decl.c (grokvardecl): Use an accurate location in error message about main as a global variable.

/cp
2019-05-10  Paolo Carlini  <paolo.carlini@oracle.com>

	* decl.c (grokvardecl): Use an accurate location in error message
	about main as a global variable.

/testsuite
2019-05-10  Paolo Carlini  <paolo.carlini@oracle.com>

	* g++.dg/diagnostic/main1.C: New.

From-SVN: r271070

gcc/cp/ChangeLog

 2019-05-10  Paolo Carlini  <paolo.carlini@oracle.com>
 
+	* decl.c (grokvardecl): Use an accurate location in error message
+	about main as a global variable.
+
+2019-05-10  Paolo Carlini  <paolo.carlini@oracle.com>
+
 	* call.c (build_call_a): Use FUNC_OR_METHOD_TYPE_P.
 	* cp-gimplify.c (cp_fold): Likewise.
 	* cp-objcp-common.c (cp_type_dwarf_attribute): Likewise.

gcc/cp/decl.c

@@ -9477,7 +9477,8 @@ grokvardecl (tree type,
   if (DECL_NAME (decl)
       && MAIN_NAME_P (DECL_NAME (decl))
       && scope == global_namespace)
-    error ("cannot declare %<::main%> to be a global variable");
+    error_at (DECL_SOURCE_LOCATION (decl),
+	      "cannot declare %<::main%> to be a global variable");
 
   /* Check that the variable can be safely declared as a concept.
      Note that this also forbids explicit specializations.  */

gcc/testsuite/ChangeLog

+2019-05-10  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	* g++.dg/diagnostic/main1.C: New.
+
 2019-05-10  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/78010 - bogus -Wsuggest-override warning on final function.

gcc/testsuite/g++.dg/diagnostic/main1.C

+int main __attribute__((unused));  // { dg-error "5:cannot declare" }