From 7ab25ad0208d00f509613e1e151aa3043cf2862f Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sun, 12 Aug 2018 18:10:10 +0200
Subject: [PATCH] C++: remove useless copy-constructor

We currently generate copy constructors such as the following
one (taken from examples/variant.yy):

    parser::stack_symbol_type::stack_symbol_type (const stack_symbol_type& that)
      : super_type (that.state, that.location)
    {
      switch (that.type_get ())
      {
        case 3: // TEXT
        case 8: // item
          value.copy< ::std::string > (that.value);
          break;

        case 7: // list
          value.copy< ::std::vector<std::string> > (that.value);
          break;

        case 4: // NUMBER
          value.copy< int > (that.value);
          break;

        default:
          break;
      }
    }

they are actually useless: we never need it.

* data/lalr1.cc: Don't generate the stack_symbol_type copy ctor.
---
 data/lalr1.cc | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/data/lalr1.cc b/data/lalr1.cc
index afebda55..2c99aacf 100644
--- a/data/lalr1.cc
+++ b/data/lalr1.cc
@@ -314,8 +314,6 @@ b4_location_define])])[
       typedef basic_symbol<by_state> super_type;
       /// Construct an empty symbol.
       stack_symbol_type ();
-      /// Copy construct.
-      stack_symbol_type (const stack_symbol_type& that);
       /// Steal the contents from \a sym to build this.
       stack_symbol_type (state_type s, symbol_type& sym);
       /// Assignment, needed by push_back.
@@ -575,14 +573,6 @@ m4_if(b4_prefix, [yy], [],
   ]b4_parser_class_name[::stack_symbol_type::stack_symbol_type ()
   {}
 
-  ]b4_parser_class_name[::stack_symbol_type::stack_symbol_type (const stack_symbol_type& that)
-    : super_type (that.state]b4_locations_if([, that.location])[)
-  {
-    ]b4_variant_if([b4_symbol_variant([that.type_get ()],
-                                      [value], [copy], [that.value])],
-                   [[value = that.value;]])[
-  }
-
   ]b4_parser_class_name[::stack_symbol_type::stack_symbol_type (state_type s, symbol_type& that)
     : super_type (s]b4_locations_if([, that.location])[)
   {