>
-  AST::Fragment expand_derive_proc_macro (T &item, std::string &trait_name)
+  AST::Fragment expand_derive_proc_macro (T &item,
+                                         const std::string &trait_name)
   {
     ProcMacro::CustomDerive macro;