[C++ Patch] Adjust one more error message to use rich_location::add_range

[Paolo Carlini]

Hi,

I was double checking my pending patch and going through the errors we 
emit in decl.c and elsewhere about thread_local and __thread and noticed 
another place, in parser.c, where using rich_location::add_range seems 
natural. Note, we could in principle swap location and 
decl_specs->locations[ds_thread] in the error basing on the gnu bool and 
ensure that the caret always points to __thread. All in all, I don't 
think it's worth it...

Thanks, Paolo.

///////////////

/cp
2018-07-02  Paolo Carlini  <paolo.carl...@oracle.com>

        * parser.c (set_and_check_decl_spec_loc): Use rich_location::add_range
        in error message about __thread and thread_local at the same time.

/testsuite
2018-07-02  Paolo Carlini  <paolo.carl...@oracle.com>

        * g++.dg/diagnostic/thread-thread_local.C: New.
Index: cp/parser.c
===================================================================
--- cp/parser.c (revision 262300)
+++ cp/parser.c (working copy)
@@ -28377,12 +28377,15 @@ set_and_check_decl_spec_loc (cp_decl_specifier_seq
       else if (ds == ds_thread)
        {
          bool gnu = token_is__thread (token);
+         gcc_rich_location richloc (location);
          if (gnu != decl_specs->gnu_thread_keyword_p)
-           error_at (location,
-                     "both %<__thread%> and %<thread_local%> specified");
+           {
+             richloc.add_range (decl_specs->locations[ds_thread], false);
+             error_at (&richloc,
+                       "both %<__thread%> and %<thread_local%> specified");
+           }
          else
            {
-             gcc_rich_location richloc (location);
              richloc.add_fixit_remove ();
              error_at (&richloc, "duplicate %qD", token->u.value);
            }
Index: testsuite/g++.dg/diagnostic/thread-thread_local.C
===================================================================
--- testsuite/g++.dg/diagnostic/thread-thread_local.C   (nonexistent)
+++ testsuite/g++.dg/diagnostic/thread-thread_local.C   (working copy)
@@ -0,0 +1,13 @@
+// { dg-options "-fdiagnostics-show-caret" }
+// { dg-do compile { target c++11 } }
+
+thread_local __thread int a;  // { dg-error "14:both .__thread. and 
.thread_local. specified" }
+/* { dg-begin-multiline-output "" }
+ thread_local __thread int a;
+ ~~~~~~~~~~~~ ^~~~~~~~
+   { dg-end-multiline-output "" } */
+__thread thread_local int b;  // { dg-error "10:both .__thread. and 
.thread_local. specified" }
+/* { dg-begin-multiline-output "" }
+ __thread thread_local int b;
+ ~~~~~~~~ ^~~~~~~~~~~~
+   { dg-end-multiline-output "" } */