Re: PR c++/20118 missing template<> causes weird errors

["Manuel López-Ibáñez" <lopezibanez at gmail dot com>]

PING: http://gcc.gnu.org/ml/gcc-patches/2008-10/msg00807.html

2008/10/20 Manuel López-Ibáñez <lopezibanez@gmail.com>:
> I have updated the patch to a recent revision, bootstrapped and
> regression tested again.
>
> OK for trunk?
>
> Manuel.
>
> 2008/8/25 Manuel López-Ibáñez <lopezibanez@gmail.com>:
>> PING: http://gcc.gnu.org/ml/gcc-patches/2008-08/msg00793.html
>>
>> 2008/8/12 Manuel López-Ibáñez <lopezibanez@gmail.com>:
>>> Bootstrapped and regression tested on x86_64-unknown-linux-gnu with
>>> --enable-languages=all,ada
>>>
>>> OK for trunk?
>>>
>>> 2008-08-12  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
>>>
>>>        PR  c++/20118
>>>        * diagnostic.c (error_at): New.
>>>        * toplev.h (error_at): Declare.
>>> cp/
>>>        * parser.c (cp_parser_check_template_parameters): Take a
>>>        cp_declarator parameter.
>>>        (cp_parser_elaborated_type_specifier): Update to
>>>        cp_parser_check_template_parameters.
>>>        (cp_parser_class_head): Likewise.
>>>        (cp_parser_check_declarator_template_parameters): Likewise.
>>>        (cp_parser_check_template_parameters): Handle first the non-error
>>>        conditions. Give more accurate diagnostics if a declarator is
>>>        given.
>>> testsuite/
>>>        * g++.dg/parse/pr20118.C: New.
>>>        * g++.dg/template/spec16.C: Update.
>>>
>>
>

Index: gcc/testsuite/g++.dg/parse/pr20118.C
===================================================================
--- gcc/testsuite/g++.dg/parse/pr20118.C	(revision 0)
+++ gcc/testsuite/g++.dg/parse/pr20118.C	(revision 0)
@@ -0,0 +1,9 @@
+// { dg-do compile }
+// { dg-options "-fshow-column" } 
+template<typename t>struct foo {
+  static const int i; };
+
+const int foo<bool>::i = 5; // { dg-error "11:specializing member .foo<bool>::i. requires .template<>. syntax" }
+
+int main() { return 0; }
+
Index: gcc/testsuite/g++.dg/template/spec16.C
===================================================================
--- gcc/testsuite/g++.dg/template/spec16.C	(revision 141233)
+++ gcc/testsuite/g++.dg/template/spec16.C	(working copy)
@@ -5,7 +5,7 @@
 template <int N>  
 struct A { 
   template<int M> void B () ; 
 }; 
 
-void A<0>::B<0>() {    // { dg-error "parameter-lists" }
+void A<0>::B<0>() {    // { dg-error "specializing member 'A<0>::B<0>' requires 'template<>' syntax" }
 } 
Index: gcc/cp/parser.c
===================================================================
--- gcc/cp/parser.c	(revision 141233)
+++ gcc/cp/parser.c	(working copy)
@@ -1909,11 +1909,11 @@ static tree cp_parser_lookup_name_simple
 static tree cp_parser_maybe_treat_template_as_class
   (tree, bool);
 static bool cp_parser_check_declarator_template_parameters
   (cp_parser *, cp_declarator *, location_t);
 static bool cp_parser_check_template_parameters
-  (cp_parser *, unsigned, location_t);
+  (cp_parser *, unsigned, location_t, cp_declarator *);
 static tree cp_parser_simple_cast_expression
   (cp_parser *);
 static tree cp_parser_global_scope_opt
   (cp_parser *, bool);
 static bool cp_parser_constructor_declarator_p
@@ -11651,11 +11651,12 @@ cp_parser_elaborated_type_specifier (cp_
 		 || cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON)));
 	  /* An unqualified name was used to reference this type, so
 	     there were no qualifying templates.  */
 	  if (!cp_parser_check_template_parameters (parser,
 						    /*num_templates=*/0,
-						    token->location))
+						    token->location,
+						    /*declarator=*/NULL))
 	    return error_mark_node;
 	  type = xref_tag (tag_type, identifier, ts, template_p);
 	}
     }
 
@@ -15241,11 +15242,12 @@ cp_parser_class_head (cp_parser* parser,
      end of this function; set "type "to the correct return value and
      use "goto done;" to return.  */
   /* Make sure that the right number of template parameters were
      present.  */
   if (!cp_parser_check_template_parameters (parser, num_templates,
-					    type_start_token->location))
+					    type_start_token->location,
+					    /*declarator=*/NULL))
     {
       /* If something went wrong, there is no point in even trying to
 	 process the class-definition.  */
       type = NULL_TREE;
       goto done;
@@ -17140,13 +17142,13 @@ cp_parser_check_declarator_template_para
 	       == TEMPLATE_ID_EXPR)
 	/* If the DECLARATOR has the form `X<y>' then it uses one
 	   additional level of template parameters.  */
 	++num_templates;
 
-      return cp_parser_check_template_parameters (parser,
-						  num_templates,
-						  declarator_location);
+      return cp_parser_check_template_parameters 
+	(parser, num_templates, declarator_location, declarator);
+
 
     case cdk_function:
     case cdk_array:
     case cdk_pointer:
     case cdk_reference:
@@ -17163,34 +17165,42 @@ cp_parser_check_declarator_template_para
   return false;
 }
 
 /* NUM_TEMPLATES were used in the current declaration.  If that is
    invalid, return FALSE and issue an error messages.  Otherwise,
-   return TRUE.  */
+   return TRUE.  If DECLARATOR is non-NULL, then we are checking a
+   declarator and we can print more accurate diagnostics.  */
 
 static bool
 cp_parser_check_template_parameters (cp_parser* parser,
 				     unsigned num_templates,
-				     location_t location)
+				     location_t location,
+				     cp_declarator *declarator)
 {
+  /* If there are the same number of template classes and parameter
+     lists, that's OK.  */
+  if (parser->num_template_parameter_lists == num_templates)
+    return true;
+  /* If there are more, but only one more, then we are referring to a
+     member template.  That's OK too.  */
+  if (parser->num_template_parameter_lists == num_templates + 1)
+    return true;
   /* If there are more template classes than parameter lists, we have
      something like:
 
        template <class T> void S<T>::R<T>::f ();  */
   if (parser->num_template_parameter_lists < num_templates)
     {
-      error ("%Htoo few template-parameter-lists", &location);
+      if (declarator)
+	error_at (location, "specializing member %<%T::%E%> "
+		  "requires %<template<>%> syntax", 
+		  declarator->u.id.qualifying_scope,
+		  declarator->u.id.unqualified_name);
+      else 
+	error_at (location, "too few template-parameter-lists");
       return false;
     }
-  /* If there are the same number of template classes and parameter
-     lists, that's OK.  */
-  if (parser->num_template_parameter_lists == num_templates)
-    return true;
-  /* If there are more, but only one more, then we are referring to a
-     member template.  That's OK too.  */
-  if (parser->num_template_parameter_lists == num_templates + 1)
-      return true;
   /* Otherwise, there are too many template parameter lists.  We have
      something like:
 
      template <class T> template <class U> void S::f();  */
   error ("%Htoo many template-parameter-lists", &location);