re PR c++/7412 ([DR 106] References to references)

2007-05-30  Russell Yanofsky <russ@yanofsky.org>
            Douglas Gregor <doug.gregor@gmail.com>
            Pedro Lamarao <pedro.lamarao@mndfck.org>
            Howard Hinnant <howard.hinnant@gmail.com>

	PR c++/7412
	PR c++/29939
        * g++.dg/cpp0x/rv8p.C: New.
        * g++.dg/cpp0x/temp-constructor-bug.C: New.
        * g++.dg/cpp0x/cast-bug.C: New.
        * g++.dg/cpp0x/elision_weak.C: New.
        * g++.dg/cpp0x/collapse-bug.C: New.
        * g++.dg/cpp0x/rv3p.C: New.
        * g++.dg/cpp0x/rv7n.C: New.
        * g++.dg/cpp0x/overload-conv-1.C: New.
        * g++.dg/cpp0x/rv2n.C: New.
        * g++.dg/cpp0x/deduce.C: New.
        * g++.dg/cpp0x/temp-va-arg-bug.C: New.
        * g++.dg/cpp0x/rv6p.C: New.
        * g++.dg/cpp0x/template_deduction.C: New.
        * g++.dg/cpp0x/implicit-copy.C: New.
        * g++.dg/cpp0x/rv1p.C: New.
        * g++.dg/cpp0x/cast.C: New.
        * g++.dg/cpp0x/rv5n.C: New.
        * g++.dg/cpp0x/collapse.C: New.
        * g++.dg/cpp0x/overload-conv-2.C: New.
        * g++.dg/cpp0x/rv4p.C: New.
	* g++.dg/cpp0x/rvo.C: New.
        * g++.dg/cpp0x/iop.C: New.
        * g++.dg/cpp0x/rv3n.C: New.
        * g++.dg/cpp0x/rv7p.C: New.
        * g++.dg/cpp0x/reference_collapsing.C: New.
        * g++.dg/cpp0x/overload.C: New.
        * g++.dg/cpp0x/named.C: New.
        * g++.dg/cpp0x/rv2p.C: New.
        * g++.dg/cpp0x/rv6n.C: New.
        * g++.dg/cpp0x/not_special.C: New.
        * g++.dg/cpp0x/bind.C: New.
        * g++.dg/cpp0x/rv1n.C: New.
        * g++.dg/cpp0x/rv5p.C: New.
        * g++.dg/cpp0x/elision.C: New.
        * g++.dg/cpp0x/named_refs.C: New.
        * g++.dg/cpp0x/unnamed_refs.C: New.
        * g++.dg/cpp0x/rv4n.C: New.
        * g++.dg/cpp0x/elision_neg.C: New.
        * g++.dg/init/copy7.C: Run in C++98 mode.
        * g++.dg/overload/arg1.C: Ditto.
        * g++.dg/overload/arg4.C: Ditto.
	
2007-05-30  Russell Yanofsky <russ@yanofsky.org>
            Douglas Gregor <doug.gregor@gmail.com>
            Pedro Lamarao <pedro.lamarao@mndfck.org>
            Howard Hinnant <howard.hinnant@gmail.com>

	PR c++/7412
	PR c++/29939
	* typeck.c (comptypes): Don't consider rvalue and lvalue
	reference types to be equivalent.
	(check_return_expr): Move from certain lvalues when returning
	them.
	* decl.c (grokdeclarator): Implement reference collapsing.
	(copy_fn_p): Don't consider constructors taking rvalue references
	to be copy constructors.
	(move_fn_p): New.
        * call.c (conversion): New "rvaluedness_matches_p" member.
	(convert_class_to_reference): Require reference type as first
	parameter instead of base type.
	(reference_binding): Add logic to handle rvalue references.
	(implicit_conversion): Update inaccurate comment.
	(convert_like_real): Disable creation of temporaries that are
	impossible to initialize for types with move constructors.
	(build_over_call): Elide move constructors when possible.
	(maybe_handle_implicit_object): Set "rvaluedness_matches_p".
	(maybe_handle_ref_bind): Return conversion instead of type node.
	(compare_ics): Add logic to use "rvaluedness_matches_p" values to
	determine preferred conversion sequences.
	* cp-tree.h (TYPE_REF_IS_RVALUE): New.
	(LOOKUP_PREFER_RVALUE): New.
	(DECL_MOVE_CONSTRUCTOR_P): New.
	(struct cp_declarator): Add "reference" member for reference
	types, with new "rvalue_ref" flag.
	(cp_build_reference_type): Declare.
	(move_fn_p): Declare.
	* error.c (dump_type_prefix): Format rvalue reference types
	correctly in error messages.
	* except.c (build_throw): Move from certain lvalues when
	throwing.
	* mangle.c (write_type): Mangle rvalue references differently
	than regular references.
	* parser.c (make_reference_declarator): Add boolean parameter for
	rvalue references.
	(cp_parser_make_indirect_declarator): New.
	(cp_parser_new_declarator_opt): Call
	cp_parser_make_indirect_declarator. 
	(cp_parser_conversion_declarator_opt): Ditto.
	(cp_parser_declarator): Ditto.
	(cp_parser_ptr_operator): Parse "&&" tokens into rvalue reference
	declarators.
	* pt.c (tsubst): Implement reference collapsing.
	(maybe_adjust_types_for_deduction): Implement special template
	parameter deduction rule for rvalue references.
	(type_unification_real): Update calls to
	maybe_adjust_types_for_deduction.
	(try_one_overload): Ditto.
	(unify_pack_expansion): Ditto.
	* tree.c (lvalue_p_1): Handle rvalue reference types.
	(cp_build_reference_type): New.

From-SVN: r125211

1 files changed, 54 insertions, 44 deletions

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index e7b90b2..c1a3276 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -858,7 +858,7 @@ static cp_declarator *make_array_declarator
 static cp_declarator *make_pointer_declarator
   (cp_cv_quals, cp_declarator *);
 static cp_declarator *make_reference_declarator
-  (cp_cv_quals, cp_declarator *);
+  (cp_cv_quals, cp_declarator *, bool);
 static cp_parameter_declarator *make_parameter_declarator
   (cp_decl_specifier_seq *, cp_declarator *, tree);
 static cp_declarator *make_ptrmem_declarator
@@ -960,14 +960,15 @@ make_pointer_declarator (cp_cv_quals cv_qualifiers, cp_declarator *target)
 /* Like make_pointer_declarator -- but for references.  */
 
 cp_declarator *
-make_reference_declarator (cp_cv_quals cv_qualifiers, cp_declarator *target)
+make_reference_declarator (cp_cv_quals cv_qualifiers, cp_declarator *target,
+			   bool rvalue_ref)
 {
   cp_declarator *declarator;
 
   declarator = make_declarator (cdk_reference);
   declarator->declarator = target;
-  declarator->u.pointer.qualifiers = cv_qualifiers;
-  declarator->u.pointer.class_type = NULL_TREE;
+  declarator->u.reference.qualifiers = cv_qualifiers;
+  declarator->u.reference.rvalue_ref = rvalue_ref;
   if (target)
     {
       declarator->parameter_pack_p = target->parameter_pack_p;
@@ -2015,6 +2016,8 @@ static bool cp_parser_is_keyword
   (cp_token *, enum rid);
 static tree cp_parser_make_typename_type
   (cp_parser *, tree, tree);
+static cp_declarator * cp_parser_make_indirect_declarator
+  (enum tree_code, tree, cp_cv_quals, cp_declarator *);
 
 /* Returns nonzero if we are parsing tentatively.  */
 
@@ -2689,6 +2692,27 @@ cp_parser_make_typename_type (cp_parser *parser, tree scope, tree id)
   return make_typename_type (scope, id, typename_type, tf_error);
 }
 
+/* This is a wrapper around the
+   make_{pointer,ptrmem,reference}_declarator functions that decides
+   which one to call based on the CODE and CLASS_TYPE arguments. The
+   CODE argument should be one of the values returned by
+   cp_parser_ptr_operator. */
+static cp_declarator *
+cp_parser_make_indirect_declarator (enum tree_code code, tree class_type,
+				    cp_cv_quals cv_qualifiers,
+				    cp_declarator *target)
+{
+  if (code == INDIRECT_REF)
+    if (class_type == NULL_TREE)
+      return make_pointer_declarator (cv_qualifiers, target);
+    else
+      return make_ptrmem_declarator (cv_qualifiers, class_type, target);
+  else if (code == ADDR_EXPR && class_type == NULL_TREE)
+    return make_reference_declarator (cv_qualifiers, target, false);
+  else if (code == NON_LVALUE_EXPR && class_type == NULL_TREE)
+    return make_reference_declarator (cv_qualifiers, target, true);
+  gcc_unreachable ();
+}
 
 /* Create a new C++ parser.  */
 
@@ -5532,15 +5556,8 @@ cp_parser_new_declarator_opt (cp_parser* parser)
       /* Parse another optional declarator.  */
       declarator = cp_parser_new_declarator_opt (parser);
 
-      /* Create the representation of the declarator.  */
-      if (type)
-	declarator = make_ptrmem_declarator (cv_quals, type, declarator);
-      else if (code == INDIRECT_REF)
-	declarator = make_pointer_declarator (cv_quals, declarator);
-      else
-	declarator = make_reference_declarator (cv_quals, declarator);
-
-      return declarator;
+      return cp_parser_make_indirect_declarator
+	(code, type, cv_quals, declarator);
     }
 
   /* If the next token is a `[', there is a direct-new-declarator.  */
@@ -8460,16 +8477,8 @@ cp_parser_conversion_declarator_opt (cp_parser* parser)
       /* Parse another optional declarator.  */
       declarator = cp_parser_conversion_declarator_opt (parser);
 
-      /* Create the representation of the declarator.  */
-      if (class_type)
-	declarator = make_ptrmem_declarator (cv_quals, class_type,
-					     declarator);
-      else if (code == INDIRECT_REF)
-	declarator = make_pointer_declarator (cv_quals, declarator);
-      else
-	declarator = make_reference_declarator (cv_quals, declarator);
-
-      return declarator;
+      return cp_parser_make_indirect_declarator
+	(code, class_type, cv_quals, declarator);
    }
 
   return NULL;
@@ -12072,15 +12081,8 @@ cp_parser_declarator (cp_parser* parser,
 	  && !cp_parser_parse_definitely (parser))
 	declarator = NULL;
 
-      /* Build the representation of the ptr-operator.  */
-      if (class_type)
-	declarator = make_ptrmem_declarator (cv_quals,
-					     class_type,
-					     declarator);
-      else if (code == INDIRECT_REF)
-	declarator = make_pointer_declarator (cv_quals, declarator);
-      else
-	declarator = make_reference_declarator (cv_quals, declarator);
+      declarator = cp_parser_make_indirect_declarator
+	(code, class_type, cv_quals, declarator);
     }
   /* Everything else is a direct-declarator.  */
   else
@@ -12558,12 +12560,15 @@ cp_parser_direct_declarator (cp_parser* parser,
      & cv-qualifier-seq [opt]
 
    Returns INDIRECT_REF if a pointer, or pointer-to-member, was used.
-   Returns ADDR_EXPR if a reference was used.  In the case of a
-   pointer-to-member, *TYPE is filled in with the TYPE containing the
-   member.  *CV_QUALS is filled in with the cv-qualifier-seq, or
-   TYPE_UNQUALIFIED, if there are no cv-qualifiers.  Returns
-   ERROR_MARK if an error occurred.  */
-
+   Returns ADDR_EXPR if a reference was used, or NON_LVALUE_EXPR for
+   an rvalue reference. In the case of a pointer-to-member, *TYPE is
+   filled in with the TYPE containing the member.  *CV_QUALS is
+   filled in with the cv-qualifier-seq, or TYPE_UNQUALIFIED, if there
+   are no cv-qualifiers.  Returns ERROR_MARK if an error occurred.
+   Note that the tree codes returned by this function have nothing
+   to do with the types of trees that will be eventually be created
+   to represent the pointer or reference type being parsed. They are
+   just constants with suggestive names. */
 static enum tree_code
 cp_parser_ptr_operator (cp_parser* parser,
 			tree* type,
@@ -12579,13 +12584,18 @@ cp_parser_ptr_operator (cp_parser* parser,
 
   /* Peek at the next token.  */
   token = cp_lexer_peek_token (parser->lexer);
-  /* If it's a `*' or `&' we have a pointer or reference.  */
-  if (token->type == CPP_MULT || token->type == CPP_AND)
-    {
-      /* Remember which ptr-operator we were processing.  */
-      code = (token->type == CPP_AND ? ADDR_EXPR : INDIRECT_REF);
 
-      /* Consume the `*' or `&'.  */
+  /* If it's a `*', `&' or `&&' we have a pointer or reference.  */
+  if (token->type == CPP_MULT)
+    code = INDIRECT_REF;
+  else if (token->type == CPP_AND)
+    code = ADDR_EXPR;
+  else if (flag_cpp0x && token->type == CPP_AND_AND) /* C++0x only */
+    code = NON_LVALUE_EXPR;
+
+  if (code != ERROR_MARK)
+    {
+      /* Consume the `*', `&' or `&&'.  */
       cp_lexer_consume_token (parser->lexer);
 
       /* A `*' can be followed by a cv-qualifier-seq, and so can a