1 files changed, 41 insertions, 33 deletions

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index e684870..fbe864f 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -13313,6 +13313,8 @@ cp_parser_decl_specifier_seq (cp_parser* parser,
 	   && constructor_possible_p
 	   && (cp_parser_constructor_declarator_p
 	       (parser, decl_spec_seq_has_spec_p (decl_specs, ds_friend))));
+      if (constructor_p)
+	decl_specs->constructor_p = true;
 
       /* If we don't have a DECL_SPEC yet, then we must be looking at
 	 a type-specifier.  */
@@ -19010,7 +19012,7 @@ cp_parser_init_declarator (cp_parser* parser,
   enum cpp_ttype initialization_kind;
   bool is_direct_init = false;
   bool is_non_constant_init;
-  int ctor_dtor_or_conv_p;
+  int ctor_dtor_or_conv_p = decl_specifiers->constructor_p ? -1 : 0;
   bool friend_p = cp_parser_friend_p (decl_specifiers);
   tree pushed_scope = NULL_TREE;
   bool range_for_decl_p = false;
@@ -19048,6 +19050,9 @@ cp_parser_init_declarator (cp_parser* parser,
 
   parser->default_arg_ok_p = saved_default_arg_ok_p;
 
+  if (cxx_dialect >= cxx1z)
+    scope_chain->deduction_guide_type = NULL_TREE;
+
   /* If the DECLARATOR was erroneous, there's no need to go
      further.  */
   if (declarator == cp_error_declarator)
@@ -19095,25 +19100,6 @@ cp_parser_init_declarator (cp_parser* parser,
 
   if (function_declarator_p (declarator))
     {
-      /* Handle C++17 deduction guides.  */
-      if (!decl_specifiers->type
-	  && ctor_dtor_or_conv_p <= 0
-	  && cxx_dialect >= cxx1z)
-	{
-	  cp_declarator *id = get_id_declarator (declarator);
-	  tree name = id->u.id.unqualified_name;
-	  parser->scope = id->u.id.qualifying_scope;
-	  tree tmpl = cp_parser_lookup_name_simple (parser, name, id->id_loc);
-	  if (tmpl
-	      && (DECL_CLASS_TEMPLATE_P (tmpl)
-		  || DECL_TEMPLATE_TEMPLATE_PARM_P (tmpl)))
-	    {
-	      id->u.id.unqualified_name = dguide_name (tmpl);
-	      id->u.id.sfk = sfk_deduction_guide;
-	      ctor_dtor_or_conv_p = 1;
-	    }
-	}
-
       /* Check to see if the token indicates the start of a
 	 function-definition.  */
       if (cp_parser_token_starts_function_definition_p (token))
@@ -19432,8 +19418,10 @@ cp_parser_init_declarator (cp_parser* parser,
 
    If CTOR_DTOR_OR_CONV_P is not NULL, *CTOR_DTOR_OR_CONV_P is used to
    detect constructors, destructors, deduction guides, or conversion operators.
-   It is set to -1 if the declarator is a name, and +1 if it is a
-   function. Otherwise it is set to zero. Usually you just want to
+   The caller should set it before the call, to -1 if parsing the
+   decl-specifier-seq determined that we're declaring a constructor or
+   deduction guide, or 0 otherwise.  This function sets it to -1 if the
+   declarator is a name, and +1 if it is a function. Usually you just want to
    test for >0, but internally the negative value is used.
 
    (The reason for CTOR_DTOR_OR_CONV_P is that a declaration must have
@@ -19464,11 +19452,6 @@ cp_parser_declarator (cp_parser* parser,
   tree class_type;
   tree gnu_attributes = NULL_TREE, std_attributes = NULL_TREE;
 
-  /* Assume this is not a constructor, destructor, or type-conversion
-     operator.  */
-  if (ctor_dtor_or_conv_p)
-    *ctor_dtor_or_conv_p = 0;
-
   if (cp_parser_allow_gnu_extensions_p (parser))
     gnu_attributes = cp_parser_gnu_attributes_opt (parser);
 
@@ -19766,9 +19749,6 @@ cp_parser_direct_declarator (cp_parser* parser,
 	  /* Parse an array-declarator.  */
 	  tree bounds, attrs;
 
-	  if (ctor_dtor_or_conv_p)
-	    *ctor_dtor_or_conv_p = 0;
-
 	  first = false;
 	  parser->default_arg_ok_p = false;
 	  parser->in_declarator_p = true;
@@ -20023,6 +20003,34 @@ cp_parser_direct_declarator (cp_parser* parser,
 		      *ctor_dtor_or_conv_p = -1;
 		  }
 	      }
+
+	    if (cxx_dialect >= cxx1z
+		&& sfk == sfk_none
+		&& ctor_dtor_or_conv_p
+		&& *ctor_dtor_or_conv_p == -1)
+	      {
+		/* If *ctor_dtor_or_conv_p is set and we aren't declaring a
+		   constructor, we must be declaring a deduction guide.  */
+		tree tmpl;
+		if (qualifying_scope)
+		  tmpl = (lookup_qualified_name
+			  (qualifying_scope, unqualified_name,
+			   /*prefer_type*/false, /*complain*/true));
+		else
+		  tmpl = lookup_name (unqualified_name);
+		if (tmpl
+		    && (DECL_CLASS_TEMPLATE_P (tmpl)
+			|| DECL_TEMPLATE_TEMPLATE_PARM_P (tmpl)))
+		  {
+		    unqualified_name = dguide_name (tmpl);
+		    scope_chain->deduction_guide_type
+		      = TREE_TYPE (unqualified_name);
+		    sfk = sfk_deduction_guide;
+		  }
+		else
+		  gcc_checking_assert (false);
+	      }
+
 	    declarator = make_id_declarator (qualifying_scope,
 					     unqualified_name,
 					     sfk);
@@ -23251,7 +23259,7 @@ cp_parser_member_declaration (cp_parser* parser)
 	      cp_declarator *declarator;
 	      tree initializer;
 	      tree asm_specification;
-	      int ctor_dtor_or_conv_p;
+	      int ctor_dtor_or_conv_p = decl_specifiers.constructor_p ? -1 : 0;
 
 	      /* Parse the declarator.  */
 	      declarator
@@ -28334,7 +28342,7 @@ cp_parser_cache_defarg (cp_parser *parser, bool nsdmi)
 		     declarator.  */
 		  do
 		    {
-		      int ctor_dtor_or_conv_p;
+		      int ctor_dtor_or_conv_p = 0;
 		      cp_lexer_consume_token (parser->lexer);
 		      cp_parser_declarator (parser, CP_PARSER_DECLARATOR_NAMED,
 					    &ctor_dtor_or_conv_p,
@@ -29655,7 +29663,7 @@ cp_parser_objc_class_ivars (cp_parser* parser)
 	{
 	  tree width = NULL_TREE, attributes, first_attribute, decl;
 	  cp_declarator *declarator = NULL;
-	  int ctor_dtor_or_conv_p;
+	  int ctor_dtor_or_conv_p = 0;
 
 	  /* Check for a (possibly unnamed) bitfield declaration.  */
 	  token = cp_lexer_peek_token (parser->lexer);